Crafter.Graphics/examples/RTMultiShadow/miss.wgsl
catbot f7fc441253 test(webgpu-rt): RTMultiShadow example exercising N shadow rays/pixel/bounce (#30)
Five pillars, four colored point lights; closest-hit emits one shadow ray
per light from the same invocation (raysPerPixel = 4, maxDepth = 2), so up
to four rays per pixel rtAccumulate in a single SHADE pass — the contention
case #30 exists for. Each pillar casts four separable colored shadows; an
accumulator race or capacity drop shows as flickering dark noise or a
missing shadow color. Two frames a second apart diff at 2 px / 1.85 M
(last-ulp CAS ordering), confirming no lost updates.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-06-09 22:45:33 +00:00

14 lines
648 B
WebGPU Shading Language

// RTMultiShadow miss (runs in SHADE). Shadow miss → that light is visible
// from the surface, so add its pending contribution; up to LIGHT_COUNT of
// these resolve for the same pixel in one pass (atomic rtAccumulate, #30).
// Primary miss → near-black night sky so the colored lighting carries the
// frame.
fn miss_main(ray: RayDesc, payload: ptr<function, Payload>) {
if ((*payload).shadowRay == 1u) {
rtAccumulate((*payload).color);
return;
}
let t = clamp(ray.direction.y * 0.5 + 0.5, 0.0, 1.0);
rtAccumulate(mix(vec3<f32>(0.010, 0.012, 0.022),
vec3<f32>(0.030, 0.040, 0.075), t));
}