mirror of
https://github.com/MaSzyna-EU07/maszyna.git
synced 2026-10-17 17:59:19 +02:00
9408216ae7
The tiles moved out of the scenery's pak into an archive of their own: a sorted index of fixed-size entries found by where a tile sits in the quadtree rather than by a name, each entry compressed on its own so a tile can be read without touching the rest. A name apiece would have been seventy megabytes of index to read before the first tile could be drawn. An entry carries what its tile's ground asks for - how far it departs from the finest mesh, and how long its triangles are - because which level to draw has to be settled for tiles that are not on the card yet, and the index is the only thing about them that is read up front. Until now the figure came from the tile's level, which is the worst tile in it, so one steep corner spoke for every tile that shared its level. The mesh carries a normal per vertex, octahedron-encoded into two bytes, in place of the face normal the fragment stage worked out from how the view position changed across a triangle. A face normal makes the ground read as facets, and a coarser level's facets face differently from the ones they stand for, so the light over a hillside changed as the level did. A geometry stage hands the fragment stage the three materials of the triangle it is in and the barycentric weights, so ground changes over a triangle rather than along its edge; 3.3 has no gl_BaryCoordEXT. And the level a tile is drawn at now counts the camera's height. The distance was measured on the ground plane alone, which puts the tile underfoot nought metres away from a camera a kilometre above it - and nought metres asks for the finest level there is, so a view from the air wanted the whole ground at full detail, more tiles than the buffers hold, and what would not fit came out as holes. Archives written under the old rules are refused at the door and baked again.
298 lines
10 KiB
C++
298 lines
10 KiB
C++
/*
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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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module;
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#include <algorithm>
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#include <cstddef>
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#include <cstdint>
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#include <map>
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#include <memory>
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#include <optional>
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#include <vector>
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#include <glad/glad.h>
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#include "scene/quantizedmeshreader.h"
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module eu07.rendering.terrainmesharena;
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import eu07.gl.buffer;
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import eu07.utilities.logs;
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import eu07.gl.vao;
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namespace {
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// what the buffers start at, in vertices and indices, and the most they may reach. a vertex is 16
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// bytes and an index 4, so the ceiling is about 500 MB of terrain on the card
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constexpr std::uint32_t firstvertices { 1u << 19 };
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constexpr std::uint32_t firstindices { 1u << 21 };
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constexpr std::uint32_t mostvertices { 1u << 24 };
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constexpr std::uint32_t mostindices { 1u << 26 };
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constexpr int attribute_position { 0 };
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constexpr int attribute_material { 1 };
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constexpr int attribute_normal { 2 };
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} // anonymous namespace
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void
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terrain_mesh_arena::span_list::give( std::uint32_t const At, std::uint32_t const Count ) {
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if( Count == 0 ) { return; }
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auto placed { m_free.emplace( At, Count ).first };
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// join what now touches, so that the room a tile gave back can hold a larger one
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auto after { std::next( placed ) };
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if( ( after != m_free.end() ) && ( placed->first + placed->second == after->first ) ) {
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placed->second += after->second;
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m_free.erase( after );
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}
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if( placed != m_free.begin() ) {
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auto before { std::prev( placed ) };
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if( before->first + before->second == placed->first ) {
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before->second += placed->second;
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m_free.erase( placed );
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}
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}
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}
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bool
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terrain_mesh_arena::span_list::take( std::uint32_t const Count, std::uint32_t &At ) {
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for( auto span = m_free.begin(); span != m_free.end(); ++span ) {
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if( span->second < Count ) { continue; }
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At = span->first;
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if( span->second == Count ) { m_free.erase( span ); }
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else {
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auto const left { span->second - Count };
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m_free.erase( span );
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m_free.emplace( At + Count, left );
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}
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return true;
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}
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return false;
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}
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terrain_mesh_arena::~terrain_mesh_arena() {
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destroy();
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}
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// The material is handed over as an integer that the vertex stage takes as a float: gl::vao sets
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// attributes up one way, and going around it to ask for an integer attribute would put the engine's
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// idea of what is bound out of step with what is.
