Seele/res/shaders/lib/Scene.slang

import Bounding;

struct PoolRange
{
    uint32_t offset;
    uint32_t size;
};

struct MeshletDescription
{
    AABB bounding;
    // range into vertexIndices array
    PoolRange vertexIndices;
    // range into primitiveIndices array
    PoolRange primitiveIndices;
    uint32_t indicesOffset;
    uint32_t lod;
    uint32_t pad0;
    uint32_t pad1;
};

struct MeshData
{
    AABB bounding;
    PoolRange meshletRange;
    // offset into the global index buffer
    PoolRange indicesRange;
};

static const uint32_t MAX_VERTICES = 256;
static const uint32_t MAX_PRIMITIVES = 256;

struct InstanceData
{
    float4x4 transformMatrix;
    float4x4 inverseTransformMatrix;
};

struct MeshletCullingInfo
{
    uint32_t visible;
    bool wasVisible()
    {
        return bool(visible);
    }
};

struct DrawCallOffsets
{
    uint instanceOffset;
	uint textureOffset;
	uint samplerOffset;
	uint floatOffset;
};
#ifdef RAY_TRACING
layout(shaderRecordEXT)
#else
layout(push_constant)
#endif
ConstantBuffer<DrawCallOffsets> pOffsets;

struct Scene
{
    StructuredBuffer<float> positions;
    StructuredBuffer<uint> indexBuffer;
    StructuredBuffer<InstanceData> instances;
    StructuredBuffer<MeshData> meshData;
    StructuredBuffer<MeshletDescription> meshletInfos;
    StructuredBuffer<uint8_t> primitiveIndices;
    StructuredBuffer<uint32_t> vertexIndices;
    StructuredBuffer<uint32_t> cullingOffsets;
    StructuredBuffer<MeshletCullingInfo> cullingInfos;
};
ParameterBlock<Scene> pScene;

uint32_t encodePrimitive(uint32_t meshletId)
{
    return meshletId;
}

uint decodePrimitive(uint32_t encoded)
{
    return encoded;
}

struct MeshPayload
{
    uint culledMeshlets[2048];
    uint instanceId;
    uint meshletOffset;
    uint cullingOffset;
};