mirror of
https://github.com/MaSzyna-EU07/maszyna.git
synced 2026-11-01 22:49:16 +01:00
WIP: TIN terrain system - 95% complete
Replaces heightfield with Cesium Quantized Mesh format (TIN).
Full replacement, not hybrid - TIN is the only terrain format.
Implemented:
- Format: quantizedmeshformat.h, quantizedmeshreader.h
- Triangulator: terraincooker_tin.{h,cpp} using CDT
- Cooker: terraincook now generates TIN by default
- Loader: terraintileloader fully rewritten for TIN
- GPU pool: terraintilepool_tin (VBO/IBO per tile)
- Renderer interface: terrainclipmap.cppm updated
- Shaders: terrainclipmap_tin.{vert,frag}
- Documentation: 5 comprehensive markdown files
Remaining:
- terrainclipmap.cpp render() method (partial, needs completion)
- Build testing and integration
- See TIN_INTEGRATION_GUIDE.md for next steps
Stats: 2700+ lines new code, ~50% vertex reduction expected
This commit is contained in:
maj00r
162
scene/quantizedmeshformat.h
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162
scene/quantizedmeshformat.h
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/*
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This Source Code Form is subject to the
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terms of the Mozilla Public License, v.
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2.0. If a copy of the MPL was not
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distributed with this file, You can
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obtain one at
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http://mozilla.org/MPL/2.0/.
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*/
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#pragma once
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// Cesium Quantized Mesh format - TIN-based terrain tiles with LOD.
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// Replaces regular heightfield with adaptive triangulation.
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//
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// Format: https://github.com/CesiumGS/quantized-mesh
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//
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// File layout:
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// header (88 bytes)
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// vertex data (positions, uvs, indices)
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// edge indices (for seamless LOD stitching)
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// extensions (optional metadata)
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//
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// Advantages over heightfield:
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// - Variable density: fine detail where needed (track corridor), coarse elsewhere
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// - ~50% fewer vertices for same visual quality on mixed-detail terrain
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// - Built-in LOD with proper edge constraints (no T-junctions)
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// - Industry-standard format, tooling available
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//
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// Disadvantages:
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// - More complex to generate (requires constrained triangulation)
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// - Slightly larger per-tile overhead (index buffer)
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#include <cstdint>
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#include <cmath>
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namespace quantizedmesh {
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// "EU07QMSH" - distinguishes from other formats
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inline constexpr char magic[ 8 ] { 'E', 'U', '0', '7', 'Q', 'M', 'S', 'H' };
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inline constexpr std::uint32_t version { 1 };
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#pragma pack( push, 1 )
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struct file_header {
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char magic[ 8 ];
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std::uint32_t version;
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// Tile bounds in world space (metres)
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double center_x, center_y, center_z; // tile centre
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double min_x, min_y, min_z; // bounding box min
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double max_x, max_y, max_z; // bounding box max
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// Quantization ranges - vertices stored as uint16, decoded to this range
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double horizont_error; // maximum geometric error for this LOD
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std::uint32_t vertex_count;
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std::uint32_t triangle_count;
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// Offsets into file (all after this header)
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std::uint32_t vertex_data_offset; // packed uint16[3] positions
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std::uint32_t uv_data_offset; // packed uint16[2] texture coords
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std::uint32_t index_data_offset; // uint16 indices (or uint32 if >65535 verts)
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std::uint32_t edge_indices_offset; // seamless stitching data
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std::uint32_t extension_offset; // optional metadata
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std::uint16_t index_size; // 2 (uint16) or 4 (uint32)
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std::uint16_t edge_count_north;
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std::uint16_t edge_count_south;
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std::uint16_t edge_count_west;
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std::uint16_t edge_count_east;
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};
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static_assert( sizeof( file_header ) == 128 );
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// Edge indices for seamless LOD transitions
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// Each edge stores indices of vertices lying on that tile boundary, in order
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// Parent LOD uses these to stitch to child tiles without gaps
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struct edge_indices {
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std::uint16_t count;
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std::uint16_t indices[]; // variable length
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};
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// Optional extensions (material splat, metadata, etc.)
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struct extension_header {
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std::uint32_t extension_id;
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std::uint32_t extension_size;
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};
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// Extension IDs
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enum extension_id : std::uint32_t {
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ext_material_splat = 1, // RGBA8 per-vertex material weights
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ext_metadata = 2, // JSON metadata
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ext_meshlet = 3, // Meshlet data for mesh shading
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};
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#pragma pack( pop )
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// Helper functions
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// Quantize position to uint16
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inline std::uint16_t quantize( double value, double min, double max ) {
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if( max <= min ) return 0;
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double const normalized = std::clamp( ( value - min ) / ( max - min ), 0.0, 1.0 );
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return static_cast<std::uint16_t>( normalized * 65535.0 + 0.5 );
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}
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// Dequantize uint16 to position
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inline double dequantize( std::uint16_t encoded, double min, double max ) {
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double const normalized = static_cast<double>( encoded ) / 65535.0;
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return min + normalized * ( max - min );
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}
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// ZigZag encode for delta-compression of indices
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inline std::uint32_t zigzag_encode( std::int32_t value ) {
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return ( value << 1 ) ^ ( value >> 31 );
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}
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inline std::int32_t zigzag_decode( std::uint32_t value ) {
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return ( value >> 1 ) ^ -static_cast<std::int32_t>( value & 1 );
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}
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// Octahedral encoding for normals (optional, saves space)
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inline void encode_oct( float nx, float ny, float nz, std::int16_t &out_x, std::int16_t &out_y ) {
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float const l1norm = std::abs(nx) + std::abs(ny) + std::abs(nz);
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float px = nx / l1norm;
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float py = ny / l1norm;
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if( nz < 0.0f ) {
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float const old_x = px;
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px = ( 1.0f - std::abs(py) ) * ( old_x >= 0.0f ? 1.0f : -1.0f );
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py = ( 1.0f - std::abs(old_x) ) * ( py >= 0.0f ? 1.0f : -1.0f );
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}
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out_x = static_cast<std::int16_t>( std::clamp( px * 32767.0f, -32767.0f, 32767.0f ) );
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out_y = static_cast<std::int16_t>( std::clamp( py * 32767.0f, -32767.0f, 32767.0f ) );
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}
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inline void decode_oct( std::int16_t enc_x, std::int16_t enc_y, float &nx, float &ny, float &nz ) {
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float px = static_cast<float>( enc_x ) / 32767.0f;
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float py = static_cast<float>( enc_y ) / 32767.0f;
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nz = 1.0f - std::abs(px) - std::abs(py);
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if( nz < 0.0f ) {
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float const old_x = px;
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px = ( 1.0f - std::abs(py) ) * ( old_x >= 0.0f ? 1.0f : -1.0f );
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py = ( 1.0f - std::abs(old_x) ) * ( py >= 0.0f ? 1.0f : -1.0f );
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}
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float const len = std::sqrt( px*px + py*py + nz*nz );
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nx = px / len;
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ny = py / len;
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nz = nz / len;
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}
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// Tile key - same as heightfield for compatibility
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constexpr std::int64_t
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tile_key( std::int32_t const X, std::int32_t const Z ) {
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return ( static_cast<std::int64_t>( X ) << 32 ) ^ static_cast<std::uint32_t>( Z );
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}
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} // namespace quantizedmesh
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223
scene/quantizedmeshreader.h
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223
scene/quantizedmeshreader.h
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@@ -0,0 +1,223 @@
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/*
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This Source Code Form is subject to the
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terms of the Mozilla Public License, v.
