buffers.hpp

Go to the documentation of this file.

#pragma once
 
#include <SDL3/SDL_gpu.h>
 
#include <algorithm>
#include <span>
#include <stdexcept>
 
namespace sKit {
namespace sdl {
 
// Creates a GPU buffer and uses a command buffer to queue an upload. The
// command buffer is not submitted.
template <typename T, SDL_GPUBufferUsageFlags U>
inline SDL_GPUBuffer* createBuffer(
    SDL_GPUDevice* device,
    SDL_GPUCommandBuffer* commandBuffer,
    std::span<T> data
) {
  // create transfer buffer
  Uint32 size = data.size() * sizeof(T);
  SDL_GPUTransferBufferCreateInfo info{
      .usage = SDL_GPU_TRANSFERBUFFERUSAGE_UPLOAD, .size = size
  };
  auto transfer = SDL_CreateGPUTransferBuffer(device, &info);
 
  // create target buffer
  SDL_GPUBufferCreateInfo vbInfo{.usage = U, .size = size};
  auto dstBuffer = SDL_CreateGPUBuffer(device, &vbInfo);
 
  // copy data to transfer buffer
  auto mapping = (T*)SDL_MapGPUTransferBuffer(device, transfer, false);
  std::copy(data.begin(), data.end(), mapping);
  SDL_UnmapGPUTransferBuffer(device, transfer);
 
  // copy data from transfer buffer to GPU buffers
  SDL_GPUTransferBufferLocation src{.transfer_buffer = transfer};
  SDL_GPUBufferRegion dst{.buffer = dstBuffer, .size = size};
  auto pass = SDL_BeginGPUCopyPass(commandBuffer);
  if (!pass) {
    throw std::runtime_error(SDL_GetError());
  }
  SDL_UploadToGPUBuffer(pass, &src, &dst, false);
  SDL_EndGPUCopyPass(pass);
  SDL_ReleaseGPUTransferBuffer(device, transfer);
  return dstBuffer;
}
 
}  // namespace sdl
}  // namespace sKit