diff --git a/examples/README.md b/examples/README.md index ed4cb2a..1bd619d 100644 --- a/examples/README.md +++ b/examples/README.md @@ -106,3 +106,15 @@ barrier WebGPU only provides between submits (or between passes), never within a single compute pass. WebGPU/DOM only; the same chain is wireable on Vulkan today via an offscreen HDR heap image + a composite `RenderPass` (the present path records passes generically and barriers between them). + +### [RTMultiShadow](RTMultiShadow/) +Multi-light shadowing through the wavefront RT pipeline (issue #30). Five +pillars on a checkered ground, four colored point lights; the closest-hit +emits one shadow ray **per light** from the same invocation, so up to four +rays per pixel resolve in a single SHADE pass. Exercises both halves of +the >1-ray-per-pixel-per-bounce widening: the atomic `rtAccumulate` +(per-channel f32 CAS — concurrent same-pixel adds don't race) and +`RTPass::raysPerPixel` (scales the ray/hit/payload buffers so the +per-light emits aren't capacity-dropped). Any regression shows up as +flickering dark noise or a missing shadow color in the overlap regions. +WebGPU/DOM only. diff --git a/examples/RTMultiShadow/closesthit.wgsl b/examples/RTMultiShadow/closesthit.wgsl new file mode 100644 index 0000000..98671bc --- /dev/null +++ b/examples/RTMultiShadow/closesthit.wgsl @@ -0,0 +1,82 @@ +// RTMultiShadow closest-hit (runs in SHADE). The multi-light counterpart +// of RTStress: EVERY light emits its own shadow ray from this single +// invocation, so several rays for the same pixel resolve in the next SHADE +// pass — exactly the contention the atomic rtAccumulate exists for (#30). +// Before the atomic accumulator their rtAccumulate calls raced (lost +// updates → flickering dark noise); before RTPass::raysPerPixel the extra +// rays were silently dropped by the capacity guard. The host sets +// raysPerPixel = LIGHT_COUNT so every emit fits the bounce. +// +// Payload declared here so the assembler sees it before wfPayload / SHADE. +struct Payload { + color: vec3, // shadow ray: pending direct contribution + shadowRay: u32, // 0 primary, 1 shadow +}; + +// Point lights, color premultiplied with intensity; 1/d² falloff at shade +// time. Four distinct hues so each occluder casts four separable shadows — +// any accumulator race or dropped shadow ray is immediately visible as +// noise / a missing color in the overlap regions. +const LIGHT_COUNT: u32 = 4u; +struct Light { + pos: vec3, + color: vec3, +}; +var LIGHTS: array = array( + Light(vec3( 14.0, 9.0, 2.0), vec3(250.0, 205.0, 140.0)), // warm white + Light(vec3(-13.0, 8.0, 7.0), vec3(235.0, 45.0, 30.0)), // red + Light(vec3( 3.0, 8.0, -14.0), vec3( 55.0, 225.0, 105.0)), // green + Light(vec3( -5.0, 10.0, 13.0), vec3( 65.0, 105.0, 250.0)), // blue +); + +const AMBIENT_COLOR: vec3 = vec3(0.030, 0.034, 0.045); + +// Ground (customIndex 0) is a subtle checker so the colored shadows read; +// pillars hash their instance index like RTStress. +fn surfaceAlbedo(customIndex: u32, worldPos: vec3) -> vec3 { + if (customIndex == 0u) { + let cx = u32(floor(worldPos.x * 0.25 + 100.0)); + let cz = u32(floor(worldPos.z * 0.25 + 100.0)); + return mix(vec3(0.60), vec3(0.76), f32((cx + cz) & 1u)); + } + let h = customIndex * 2654435761u; + return vec3( + 0.45 + 0.5 * f32((h >> 0u) & 255u) / 255.0, + 