144 lines
No EOL
4.1 KiB
Text
144 lines
No EOL
4.1 KiB
Text
/* Copyright (c) 2025, Sascha Willems
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*
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* SPDX-License-Identifier: MIT
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*
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*/
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RaytracingAccelerationStructure accelStruct;
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RWTexture2D<float4> image;
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struct CameraProperties
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{
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float4x4 viewInverse;
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float4x4 projInverse;
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float4 lightPos;
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int vertexSize;
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};
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ConstantBuffer<CameraProperties> ubo;
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StructuredBuffer<float4> vertices;
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StructuredBuffer<uint> indices;
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// Max. number of recursion is passed via a specialization constant
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[SpecializationConstant] const int MAX_RECURSION = 0;
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struct Attributes
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{
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float2 bary;
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};
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struct RayPayload
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{
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float3 color;
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float distance;
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float3 normal;
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float reflector;
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};
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struct Vertex
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{
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float3 pos;
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float3 normal;
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float2 uv;
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float4 color;
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float4 _pad0;
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float4 _pad1;
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};
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Vertex unpack(uint index)
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{
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// Unpack the vertices from the SSBO using the glTF vertex structure
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// The multiplier is the size of the vertex divided by four float components (=16 bytes)
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const int m = ubo.vertexSize / 16;
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float4 d0 = vertices[m * index + 0];
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float4 d1 = vertices[m * index + 1];
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float4 d2 = vertices[m * index + 2];
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Vertex v;
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v.pos = d0.xyz;
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v.normal = float3(d0.w, d1.x, d1.y);
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v.color = float4(d2.x, d2.y, d2.z, 1.0);
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return v;
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}
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[shader("raygeneration")]
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void raygenerationMain()
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{
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uint3 LaunchID = DispatchRaysIndex();
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uint3 LaunchSize = DispatchRaysDimensions();
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const float2 pixelCenter = float2(LaunchID.xy) + float2(0.5, 0.5);
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const float2 inUV = pixelCenter / float2(LaunchSize.xy);
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float2 d = inUV * 2.0 - 1.0;
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float4 target = mul(ubo.projInverse, float4(d.x, d.y, 1, 1));
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RayDesc rayDesc;
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rayDesc.Origin = mul(ubo.viewInverse, float4(0, 0, 0, 1)).xyz;
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rayDesc.Direction = mul(ubo.viewInverse, float4(normalize(target.xyz), 0)).xyz;
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rayDesc.TMin = 0.001;
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rayDesc.TMax = 10000.0;
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float3 color = float3(0.0, 0.0, 0.0);
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for (int i = 0; i < MAX_RECURSION; i++) {
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RayPayload rayPayload;
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TraceRay(accelStruct, RAY_FLAG_FORCE_OPAQUE, 0xff, 0, 0, 0, rayDesc, rayPayload);
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float3 hitColor = rayPayload.color;
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if (rayPayload.distance < 0.0f) {
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color += hitColor;
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break;
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} else if (rayPayload.reflector == 1.0f) {
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const float3 hitPos = rayDesc.Origin + rayDesc.Direction * rayPayload.distance;
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rayDesc.Origin = hitPos + rayPayload.normal * 0.001f;
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rayDesc.Direction = reflect(rayDesc.Direction, rayPayload.normal);
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} else {
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color += hitColor;
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break;
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}
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}
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image[int2(LaunchID.xy)] = float4(color, 0.0);
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}
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[shader("closesthit")]
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void closesthitMain(inout RayPayload rayPayload, in Attributes attribs)
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{
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uint PrimitiveID = PrimitiveIndex();
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int3 index = int3(indices[3 * PrimitiveID], indices[3 * PrimitiveID + 1], indices[3 * PrimitiveID + 2]);
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Vertex v0 = unpack(index.x);
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Vertex v1 = unpack(index.y);
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Vertex v2 = unpack(index.z);
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// Interpolate normal
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const float3 barycentricCoords = float3(1.0f - attribs.bary.x - attribs.bary.y, attribs.bary.x, attribs.bary.y);
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float3 normal = normalize(v0.normal * barycentricCoords.x + v1.normal * barycentricCoords.y + v2.normal * barycentricCoords.z);
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// Basic lighting
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float3 lightVector = normalize(ubo.lightPos.xyz);
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float dot_product = max(dot(lightVector, normal), 0.6);
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rayPayload.color.rgb = v0.color.rgb * dot_product;
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rayPayload.distance = RayTCurrent();
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rayPayload.normal = normal;
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// Objects with full white vertex color are treated as reflectors
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rayPayload.reflector = ((v0.color.r == 1.0f) && (v0.color.g == 1.0f) && (v0.color.b == 1.0f)) ? 1.0f : 0.0f;
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}
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[shader("miss")]
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void missMain(inout RayPayload rayPayload)
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{
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float3 worldRayDirection = WorldRayDirection();
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// View-independent background gradient to simulate a basic sky background
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const float3 gradientStart = float3(0.5, 0.6, 1.0);
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const float3 gradientEnd = float3(1.0, 1.0, 1.0);
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float3 unitDir = normalize(worldRayDirection);
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float t = 0.5 * (unitDir.y + 1.0);
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rayPayload.color = (1.0 - t) * gradientStart + t * gradientEnd;
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rayPayload.distance = -1.0f;
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rayPayload.normal = float3(0, 0, 0);
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rayPayload.reflector = 0.0f;
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} |