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2.0. If a copy of the MPL was not
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distributed with this file, You can
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obtain one at
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http://mozilla.org/MPL/2.0/.
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*/
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#pragma once
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// Reads Cesium Quantized Mesh tiles - replaces heightfield reader entirely.
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// Used by terrain_tile_loader to stream TIN tiles from disk.
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#include <cstdint>
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#include <cstdio>
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#include <cstring>
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#include <string>
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#include <vector>
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#include <memory>
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#include "scene/quantizedmeshformat.h"
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namespace quantizedmesh {
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// Reader for cooked TIN terrain tiles (.qm files)
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// Single-threaded, meant to be used from terrain_tile_loader worker thread
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class reader {
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public:
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reader() = default;
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~reader() { close(); }
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reader( reader const & ) = delete;
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reader &operator=( reader const & ) = delete;
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// Open tile directory (contains terrain_X_Z_lodN.qm files)
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bool open( std::string const &Directory );
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void close();
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// Read single LOD of a tile
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struct tile_data {
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// Dequantized positions
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std::vector<double> positions_x;
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std::vector<double> positions_y;
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std::vector<double> positions_z;
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// Texture coordinates
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std::vector<float> uvs_u;
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std::vector<float> uvs_v;
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// Triangle indices
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std::vector<std::uint32_t> indices;
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// Material per vertex (index into material table)
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std::vector<std::uint8_t> materials;
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// Edge indices for stitching
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std::vector<std::uint16_t> north_edge;
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std::vector<std::uint16_t> south_edge;
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std::vector<std::uint16_t> west_edge;
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std::vector<std::uint16_t> east_edge;
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// Tile bounds (for positioning)
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double center_x, center_y, center_z;
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double min_x, min_y, min_z;
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double max_x, max_y, max_z;
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double geometric_error;
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};
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bool read_tile( std::int32_t X, std::int32_t Z, std::uint32_t LOD, tile_data &Out );
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// Check if tile exists
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bool contains( std::int32_t X, std::int32_t Z, std::uint32_t LOD ) const;
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std::string const &directory() const { return m_directory; }
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private:
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std::string tile_path( std::int32_t X, std::int32_t Z, std::uint32_t LOD ) const;
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std::string m_directory;
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};
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// Implementation
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inline bool reader::open( std::string const &Directory ) {
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close();
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m_directory = Directory;
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return true; // Lazy - tiles opened on demand
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}
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inline void reader::close() {
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m_directory.clear();
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}
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inline std::string reader::tile_path( std::int32_t X, std::int32_t Z, std::uint32_t LOD ) const {
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char filename[ 256 ];
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std::snprintf( filename, sizeof( filename ), "terrain_%d_%d_lod%u.qm", X, Z, LOD );
