5 Commits

Author	SHA1	Message	Date
maj00r	951a54cde7	Bake only the ground a heightfield replaces, at a step suited to each triangle ... Three changes to what goes into a baked heightfield and how it meets the geometry drawn beside it. The heightfield held every triangle laid in it, including those it does not replace and that are therefore drawn as geometry too - so they were drawn twice, and a roof or a bridge deck left in it bent the ground. Now the first pass lays everything and decides what is replaced; the second lays the replaced triangles together with the neighbours that support them - the owners of the corner samples of the cells around them, without which those cells are not drawn - and only that is written. A first attempt that repeated passes, dropping whatever bordered a hole, eroded the whole terrain away one ring per pass: the edge of the ground is always a hole. The replaced triangles stay replaced in the second pass, since their supports are all there and they have fewer rivals. The triangles bake no longer keep in memory; they wait in a spill file beside the heightfield while the scenery parses. Triangles were refused for an edge longer than 200 m, meant for a water plane under the whole map. On baltyk and tomaszewo that refused thousands of ordinary fields of a hand-modelled terrain, and nothing there comes near a whole-map plane. Only triangles standing on their edge - walls, trees, fences - are refused now. The bake log says why the triangles not replaced are not: standing on edge, too small, under other surfaces, next to a hole. Hand-modelled terrain has triangles hundreds of metres long, elevation-model terrain small ones along the line, and one grid step either loses the detail or samples a field every metre. A bake now writes three heightfields a factor of four apart - <scenario>.ehf, <scenario>.1.ehf, <scenario>.2.ehf - and each triangle goes to the coarsest one that still puts sixteen samples along its longest edge, and to every coarser one too, so the coarsest holds all the ground and a triangle at the edge of a finer field can be replaced by a coarser field beneath it. All of them are picked up together, and a missing or stale one sends the whole set to be baked again. Where fields overlap each other or the geometry, the depth test decides: the terrain is drawn with a polygon offset, negative for the reversed depth buffer and larger for each coarser field, instead of being lowered by 2 cm - so geometry lying on the ground wins at any distance and on any slope, and a finer field wins over a coarser one. On tomaszewo the heightfields went from 176 MB to 10 MB, the load that bakes them from 5:16 to 3:11 and its peak memory from 15.7 GB to 8.5 GB - the scenery alone takes 8.0 - while the triangles replaced went from 37,130 to 40,402. On baltyk from 19 MB to 2 MB, with 6,670 triangles replaced against 4,040.	2026-09-17 17:24:25 +02:00
maj00r	d2a5f284e3	Draw terrain one call per level, from texture arrays, culled to the view ... Each resident tile had a height texture and a material texture of its own, uploaded with glTexImage2D, and was drawn once per material it held with every other material's fragments discarded, all of them whether in view or not. Thousands of draws a frame. Now the tiles of a level live in one pair of texture arrays (terrain_tile_pool), a layer per tile. A pool starts at sixteen layers and doubles when full, copying what it holds on the gpu, so a level takes only the memory its tiles need; uploads go through a pixel buffer orphaned for each tile. The ground textures of every material are gathered into one sRGB array with mipmaps (terrain_ground) - drawn into it layer by layer by a small shader once the engine has each texture ready, since the scenery's textures are compressed and cannot be blitted - with a table of placeholder colours and measured tiling beside it. Each frame the tiles in range are tested against the frustum by bounding sphere and gathered per level into a buffer texture of instance data, and each level is drawn in one instanced call. The fragment shader reads the four samples around it, drops the cell when any of them carries no ground - exactly the rule the bake already assumed - and blends the ground textures of their materials by distance, so material boundaries follow the samples smoothly instead of stepping along triangle edges. State the copy pass changes is captured and put back, and the texture unit cache is reset after raw binds, so the rest of the renderer finds things as it left them. On baltyk: all 30 materials land in the array, 663 of the 1120 tiles in range are drawn after culling, and a frame is at most six terrain draws. The residency line in the log now says how many tiles in range were drawn.	2026-09-17 16:28:43 +02:00
maj00r	be4d691ae2	Choose terrain levels from what the screen can resolve ... Levels changed at fixed distances - 512 m, 1 km, 2 km and on - whatever the window, the field of view or the zoom. Now a level is used out to the distance where one of its sample spacings covers terraindetail pixels on screen, 3 by default, which follows from the viewport height and the vertical field of view with the zoom applied; each level doubles the spacing, so each doubles the distance. Zooming in or a taller window pushes detail further, a coarser setting pulls it in. The finest range never drops below four tile sides, which the morphing needs to close the seams. Levels and morphing both follow the finest range the last scan used, so they always agree, and a change of more than a percent - a zoom, a resize - triggers a rescan. tools/terraincook/seamcheck.py now also tries finest ranges of 5.7 and 11.3 tiles, and finds no gap in any of them. terraindetail is in the ini and on a slider in the debug panel; the panel's level table and the residency line in the log show the resulting ranges. On baltyk the current window works out to 484 m, so the 512 m minimum applies and nothing changes by default; a scenery setting terraindetail 1 got 1349 m, and the samples on the gpu went from 3 MB to 10 MB with it.	2026-09-17 16:11:41 +02:00
