Hello triangle

headers/shapes.h

@@ -0,0 +1,16 @@
+float tri_vertices[] = {-0.5f, -0.5f, 0.0f, 0.5f, -0.5f, 0.0f, 0.0f, 0.5f, 0.0f};
+
+
+const char *basicVertexShaderSource = "#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"
+    "}\0";
+
+const char *basicFragmentShaderSource = "#version 330 core\n"
+  "out vec4 FragColor;\n"
+  "void main()\n"
+  "{\n"
+  "    FragColor = vec4(1.0f, 0.5f, 0.2f, 1.0f);\n"
+  "}\n";

src/main.cpp

@@ -1,10 +1,18 @@
 #include <glad/glad.h>
 #include <GLFW/glfw3.h>
 #include <cassert>
+#include <iostream>
+#include <shapes.h>
 
 #define UNUSED(x) (void)(x)
 
+void processInput(GLFWwindow *window);
 void framebuffer_size_callback(GLFWwindow *window, int width, int height);
+unsigned int shaderCMPL(GLenum type, const char *src);
+void shaderERR(unsigned int shader);
+unsigned int shaderProgramCMPL(const char *vertexSource,
+                               const char *fragmentSource);
+void shaderProgramERR(unsigned int shaderProgram);
 
 int main(void) {
   int tmp = 0;
@@ -24,9 +32,34 @@ int main(void) {
   glViewport(0, 0, 800, 600);
   glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
 
-  while(!glfwWindowShouldClose(window))
-    {
+  unsigned int VBO,VAO;
+  glGenVertexArrays(1, &VAO);
+  glBindVertexArray(VAO);
+
+  glGenBuffers(1, &VBO);
+  glBindBuffer(GL_ARRAY_BUFFER, VBO);
+
+  glBufferData(GL_ARRAY_BUFFER, sizeof(tri_vertices), tri_vertices,
+               GL_STATIC_DRAW);
+
+  glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void *)0);
+  glEnableVertexAttribArray(0);
+
+  unsigned int shaderProgram =
+      shaderProgramCMPL(basicVertexShaderSource, basicFragmentShaderSource);
+  glUseProgram(shaderProgram);
+
+  while (!glfwWindowShouldClose(window)) {
+    processInput(window);
+
+    glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
+    glClear(GL_COLOR_BUFFER_BIT);
+
+    glUseProgram(shaderProgram);
+    glBindVertexArray(VAO);
+    glDrawArrays(GL_TRIANGLES, 0, 3);
     glfwSwapBuffers(window);
+
     glfwPollEvents();
   }
 
@@ -34,7 +67,65 @@ int main(void) {
   return 0;
 }
 
+void processInput(GLFWwindow *window) {
+  if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
+    glfwSetWindowShouldClose(window, true);
+}
+
 void framebuffer_size_callback(GLFWwindow *window, int width, int height) {
   UNUSED(window);
   glViewport(0, 0, width, height);
 }
+
+unsigned int shaderCMPL(GLenum type, const char *src) {
+  unsigned int shader;
+  shader = glCreateShader(type);
+  glShaderSource(shader, 1, &src, NULL);
+  glCompileShader(shader);
+  return shader;
+}
+
+void shaderERR(unsigned int shader) {
+  int success;
+  char infoLog[512];
+  glGetShaderiv(shader, GL_COMPILE_STATUS, &success);
+
+  if (!success) {
+    glGetShaderInfoLog(shader, 512, NULL, infoLog);
+    std::cout << "ERROR::SHADER::COMPILATION_FAILED\n" << infoLog << std::endl;
+  }
+}
+
+unsigned int shaderProgramCMPL(const char *vertexSource,
+                               const char *fragmentSource) {
+  unsigned int vertexShader;
+  vertexShader = shaderCMPL(GL_VERTEX_SHADER, vertexSource);
+  shaderERR(vertexShader);
+
+  unsigned int fragmentShader;
+  fragmentShader = shaderCMPL(GL_FRAGMENT_SHADER, fragmentSource);
+  shaderERR(fragmentShader);
+
+  unsigned int shaderProgram;
+  shaderProgram = glCreateProgram();
+
+  glAttachShader(shaderProgram, vertexShader);
+  glAttachShader(shaderProgram, fragmentShader);
+  glLinkProgram(shaderProgram);
+  shaderProgramERR(shaderProgram);
+  glDeleteShader(vertexShader);
+  glDeleteShader(fragmentShader);
+
+  return shaderProgram;
+}
+
+void shaderProgramERR(unsigned int shaderProgram) {
+  int success;
+  char infoLog[512];
+  glGetProgramiv(shaderProgram, GL_LINK_STATUS, &success);
+
+  if (!success) {
+    glGetProgramInfoLog(shaderProgram, 512, NULL, infoLog);
+    std::cout << "ERROR::SHADER::PROGRAM::FAILED\n" << infoLog << std::endl;
+  }
+}