engineer-thesis-WUT/breakout/resourceManager.cpp

// Copyright [2023] Krzysztof Rudnicki
#ifndef HOME_KUCHY_ENGINEER_THESIS_WUT_BREAKOUT_RESOURCEMANAGER_CPP
#define HOME_KUCHY_ENGINEER_THESIS_WUT_BREAKOUT_RESOURCEMANAGER_CPP

#include "../breakout/resourceManager.hpp"
#include "./shader.hpp"
#include "./stb_image.h"
#include "./texture.hpp"

// Instantiate static variables
std::map<std::string, Texture2D> ResourceManager::Textures;
std::map<std::string, Shader> ResourceManager::Shaders;

auto ResourceManager::LoadShader(const char *vShaderFile,
                                 const char *fShaderFile,
                                 const char *gShaderFile,
                                 const std::string &name) -> Shader {
  Shaders[name] = loadShaderFromFile(vShaderFile, fShaderFile, gShaderFile);
  return Shaders[name];
}

auto ResourceManager::GetShader(const std::string &name) -> Shader {
  return Shaders[name];
}

auto ResourceManager::LoadTexture(const char *file, bool alpha,
                                  const std::string &name) -> Texture2D {
  Textures[name] = loadTextureFromFile(file, alpha);
  return Textures[name];
}

auto ResourceManager::GetTexture(const std::string &name) -> Texture2D {
  return Textures[name];
}

void ResourceManager::Clear() {
  // (properly) delete all shaders
  for (const auto &iter : Shaders) {
    glDeleteProgram(iter.second.ID);
  }
  // (properly) delete all textures
  for (const auto &iter : Textures) {
    glDeleteTextures(1, &iter.second.ID);
  }
}

auto ResourceManager::loadShaderFromFile(const char *vShaderFile,
                                         const char *fShaderFile,
                                         const char *gShaderFile) -> Shader {
  // 1. retrieve the vertex/fragment source code from filePath
  std::string vertexCode;
  std::string fragmentCode;
  std::string geometryCode;
  try {
    // open files
    std::ifstream vertexShaderFile(vShaderFile);
    std::ifstream fragmentShaderFile(fShaderFile);
    std::stringstream vShaderStream;
    std::stringstream fShaderStream;
    // read file's buffer contents into streams
    vShaderStream << vertexShaderFile.rdbuf();
    fShaderStream << fragmentShaderFile.rdbuf();
    // close file handlers
    vertexShaderFile.close();
    fragmentShaderFile.close();
    // convert stream into string
    vertexCode = vShaderStream.str();
    fragmentCode = fShaderStream.str();
    // if geometry shader path is present, also load a geometry shader
    if (gShaderFile != nullptr) {
      std::ifstream geometryShaderFile(gShaderFile);
      std::stringstream gShaderStream;
      gShaderStream << geometryShaderFile.rdbuf();
      geometryShaderFile.close();
      geometryCode = gShaderStream.str();
    }
  } catch (std::exception const &) {
    std::cout << "ERROR::SHADER: Failed to read shader files" << std::endl;
  }
  const char *vShaderCode = vertexCode.c_str();
  const char *fShaderCode = fragmentCode.c_str();
  const char *gShaderCode = geometryCode.c_str();
  // 2. now create shader object from source code
  Shader shader;
  shader.Compile(vShaderCode, fShaderCode,
                 gShaderFile != nullptr ? gShaderCode : nullptr);
  return shader;
}

auto ResourceManager::loadTextureFromFile(const char *file, bool alpha)
    -> Texture2D {
  // create texture object
  Texture2D texture;
  if (alpha) {
    texture.Internal_Format = GL_RGBA;
    texture.Image_Format = GL_RGBA;
  }
  // load image
  int width;
  int height;
  int nrChannels;
  unsigned char *data = stbi_load(file, &width, &height, &nrChannels, 0);
  // now generate texture
  texture.Generate(width, height, data);
  // and finally free image data
  stbi_image_free(data);
  return texture;
}

#endif