procedural-3d-engine/shaders/slang/raytracingcallable/raytracingcallable.slang
2025-05-18 10:38:49 +02:00

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/* Copyright (c) 2025, Sascha Willems
*
* SPDX-License-Identifier: MIT
*
*/
RaytracingAccelerationStructure accelStruct;
RWTexture2D<float4> image;
struct CameraProperties
{
float4x4 viewInverse;
float4x4 projInverse;
};
ConstantBuffer<CameraProperties> cam;
struct Payload
{
float3 hitValue;
};
struct CallData
{
float3 outColor;
};
struct Attributes
{
float2 bary;
};
[shader("raygeneration")]
void raygenerationMain()
{
uint3 LaunchID = DispatchRaysIndex();
uint3 LaunchSize = DispatchRaysDimensions();
const float2 pixelCenter = float2(LaunchID.xy) + float2(0.5, 0.5);
const float2 inUV = pixelCenter / float2(LaunchSize.xy);
float2 d = inUV * 2.0 - 1.0;
float4 target = mul(cam.projInverse, float4(d.x, d.y, 1, 1));
RayDesc rayDesc;
rayDesc.Origin = mul(cam.viewInverse, float4(0, 0, 0, 1)).xyz;
rayDesc.Direction = mul(cam.viewInverse, float4(normalize(target.xyz), 0)).xyz;
rayDesc.TMin = 0.001;
rayDesc.TMax = 10000.0;
Payload payload;
TraceRay(accelStruct, RAY_FLAG_FORCE_OPAQUE, 0xff, 0, 0, 0, rayDesc, payload);
image[int2(LaunchID.xy)] = float4(payload.hitValue, 0.0);
}
[shader("closesthit")]
void closesthitMain(inout Payload p, in Attributes attribs)
{
// Execute the callable shader indexed by the current geometry being hit
// For our sample this means that the first callable shader in the SBT is invoked for the first triangle, the second callable shader for the second triangle, etc.
CallData callData;
CallShader(GeometryIndex(), callData);
p.hitValue = callData.outColor;
}
[shader("miss")]
void missMain(inout Payload p)
{
p.hitValue = float3(0.0, 0.0, 0.2);
}