GPUBufferScatter.hpp

#pragma once
#include <Gfx/Graph/RenderState.hpp>
 
#include <private/qrhi_p.h>
 
namespace score::gfx
{
 
class GPUBufferScatter
{
public:
  struct Params
  {
    QRhiBuffer* staging{};    // Source SSBO (raw CPU data, uploaded as-is)
    QRhiBuffer* output{};     // Destination SSBO (format-converted result)
    uint32_t element_count{};
    uint32_t src_components{}; // Floats per source element (1-4)
    uint32_t dst_components{}; // Floats per destination element (1-4)
    uint32_t src_stride_floats{}; // Stride between source elements (in floats, >= src_components)
    uint32_t src_offset_floats{}; // Starting offset in source buffer (in floats)
  };
 
  bool init(RenderState& state);
  void release();
 
  struct PreparedOp
  {
    QRhiShaderResourceBindings* srb{};
    QRhiBuffer* paramsUBO{};
  };
  PreparedOp prepare(QRhi& rhi, const Params& p);
 
  void updateParams(QRhiResourceUpdateBatch& res, const PreparedOp& op, const Params& p);
 
  void dispatch(QRhiCommandBuffer& cb, const PreparedOp& op, const Params& p);
 
  static constexpr int LocalSize = 256;
 
private:
  QRhiComputePipeline* m_pipeline{};
  QShader m_shader;
};
 
} // namespace score::gfx