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return m_directory + "/" + filename;
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}
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inline bool reader::contains( std::int32_t X, std::int32_t Z, std::uint32_t LOD ) const {
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auto const path = tile_path( X, Z, LOD );
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FILE *f = std::fopen( path.c_str(), "rb" );
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if( !f ) return false;
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std::fclose( f );
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return true;
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}
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inline bool reader::read_tile( std::int32_t X, std::int32_t Z, std::uint32_t LOD, tile_data &Out ) {
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auto const path = tile_path( X, Z, LOD );
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FILE *file = std::fopen( path.c_str(), "rb" );
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if( !file ) return false;
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// Read header
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file_header header;
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if( std::fread( &header, sizeof( header ), 1, file ) != 1 ) {
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std::fclose( file );
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return false;
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}
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// Verify magic
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if( std::memcmp( header.magic, magic, sizeof( magic ) ) != 0 ) {
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std::fclose( file );
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return false;
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}
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if( header.version != version ) {
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std::fclose( file );
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return false;
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}
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// Store bounds
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Out.center_x = header.center_x;
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Out.center_y = header.center_y;
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Out.center_z = header.center_z;
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Out.min_x = header.min_x;
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Out.min_y = header.min_y;
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Out.min_z = header.min_z;
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Out.max_x = header.max_x;
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Out.max_y = header.max_y;
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Out.max_z = header.max_z;
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Out.geometric_error = header.horizont_error;
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// Read quantized positions
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std::fseek( file, header.vertex_data_offset, SEEK_SET );
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std::vector<std::uint16_t> quantized_x( header.vertex_count );
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std::vector<std::uint16_t> quantized_y( header.vertex_count );
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std::vector<std::uint16_t> quantized_z( header.vertex_count );
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for( std::uint32_t i = 0; i < header.vertex_count; ++i ) {
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std::fread( &quantized_x[ i ], sizeof( std::uint16_t ), 1, file );
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std::fread( &quantized_y[ i ], sizeof( std::uint16_t ), 1, file );
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std::fread( &quantized_z[ i ], sizeof( std::uint16_t ), 1, file );
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}
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// Dequantize positions
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Out.positions_x.resize( header.vertex_count );
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Out.positions_y.resize( header.vertex_count );
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Out.positions_z.resize( header.vertex_count );
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for( std::uint32_t i = 0; i < header.vertex_count; ++i ) {
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Out.positions_x[ i ] = dequantize( quantized_x[ i ], header.min_x, header.max_x );
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Out.positions_y[ i ] = dequantize( quantized_y[ i ], header.min_y, header.max_y );
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Out.positions_z[ i ] = dequantize( quantized_z[ i ], header.min_z, header.max_z );
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}
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// Read UVs
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std::fseek( file, header.uv_data_offset, SEEK_SET );
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Out.uvs_u.resize( header.vertex_count );
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Out.uvs_v.resize( header.vertex_count );
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for( std::uint32_t i = 0; i < header.vertex_count; ++i ) {
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std::uint16_t u, v;
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std::fread( &u, sizeof( std::uint16_t ), 1, file );
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std::fread( &v, sizeof( std::uint16_t ), 1, file );
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Out.uvs_u[ i ] = static_cast<float>( dequantize( u, 0.0, 1.0 ) );
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Out.uvs_v[ i ] = static_cast<float>( dequantize( v, 0.0, 1.0 ) );
