PipelineBuilder.cpp

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#include "PipelineBuilder.hpp"
 
#include <iostream>
#include <stdexcept>
 
namespace sKit {
namespace SDL {
 
auto PipelineBuilder::shaders(
    SDL_GPUShader* vertexShader,
    SDL_GPUShader* fragmentShader
) -> PipelineBuilder& {
  vs_ = vertexShader;
  fs_ = fragmentShader;
  return *this;
}
 
auto PipelineBuilder::addBuffer(
    Uint32 slot,
    Uint32 stride,
    SDL_GPUVertexInputRate inputRate
) -> PipelineBuilder& {
  bufferDescs_.emplace_back(SDL_GPUVertexBufferDescription {
      .slot = slot, .pitch = stride, .input_rate = inputRate
  });
  return *this;
}
 
auto PipelineBuilder::addAttribute(
    Uint32 location,
    Uint32 bufferSlot,
    Uint32 offset,
    SDL_GPUVertexElementFormat format
) -> PipelineBuilder& {
  vertexAttribs_.emplace_back(SDL_GPUVertexAttribute {
      .location = location,
      .buffer_slot = bufferSlot,
      .format = format,
      .offset = offset,
  });
  return *this;
}
 
auto PipelineBuilder::addColorTarget(SDL_GPUTextureFormat format)
    -> PipelineBuilder& {
  SDL_GPUColorTargetDescription colorDesc {.format = format};
  colorTargetDescs_.push_back(colorDesc);
  return *this;
}
 
auto PipelineBuilder::cullMode(SDL_GPUCullMode cullMode) -> PipelineBuilder& {
  cullMode_ = cullMode;
  return *this;
};
 
auto PipelineBuilder::build(SDL_GPUDevice* device) -> SDL_GPUGraphicsPipeline* {
  if (colorTargetDescs_.empty()) {
    std::cerr << "Warning: no color target specified during pipeline creation"
              << std::endl;
  }
 
  SDL_GPUVertexInputState vertexState {
      .vertex_buffer_descriptions = bufferDescs_.data(),
      .num_vertex_buffers = static_cast<Uint32>(bufferDescs_.size()),
      .vertex_attributes = vertexAttribs_.data(),
      .num_vertex_attributes = static_cast<Uint32>(vertexAttribs_.size())
  };
  SDL_GPURasterizerState rasterizerState {
      .cull_mode = cullMode_, .front_face = frontFace_
  };
  SDL_GPUGraphicsPipelineCreateInfo info {
      .vertex_shader = vs_,
      .fragment_shader = fs_,
      .vertex_input_state = vertexState,
      .primitive_type = SDL_GPU_PRIMITIVETYPE_TRIANGLELIST,
      .rasterizer_state = rasterizerState,
      .target_info =
          {.color_target_descriptions = colorTargetDescs_.data(),
           .num_color_targets = static_cast<Uint32>(colorTargetDescs_.size())}
  };
  if (auto pl = SDL_CreateGPUGraphicsPipeline(device, &info)) {
    return pl;
  } else {
    throw std::runtime_error(SDL_GetError());
  }
}
 
}  // namespace SDL
}  // namespace sKit