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// shaders.slang
struct Uniforms
{
float screenWidth, screenHeight;
float focalLength, frameHeight;
float4 cameraDir;
float4 cameraUp;
float4 cameraRight;
float4 cameraPosition;
float4 lightDir;
};
struct Primitive
{
float4 data0;
float4 color;
float3 getNormal() { return data0.xyz; }
float3 getColor() { return color.xyz; }
};
bool traceRayFirstHit(
RaytracingAccelerationStructure sceneBVH,
float3 rayOrigin,
float3 rayDir,
out float t,
out int primitiveIndex)
{
RayDesc ray;
ray.Origin = rayOrigin;
ray.TMin = 0.01f;
ray.Direction = rayDir;
ray.TMax = 1e4f;
RayQuery<RAY_FLAG_SKIP_PROCEDURAL_PRIMITIVES |
RAY_FLAG_ACCEPT_FIRST_HIT_AND_END_SEARCH> q;
let rayFlags = RAY_FLAG_SKIP_PROCEDURAL_PRIMITIVES |
RAY_FLAG_ACCEPT_FIRST_HIT_AND_END_SEARCH;
q.TraceRayInline(
sceneBVH,
rayFlags,
0xff,
ray);
q.Proceed();
if(q.CommittedStatus() == COMMITTED_TRIANGLE_HIT)
{
t = q.CommittedRayT();
primitiveIndex = q.CommittedPrimitiveIndex();
return true;
}
primitiveIndex = q.CandidatePrimitiveIndex();
unused(t);
return false;
}
bool traceRayNearestHit(
RaytracingAccelerationStructure sceneBVH,
float3 rayOrigin,
float3 rayDir,
out float t,
out int primitiveIndex)
{
RayDesc ray;
ray.Origin = rayOrigin;
ray.TMin = 0.01f;
ray.Direction = rayDir;
ray.TMax = 1e4f;
RayQuery<RAY_FLAG_NONE> q;
let rayFlags = RAY_FLAG_NONE;
q.TraceRayInline(
sceneBVH,
rayFlags,
0xff,
ray);
q.Proceed();
if(q.CommittedStatus() == COMMITTED_TRIANGLE_HIT)
{
t = q.CommittedRayT();
primitiveIndex = q.CommittedPrimitiveIndex();
return true;
}
primitiveIndex = q.CandidatePrimitiveIndex();
unused(t);
return false;
}
[shader("compute")]
[numthreads(16,16,1)]
void computeMain(
uint3 threadIdx : SV_DispatchThreadID,
uniform RWTexture2D resultTexture,
uniform RaytracingAccelerationStructure sceneBVH,
uniform StructuredBuffer<Primitive> primitiveBuffer,
uniform Uniforms uniforms)
{
if (threadIdx.x >= (int)uniforms.screenWidth) return;
if (threadIdx.y >= (int)uniforms.screenHeight) return;
float frameWidth = uniforms.screenWidth / uniforms.screenHeight * uniforms.frameHeight;
float imageY = (threadIdx.y / uniforms.screenHeight - 0.5f) * uniforms.frameHeight;
float imageX = (threadIdx.x / uniforms.screenWidth - 0.5f) * frameWidth;
float imageZ = uniforms.focalLength;
float3 rayDir = normalize(uniforms.cameraDir.xyz*imageZ - uniforms.cameraUp.xyz * imageY + uniforms.cameraRight.xyz * imageX);
float4 resultColor = 0;
int primitiveIndex = 0;
float intersectionT;
if (traceRayNearestHit(sceneBVH, uniforms.cameraPosition.xyz, rayDir, intersectionT, primitiveIndex))
{
float3 hitLocation = uniforms.cameraPosition.xyz + rayDir * intersectionT;
float3 shadowRayDir = uniforms.lightDir.xyz;
float shadow = 1.0;
float shadowIntersectionT;
int shadowPrimitiveIndex;
if (traceRayFirstHit(sceneBVH, hitLocation, shadowRayDir, shadowIntersectionT, shadowPrimitiveIndex))
{
shadow = 0.0f;
}
float3 normal = primitiveBuffer[primitiveIndex].getNormal();
float3 color = primitiveBuffer[primitiveIndex].getColor();
float ndotl = max(0.0, shadow * dot(normal, uniforms.lightDir.xyz));
float intensity = ndotl * 0.7 + 0.3;
resultColor = float4(color * intensity, 1.0f);
}
resultTexture[threadIdx.xy] = resultColor;
}
/// Vertex and fragment shader for displaying the final image.
[shader("vertex")]
float4 vertexMain(float2 position : POSITION)
: SV_Position
{
return float4(position, 0.5, 1.0);
}
[shader("fragment")]
float4 fragmentMain(
float4 sv_position : SV_Position,
uniform RWTexture2D t)
: SV_Target
{
return t.Load(uint2(sv_position.xy));
}
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