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}
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// Read indices
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std::fseek( file, header.index_data_offset, SEEK_SET );
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Out.indices.resize( header.triangle_count * 3 );
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if( header.index_size == 2 ) {
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for( std::uint32_t i = 0; i < header.triangle_count * 3; ++i ) {
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std::uint16_t idx;
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std::fread( &idx, sizeof( std::uint16_t ), 1, file );
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Out.indices[ i ] = idx;
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}
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} else {
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std::fread( Out.indices.data(), sizeof( std::uint32_t ), header.triangle_count * 3, file );
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}
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// Read edge indices
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std::fseek( file, header.edge_indices_offset, SEEK_SET );
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Out.north_edge.resize( header.edge_count_north );
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Out.south_edge.resize( header.edge_count_south );
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Out.west_edge.resize( header.edge_count_west );
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Out.east_edge.resize( header.edge_count_east );
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if( header.edge_count_north > 0 )
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std::fread( Out.north_edge.data(), sizeof( std::uint16_t ), header.edge_count_north, file );
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if( header.edge_count_south > 0 )
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std::fread( Out.south_edge.data(), sizeof( std::uint16_t ), header.edge_count_south, file );
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if( header.edge_count_west > 0 )
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std::fread( Out.west_edge.data(), sizeof( std::uint16_t ), header.edge_count_west, file );
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if( header.edge_count_east > 0 )
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std::fread( Out.east_edge.data(), sizeof( std::uint16_t ), header.edge_count_east, file );
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// Materials - for now, all zeros (placeholder)
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Out.materials.resize( header.vertex_count, 0 );
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std::fclose( file );
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return true;
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}
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} // namespace quantizedmesh
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579
scene/terraincooker_tin.cpp
Normal file
579
scene/terraincooker_tin.cpp
Normal file
@@ -0,0 +1,579 @@
|
||||
/*
|
||||
This Source Code Form is subject to the
|
||||
terms of the Mozilla Public License, v.
|
||||
2.0. If a copy of the MPL was not
|
||||
distributed with this file, You can
|
||||
obtain one at
|
||||
http://mozilla.org/MPL/2.0/.
|
||||
*/
|
||||
|
||||
#include "scene/terraincooker_tin.h"
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||||
#include "scene/terraincooker.h"
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#include <algorithm>
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#include <cassert>
|
||||
#include <cmath>
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#include <fstream>
|
||||
#include <iostream>
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#include <queue>
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#include <unordered_set>
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|
||||
namespace terrain {
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||||
namespace {
|
||||
|
||||
// Hash for int64 tile key
|
||||
struct tile_key_hash {
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std::size_t operator()( std::int64_t key ) const noexcept {
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||||
return static_cast<std::size_t>( key ^ ( key >> 32 ) );
|
||||
}
|
||||
};
|
||||
|
||||
// Calculate tile coordinates from world position
|
||||
std::int32_t tile_coord( double world_pos, double tile_size ) {
|
||||
return static_cast<std::int32_t>( std::floor( world_pos / tile_size ) );
|
||||
}
|
||||
|
||||
std::int64_t make_tile_key( std::int32_t x, std::int32_t z ) {
|
||||
return ( static_cast<std::int64_t>( x ) << 32 ) | static_cast<std::uint32_t>( z );
|
||||
}
|
||||
|
||||
} // anonymous namespace
|
||||
|
||||
void tin_cooker::configure(
|
||||
double TileSize,
|
||||
std::uint32_t LodLevels,
|
||||
double ErrorMultiplier
|
||||
) {
|
||||
m_tilesize = TileSize;
|
||||
m_lodlevels = std::max( 1u, LodLevels );
|
||||
m_errormultiplier = std::max( 1.1, ErrorMultiplier );
|
||||
}
|
||||
|
||||
void tin_cooker::rasterize(
|
||||
vertex const &A,
|
||||
vertex const &B,
|
||||
vertex const &C,
|
||||
std::string_view Material
|
||||
) {
|
||||
++m_triangles_in;
|
||||
|
||||
// Find centroid to determine tile
|
||||
double const cx = ( A.x + B.x + C.x ) / 3.0;
|
||||
double const cz = ( A.z + B.z + C.z ) / 3.0;
|
||||
|
||||
std::int32_t const tile_x = tile_coord( cx, m_tilesize );
|
||||
std::int32_t const tile_z = tile_coord( cz, m_tilesize );
|
||||
|
||||
std::int64_t const key = make_tile_key( tile_x, tile_z );
|
||||
|
||||
auto &tile = m_tiles[ key ];
|
||||
tile.triangles.push_back( { { A, B, C }, std::string( Material ) } );
|
||||
tile.dirty = true;
|
||||
}
|
||||
|
||||
void tin_cooker::add_constraint( vertex const &A, vertex const &B ) {
|
||||
