feat: added FullscreenQuad

FullScreenQuad.hpp

@@ -0,0 +1,33 @@
+#include <GL/glew.h>
+
+
+class FullScreenQuad {
+private:
+    unsigned int vao;
+public:
+    FullScreenQuad();
+    int getVAO() { return vao;}
+};
+
+FullScreenQuad::FullScreenQuad(){
+    float quadVertices[] = { // vertex attributes for a quad that fills the entire screen in Normalized Device Coordinates.
+        // positions   // texCoords
+        -1.0f,  1.0f,  0.0f, 1.0f,
+        -1.0f, -1.0f,  0.0f, 0.0f,
+         1.0f, -1.0f,  1.0f, 0.0f,
+
+        -1.0f,  1.0f,  0.0f, 1.0f,
+         1.0f, -1.0f,  1.0f, 0.0f,
+         1.0f,  1.0f,  1.0f, 1.0f
+    };
+    unsigned int vbo;
+    glGenVertexArrays(1, &vao);
+    glGenBuffers(1, &vbo);
+    glBindVertexArray(vao);
+    glBindBuffer(GL_ARRAY_BUFFER, vbo);
+    glBufferData(GL_ARRAY_BUFFER, sizeof(quadVertices), &quadVertices, GL_STATIC_DRAW);
+    glEnableVertexAttribArray(0);
+    glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(float), (void*)0);
+    glEnableVertexAttribArray(1);
+    glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(float), (void*)(2 * sizeof(float)));
+}

main.cpp

@@ -1,6 +1,7 @@
 #include <GL/glew.h>
 #include <GLFW/glfw3.h>
 #include <cstdio>
+#include "FullScreenQuad.hpp"
 
 float vertices[] = {
     -0.5f, -0.5f, 0.0f,
@@ -92,6 +93,10 @@ void linkVBO() {
     glEnableVertexAttribArray(0); 
 }
 
+void framebuffer_size_callback(GLFWwindow* window, int width, int height)
+{
+    glViewport(0, 0, width, height);
+}  
 
 int main(int argc, char** argv) {
 
@@ -100,7 +105,7 @@ int main(int argc, char** argv) {
     if (!glfwInit())
         return -1;
 
-    window = glfwCreateWindow(640, 480, "Hello World", NULL, NULL);
+    window = glfwCreateWindow(800, 600, "Hello World", NULL, NULL);
 
     if (!window)
     {
@@ -119,9 +124,14 @@ int main(int argc, char** argv) {
 
     glViewport(0, 0, 800, 600);
 
+
+    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);  
+
     unsigned int shaderProgramm = compShader();
     unsigned int VAO = initVAO();
 
+    FullScreenQuad fsq{};
+
     while (!glfwWindowShouldClose(window))
     {
         processInput(window);
@@ -136,6 +146,9 @@ int main(int argc, char** argv) {
 
         glBindVertexArray(VAO);
 	glDrawArrays(GL_TRIANGLES, 0, 3);
+	glBindVertexArray(fsq.getVAO());	
+	glDrawArrays(GL_TRIANGLES, 0, 6);
+
         /* Poll for and process events */
         glfwPollEvents();