procedural-3d-engine/shaders/slang/raytracingsbtdata/raytracingsbtdata.slang
2025-05-13 19:32:35 +02:00

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/* Copyright (c) 2025, Sascha Willems
*
* SPDX-License-Identifier: MIT
*
*/
struct Attributes
{
float2 bary;
};
struct Payload
{
float3 hitValue;
};
RaytracingAccelerationStructure accelStruct;
RWTexture2D<float4> image;
struct CameraProperties
{
float4x4 viewInverse;
float4x4 projInverse;
};
ConstantBuffer<CameraProperties> cam;
struct SBT {
float r;
float g;
float b;
};
[[vk::shader_record]] ConstantBuffer<SBT> sbt;
[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;
// use border to demonstrate raygen record data
if (all(LaunchID.xy > int2(16, 16)) && all(LaunchID.xy < LaunchSize.xy - int2(16, 16)))
{
// Generate a checker board pattern to trace out rays or use hit record data
int2 pos = int2(LaunchID.xy / 16);
if (((pos.x + pos.y % 2) % 2) == 0) {
// This will set hit value to either hit or miss SBT record color
TraceRay(accelStruct, RAY_FLAG_FORCE_OPAQUE, 0xff, 0, 0, 0, rayDesc, payload);
}
else {
// Set the hit value to the raygen SBT data
payload.hitValue = float3(sbt.r, sbt.g, sbt.b);
}
}
else {
// Set hit value to black
payload.hitValue = float3(0.0, 0.0, 0.0);
}
image[int2(LaunchID.xy)] = float4(payload.hitValue, 0.0);
}
[shader("closesthit")]
void closesthitMain(inout Payload payload, in Attributes attribs)
{
// Update the hit value to the hit record SBT data associated with this
// geometry ID and ray ID
payload.hitValue = float3(sbt.r, sbt.g, sbt.g);
}
[shader("miss")]
void missMain(inout Payload payload)
{
// Update the hit value to the hit record SBT data associated with this
// miss record
payload.hitValue = float3(sbt.r, sbt.g, sbt.g);
}