procedural-3d-engine/shaders/slang/raytracingbasic/raytracingbasic.slang
2025-04-27 17:40:20 +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 Attributes
{
float2 bary;
};
struct Payload
{
float3 hitValue;
};
[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)
{
const float3 barycentricCoords = float3(1.0f - attribs.bary.x - attribs.bary.y, attribs.bary.x, attribs.bary.y);
p.hitValue = barycentricCoords;
}
[shader("miss")]
void missMain(inout Payload p)
{
p.hitValue = float3(0.0, 0.0, 0.2);
}