// Add constraint to all tiles it intersects
|
||||
double const minx = std::min( A.x, B.x );
|
||||
double const maxx = std::max( A.x, B.x );
|
||||
double const minz = std::min( A.z, B.z );
|
||||
double const maxz = std::max( A.z, B.z );
|
||||
|
||||
std::int32_t const tile_x0 = tile_coord( minx, m_tilesize );
|
||||
std::int32_t const tile_z0 = tile_coord( minz, m_tilesize );
|
||||
std::int32_t const tile_x1 = tile_coord( maxx, m_tilesize );
|
||||
std::int32_t const tile_z1 = tile_coord( maxz, m_tilesize );
|
||||
|
||||
for( std::int32_t tx = tile_x0; tx <= tile_x1; ++tx ) {
|
||||
for( std::int32_t tz = tile_z0; tz <= tile_z1; ++tz ) {
|
||||
std::int64_t const key = make_tile_key( tx, tz );
|
||||
auto &tile = m_tiles[ key ];
|
||||
tile.constraints.push_back( { A, B } );
|
||||
tile.dirty = true;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
std::vector<tin_tile> tin_cooker::finish() {
|
||||
std::vector<tin_tile> result;
|
||||
result.reserve( m_tiles.size() );
|
||||
|
||||
std::size_t total_tiles = m_tiles.size();
|
||||
std::size_t processed = 0;
|
||||
|
||||
for( auto &[ key, accumulator ] : m_tiles ) {
|
||||
if( !accumulator.dirty || accumulator.triangles.empty() ) {
|
||||
continue;
|
||||
}
|
||||
|
||||
++processed;
|
||||
if( processed % 100 == 0 || processed == total_tiles ) {
|
||||
std::printf( "\rTriangulating tiles: %zu/%zu", processed, total_tiles );
|
||||
std::fflush( stdout );
|
||||
}
|
||||
|
||||
std::int32_t const tile_x = static_cast<std::int32_t>( key >> 32 );
|
||||
std::int32_t const tile_z = static_cast<std::int32_t>( key & 0xffffffff );
|
||||
|
||||
tin_tile tile;
|
||||
tile.x = tile_x;
|
||||
tile.z = tile_z;
|
||||
|
||||
// Tile bounds
|
||||
tile.minx = tile_x * m_tilesize;
|
||||
tile.minz = tile_z * m_tilesize;
|
||||
tile.maxx = tile.minx + m_tilesize;
|
||||
tile.maxz = tile.minz + m_tilesize;
|
||||
tile.miny = std::numeric_limits<double>::max();
|
||||
tile.maxy = std::numeric_limits<double>::lowest();
|
||||
|
||||
// Collect unique vertices from triangles
|
||||
std::vector<vertex> points;
|
||||
points.reserve( accumulator.triangles.size() * 3 );
|
||||
|
||||
for( auto const &tri : accumulator.triangles ) {
|
||||
for( auto const &v : tri.v ) {
|
||||
points.push_back( v );
|
||||
tile.miny = std::min( tile.miny, v.y );
|
||||
tile.maxy = std::max( tile.maxy, v.y );
|
||||
}
|
||||
}
|
||||
|
||||
// Build material table
|
||||
for( auto const &tri : accumulator.triangles ) {
|
||||
get_material_index( tile, tri.material );
|
||||
}
|
||||
|
||||
// Generate LODs from finest to coarsest
|
||||
double current_error = 0.1; // Start with very fine detail
|
||||
|
||||
for( std::uint32_t lod = 0; lod < m_lodlevels; ++lod ) {
|
||||
tin_lod level;
|
||||
|
||||
if( lod == 0 ) {
|
||||
// Finest LOD: triangulate all points with constraints
|
||||
level = triangulate_lod( points, accumulator.constraints, current_error );
|
||||
} else {
|
||||
// Coarser LODs: simplify previous level
|
||||
level = simplify_lod( tile.lods.back(), current_error );
|
||||
}
|
||||
|
||||
level.geometric_error = current_error;
|
||||
extract_edges( level, tile.minx, tile.minz, tile.maxx, tile.maxz );
|
||||
|
||||
tile.lods.push_back( std::move( level ) );
|
||||
|
||||
m_triangles_out += level.indices.size() / 3;
|
||||
m_vertices_out += level.vertices.size();
|
||||
|
||||
current_error *= m_errormultiplier;
|
||||
}
|
||||
|
||||
result.push_back( std::move( tile ) );
|
||||
}
|
||||
|
||||
std::printf( "\n" );
|
||||
std::printf( "Triangulation complete:\n" );
|
||||
std::printf( " Input triangles: %zu\n", m_triangles_in );
|
||||
std::printf( " Output triangles: %zu\n", m_triangles_out );
|
||||
std::printf( " Output vertices: %zu\n", m_vertices_out );
|
||||
std::printf( " Reduction: %.1f%%\n",
|
||||
m_triangles_in > 0 ? 100.0 * ( 1.0 - static_cast<double>( m_triangles_out ) / m_triangles_in ) : 0.0 );
|
||||
|
||||
return result;
|
||||
}
|
||||
|
||||
tin_lod tin_cooker::triangulate_lod(
|
||||
std::vector<vertex> const &Points,
|
||||
std::vector<tin_constraint> const &Constraints,
|
||||
double TargetError
|
||||
) {
|
||||
tin_lod result;
|
||||
|
||||
if( Points.empty() ) {
|
||||
return result;
|
||||
}
|
||||
|
||||
// Convert points to CDT format, removing duplicates
|
||||
std::vector<CDT::V2d<double>> cdt_points;
|
||||
std::vector<CDT::Edge> cdt_edges;
|
||||
|
||||
cdt_points.reserve( Points.size() );
|
||||
std::unordered_map<std::uint64_t, std::uint32_t> point_map;
|
||||
|
||||
auto hash_point = []( vertex const &v ) -> std::uint64_t {
|
||||
// Hash to 1cm precision
|
||||
std::uint32_t const x = static_cast<std::uint32_t>( std::round( v.x * 100.0 ) );
|
||||
std::uint32_t const z = static_cast<std::uint32_t>( std::round( v.z * 100.0 ) );
|
||||
return ( static_cast<std::uint64_t>( x ) << 32 ) | z;
|
||||
};
|
||||
|
||||
for( auto const &v : Points ) {
|
||||
std::uint64_t const h = hash_point( v );
|
||||
auto const [ it, inserted ] = point_map.try_emplace( h, static_cast<std::uint32_t>( cdt_points.size() ) );
|
||||
|
||||
if( inserted ) {
|
||||
cdt_points.push_back( to_cdt_point( v ) );
|
||||
result.vertices.push_back( v );
|
||||
}
|
||||
}
|
||||
|
||||
// Add constraint edges
|
||||
for( auto const &constraint : Constraints ) {
|
||||
std::uint64_t const h0 = hash_point( constraint.a );
|
||||
std::uint64_t const h1 = hash_point( constraint.b );
|
||||
|
||||
auto it0 = point_map.find( h0 );
|
||||
auto it1 = point_map.find( h1 );
|
||||
|
||||
if( it0 != point_map.end() && it1 != point_map.end() && it0->second != it1->second ) {
|
||||
cdt_edges.push_back( CDT::Edge( it0->second, it1->second ) );
|
||||
}
|
||||
}
|
||||
|
||||
// Run CDT
|
||||
CDT::Triangulation<double> cdt;
|
||||
cdt.insertVertices( cdt_points );
|
||||
|
||||
if( !cdt_edges.empty() ) {
|
||||
cdt.insertEdges( cdt_edges );
|
||||
cdt.eraseOuterTrianglesAndHoles();
|
||||
}
|
||||
|
||||
// Extract triangles
|
||||
result.indices.reserve( cdt.triangles.size() * 3 );
|
||||
|
||||
for( auto const &tri : cdt.triangles ) {
|
||||
result.indices.push_back( tri.vertices[ 0 ] );
|
||||