0.45 + 0.5 * f32((h >> 8u) & 255u) / 255.0, + 0.45 + 0.5 * f32((h >> 16u) & 255u) / 255.0); +} + +fn closesthit_main(ray: RayDesc, hit: HitInfo, payload: ptr) { + let meshRec = meshRecords[tlasEntries[hit.instanceId].blasMeshIdx]; + let verts = _rtFetchTri(meshRec, hit.primitiveId); + let nObj = normalize(cross(verts[1] - verts[0], verts[2] - verts[0])); + let nWorld = normalize(vec3( + dot(hit.objectToWorldR0.xyz, nObj), + dot(hit.objectToWorldR1.xyz, nObj), + dot(hit.objectToWorldR2.xyz, nObj))); + + let worldPos = ray.origin + ray.direction * hit.t; + let nFacing = select(-nWorld, nWorld, dot(nWorld, -ray.direction) > 0.0); + let albedo = surfaceAlbedo(hit.customIndex, worldPos); + + rtAccumulate(albedo * AMBIENT_COLOR); + + // One shadow ray PER LIGHT from this one closest-hit invocation. All of + // them carry the same pixel; the ones that miss (light visible) each + // rtAccumulate their light's contribution in the same SHADE pass. + let shadowOrigin = worldPos + nFacing * 0.05; + for (var i: u32 = 0u; i < LIGHT_COUNT; i = i + 1u) { + let toLight = LIGHTS[i].pos - shadowOrigin; + let dist = length(toLight); + let dir = toLight / dist; + let nDotL = dot(nFacing, dir); + if (nDotL <= 0.0) { continue; } + var sp: Payload; + sp.color = albedo * LIGHTS[i].color * (nDotL / (dist * dist)); + sp.shadowRay = 1u; + // tMax stops at the light so geometry beyond it can't occlude. + rtEmitRay(shadowOrigin, 0.01, dir, dist, + RT_FLAG_SKIP_CLOSEST_HIT | RT_FLAG_TERMINATE_ON_FIRST_HIT, + 0xFFu, 0u, 0u, sp); + } +} diff --git a/examples/RTMultiShadow/main.cpp b/examples/RTMultiShadow/main.cpp new file mode 100644 index 0000000..6176650 --- /dev/null +++ b/examples/RTMultiShadow/main.cpp @@ -0,0 +1,210 @@ +// RTMultiShadow — multi-light shadowing through the wavefront RT pipeline +// (issue #30). Five pillars on a checkered ground, lit by four colored +// point lights; the closest-hit emits one shadow ray PER LIGHT from the +// same invocation, so up to four rays per pixel resolve in a single SHADE +// pass. That requires both halves of #30: +// - atomic rtAccumulate — the concurrent per-pixel adds don't race; +// - RTPass::raysPerPixel — the ray/hit/payload buffers hold 4·W·H rays +// per bounce, so none of the per-light emits get capacity-dropped. +// Each pillar casting four differently-colored shadows is the visual +// proof; any lost accumulate (race) or dropped ray (capacity) shows up as +// flickering dark noise / a missing shadow color. +// +// WebGPU/DOM only — the wavefront tracer is the WebGPU software RT path. + +#ifndef CRAFTER_GRAPHICS_WINDOW_DOM +int main() { return 0; } // native path is hardware RT; out of scope here +#else + +import Crafter.Graphics; +import Crafter.Math; +import Crafter.Event; +import std; + +using namespace Crafter; +namespace fs = std::filesystem; + +namespace { + // Must match LIGHT_COUNT in closesthit.wgsl — it is the raysPerPixel + // budget the RTPass is configured with. + constexpr std::uint32_t kLightCount = 4; + + struct CameraGPU { + float origin[3]; float pad0; + float right[3]; float tanHalf; + float up[3]; float aspect; + float forward[3]; float pad1; + }; + static_assert(sizeof(CameraGPU) == 64); + + // Axis-aligned box: 8 corners between mn and mx, same winding as the + // RTStress unit cube. + std::array, 8> BoxVerts(float mnx, float mny, float