https://vidar.games/Game rendering and simulation techniques, rebuilt from open-source code and shown side by side.Thu, 12 Nov 2026 14:25:55 +0000https://vidar.games/posts/ltc-area-lights/https://vidar.games/posts/ltc-area-lights/Thu, 12 Nov 2026 13:00:00 +0000A video screen, two light tubes and a tilted triangle light this room as real polygons. On polished tiles the screen reflects as a sharp picture, on rough tiles as a soft glow.https://vidar.games/posts/anime-crystal/https://vidar.games/posts/anime-crystal/Thu, 12 Nov 2026 00:02:00 +0000These gems have no transparency and no real refraction. The sparkle is two layers of triangle noise, looked up through a bent view vector and lit by the light behind the face.https://vidar.games/posts/sky-atmosphere/https://vidar.games/posts/sky-atmosphere/Wed, 11 Nov 2026 21:00:00 +0000A sunrise over seven ridge lines, built from four lookup tables. The far ridges sink into the sky because the sky and the distance haze come from the same scattering maths.https://vidar.games/posts/oot-ground-fog/https://vidar.games/posts/oot-ground-fog/Wed, 11 Nov 2026 18:00:00 +0000Ground fog that opens when someone walks through it, curls into the gap, then slowly closes again. Underneath is a 2D fluid sim on a 256 x 256 grid, drawn as 16 flat planes.https://vidar.games/posts/strand-hair-sim/https://vidar.games/posts/strand-hair-sim/Wed, 11 Nov 2026 15:30:00 +00006,000 strands on a turning head. On the left only gravity and length hold them, and the hair drops straight through the skull. On the right, shape constraints and two spheres keep the style.https://vidar.games/posts/pbd-fluid/https://vidar.games/posts/pbd-fluid/Wed, 11 Nov 2026 13:00:00 +000029,160 particles fall as an 8 m column into a tank with a baffle. Without a density constraint they fold into one flat sheet. With it they splash over the baffle and keep their volume.https://vidar.games/posts/lens-flare-occlusion/https://vidar.games/posts/lens-flare-occlusion/Wed, 11 Nov 2026 00:00:00 +0000A low sun behind a line of pines. The lens flare switches off when a trunk covers the sun and comes back when it clears, decided by one depth texel per frame.https://vidar.games/posts/csg-booleans/https://vidar.games/posts/csg-booleans/Tue, 10 Nov 2026 21:00:00 +0000A cube, a sphere and three cylinders. Four boolean cuts on plain triangle meshes, each one a BSP tree clipping another BSP tree.https://vidar.games/posts/grass-bending/https://vidar.games/posts/grass-bending/Tue, 10 Nov 2026 18:00:00 +0000A stone ball rolls through 48,000 grass billboards. Every tuft checks up to 16 benders in its vertex shader and leans away from any it is inside.https://vidar.games/posts/marching-cubes-terraforming/https://vidar.games/posts/marching-cubes-terraforming/Tue, 10 Nov 2026 15:30:00 +0000A glowing brush digs a cave into a hillside, then builds an arch out of thin air. Underneath: byte voxels and marching cubes, re-meshed one 16-voxel chunk at a time.https://vidar.games/posts/projected-mesh-decals/https://vidar.games/posts/projected-mesh-decals/Tue, 10 Nov 2026 13:02:00 +0000A flat decal quad floats off a round pillar, sinks into steps and flickers on the floor. driven-decals cuts a new mesh from the surfaces inside the decal box instead, so the paint follows every step.https://vidar.games/posts/ssr/https://vidar.games/posts/ssr/Tue, 10 Nov 2026 00:01:00 +0000A polished floor often reflects a baked cubemap, so a rolling ball never shows up in it. Screen-space reflections march rays through the depth buffer and reuse the frame already drawn.https://vidar.games/posts/gpu-boids/https://vidar.games/posts/gpu-boids/Mon, 09 Nov 2026 21:01:00 +00004,096 fish, same seed, same moving target. Left: each fish only steers at the target, and they pile into a clump. Right: three local rules, checked against every other fish each step, make a school.https://vidar.games/posts/volumetric-fog/https://vidar.games/posts/volumetric-fog/Mon, 09 Nov 2026 18:02:00 +0000Same ruined hall, same sun, same frame. Left: the usual height fog, one grey layer. Right: the fog is stored in 1.8 million cells, each lit and shadowed on its own, so light shafts appear.https://vidar.games/posts/gpu-cloth/https://vidar.games/posts/gpu-cloth/Mon, 09 Nov 2026 15:30:00 +0000A cloth that waves from a sine wave looks fine until something touches it. A mass-spring