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void
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terrain_mesh_arena::describe_vertices() {
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auto const stride { static_cast<int>( sizeof( quantizedmesh::render_vertex ) ) };
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m_vao->setup_attrib(
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*m_vertexbuffer, attribute_position, 3, GL_FLOAT, stride,
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static_cast<int>( offsetof( quantizedmesh::render_vertex, x ) ) );
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m_vao->setup_attrib(
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*m_vertexbuffer, attribute_material, 1, GL_UNSIGNED_SHORT, stride,
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static_cast<int>( offsetof( quantizedmesh::render_vertex, material ) ) );
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// the normal, still folded onto its octahedron; the vertex stage unfolds it
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m_vao->setup_attrib(
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*m_vertexbuffer, attribute_normal, 2, GL_UNSIGNED_BYTE, stride,
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static_cast<int>( offsetof( quantizedmesh::render_vertex, normal0 ) ) );
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}
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bool
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terrain_mesh_arena::create( bool const Wideindices ) {
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destroy();
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m_wideindices = Wideindices;
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m_vao.emplace();
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m_vertexbuffer = std::make_unique<gl::buffer>();
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m_indexbuffer = std::make_unique<gl::buffer>();
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m_vao->bind();
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m_vertexbuffer->allocate(
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gl::buffer::ARRAY_BUFFER,
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static_cast<GLsizeiptr>( firstvertices ) * sizeof( quantizedmesh::render_vertex ), GL_DYNAMIC_DRAW );
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m_indexbuffer->allocate(
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gl::buffer::ELEMENT_ARRAY_BUFFER,
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static_cast<GLsizeiptr>( firstindices ) * indexwidth(), GL_DYNAMIC_DRAW );
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describe_vertices();
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m_vao->setup_ebo( *m_indexbuffer );
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unbind();
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m_vertexroom = firstvertices;
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m_indexroom = firstindices;
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m_freevertices.clear();
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m_freeindices.clear();
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m_freevertices.give( 0, m_vertexroom );
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m_freeindices.give( 0, m_indexroom );
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m_verticesheld = 0;
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return true;
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}
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void
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terrain_mesh_arena::destroy() {
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if( true == m_vao.has_value() ) { m_vao->unbind(); }
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gl::buffer::unbind( gl::buffer::ARRAY_BUFFER );
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gl::buffer::unbind( gl::buffer::ELEMENT_ARRAY_BUFFER );
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m_vao.reset();
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m_vertexbuffer.reset();
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m_indexbuffer.reset();
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m_vertexroom = m_indexroom = 0;
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m_freevertices.clear();
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m_freeindices.clear();
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m_verticesheld = 0;
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m_indicesheld = 0;
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}
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void
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terrain_mesh_arena::bind() {
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if( false == m_vao.has_value() ) { return; }
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m_vao->bind();
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}
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void
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terrain_mesh_arena::unbind() {
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if( true == m_vao.has_value() ) { m_vao->unbind(); }
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gl::buffer::unbind( gl::buffer::ARRAY_BUFFER );
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gl::buffer::unbind( gl::buffer::COPY_READ_BUFFER );
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gl::buffer::unbind( gl::buffer::COPY_WRITE_BUFFER );
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}
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// Growing copies what is there into a larger buffer on the card: the pieces keep their places, so
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// nothing has to be read back or sent again.
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bool
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terrain_mesh_arena::grow_vertices( std::uint32_t const Wanted ) {
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auto room { m_vertexroom };
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while( ( room < m_vertexroom + Wanted ) && ( room < mostvertices ) ) { room *= 2; }
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if( room <= m_vertexroom ) { return false; }
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auto grown { std::make_unique<gl::buffer>() };
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grown->allocate(
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gl::buffer::COPY_WRITE_BUFFER,
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static_cast<GLsizeiptr>( room ) * sizeof( quantizedmesh::render_vertex ), GL_DYNAMIC_DRAW );
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m_vertexbuffer->bind( gl::buffer::COPY_READ_BUFFER );
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::glCopyBufferSubData( GL_COPY_READ_BUFFER, GL_COPY_WRITE_BUFFER, 0, 0,
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static_cast<GLsizeiptr>( m_vertexroom ) * sizeof( quantizedmesh::render_vertex ) );
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gl::buffer::unbind( gl::buffer::COPY_READ_BUFFER );
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gl::buffer::unbind( gl::buffer::COPY_WRITE_BUFFER );
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// the tracker has to forget the buffer before it is destroyed: gl reuses the name of a deleted
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// buffer, so the next one can come back with the same number, and a bind of it would be skipped as
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// already in place while nothing is actually bound
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gl::buffer::unbind( gl::buffer::ARRAY_BUFFER );
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m_vertexbuffer = std::move( grown );
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m_vao->bind();
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describe_vertices();
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m_freevertices.give( m_vertexroom, room - m_vertexroom );
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WriteLog( "Terrain: vertex buffer grown from " + std::to_string( m_vertexroom ) + " to "
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+ std::to_string( room ) + " vertices" );
