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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; }
};
struct [raypayload] RayPayload
{
float4 color : read(caller) : write(caller, closesthit, miss);
};
uniform RWTexture2D resultTexture;
uniform RaytracingAccelerationStructure sceneBVH;
uniform StructuredBuffer<Primitive> primitiveBuffer;
uniform Uniforms uniforms;
[shader("raygeneration")]
void rayGenShader()
{
uint2 threadIdx = DispatchRaysIndex().xy;
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);
// Trace the ray.
RayDesc ray;
ray.Origin = uniforms.cameraPosition.xyz;
ray.Direction = rayDir;
ray.TMin = 0.001;
ray.TMax = 10000.0;
RayPayload payload = { float4(0, 0, 0, 0) };
TraceRay(sceneBVH, RAY_FLAG_NONE, ~0, 0, 0, 0, ray, payload);
resultTexture[threadIdx.xy] = payload.color;
}
[shader("miss")]
void missShader(inout RayPayload payload)
{
payload.color = float4(0, 0, 0, 1);
}
[shader("closesthit")]
void closestHitShader(inout RayPayload payload, in BuiltInTriangleIntersectionAttributes attr)
{
float3 hitLocation = WorldRayOrigin() + WorldRayDirection() * RayTCurrent();
float3 shadowRayDir = uniforms.lightDir.xyz;
RayDesc ray;
ray.Origin = hitLocation;
ray.Direction = shadowRayDir;
ray.TMin = 0.001;
ray.TMax = 10000.0;
RayPayload shadowPayload = { float4(0, 0, 0, 0) };
TraceRay(sceneBVH, RAY_FLAG_ACCEPT_FIRST_HIT_AND_END_SEARCH, ~0, 1, 0, 0, ray, shadowPayload);
float shadow = 1.0 - shadowPayload.color.x;
let primitiveIndex = PrimitiveIndex();
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;
payload.color = float4(color * intensity, 1.0f);
}
[shader("closesthit")]
void shadowRayHitShader(inout RayPayload payload, in BuiltInTriangleIntersectionAttributes attr)
{
payload.color = float4(1.0, 1.0, 1.0, 1.0);
}
/// 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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