rgb tri

headers/shapes.h

@@ -0,0 +1,56 @@
+float tri_vertices[] = {-0.5f, -0.5f, 0.0f, 0.5f, -0.5f,
+                        0.0f,  0.0f,  0.5f, 0.0f};
+float tri_rgb_vertices[] = {
+    0.5f,  -0.5f, 0.0f, 1.0f, 0.0f, 0.0f, /**/
+    -0.5f, -0.5f, 0.0f, 0.0f, 1.0f, 0.0f, /**/
+    0.0f,  0.5f,  0.0f, 0.0f, 0.0f, 1.0f  /**/
+};
+
+float sqr_vertices[] = {
+    0.5f,  0.5f,  0.0f, /*top R*/
+    0.5f,  -0.5f, 0.0f, /*bottom R*/
+    -0.5f, -0.5f, 0.0f, /*bottom L*/
+    -0.5f, 0.5f,  0.0f  /*top R*/
+};
+
+unsigned int sqr_indices[] = {
+    0, 1, 3, /*tl triangle*/
+    1, 2, 3  /*br triangle*/
+};
+
+const char *basicVertexShaderSource =
+    "#version 330 core\n"
+    "layout (location = 0) in vec3 aPos;\n"
+    "out vec3 color;\n"
+    "void main()\n"
+    "{\n"
+    "   color = aPos;"
+    "   gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);\n"
+    "}\0";
+
+const char *basicFragmentShaderSource = "#version 330 core\n"
+                                        "out vec3 FragColor;\n"
+                                        "in vec3 color;"
+                                        "void main()\n"
+                                        "{\n"
+                                        "    FragColor = (color/2+.5)*1.5;\n"
+                                        "}\n";
+
+const char *rgbVertexShaderSource =
+    "#version 330 core\n"
+    "layout (location = 0) in vec3 aPos;\n"
+    "layout (location = 1) in vec3 aColor;\n"
+    "out vec3 color;\n"
+    "void main()\n"
+    "{\n"
+    "   color = aColor;\n"
+    "   gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);\n"
+    "}\0";
+
+const char *rgbFragmentShaderSource = "#version 330 core\n"
+                                      "out vec4 FragColor;\n"
+                                      "in vec3 color;\n"
+                                      "void main()\n"
+                                      "{\n"
+                                      "    FragColor = vec4(color, 1.0);\n"
+                                      "}\0";

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 framebuffer_size_callback(GLFWwindow* window, int width, int height);
+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 +32,43 @@ int main(void) {
   glViewport(0, 0, 800, 600);
   glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
 
-  while(!glfwWindowShouldClose(window))
+  unsigned int VBO,VAO,EBO;
-    {
+  glGenVertexArrays(1, &VAO);
+  glBindVertexArray(VAO);
+
+  glGenBuffers(1, &VBO);
+  glBindBuffer(GL_ARRAY_BUFFER, VBO);
+
+  glBufferData(GL_ARRAY_BUFFER, sizeof(tri_rgb_vertices), tri_rgb_vertices,
+               GL_STATIC_DRAW);
+  glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void *)0);
+  glEnableVertexAttribArray(0);
+  glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void *)(3 * sizeof(float)));
+  glEnableVertexAttribArray(1);
+
+  /*
+  glGenBuffers(1, &EBO);
+  glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
+  glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(sqr_indices), sqr_indices, GL_STATIC_DRAW);
+  */
+
+  unsigned int shaderProgram =
+      shaderProgramCMPL(rgbVertexShaderSource, rgbFragmentShaderSource);
+  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);
+
+    //glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
+    glDrawArrays(GL_TRIANGLES, 0, 3);
     glfwSwapBuffers(window);
+
     glfwPollEvents();
   }
 
@@ -34,7 +76,65 @@ int main(void) {
   return 0;
 }
 
-void framebuffer_size_callback(GLFWwindow* window, int width, int height) {
+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;
+  }
+}