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

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

#include <glad/glad.h>

#include <string>
#include <fstream>
#include <sstream>
#include <iostream>
#include "./shader.hpp"

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()),
        reinterpret_cast<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