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m_vertexroom = room;
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return true;
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}
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bool
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terrain_mesh_arena::grow_indices( std::uint32_t const Wanted ) {
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auto room { m_indexroom };
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while( ( room < m_indexroom + Wanted ) && ( room < mostindices ) ) { room *= 2; }
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if( room <= m_indexroom ) { return false; }
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auto grown { std::make_unique<gl::buffer>() };
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grown->allocate(
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gl::buffer::COPY_WRITE_BUFFER,
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static_cast<GLsizeiptr>( room ) * indexwidth(), GL_DYNAMIC_DRAW );
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m_indexbuffer->bind( gl::buffer::COPY_READ_BUFFER );
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::glCopyBufferSubData( GL_COPY_READ_BUFFER, GL_COPY_WRITE_BUFFER, 0, 0,
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static_cast<GLsizeiptr>( m_indexroom ) * indexwidth() );
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gl::buffer::unbind( gl::buffer::COPY_READ_BUFFER );
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gl::buffer::unbind( gl::buffer::COPY_WRITE_BUFFER );
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gl::buffer::unbind( gl::buffer::ELEMENT_ARRAY_BUFFER );
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m_indexbuffer = std::move( grown );
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m_vao->bind();
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m_vao->setup_ebo( *m_indexbuffer );
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m_freeindices.give( m_indexroom, room - m_indexroom );
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WriteLog( "Terrain: index buffer grown from " + std::to_string( m_indexroom ) + " to "
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+ std::to_string( room ) + " indices" );
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m_indexroom = room;
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return true;
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}
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terrain_mesh_arena::piece
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terrain_mesh_arena::put( quantizedmesh::reader::tile_data const &Tile ) {
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piece where;
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if( ( false == m_vao.has_value() ) || ( nullptr == m_vertexbuffer ) || ( true == Tile.vertices.empty() ) || ( true == Tile.indices.empty() ) ) {
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return where;
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}
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if( Tile.vertices.size() > vertexlimit() ) { return where; }
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auto const vertices { static_cast<std::uint32_t>( Tile.vertices.size() ) };
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auto const indices { static_cast<std::uint32_t>( Tile.indices.size() ) };
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std::uint32_t atvertex { 0 };
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if( false == m_freevertices.take( vertices, atvertex ) ) {
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if( false == grow_vertices( vertices ) ) { return where; }
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if( false == m_freevertices.take( vertices, atvertex ) ) { return where; }
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}
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std::uint32_t atindex { 0 };
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if( false == m_freeindices.take( indices, atindex ) ) {
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if( false == grow_indices( indices ) ) {
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m_freevertices.give( atvertex, vertices );
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return where;
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}
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if( false == m_freeindices.take( indices, atindex ) ) {
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m_freevertices.give( atvertex, vertices );
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return where;
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}
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}
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// this vertex array first: which element buffer is bound belongs to it, and writing indices
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// with the scenery's array bound would take its own indices away
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m_vao->bind();
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m_vertexbuffer->upload(
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gl::buffer::ARRAY_BUFFER, Tile.vertices.data(),
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static_cast<int>( atvertex * sizeof( quantizedmesh::render_vertex ) ),
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static_cast<GLsizeiptr>( vertices ) * sizeof( quantizedmesh::render_vertex ) );
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// the indices are stored as the tile had them, counted from its own first vertex; where the tile
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// sits in the buffer is given to the draw as its base vertex
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if( true == m_wideindices ) {
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m_indexbuffer->upload(
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gl::buffer::ELEMENT_ARRAY_BUFFER, Tile.indices.data(),
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static_cast<int>( atindex * sizeof( std::uint32_t ) ),
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static_cast<GLsizeiptr>( indices ) * sizeof( std::uint32_t ) );
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}
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else {
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m_narrow.assign( Tile.indices.begin(), Tile.indices.end() );
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m_indexbuffer->upload(
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gl::buffer::ELEMENT_ARRAY_BUFFER, m_narrow.data(),
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static_cast<int>( atindex * sizeof( std::uint16_t ) ),
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static_cast<GLsizeiptr>( indices ) * sizeof( std::uint16_t ) );
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}
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unbind();
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where.firstvertex = atvertex;
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where.vertices = vertices;
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where.firstindex = atindex;
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where.indices = indices;
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m_verticesheld += vertices;
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m_indicesheld += indices;
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return where;
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}
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void
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terrain_mesh_arena::take( piece &Piece ) {
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if( false == Piece.held() ) { return; }
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m_freevertices.give( Piece.firstvertex, Piece.vertices );
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m_freeindices.give( Piece.firstindex, Piece.indices );
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m_verticesheld -= Piece.vertices;
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m_indicesheld -= Piece.indices;
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Piece = piece {};
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}
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