render simple triangle

main.cpp

@@ -1,18 +1,134 @@
+#include <iostream>
 #include "glad/glad.h"
 #include "GLFW/glfw3.h"
 
-int main(int argc, char** const argv){
+void frameBufferSizeChange(GLFWwindow *window, int width, int height) {
+    glViewport(0, 0, width, height);
+}
+
+void processInput(GLFWwindow *window) {
+    if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS) {
+        glfwSetWindowShouldClose(window, true);
+    }
+}
+
+void CheckShader(unsigned int shaderIndex, bool isPorgram = false) {
+    int successful;
+    char logInfo[512];
+    if (isPorgram) {
+        glad_glGetProgramiv(shaderIndex, GL_LINK_STATUS, &successful);
+    } else {
+        glad_glGetShaderiv(shaderIndex, GL_COMPILE_STATUS, &successful);
+    }
+    if (!successful){
+        if(isPorgram){
+            glad_glGetProgramInfoLog(shaderIndex, 512, nullptr, logInfo);
+        }else{
+            glad_glGetShaderInfoLog(shaderIndex, 512, nullptr, logInfo);
+        }
+        std::cout<<logInfo<<std::endl;
+    }
+}
+
+const char *vertexShaderSource = "#version 330 core\n"
+                                 "layout (location = 0) in vec3 aPos;\n"
+                                 "void main()\n"
+                                 "{\n"
+                                 "  gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);\n"
+                                 "}\n";
+
+const char *fragmentShaderSource = "#version 330 core\n"
+                                   "out vec4 FragColor;\n"
+                                   "void main()\n"
+                                   "{\n"
+                                   "   FragColor = vec4(1.0f, 0.5f, 0.2f, 1.0f);\n"
+                                   "}\n\0";
+
+
+int main(int argc, char **const argv) {
     glfwInit();
-    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
     glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
+    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
     glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
 
-    auto window = glfwCreateWindow(800, 600, "Window", nullptr, nullptr);
-    glfwMakeContextCurrent(window);
-
-    if(!gladLoadGLLoader((GLADloadproc) glfwGetProcAddress)){
-        auto error = glad_glGetError();
-        return error;
+    GLFWwindow *window = glfwCreateWindow(800, 600, "Windows", nullptr, nullptr);
+    if (window == nullptr) {
+        return -1;
     }
+    glfwMakeContextCurrent(window);
+    glfwSetWindowSizeCallback(window, frameBufferSizeChange);
+
+    if (!gladLoadGLLoader((GLADloadproc) glfwGetProcAddress)) {
+        auto error = glad_glGetError();
+        return static_cast<int>(error);
+    }
+
+    float vertices[] = {
+            -0.5, 0.5f, 0.0f,
+            0.5f, 0.5f, 0.0f,
+            0.5f, -0.5f, 0.0f,
+            -0.5f, -0.5f, 0.0f,
+    };
+
+    unsigned int indices[] = {
+            0, 1, 3,
+            1, 2, 3,
+    };
+
+    unsigned int VAO, VBO, EBO;
+    glGenVertexArrays(1, &VAO);
+    glGenBuffers(1, &VBO);
+    glGenBuffers(1, &EBO);
+
+    glBindVertexArray(VAO);
+    glBindBuffer(GL_ARRAY_BUFFER, VBO);
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
+
+    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
+    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
+    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void *) 0);
+
+    glEnableVertexAttribArray(0);
+    glBindVertexArray(0);
+
+
+    unsigned int vertexShader, fragmentShader, shaderProgram;
+    vertexShader = glCreateShader(GL_VERTEX_SHADER);
+    fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
+    shaderProgram = glCreateProgram();
+    glShaderSource(vertexShader, 1, &vertexShaderSource, nullptr);
+    CheckShader(vertexShader);
+    glShaderSource(fragmentShader, 1, &fragmentShaderSource, nullptr);
+    CheckShader(fragmentShader);
+
+    glAttachShader(shaderProgram, vertexShader);
+    glAttachShader(shaderProgram, fragmentShader);
+    glLinkProgram(shaderProgram);
+    CheckShader(shaderProgram, true);
+
+    glDeleteShader(vertexShader);
+    glDeleteShader(fragmentShader);
+
+    glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
+
+    while (!glfwWindowShouldClose(window)) {
+        processInput(window);
+
+        glClearColor(.2f, .3f, .3f, 1.0f);
+        glClear(GL_COLOR_BUFFER_BIT);
+
+        glUseProgram(shaderProgram);
+        glBindVertexArray(VAO);
+//        glDrawArrays(GL_TRIANGLES, 0, 3);
+        glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
+        glfwSwapBuffers(window);
+        glfwPollEvents();
+    }
+
+    glDeleteVertexArrays(1, &VAO);
+    glDeleteBuffers(1, &VBO);
+    glDeleteProgram(shaderProgram);
+
+    glfwTerminate();
     return 0;
 }