engineer-thesis-WUT/Engine/engine/shader.cpp

// "Copyright [2023] <Krzysztof Rudnicki>"
#ifndef SHADER_CPP
#define SHADER_CPP

#include "./shader.hpp"

#include <glad/glad.h>

#include <fstream>
#include <iostream>
#include <sstream>
#include <string>

const std::string Shader::fileToShader(const std::string shaderPath) {
  // 1. retrieve the vertex/fragment source code from filePath
  std::string shaderCode;
  std::ifstream shaderFile;
  // ensure ifstream objects can throw exceptions:
  shaderFile.exceptions(std::ifstream::failbit | std::ifstream::badbit);
  try {
    // open files
    shaderFile.open(shaderPath);
    std::stringstream shaderStream;
    // read file's buffer contents into streams
    shaderStream << shaderFile.rdbuf();
    // close file handlers
    shaderFile.close();
    // convert stream into string
    shaderCode = shaderStream.str();
  } catch (std::ifstream::failure &e) {
    std::cout << "ERROR::SHADER::FILE_NOT_SUCCESSFULLY_READ: " << e.what()
              << std::endl;
  }
  return shaderCode;
}

Shader::Shader(const std::string vertexPath, const std::string fragmentPath) {
  const std::string vshaderCodeString = this->fileToShader(vertexPath);
  const std::string fShaderCodeString = this->fileToShader(fragmentPath);

  const char *vShaderCode = vshaderCodeString.c_str();
  const char *fShaderCode = fShaderCodeString.c_str();
  // 2. compile shaders
  unsigned int vertex, fragment;
  // vertex shader
  vertex = glCreateShader(GL_VERTEX_SHADER);
  glShaderSource(vertex, 1, &vShaderCode, NULL);
  glCompileShader(vertex);
  checkCompileErrors(vertex, "VERTEX");
  // fragment Shader
  fragment = glCreateShader(GL_FRAGMENT_SHADER);
  glShaderSource(fragment, 1, &fShaderCode, NULL);
  glCompileShader(fragment);
  checkCompileErrors(fragment, "FRAGMENT");
  // shader Program
  ID = glCreateProgram();
  glAttachShader(ID, vertex);
  glAttachShader(ID, fragment);
  glLinkProgram(ID);
  checkCompileErrors(ID, "PROGRAM");
  // delete the shaders as they're linked
  // into our program now and no longer necessary
  glDeleteShader(vertex);
  glDeleteShader(fragment);
}

void Shader::use() { glUseProgram(ID); }

void Shader::setBool(const std::string &name, bool value) const {
  glUniform1i(glGetUniformLocation(ID, name.c_str()), int(value));
}

void Shader::setInt(const std::string &name, int value) const {
  glUniform1i(glGetUniformLocation(ID, name.c_str()), value);
}

void Shader::setFloat(const std::string &name, float value) const {
  glUniform1f(glGetUniformLocation(ID, name.c_str()), value);
}

void Shader::checkCompileErrors(unsigned int shader, std::string type) {
  int success;
  char infoLog[1024];
  if (type != "PROGRAM") {
    glGetShaderiv(shader, GL_COMPILE_STATUS, &success);
    if (!success) {
      glGetShaderInfoLog(shader, 1024, NULL, infoLog);
      std::cout
          << "ERROR::SHADER_COMPILATION_ERROR of type: " << type << "\n"
          << infoLog
          << "\n -- --------------------------------------------------- -- "
          << std::endl;
    }
  } else {
    glGetProgramiv(shader, GL_LINK_STATUS, &success);
    if (!success) {
      glGetProgramInfoLog(shader, 1024, NULL, infoLog);
      std::cout
          << "ERROR::PROGRAM_LINKING_ERROR of type: " << type << "\n"
          << infoLog
          << "\n -- --------------------------------------------------- -- "
          << std::endl;
    }
  }
}

#endif  // SHADER_CPP