maj00r	37ab4a35b3	Morph terrain levels into each other so neighbours meet without cracks ... Tiles drawn at the same level met exactly, but a finer tile beside a coarser one has samples on their shared edge that the coarser one skips, and the ground between them could open up. This closes the gap the standard way (CDLOD): each vertex slides towards the next coarser level as its distance nears the end of its level's range, so that by the end of the band a tile is, vertex for vertex, the coarser tile beyond it. Levels also stop popping when they change. The mip chain is point sampled, so the next level's grid is this level's even samples. An odd vertex slides onto its even neighbour and takes its height, and the grid, whose diagonals all run the same way at every level, collapses exactly into the coarser triangulation. No second texture and no neighbour information is needed; the morph is computed per vertex from its distance to the camera, the same distance the level is chosen by. Two things the geometry demands, both settled by tools/terraincook/seamcheck.py, which walks random camera positions over 128 m, 256 m and 12.8 km tiles and counts every edge vertex where the finer side has not finished morphing or the coarser side has started: - the band ends a rescan's worth of travel (a quarter tile) short of the level's range. Levels are chosen where the camera stood at the last rescan, the morph follows it every frame, and a band ending at the range itself left gaps at every level boundary; - the band is a fifth of the range wide, and level ranges are counted in tiles (four for the finest level) rather than fixed metres, which keeps the coarser tile's band clear of any edge a finer tile reaches, whatever the tile size. The script finds no gap with these values. In the game on baltyk, a low view differs from the unmorphed shader only in a strip of distant ground at the horizon, and nearer than the first band the picture is identical. The cooker's comment claimed tile seams were identical at every level; that held only for neighbours at the same level, and now says so.	2026-09-17 15:58:05 +02:00
maj00r	2660d14565	Stream the scenery: a baked terrain heightfield, a logic container, and prefabs ... Today's work on the binary scene format plan (binary-scene-format-plan.md), from the first measurement to a terrain that bakes itself on first run and streams from a thread. The step-by-step history is kept on backup/scene-streaming-format-presquash-0916. Measuring first. -loadprofile times a scenery load by stage and by node kind and reports node counts and resident memory. On l204 terrain is 95% of the bytes and 99.8% of the nodes; on quarkmce2007 vehicles, not models, dominate what is left. The terrain turned out to be a heightfield in all but name, a ribbon covering 12% of its bounding box. The heightfield. scene/heightfieldformat.h is the .ehf layout: Morton-ordered tiles of 128 samples with one shared edge sample, a point-sampled mip chain, zstd per tile, a nodata sentinel, a material palette with a measured tiling per material, and a stamp of the rules that decided what counted as terrain. scene/heightfieldreader.h reads it for the tool, the renderer and the loader alike, and scene/terraincooker.h writes it, shared by the terraincook tool and the engine so a first-run bake is the file the tool would have made. The cooker rasterises every triangle where it is drawn (through scene::place_in_world, the placement the region applies too), keeps an upper surface laid within half a metre over another and the lower of two further apart, and then asks each triangle whether the heightfield shows it: laid, reaching a sample, keeping nearly all it claimed, and with the ground around it drawn at every level out to 2 km. Baking on first run. simulation/terrainbake bakes <scenario>.ehf the first time a scenery is opened, choosing the grid step from the first 200,000 vertices, and on later loads leaves out the triangles its node table says the heightfield shows. Everything else - trees, grass tufts, gantries, bridge decks - is drawn as written, so a bad bake can at worst draw something twice, and the heightfield sits 2 cm under the triangles so the original wins there. Nodes are keyed by file, line, include parameters and placement; an edited file changes its keys and those nodes are drawn again. A bake under older rules, or without its table, is thrown away and redone. A launcher copy named $scenario shares the scenario's files. -nobaketerrain shows the triangles as written. A scenery can still name hand-cooked fields, several at different steps. Drawing and streaming. rendering/terrainclipmap draws resident tiles at the mip level their distance earns, deriving the grid from gl_VertexID and texturing in world space with the scenery's own materials. rendering/terraintileloader reads and decodes tiles on a thread of its own; the renderer rescans what is in range only after moving a quarter of a tile, asks for what is missing nearest first, uploads at most 32 tiles a frame, drops arrivals the camera has moved past, and keeps drawing a tile at the level it has until the right one arrives. The terrain has its own range, terrainrange in the ini and a slider in the debug panel, 20 km by default and independent of basedrawrange; the far plane of an ordinary view is pushed out to it. The debug panel shows the range, tiles in view, on the gpu, wanted and queued, and how many sit at each level. Events. The event queue moved out of the events into a binary heap with a deterministic tie-break, and an event is handed its activator instead of storing it, so basic_event is a definition and nothing else. The logic container. scene/logicformat.h and scene/logiccontainer write a scenery's events, their targets and sibling chains as flat, deterministic arrays with a schema hash that refuses a mismatched build. simulation/logiccook cooks it from the loaded state whenever it is missing, stale or unreadable, reads it straight back to check it, and resolves each target to a position in the registry its event kind searches. -cooklogic forces a cook, -verifylogic only checks. Nothing reads it at load yet. Prefabs. scene/prefab describes a signal by the aspects it can show - lights, speeds, animation channels, a sound - instead of pasting an .inc per variant, and expands an instance to ordinary scenery text. Tried on a light signal and a shape signal. Screenshots without a person present: -shot x,y,z[,yaw[,pitch]], -shotsettle, -shotstay.	2026-09-16 23:18:09 +02:00