#pragma kernel ClearDispatchIndirect
#pragma kernel ClearDrawProceduralIndirect
#pragma only_renderers d3d11 playstation xboxone xboxseries vulkan metal switch

RWBuffer<uint> g_DispatchIndirectBuffer : register( u0 );   // Indirect arguments have to be in a _buffer_, not a structured buffer

#include "Packages/com.unity.render-pipelines.core/ShaderLibrary/Common.hlsl"
#include "Packages/com.unity.render-pipelines.high-definition/Runtime/Lighting/LightLoop/LightLoop.cs.hlsl"

#ifdef PLATFORM_LANE_COUNT
#define NR_THREADS              PLATFORM_LANE_COUNT
#else
#define NR_THREADS              64                                  // default to 64 threads per group on other platforms..
#endif

uniform uint g_NumTiles;
uniform uint g_VertexPerTile;

[numthreads(NR_THREADS, 1, 1)]
void ClearDispatchIndirect(uint dispatchThreadId : SV_DispatchThreadID)
{
    // On iOS, we get a GPU hang/reset based upon the execution of the ClearDispatchIndirect kernel.
    // The buffer is created using the 'NUM_FEATURE_VARIANTS' constant but we're dispatching a threadgroup of 64 threads, so we are presumably going out of bounds (Metal GPU errors are not terribly descriptive, but this is a common cause).
    // In DirectX out-of-bounds reads are always zero and out-of-bounds writes are are a no op.
    if (dispatchThreadId >= NUM_FEATURE_VARIANTS)
        return;

    g_DispatchIndirectBuffer[dispatchThreadId * 3 + 0] = 0; // ThreadGroupCountX
    g_DispatchIndirectBuffer[dispatchThreadId * 3 + 1] = 1; // ThreadGroupCountY
    g_DispatchIndirectBuffer[dispatchThreadId * 3 + 2] = 1; // ThreadGroupCountZ
}

[numthreads(NR_THREADS, 1, 1)]
void ClearDrawProceduralIndirect(uint dispatchThreadId : SV_DispatchThreadID)
{
    // On iOS, we get a GPU hang/reset based upon the execution of the ClearDispatchIndirect kernel.
    // The buffer is created using the 'NUM_FEATURE_VARIANTS' constant but we're dispatching a threadgroup of 64 threads, so we are presumably going out of bounds (Metal GPU errors are not terribly descriptive, but this is a common cause).
    // In DirectX out-of-bounds reads are always zero and out-of-bounds writes are are a no op.
    if (dispatchThreadId >= NUM_FEATURE_VARIANTS)
        return;

    g_DispatchIndirectBuffer[dispatchThreadId * 4 + 0] = g_VertexPerTile; // VertexCountPerInstance
    g_DispatchIndirectBuffer[dispatchThreadId * 4 + 1] = 0; // InstanceCount
    g_DispatchIndirectBuffer[dispatchThreadId * 4 + 2] = 0; // StartVertexLocation
    g_DispatchIndirectBuffer[dispatchThreadId * 4 + 3] = dispatchThreadId * g_NumTiles; // StartInstanceLocation
}