shader.h

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/*
* ECVL - European Computer Vision Library
* Version: 1.0.0
* copyright (c) 2021, Università degli Studi di Modena e Reggio Emilia (UNIMORE), AImageLab
* Authors:
*    Costantino Grana (costantino.grana@unimore.it)
*    Federico Bolelli (federico.bolelli@unimore.it)
*    Michele Cancilla (michele.cancilla@unimore.it)
*    Laura Canalini (laura.canalini@unimore.it)
*    Stefano Allegretti (stefano.allegretti@unimore.it)
* All rights reserved.
*/

#ifndef ECVL_SHADER_H
#define ECVL_SHADER_H

#include <glm/glm.hpp>

#include <string>
#include <iostream>

namespace ecvl {

struct Shader {
public:
    unsigned int ID;
    // constructor generates the shader on the fly
    // ------------------------------------------------------------------------
    Shader()
    {
    }

    void init(const std::string& vertexCode, const std::string& fragmentCode/*, const std::string& geometryCode = nullptr*/)
    {
        // 1. retrieve the vertex/fragment source code from filePath
        const char* vShaderCode = vertexCode.c_str();
        const char* fShaderCode = fragmentCode.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 necessery
        glDeleteShader(vertex);
        glDeleteShader(fragment);
    }

    // activate the shader
    // ------------------------------------------------------------------------
    void use()
    {
        glUseProgram(ID);
    }
    // utility uniform functions
    // ------------------------------------------------------------------------
    void setBool(const std::string& name, bool value) const
    {
        glUniform1i(glGetUniformLocation(ID, name.c_str()), (int)value);
    }
    // ------------------------------------------------------------------------
    void setInt(const std::string& name, int value) const
    {
        glUniform1i(glGetUniformLocation(ID, name.c_str()), value);
    }
    // ------------------------------------------------------------------------
    void setFloat(const std::string& name, float value) const
    {
        glUniform1f(glGetUniformLocation(ID, name.c_str()), value);
    }
    // ------------------------------------------------------------------------
    void setVec2(const std::string& name, const glm::vec2& value) const
    {
        glUniform2fv(glGetUniformLocation(ID, name.c_str()), 1, &value[0]);
    }
    void setVec2(const std::string& name, float x, float y) const
    {
        glUniform2f(glGetUniformLocation(ID, name.c_str()), x, y);
    }
    // ------------------------------------------------------------------------
    void setVec3(const std::string& name, const glm::vec3& value) const
    {
        glUniform3fv(glGetUniformLocation(ID, name.c_str()), 1, &value[0]);
    }
    void setVec3(const std::string& name, float x, float y, float z) const
    {
        glUniform3f(glGetUniformLocation(ID, name.c_str()), x, y, z);
    }
    // ------------------------------------------------------------------------
    void setVec4(const std::string& name, const glm::vec4& value) const
    {
        glUniform4fv(glGetUniformLocation(ID, name.c_str()), 1, &value[0]);
    }
    void setVec4(const std::string& name, float x, float y, float z, float w)
    {
        glUniform4f(glGetUniformLocation(ID, name.c_str()), x, y, z, w);
    }
    // ------------------------------------------------------------------------
    void setMat2(const std::string& name, const glm::mat2& mat) const
    {
        glUniformMatrix2fv(glGetUniformLocation(ID, name.c_str()), 1, GL_FALSE, &mat[0][0]);
    }
    // ------------------------------------------------------------------------
    void setMat3(const std::string& name, const glm::mat3& mat) const
    {
        glUniformMatrix3fv(glGetUniformLocation(ID, name.c_str()), 1, GL_FALSE, &mat[0][0]);
    }
    // ------------------------------------------------------------------------
    void setMat4(const std::string& name, const glm::mat4& mat) const
    {
        glUniformMatrix4fv(glGetUniformLocation(ID, name.c_str()), 1, GL_FALSE, &mat[0][0]);
    }

private:
    // utility function for checking shader compilation/linking errors.
    // ------------------------------------------------------------------------
    void checkCompileErrors(GLuint shader, std::string type)
    {
        GLint success;
        GLchar infoLog[1024];
        if (type != "PROGRAM")
        {
            glGetShaderiv(shader, GL_COMPILE_STATUS, &success);
            if (!success)
            {
                glGetShaderInfoLog(shader, 1024, NULL, infoLog);
                std::cerr << "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::cerr << "ERROR::PROGRAM_LINKING_ERROR of type: " << type << "\n" << infoLog << "\n -- --------------------------------------------------- -- " << std::endl;
            }
        }
    }
};

}

#endif // ECVL_SHADER_H