grid on the GPU has 4,096 nodes, each pulled by up to 8 neighbours, so a ball shoves it out of the way.https://vidar.games/posts/ssgi/https://vidar.games/posts/ssgi/Mon, 09 Nov 2026 13:01:00 +0000A spotlight hits a red wall and only the wall gets lit. Screen-space GI shoots rays from every pixel, reads the colour they hit on screen, and spills that red onto the floor, boxes and ceiling.https://vidar.games/posts/wind-field-simulation/https://vidar.games/posts/wind-field-simulation/Sun, 08 Nov 2026 21:00:00 +0000Sine wind sways every blade in step. A wind field remembers where air was pushed: a blast spreads out, a rolling rock leaves a wake, a vortex swirls and then fades.https://vidar.games/posts/temporal-aa/https://vidar.games/posts/temporal-aa/Sun, 08 Nov 2026 18:01:00 +0000Thin wires and a checker floor shimmer at 1 sample per pixel. TAA shifts the camera by under a pixel every frame and blends each frame with the last.https://vidar.games/posts/dual-quaternion-skinning/https://vidar.games/posts/dual-quaternion-skinning/Sun, 08 Nov 2026 15:30:00 +0000Same arm, same two bones, same weights. Left: linear blend skinning. Twist the forearm 180° and the joint pinches to nothing. Right: dual quaternion skinning. Volume holds at 99.9%.https://vidar.games/posts/hiz-chunk-culling/https://vidar.games/posts/hiz-chunk-culling/Sun, 08 Nov 2026 13:02:00 +000040,000 small objects in a city of grey blocks. Left draws everything inside the view: 12,364. Right tests chunks, then objects, against a Hi-Z depth pyramid: 1,953.https://vidar.games/posts/pcss-soft-shadows/https://vidar.games/posts/pcss-soft-shadows/Sun, 08 Nov 2026 00:00:00 +0000Real shadows are sharp where an object touches the ground and soft where it is far away. A single shadow-map test can't do that. PCSS can, from the same shadow map.https://vidar.games/posts/vxgi-cone-tracing/https://vidar.games/posts/vxgi-cone-tracing/Sat, 07 Nov 2026 21:00:00 +0000One light moving through a closed room. Left of the line: direct light only. Right: voxel cone tracing adds the bounce, so the red and green walls tint the floor, ceiling and boxes.https://vidar.games/posts/interior-mapping/https://vidar.games/posts/interior-mapping/Sat, 07 Nov 2026 18:00:00 +00001,490 rooms in this city, and not one of them is geometry. Each window is a flat quad. Per pixel, a ray goes into an imagined box and picks floor, ceiling or wall.https://vidar.games/posts/motion-matching/https://vidar.games/posts/motion-matching/Sat, 07 Nov 2026 15:30:00 +0000Same stick input, same 5 minutes of mocap. Left: idle, walk and run clips with crossfades. Right: motion matching searches the whole take for the best next frame.https://vidar.games/posts/xegtao/https://vidar.games/posts/xegtao/Sat, 07 Nov 2026 13:01:00 +0000Same shot three times: no AO, a basic 16-sample SSAO, and Intel's XeGTAO ported from HLSL to three.js.https://vidar.games/posts/animated-crowd-instancing/https://vidar.games/posts/animated-crowd-instancing/Sat, 07 Nov 2026 00:00:00 +0000Left: 300 creatures, each its own skinned mesh and skeleton, 300 draw calls. Right: 5,000 of the same creature in 1 draw call, each wriggling on its own beat.https://vidar.games/posts/dense-particle-tricks/https://vidar.games/posts/dense-particle-tricks/Fri, 06 Nov 2026 21:00:00 +0000Same 400 particles on both halves, same emitters, same motion. Left: plain round sprites. Right: six cheap tricks stacked, the kind PS2-era effects leaned on.https://vidar.games/posts/wang-tile-terrain/https://vidar.games/posts/wang-tile-terrain/Fri, 06 Nov 2026 18:00:00 +0000Same grass and water grid on both halves, 16 pixel tiles each. Left: each cell checks 4 neighbours. Right: 2-corner Wang tiles, so every corner gets a curved shore.https://vidar.games/posts/gpu-particle-shatter/https://vidar.games/posts/gpu-particle-shatter/Fri, 06 Nov 2026 15:30:00 +0000One rendered frame of a room becomes 115,200 GPU particles. Left: the hit throws them through the floor. Right: a voxel grid built from the particles stops them, and they pile up.https://vidar.games/posts/parkour-momentum/https://vidar.games/posts/parkour-momentum/Fri, 06 Nov 2026 13:00:00 +0000Same rooftop course, same jump presses. Left: every move is its own state, and speed resets at each one. Right: speed carries through the vault, jump, landing and wall climb. Finish: 5.30 s vs 3.93 s.