add: shader class

CMakeLists.txt

@@ -5,5 +5,5 @@ set(CMAKE_CXX_STANDARD 20)
 include_directories(include)
 add_compile_options(-lglfw3 -lGL -lX11 -lpthread -lXrandr -lXi -ldl)
 
-add_executable(app main.cpp src/glad.c)
+add_executable(app main.cpp src/Shader.cpp src/glad.c)
 target_link_libraries(app glfw)

main.cpp

@@ -6,6 +6,7 @@
 
 #include <glad/glad.h>
 #include <GLFW/glfw3.h>
+#include "src/Shader.h"
 
 
 void framebuffer_size_callback(GLFWwindow* window, int width, int height);
@@ -38,12 +39,62 @@ int main() {
     glViewport(0, 0, 800, 600);
     glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
 
+    //// Setup geometry
+    float vertices[] = {
+            0.5f,  0.5f, 0.0f, 1.0f, 1.0f, 0.0f,  // top right
+            0.5f, -0.5f, 0.0f, 0.0f, 1.0f, 0.0f,  // bottom right
+            -0.5f, -0.5f, 0.0f,0.0f, 0.0f, 1.0f, // bottom left
+            -0.5f,  0.5f, 0.0f,1.0f, 0.0f, 0.0f // top left
+    };
+    unsigned int indices[] = {
+            0, 1, 3, // first triangle
+            1, 2, 3  // second triangle
+    };
+
+    unsigned int VBO, VAO, EBO;
+
+
+    //generate buffers
+    glGenBuffers(1, &VBO);
+    glGenVertexArrays(1, &VAO);
+    glGenBuffers(1, &EBO);
+
+    //Bind buffers
+    glBindBuffer(GL_ARRAY_BUFFER, VBO);
+    glBindVertexArray(VAO);
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
+
+    //copy data to buffers
+    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
+    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
+
+    //SetVertexAttribPointer
+    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), nullptr);
+    glEnableVertexAttribArray(0);
+    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)(3*sizeof(float)));
+    glEnableVertexAttribArray(1);
+
+
+    //Create shaders
+    Shader ourShader("src/shaders/shader.vert", "src/shaders/shader.frag");
+    ourShader.use();
+
+
+
+
     // Render loop
     while(!glfwWindowShouldClose(window)) {
         // Render
         glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
         glClear(GL_COLOR_BUFFER_BIT);
 
+        ourShader.use();
+        glBindVertexArray(VAO);
+        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
+
+        glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, nullptr);
+
+
         // Swap buffers
         glfwSwapBuffers(window);
         glfwPollEvents();

src/Shader.cpp

@@ -0,0 +1,92 @@
+//
+// Created by olivier on 5/3/22.
+//
+
+#include "Shader.h"
+
+Shader::Shader(const char* vertexPath, const char* fragmentPath){
+    // 1. retrieve the vertex/fragment source code from filePath
+    std::string vertexCode;
+    std::string fragmentCode;
+    std::ifstream vShaderFile;
+    std::ifstream fShaderFile;
+    // ensure ifstream objects can throw exceptions:
+    vShaderFile.exceptions (std::ifstream::failbit | std::ifstream::badbit);
+    fShaderFile.exceptions (std::ifstream::failbit | std::ifstream::badbit);
+    try{
+        // open files
+        vShaderFile.open(vertexPath);
+        fShaderFile.open(fragmentPath);
+        std::stringstream vShaderStream, fShaderStream;
+        // read file's buffer contents into streams
+        vShaderStream << vShaderFile.rdbuf();
+        fShaderStream << fShaderFile.rdbuf();
+        // close file handlers
+        vShaderFile.close();
+        fShaderFile.close();
+        // convert stream into string
+        vertexCode = vShaderStream.str();
+        fragmentCode = fShaderStream.str();
+    }
+    catch (std::ifstream::failure &e){
+        std::cout << "ERROR::SHADER::FILE_NOT_SUCCESFULLY_READ" << std::endl;
+    }
+    const char* vShaderCode = vertexCode.c_str();
+    const char* fShaderCode = fragmentCode.c_str();
+    // 2. compile shaders
+    unsigned int vertex, fragment;
+    int success;
+    char infoLog[512];
+    // vertex shader
+    vertex = glCreateShader(GL_VERTEX_SHADER);
+    glShaderSource(vertex, 1, &vShaderCode, nullptr);
+    glCompileShader(vertex);
+    // check for shader compile errors
+    glGetShaderiv(vertex, GL_COMPILE_STATUS, &success);
+    if (!success){
+        glGetShaderInfoLog(vertex, 512, nullptr, infoLog);
+        std::cout << vShaderCode << std::endl;
+        std::cout << "ERROR::SHADER::VERTEX::COMPILATION_FAILED\n" << infoLog << std::endl;
+    }
+    // fragment shader
+    fragment = glCreateShader(GL_FRAGMENT_SHADER);
+    glShaderSource(fragment, 1, &fShaderCode, nullptr);
+    glCompileShader(fragment);
+    // check for shader compile errors
+    glGetShaderiv(fragment, GL_COMPILE_STATUS, &success);
+    if (!success){
+        glGetShaderInfoLog(fragment, 512, nullptr, infoLog);
+        std::cout << fShaderCode << std::endl;
+        std::cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED\n" << infoLog << std::endl;
+    }
+    // shader program
+    ID = glCreateProgram();
+    glAttachShader(ID, vertex);
+    glAttachShader(ID, fragment);
+    glLinkProgram(ID);
+    // check for linking errors
+    if (!success){
+        glGetProgramiv(ID, GL_LINK_STATUS, &success);
+        if (!success){
+            glGetProgramInfoLog(ID, 512, nullptr, infoLog);
+            std::cout << "ERROR::SHADER::PROGRAM::LINKING_FAILED\n" << infoLog << std::endl;
+        }
+    }
+    // delete the shaders as they're linked into our program now and no longer necessery
+    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);
+}

src/Shader.h

@@ -0,0 +1,29 @@
+//
+// Created by olivier on 5/3/22.
+//
+
+#ifndef OPENGL_TEMPLATE_SHADER_H
+#define OPENGL_TEMPLATE_SHADER_H
+
+
+#include <string>
+#include <fstream>
+#include <sstream>
+#include <iostream>
+#include "glad/glad.h"
+
+class Shader {
+public:
+    unsigned int ID;
+
+    Shader(const char* vertexPath, const char* fragmentPath);
+    // activate the shader
+    void use();
+    // utility uniform functions
+    void setBool(const std::string &name, bool value) const;
+    void setInt(const std::string &name, int value) const;
+    void setFloat(const std::string &name, float value) const;
+};
+
+
+#endif //OPENGL_TEMPLATE_SHADER_H

src/shaders/shader.frag

@@ -0,0 +1,8 @@
+#version 330 core
+out vec4 FragColor;
+in vec3 ourColor;
+
+void main()
+{
+    FragColor = vec4(ourColor, 1.0);
+}

src/shaders/shader.vert

@@ -0,0 +1,11 @@
+#version 330 core
+layout (location = 0) in vec3 aPos;   // the position variable has attribute position 0
+layout (location = 1) in vec3 aColor; // the color variable has attribute position 1
+
+out vec3 ourColor; // output a color to the fragment shader
+
+void main()
+{
+   gl_Position = vec4(aPos, 1.0);
+   ourColor = aColor; // set ourColor to the input color we got from the vertex data
+}