shader.hpp

/*
 * MIT License
 *
 * Copyright (c) 2024 Giovanni Santini
 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 */
 
#pragma once
 
#include "engine_logger.hpp"
 
#include <algorithm>
#include <fstream>
#include <glad/glad.h> /* OpenGL driver */
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>
#include <iostream>
#include <sstream>
#include <string>
#include <unordered_map>
#include <vector>
 
namespace brenta
{
 
namespace types
{
 
typedef std::string shader_name_t;
 
} // namespace types
 
class shader
{
  public:
    static std::unordered_map<types::shader_name_t, unsigned int> shaders;
 
    template <typename... Args>
    static void create(std::string shader_name, GLenum type, std::string path,
                       Args... args)
    {
        std::vector<unsigned int> compiled_shaders = {};
        compile_shaders(compiled_shaders, type, path, args...);
 
        /* shader Program */
        unsigned int ID = glCreateProgram();
        std::for_each(compiled_shaders.begin(), compiled_shaders.end(),
                      [&ID](auto shader) { glAttachShader(ID, shader); });
 
        glLinkProgram(ID);
        shader::check_compile_errors(ID, "PROGRAM");
 
        shader::shaders.insert({shader_name, ID});
        std::for_each(compiled_shaders.begin(), compiled_shaders.end(),
                      [](auto shader) { glDeleteShader(shader); });
    }
 
    template <typename... Args>
    static void create(const GLchar **feedback_varyings, int num_varyings,
                       std::string shader_name, GLenum type, std::string path,
                       Args... args)
    {
        std::vector<unsigned int> compiled_shaders = {};
        compile_shaders(compiled_shaders, type, path, args...);
 
        /* shader Program */
        unsigned int ID = glCreateProgram();
        std::for_each(compiled_shaders.begin(), compiled_shaders.end(),
                      [&ID](auto shader) { glAttachShader(ID, shader); });
 
        if (feedback_varyings != nullptr)
        {
            glTransformFeedbackVaryings(ID, num_varyings, feedback_varyings,
                                        GL_INTERLEAVED_ATTRIBS);
        }
 
        glLinkProgram(ID);
        shader::check_compile_errors(ID, "PROGRAM");
 
        shader::shaders.insert({shader_name, ID});
        std::for_each(compiled_shaders.begin(), compiled_shaders.end(),
                      [](auto shader) { glDeleteShader(shader); });
    }
 
    static void compile_shaders(std::vector<unsigned int> &compiled)
    {
        return;
    }
 
    template <typename... Args>
    static void compile_shaders(std::vector<unsigned int> &compiled,
                                GLenum type, std::string path, Args... args)
    {
        std::string code;
        std::ifstream file;
        file.exceptions(std::ifstream::failbit | std::ifstream::badbit);
 
        try
        {
            file.open(path);
            std::stringstream stream;
            stream << file.rdbuf();
            file.close();
            code = stream.str();
        }
        catch (std::ifstream::failure &e)
        {
            ERROR("Error reading shader file: {}", path);
            return;
        }
 
        const char *shader_code = code.c_str();
        unsigned int shader = glCreateShader(type);
        glShaderSource(shader, 1, &shader_code, NULL);
        glCompileShader(shader);
        shader::check_compile_errors(shader, "SHADER");
 
        compiled.push_back(shader);
        compile_shaders(compiled, args...);
    }
 
    static unsigned int get_id(types::shader_name_t shader_name);
 
    static void use(types::shader_name_t shader_name);
 
    /* Utility uniform functions */
 
    static void set_bool(types::shader_name_t shader_name,
                         const std::string &name, bool value);
    static void set_int(types::shader_name_t shader_name,
                        const std::string &name, int value);
    static void set_float(types::shader_name_t shader_name,
                          const std::string &name, float value);
    static void set_mat4(types::shader_name_t shader_name, const GLchar *name,
                         glm::mat4 value);
    static void set_vec3(types::shader_name_t shader_name, const GLchar *name,
                         float x, float y, float z);
    static void set_vec3(types::shader_name_t shader_name, const GLchar *name,
                         glm::vec3 value);
 
  private:
    static void check_compile_errors(unsigned int shader, std::string type);
};
 
} // namespace brenta