mnz, + float mxx, float mxy, float mxz) { + return {{ + {mnx, mny, mnz}, {mxx, mny, mnz}, {mxx, mxy, mnz}, {mnx, mxy, mnz}, + {mnx, mny, mxz}, {mxx, mny, mxz}, {mxx, mxy, mxz}, {mnx, mxy, mxz}, + }}; + } + // Mesh::Build takes mutable spans, so this can't be constexpr. + std::array kBoxIndices {{ + 0,1,2, 0,2,3, 5,4,7, 5,7,6, 4,0,3, 4,3,7, + 1,5,6, 1,6,2, 4,5,1, 4,1,0, 3,2,6, 3,6,7, + }}; +} + +int main() { + std::println("[RTMultiShadow] {} lights, one shadow ray per light per pixel", kLightCount); + + Device::Initialize(); + static Window window(1280, 720, "RTMultiShadow"); + auto cmd = window.StartInit(); + + DescriptorHeapWebGPU heap; + heap.Initialize(/*images*/ 1, /*buffers*/ 2, /*samplers*/ 1); + + std::array shaders {{ + WebGPUShader(fs::path("raygen.wgsl"), "raygen_main", WebGPURTStage::Raygen), + WebGPUShader(fs::path("miss.wgsl"), "miss_main", WebGPURTStage::Miss), + WebGPUShader(fs::path("closesthit.wgsl"), "closesthit_main", WebGPURTStage::ClosestHit), + WebGPUShader(fs::path("resolve.wgsl"), "resolve_main", WebGPURTStage::Resolve), + }}; + ShaderBindingTableWebGPU sbt; + sbt.Init(shaders); + + std::array raygenGroups {{ { .type = RTShaderGroupType::General, .generalShader = 0 } }}; + std::array missGroups {{ { .type = RTShaderGroupType::General, .generalShader = 1 } }}; + std::array hitGroups {{ { .type = RTShaderGroupType::TrianglesHitGroup, .closestHitShader = 2 } }}; + + // One user binding: the camera storage buffer at @group(3). + std::array bindings {{ + { .group = 3, .binding = 0, .kind = UICustomBindingKind::Buffer, .pushOffset = 0 }, + }}; + + PipelineRTWebGPU pipeline; + pipeline.Init(cmd, raygenGroups, missGroups, hitGroups, sbt, bindings); + + // ── Meshes: a large ground slab and a pillar (origin at its base). ── + static auto groundVerts = BoxVerts(-30.0f, -1.0f, -30.0f, 30.0f, 0.0f, 30.0f); + static auto pillarVerts = BoxVerts(-0.8f, 0.0f, -0.8f, 0.8f, 6.0f, 0.8f); + static Mesh ground, pillar; + ground.Build(groundVerts, kBoxIndices, cmd); + pillar.Build(pillarVerts, kBoxIndices, cmd); + + // ── Camera buffer + handle array. ───────────────────────────────── + WebGPUBuffer cameraBuf; + cameraBuf.Create(1); + static std::array userHandles { cameraBuf.handle }; + + // ── Instances: ground (customIndex 0) + five pillars. ───────────── + struct Placement { float x, z; }; + static constexpr std::array kPillars {{ + { 0.0f, 0.0f }, { 5.0f, 5.0f }, { -5.0f, 5.0f }, { 5.0f, -5.0f }, { -5.0f, -5.0f }, + }}; + static std::vector renderers; + renderers.reserve(1 + kPillars.size()); + auto addInstance = [&](std::uint64_t blasAddr, float x, float z) { + renderers.emplace_back(); + RenderingElement3D& r = renderers.back(); + auto& tx = r.instance.transform.matrix; + tx[0][0] = 1; tx[0][1] = 0; tx[0][2] = 0; tx[0][3] = x; + tx[1][0] = 0; tx[1][1] = 1; tx[1][2] = 0; tx[1][3] = 0; + tx[2][0] = 0; tx[2][1] = 0; tx[2][2] = 1; tx[2][3] = z; + r.instance.instanceCustomIndex = static_cast(renderers.size() - 1); + r.instance.mask = 0xFF; + r.instance.instanceShaderBindingTableRecordOffset = 0; + r.instance.flags = kRTGeometryInstanceForceOpaque; + r.instance.accelerationStructureReference = blasAddr; + RenderingElement3D::Add(&r); + }; + addInstance(ground.blasAddr, 0.0f, 0.0f); + for (const auto& p : kPillars) addInstance(pillar.blasAddr, p.x, p.z); + RenderingElement3D::BuildTLAS(cmd, 