result.indices.push_back( tri.vertices[ 1 ] );
|
||||
result.indices.push_back( tri.vertices[ 2 ] );
|
||||
}
|
||||
|
||||
// Assign material indices (simplified - use most common material for now)
|
||||
result.materials.resize( result.vertices.size(), 0 );
|
||||
|
||||
return result;
|
||||
}
|
||||
|
||||
tin_lod tin_cooker::simplify_lod(
|
||||
tin_lod const &FineLod,
|
||||
double TargetError
|
||||
) {
|
||||
// Edge collapse simplification
|
||||
// For now: simple vertex removal based on geometric error
|
||||
|
||||
tin_lod result = FineLod; // Start with copy
|
||||
|
||||
if( FineLod.vertices.size() < 100 ) {
|
||||
// Too small to simplify meaningfully
|
||||
return result;
|
||||
}
|
||||
|
||||
// Build adjacency information
|
||||
std::unordered_map<std::uint32_t, std::vector<std::uint32_t>> adjacency;
|
||||
|
||||
for( std::size_t i = 0; i < FineLod.indices.size(); i += 3 ) {
|
||||
std::uint32_t const i0 = FineLod.indices[ i + 0 ];
|
||||
std::uint32_t const i1 = FineLod.indices[ i + 1 ];
|
||||
std::uint32_t const i2 = FineLod.indices[ i + 2 ];
|
||||
|
||||
adjacency[ i0 ].push_back( i1 );
|
||||
adjacency[ i0 ].push_back( i2 );
|
||||
adjacency[ i1 ].push_back( i0 );
|
||||
adjacency[ i1 ].push_back( i2 );
|
||||
adjacency[ i2 ].push_back( i0 );
|
||||
adjacency[ i2 ].push_back( i1 );
|
||||
}
|
||||
|
||||
// Calculate error for each vertex
|
||||
struct vertex_error {
|
||||
std::uint32_t index;
|
||||
double error;
|
||||
|
||||
bool operator>( vertex_error const &other ) const {
|
||||
return error > other.error; // Min-heap
|
||||
}
|
||||
};
|
||||
|
||||
std::priority_queue<vertex_error, std::vector<vertex_error>, std::greater<vertex_error>> error_queue;
|
||||
std::unordered_set<std::uint32_t> removed;
|
||||
|
||||
for( std::uint32_t i = 0; i < FineLod.vertices.size(); ++i ) {
|
||||
auto it = adjacency.find( i );
|
||||
if( it == adjacency.end() || it->second.empty() ) {
|
||||
continue;
|
||||
}
|
||||
|
||||
std::vector<vertex> neighbours;
|
||||
for( auto const j : it->second ) {
|
||||
neighbours.push_back( FineLod.vertices[ j ] );
|
||||
}
|
||||
|
||||
double const error = calculate_error( FineLod.vertices[ i ], neighbours );
|
||||
|
||||
if( error < TargetError ) {
|
||||
error_queue.push( { i, error } );
|
||||
}
|
||||
}
|
||||
|
||||
// Remove vertices with low error (target: remove ~30%)
|
||||
std::size_t const target_removals = FineLod.vertices.size() * 3 / 10;
|
||||
|
||||
while( !error_queue.empty() && removed.size() < target_removals ) {
|
||||
auto const top = error_queue.top();
|
||||
error_queue.pop();
|
||||
|
||||
if( removed.count( top.index ) > 0 ) {
|
||||
continue;
|
||||
}
|
||||
|
||||
removed.insert( top.index );
|
||||
}
|
||||
|
||||
// Rebuild mesh without removed vertices
|
||||
std::unordered_map<std::uint32_t, std::uint32_t> index_remap;
|
||||
std::vector<vertex> new_vertices;
|
||||
std::vector<std::uint8_t> new_materials;
|
||||
|
||||
for( std::uint32_t i = 0; i < FineLod.vertices.size(); ++i ) {
|
||||
if( removed.count( i ) == 0 ) {
|
||||
index_remap[ i ] = static_cast<std::uint32_t>( new_vertices.size() );
|
||||
new_vertices.push_back( FineLod.vertices[ i ] );
|
||||
if( i < FineLod.materials.size() ) {
|
||||
new_materials.push_back( FineLod.materials[ i ] );
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
result.vertices = std::move( new_vertices );
|
||||
result.materials = std::move( new_materials );
|
||||
|
||||
// Re-triangulate (simple approach: use CDT again)
|
||||
std::vector<CDT::V2d<double>> cdt_points;
|
||||
cdt_points.reserve( result.vertices.size() );
|
||||
|
||||
for( auto const &v : result.vertices ) {
|
||||
cdt_points.push_back( to_cdt_point( v ) );
|
||||
}
|
||||
|
||||
CDT::Triangulation<double> cdt;
|
||||
cdt.insertVertices( cdt_points );
|
||||
|
||||
result.indices.clear();
|
||||
result.indices.reserve( cdt.triangles.size() * 3 );
|
||||
|
||||
for( auto const &tri : cdt.triangles ) {
|
||||
result.indices.push_back( tri.vertices[ 0 ] );
|
||||
result.indices.push_back( tri.vertices[ 1 ] );
|
||||
result.indices.push_back( tri.vertices[ 2 ] );
|
||||
}
|
||||
|
||||
return result;
|
||||
}
|
||||
|
||||
double tin_cooker::calculate_error(
|
||||
vertex const &V,
|
||||
std::vector<vertex> const &Neighbours
|
||||
) {
|
||||
if( Neighbours.size() < 3 ) {
|
||||
return std::numeric_limits<double>::max();
|
||||
}
|
||||
|
||||
// Calculate maximum distance to plane fitted through neighbours
|
||||
// Simplified: just use average height difference
|
||||
|
||||
double sum_y = 0.0;
|
||||
for( auto const &n : Neighbours ) {
|
||||
sum_y += n.y;
|
||||
}
|
||||
double const avg_y = sum_y / Neighbours.size();
|
||||
|
||||
return std::abs( V.y - avg_y );
|
||||
}
|
||||
|
||||
void tin_cooker::extract_edges(
|
||||
tin_lod &Lod,
|
||||
double TileMinX,
|
||||
double TileMinZ,
|
||||
double TileMaxX,
|
||||
double TileMaxZ
|
||||
) {
|
||||
constexpr double edge_epsilon = 0.01;
|
||||
|
||||
Lod.north_edge.clear();
|
||||
Lod.south_edge.clear();
|
||||
Lod.west_edge.clear();
|
||||
Lod.east_edge.clear();
|
||||
|
||||
for( std::uint32_t i = 0; i < Lod.vertices.size(); ++i ) {
|
||||
auto const &v = Lod.vertices[ i ];
|
||||
|
||||
bool on_edge = false;
|
||||
|
||||
if( std::abs( v.x - TileMinX ) < edge_epsilon ) {
|
||||
Lod.west_edge.push_back( static_cast<std::uint16_t>( i ) );
|
||||
on_edge = true;
|
||||
}
|
||||
if( std::abs( v.x - TileMaxX ) < edge_epsilon ) {
|
||||
Lod.east_edge.push_back( static_cast<std::uint16_t>( i ) );
|
||||
on_edge = true;
|
||||
}
|
||||
if( std::abs( v.z - TileMinZ ) < edge_epsilon ) {
|
||||
Lod.south_edge.push_back( static_cast<std::uint16_t>( i ) );
|
||||
on_edge = true;
|
||||
}
|
||||
if( std::abs( v.z - TileMaxZ ) < edge_epsilon ) {
|
||||
Lod.north_edge.push_back( static_cast<std::uint16_t>( i ) );
|
||||
on_edge = true;
|
||||
}
|
||||
}
|
||||
|
||||
// Sort edges by position (west/east by Z, north/south by X)
|
||||
auto sort_west_east = [ &Lod ]( std::uint16_t a, std::uint16_t b ) {
|
||||
return Lod.vertices[ a ].z < Lod.vertices[ b ].z;
|
||||
};
|
||||
auto sort_north_south = [ &Lod ]( std::uint16_t a, std::uint16_t b ) {
|
||||
return Lod.vertices[ a ].x < Lod.vertices[ b ].x;
|
||||
};
|
||||
|
||||
std::sort( Lod.west_edge.begin(), Lod.west_edge.end(), sort_west_east );
|
||||
std::sort( Lod.east_edge.begin(), Lod.east_edge.end(), sort_west_east );
|
||||
std::sort( Lod.north_edge.begin(), Lod.north_edge.end(), sort_north_south );
|
||||
std::sort( Lod.south_edge.begin(), Lod.south_edge.end(), sort_north_south );
|
||||
}
|
||||
|
||||
std::uint8_t tin_cooker::get_material_index( tin_tile &Tile, std::string const &Material ) {
|
||||
auto it = Tile.material_lookup.find( Material );
|
||||
|
||||
if( it != Tile.material_lookup.end() ) {
|
||||
return it->second;
|
||||
}
|
||||
|
||||
std::uint8_t const index = static_cast<std::uint8_t>( Tile.materials.size() );
|
||||
Tile.materials.push_back( Material );
|
||||
Tile.material_lookup[ Material ] = index;
|
||||
|
||||
return index;
|
||||
}
|
||||
|
||||
bool tin_cooker::write_tile(
|
||||
tin_tile const &Tile,
|
||||
std::uint32_t LodIndex,
|
||||
std::string const &Path,
|
||||
bool Compress
|
||||
) {
|
||||
if( LodIndex >= Tile.lods.size() ) {
|
||||
return false;
|
||||
}
|
||||
|
||||
auto const &lod = Tile.lods[ LodIndex ];
|
||||
|
||||
// Calculate bounding box centre
|
||||
double const cx = ( Tile.minx + Tile.maxx ) * 0.5;
|
||||
double const cy = ( Tile.miny + Tile.maxy ) * 0.5;
|
||||
double const cz = ( Tile.minz + Tile.maxz ) * 0.5;
|
||||
|
||||
// Build header
|
||||
quantizedmesh::file_header header{};
|
||||
std::memcpy( header.magic, quantizedmesh::magic, sizeof( header.magic ) );
|
||||
header.version = quantizedmesh::version;
|
||||
|
||||
header.center_x = cx;
|
||||
header.center_y = cy;
|
||||
header.center_z = cz;
|
||||
|
||||
header.min_x = Tile.minx;
|
||||
header.min_y = Tile.miny;
|
||||
header.min_z = Tile.minz;
|
||||
|
||||
header.max_x = Tile.maxx;
|
||||
header.max_y = Tile.maxy;
|
||||
header.max_z = Tile.maxz;
|
||||
|
||||
header.horizont_error = lod.geometric_error;
|
||||
header.vertex_count = static_cast<std::uint32_t>( lod.vertices.size() );
|
||||
header.triangle_count = static_cast<std::uint32_t>( lod.indices.size() / 3 );
|
||||
|
||||
header.index_size = lod.vertices.size() > 65535 ? 4 : 2;
|
||||
header.edge_count_north = static_cast<std::uint16_t>( lod.north_edge.size() );
|
||||
header.edge_count_south = static_cast<std::uint16_t>( lod.south_edge.size() );
|
||||
header.edge_count_west = static_cast<std::uint16_t>( lod.west_edge.size() );
|
||||
header.edge_count_east = static_cast<std::uint16_t>( lod.east_edge.size() );
|
||||
|
||||
// Calculate offsets
|
||||
std::uint32_t offset = sizeof( header );
|
||||
|
||||
header.vertex_data_offset = offset;
|
||||
offset += header.vertex_count * 3 * sizeof( std::uint16_t );
|
||||
|
||||
header.uv_data_offset = offset;
|
||||
offset += header.vertex_count * 2 * sizeof( std::uint16_t );
|
||||
|
||||
header.index_data_offset = offset;
|
||||
offset += header.triangle_count * 3 * header.index_size;
|
||||
|
||||
header.edge_indices_offset = offset;
|
||||
std::uint32_t const edge_data_size =
|
||||
( header.edge_count_north + header.edge_count_south +
|
||||
header.edge_count_west + header.edge_count_east ) * sizeof( std::uint16_t );
|
||||
offset += edge_data_size;
|
||||
|
||||
header.extension_offset = offset;
|
||||
|
||||
// Write file
|
||||
std::ofstream file( Path, std::ios::binary );
|
||||
if( !file.good() ) {
|
||||
return false;
|
||||
}
|
||||
|
||||
file.write( reinterpret_cast<char const *>( &header ), sizeof( header ) );
|
||||
|
||||
// Write quantized vertex positions
|
||||
for( auto const &v : lod.vertices ) {
|
||||
std::uint16_t const qx = quantizedmesh::quantize( v.x, Tile.minx, Tile.maxx );
|
||||
std::uint16_t const qy = quantizedmesh::quantize( v.y, Tile.miny, Tile.maxy );
|
||||
std::uint16_t const qz = quantizedmesh::quantize( v.z, Tile.minz, Tile.maxz );
|
||||
|
||||
file.write( reinterpret_cast<char const *>( &qx ), sizeof( qx ) );
|
||||
file.write( reinterpret_cast<char const *>( &qy ), sizeof( qy ) );
|
||||
file.write( reinterpret_cast<char const *>( &qz ), sizeof( qz ) );
|
||||
}
|
||||
|
||||
// Write UV coordinates (from texture coords in vertex)
|
||||
for( auto const &v : lod.vertices ) {
|
||||
std::uint16_t const u = quantizedmesh::quantize( v.u, 0.0, 1.0 );
|
||||
std::uint16_t const uv = quantizedmesh::quantize( v.v, 0.0, 1.0 );
|
||||
|
||||
file.write( reinterpret_cast<char const *>( &u ), sizeof( u ) );
|
||||
file.write( reinterpret_cast<char const *>( &uv ), sizeof( uv ) );
|
||||
}
|
||||
|
||||
// Write indices
|
||||
for( auto const idx : lod.indices ) {
|
||||
if( header.index_size == 2 ) {
|
||||
std::uint16_t const idx16 = static_cast<std::uint16_t>( idx );
|
||||
file.write( reinterpret_cast<char const *>( &idx16 ), sizeof( idx16 ) );
|
||||
} else {
|
||||
file.write( reinterpret_cast<char const *>( &idx ), sizeof( idx ) );
|
||||
}
|
||||
}
|
||||
|
||||
// Write edge indices
|
||||
for( auto const idx : lod.north_edge ) {
|
||||
file.write( reinterpret_cast<char const *>( &idx ), sizeof( idx ) );
|
||||
}
|
||||
for( auto const idx : lod.south_edge ) {
|
||||
file.write( reinterpret_cast<char const *>( &idx ), sizeof( idx ) );
|
||||
}
|
||||
for( auto const idx : lod.west_edge ) {
|
||||
file.write( reinterpret_cast<char const *>( &idx ), sizeof( idx ) );
|
||||
}
|
||||
for( auto const idx : lod.east_edge ) {
|
||||
file.write( reinterpret_cast<char const *>( &idx ), sizeof( idx ) );
|
||||
}
|
||||
|
||||
file.close();
|
||||
return file.good();
|
||||
}
|
||||
|
||||
} // namespace terrain
|
||||
196
scene/terraincooker_tin.h
Normal file
196
scene/terraincooker_tin.h
Normal file
@@ -0,0 +1,196 @@
|
||||
/*
|
||||
This Source Code Form is subject to the
|
||||
terms of the Mozilla Public License, v.
|
||||
2.0. If a copy of the MPL was not
|
||||
distributed with this file, You can
|
||||
obtain one at
|
||||
http://mozilla.org/MPL/2.0/.
|
||||
*/
|
||||
|
||||
#pragma once
|
||||
|
||||
// Triangulates terrain into TIN with multiple LODs using Constrained Delaunay.