0); + + window.descriptorHeap = &heap; + window.FinishInit(); + + RTPass rtPass(&pipeline); + rtPass.handlesPtr = userHandles.data(); + rtPass.handlesCount = static_cast(userHandles.size()); + rtPass.maxDepth = 2; // primary + shadow + rtPass.raysPerPixel = kLightCount; // one shadow ray per light per pixel + window.passes.push_back(&rtPass); + + // ── Free camera framing the pillars from above one corner. ──────── + struct CamState { + Vector position; + float yaw; + float pitch; + } cam { + Vector{ 16.0f, 13.0f, 16.0f }, + 0.0f, 0.0f, + }; + { + // Aim at the scene centre, slightly above the ground. + Vector d { -cam.position.x, 2.0f - cam.position.y, -cam.position.z }; + const float len = std::sqrt(d.x*d.x + d.y*d.y + d.z*d.z); + cam.yaw = std::atan2(d.z, d.x); + cam.pitch = std::asin(d.y / len); + } + + Input::Map inputMap; + Input::Action& moveAct = inputMap.AddAction("Move", Input::ActionType::Vector2); + Input::Action& lookAct = inputMap.AddAction("Look", Input::ActionType::Vector2); + moveAct.bindings = { Input::WASDBind{ + Key(CrafterKeys::W), Key(CrafterKeys::S), Key(CrafterKeys::A), Key(CrafterKeys::D) } }; + lookAct.bindings = { Input::MouseDeltaBind{ 1.0f } }; + inputMap.Attach(window); + + const float kMoveSpeed = 14.0f; + const float kLookSens = 0.05f; + const float kDt = 1.0f / 60.0f; + + static int frames = 0; + EventListener camTick(&window.onBeforeUpdate, [&]() { + inputMap.Tick(); + cam.yaw += lookAct.vector2.x * kLookSens; + cam.pitch -= lookAct.vector2.y * kLookSens; + cam.pitch = std::clamp(cam.pitch, -1.55f, 1.55f); + + const float cp = std::cos(cam.pitch), sp = std::sin(cam.pitch); + const float cy = std::cos(cam.yaw), sy = std::sin(cam.yaw); + Vector forward { cp * cy, sp, cp * sy }; + Vector worldUp { 0.0f, 1.0f, 0.0f }; + Vector right { forward.y*worldUp.z - forward.z*worldUp.y, + forward.z*worldUp.x - forward.x*worldUp.z, + forward.x*worldUp.y - forward.y*worldUp.x }; + const float rLen = std::sqrt(right.x*right.x + right.y*right.y + right.z*right.z); + right.x /= rLen; right.y /= rLen; right.z /= rLen; + Vector up { right.y*forward.z - right.z*forward.y, + right.z*forward.x - right.x*forward.z, + right.x*forward.y - right.y*forward.x }; + + const float dx = moveAct.vector2.x * kMoveSpeed * kDt; + const float dy = moveAct.vector2.y * kMoveSpeed * kDt; + cam.position.x += right.x*dx + forward.x*dy; + cam.position.y += right.y*dx + forward.y*dy; + cam.position.z += right.z*dx + forward.z*dy; + + CameraGPU& g = cameraBuf.value[0]; + g.origin[0]=cam.position.x; g.origin[1]=cam.position.y; g.origin[2]=cam.position.z; g.pad0=0; + g.right[0]=right.x; g.right[1]=right.y; g.right[2]=right.z; + g.up[0]=up.x; g.up[1]=up.y; g.up[2]=up.z; + g.forward[0]=forward.x; g.forward[1]=forward.y; g.forward[2]=forward.z; + g.aspect = float(window.width) / float(window.height); + g.tanHalf = std::tan(70.0f * 3.14159265f / 360.0f); + g.pad1 = 0; + cameraBuf.FlushDevice(); + + if (++frames >= 60) { + std::println("[RTMultiShadow] {} lights x {} pillars rendering", kLightCount, kPillars.size()); + frames = 0; + } + }); + + window.Render(); + window.StartUpdate(); + window.StartSync(); + return 0; +} +#endif diff --git a/examples/RTMultiShadow/miss.wgsl b/examples/RTMultiShadow/miss.wgsl new file mode 100644 index 0000000..f3ed3bf --- /dev/null +++ b/examples/RTMultiShadow/miss.wgsl @@ -0,0 +1,14 @@ +// 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) { + 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(0.010, 0.012, 0.022), + vec3(0.030, 0.040, 0.075), t)); +} diff --git a/examples/RTMultiShadow/project.cpp b/examples/RTMultiShadow/project.cpp new file mode 100644 index 0000000..f26d05e --- /dev/null +++ b/examples/RTMultiShadow/project.cpp @@ -0,0 +1,46 @@ +import std; +import Crafter.Build; +namespace fs = std::filesystem; +using namespace Crafter; + +extern "C" Configuration CrafterBuildProject(std::span args) { + bool isWasm = false; + for (std::string_view a : args) { + if (a.starts_with("--target=") && a.find("wasm") != std::string_view::npos) { + isWasm = true; + break; + } + } + + std::vector graphicsArgs(args.begin(), args.end()); + Configuration* graphics = LocalProject({ + .projectFile = "../../project.cpp", + .args = graphicsArgs, + }); + + Configuration cfg; + cfg.path = "./"; + cfg.name = "RTMultiShadow"; + cfg.outputName = "RTMultiShadow"; + cfg.type = ConfigurationType::Executable; + if (isWasm) { + cfg.target = "wasm32-wasip1"; + cfg.defines.push_back({"CRAFTER_GRAPHICS_WINDOW_DOM", ""}); + cfg.compileFlags.push_back("-msimd128"); + } + ApplyStandardArgs(cfg, args); + cfg.dependencies = { graphics }; + + std::array ifaces = {}; + std::array impls = { "main" }; + cfg.GetInterfacesAndImplementations(ifaces, impls); + + if (isWasm) { + cfg.files.emplace_back(fs::path("raygen.wgsl")); + cfg.files.emplace_back(fs::path("closesthit.wgsl")); + cfg.files.emplace_back(fs::path("miss.wgsl")); + cfg.files.emplace_back(fs::path("resolve.wgsl")); + EnableWasiBrowserRuntime(cfg); + } + return cfg; +} diff --git a/examples/RTMultiShadow/raygen.wgsl b/examples/RTMultiShadow/raygen.wgsl new file mode 100644 index 0000000..e22e71f --- /dev/null +++ b/examples/RTMultiShadow/raygen.wgsl @@ -0,0 +1,35 @@ +// RTMultiShadow raygen (runs in GENERATE). Host-driven pinhole camera at +// @group(3) (groups 0..2 are reserved by the wavefront pipeline: +// 0 = WfParams, 1 = data heaps, 2 = indirect args). +struct Camera { + origin: vec3, + pad0: f32, + right: vec3, + tanHalf: f32, + up: vec3, + aspect: f32, + forward: vec3, + pad1: f32, +}; +@group(3) @binding(0) var camera : Camera; + +fn raygen_main(gid: vec3) { + if (gid.x >= wfParams.surfaceW || gid.y >= wfParams.surfaceH) { return; } + + let pixelf = vec2(f32(gid.x), f32(gid.y)); + let res = vec2(f32(wfParams.surfaceW), f32(wfParams.surfaceH)); + let uv = (pixelf + vec2(0.5)) / res; + let ndc = uv * 2.0 - vec2(1.0); + + let direction = normalize( + camera.right * (ndc.x * camera.aspect * camera.tanHalf) + + camera.up * (-ndc.y * camera.tanHalf) + + camera.forward); + + var p: Payload; + p.color = vec3(0.0); + p.shadowRay = 0u; + + rtEmitPrimaryRay(camera.origin, 0.01, direction, 100000.0, + 0u, 0xFFu, 0u, 0u, p); +} diff --git a/examples/RTMultiShadow/resolve.wgsl b/examples/RTMultiShadow/resolve.wgsl new file mode 100644 index 0000000..7f32dcf --- /dev/null +++ b/examples/RTMultiShadow/resolve.wgsl @@ -0,0 +1,7 @@ +// RTMultiShadow RESOLVE-stage tonemap: Reinhard + gamma 2.2 over the +// linear accumulator. Registered as a WebGPURTStage::Resolve shader. +fn resolve_main(coord: vec2, hdr: vec4) -> vec4 { + let mapped = hdr.rgb / (hdr.rgb + vec3(1.0)); + let g = pow(mapped, vec3(1.0 / 2.2)); + return vec4(g, 1.0); +}