|
||||
// Input: triangle soup from scenery (same as heightfield cooker)
|
||||
// Output: quantized mesh tiles with proper edge constraints for seamless LOD
|
||||
|
||||
#include <algorithm>
|
||||
#include <cmath>
|
||||
#include <cstdint>
|
||||
#include <limits>
|
||||
#include <memory>
|
||||
#include <string>
|
||||
#include <string_view>
|
||||
#include <unordered_map>
|
||||
#include <vector>
|
||||
|
||||
#include <CDT.h>
|
||||
|
||||
#include "scene/quantizedmeshformat.h"
|
||||
|
||||
namespace terrain {
|
||||
|
||||
// Forward declarations from terraincooker.h
|
||||
struct vertex;
|
||||
|
||||
// Triangle with material
|
||||
struct tin_triangle {
|
||||
vertex v[ 3 ];
|
||||
std::string material;
|
||||
};
|
||||
|
||||
// Constraint edge (e.g. track corridor boundary)
|
||||
struct tin_constraint {
|
||||
vertex a, b;
|
||||
};
|
||||
|
||||
// Single LOD level of a TIN tile
|
||||
struct tin_lod {
|
||||
std::vector<vertex> vertices;
|
||||
std::vector<std::uint32_t> indices;
|
||||
std::vector<std::uint8_t> materials; // Per-vertex material indices
|
||||
|
||||
// Edge vertices for seamless stitching (indices into vertices array)
|
||||
std::vector<std::uint16_t> north_edge;
|
||||
std::vector<std::uint16_t> south_edge;
|
||||
std::vector<std::uint16_t> west_edge;
|
||||
std::vector<std::uint16_t> east_edge;
|
||||
|
||||
double geometric_error; // Maximum error vs. finer LOD
|
||||
};
|
||||
|
||||
// Complete TIN tile with all LODs
|
||||
struct tin_tile {
|
||||
std::int32_t x, z; // Tile coordinates
|
||||
|
||||
std::vector<tin_lod> lods; // Finest to coarsest
|
||||
|
||||
// Bounding box
|
||||
double minx, miny, minz;
|
||||
double maxx, maxy, maxz;
|
||||
|
||||
// Material table (shared across LODs)
|
||||
std::vector<std::string> materials;
|
||||
std::unordered_map<std::string, std::uint8_t> material_lookup;
|
||||
};
|
||||
|
||||
class tin_cooker {
|
||||
public:
|
||||
tin_cooker() = default;
|
||||
|
||||
// Configure tile size and LOD parameters
|
||||
void configure(
|
||||
double TileSize, // Metres per tile side
|
||||
std::uint32_t LodLevels = 4, // Number of LOD levels
|
||||
double ErrorMultiplier = 2.0 // Geometric error growth per LOD
|
||||
);
|
||||
|
||||
// Accumulate terrain triangles (same interface as heightfield cooker)
|
||||
void rasterize(
|
||||
vertex const &A,
|
||||
vertex const &B,
|
||||
vertex const &C,
|
||||
std::string_view Material
|
||||
);
|
||||
|
||||
// Add constraint edges (track corridors, roads, water boundaries)
|
||||
void add_constraint( vertex const &A, vertex const &B );
|
||||
|
||||
// Generate all tiles with LODs
|
||||
std::vector<tin_tile> finish();
|
||||
|
||||
// Export single tile to Quantized Mesh format
|
||||
static bool write_tile(
|
||||
tin_tile const &Tile,
|
||||
std::uint32_t LodIndex,
|
||||
std::string const &Path,
|
||||
bool Compress = true
|
||||
);
|
||||
|
||||
private:
|
||||
struct tile_accumulator {
|
||||
std::vector<tin_triangle> triangles;
|
||||
std::vector<tin_constraint> constraints;
|
||||
bool dirty { false };
|
||||
};
|
||||
|
||||
// Build single LOD level using CDT
|
||||
tin_lod triangulate_lod(
|
||||
std::vector<vertex> const &Points,
|
||||
std::vector<tin_constraint> const &Constraints,
|
||||
double TargetError
|
||||
);
|
||||
|
||||
// Simplify LOD by removing vertices with low geometric error
|
||||
tin_lod simplify_lod(
|
||||
tin_lod const &FineLod,
|
||||
double TargetError
|
||||
);
|
||||
|
||||
// Calculate geometric error of removing a vertex
|
||||
double calculate_error(
|
||||
vertex const &V,
|
||||
std::vector<vertex> const &Neighbours
|
||||
);
|
||||
|
||||
// Extract edge vertices for stitching
|
||||
void extract_edges( tin_lod &Lod, double TileMinX, double TileMinZ, double TileMaxX, double TileMaxZ );
|
||||
|
||||
// Find material index, adding to table if new
|
||||
std::uint8_t get_material_index( tin_tile &Tile, std::string const &Material );
|
||||
|
||||
double m_tilesize { 256.0 };
|
||||
std::uint32_t m_lodlevels { 4 };
|
||||
double m_errormultiplier { 2.0 };
|
||||
|
||||
std::unordered_map<std::int64_t, tile_accumulator> m_tiles;
|
||||
|
||||
// Statistics
|
||||
std::size_t m_triangles_in { 0 };
|
||||
std::size_t m_triangles_out { 0 };
|
||||
std::size_t m_vertices_out { 0 };
|
||||
};
|
||||
|
||||
// Helper: convert CDT point to our vertex
|
||||
inline vertex from_cdt_point( CDT::V2d<double> const &P, double Y = 0.0 ) {
|
||||
return vertex{ P.x, Y, P.y };
|
||||
}
|
||||
|
||||
// Helper: convert vertex to CDT point
|
||||
inline CDT::V2d<double> to_cdt_point( vertex const &V ) {
|
||||
return CDT::V2d<double>::make( V.x, V.z );
|
||||
}
|
||||
|
||||
// Helper: calculate distance from point to line segment
|
||||
inline double point_to_segment_distance(
|
||||
vertex const &Point,
|
||||
vertex const &SegmentA,
|
||||
vertex const &SegmentB
|
||||
) {
|
||||
double const dx = SegmentB.x - SegmentA.x;
|
||||
double const dz = SegmentB.z - SegmentA.z;
|
||||
double const len_sq = dx * dx + dz * dz;
|
||||
|
||||
if( len_sq < 1e-10 ) {
|
||||
// Degenerate segment
|
||||
double const pdx = Point.x - SegmentA.x;
|
||||
double const pdz = Point.z - SegmentA.z;
|
||||
return std::sqrt( pdx * pdx + pdz * pdz );
|
||||
}
|
||||
|
||||
// Project point onto line
|
||||
double const t = std::clamp(
|
||||
( ( Point.x - SegmentA.x ) * dx + ( Point.z - SegmentA.z ) * dz ) / len_sq,
|
||||
0.0, 1.0
|
||||
);
|
||||
|
||||
double const proj_x = SegmentA.x + t * dx;
|
||||
double const proj_z = SegmentA.z + t * dz;
|
||||
|
||||
double const pdx = Point.x - proj_x;
|
||||
double const pdy = Point.y - ( SegmentA.y + t * ( SegmentB.y - SegmentA.y ) );
|
||||
double const pdz = Point.z - proj_z;
|
||||
|
||||
return std::sqrt( pdx * pdx + pdy * pdy + pdz * pdz );
|
||||
}
|
||||
|
||||
} // namespace terrain
|
||||
Reference in New Issue
Block a user