opengl-test

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commit 30a165a3e371b3be8856e4f99f0f6735734c7918
parent 9ef8bcb2a409b0419c46cf7522e9192305a0a7d5
Author: mjkloeckner <martin.cachari@gmail.com>
Date:   Fri, 30 Dec 2022 17:52:44 -0300

add framebufferSizeCallback and downgrade GLSL version

add framebufferSizeCallback to resize content on window when it gets
resized

GLSL version downgraded to 3.30 for legacy support

Diffstat:
M
main.c
 | 
31
++++++++++++++++++++++---------
M
main.frag
 | 
2
+-
M
main.vert
 | 
6
+++---

3 files changed, 26 insertions(+), 13 deletions(-)
diff --git a/main.c b/main.c
@@ -15,6 +15,10 @@ void glfwPrintError(int e, const char *s) {
     fprintf(stderr, "%s\n", s);
 }
 
+void framebufferSizeCallback(GLFWwindow* win, int width, int height) {
+    glViewport(0, 0, width, height);
+}
+
 char *loadShaderFromFile(const char *filename) {
     char *buffer;
     long len;
@@ -27,7 +31,7 @@ char *loadShaderFromFile(const char *filename) {
         buffer = (char *)malloc(len + 1);
         buffer[len] = '\0';
 
-        if(buffer)
+        if(buffer) 
             fread (buffer, 1, len, f);
 
         fclose (f);
@@ -40,7 +44,7 @@ int main (void) {
     GLenum err;
     GLFWwindow *win;
     unsigned int VBO, VAO; /* Vertex Buffer Objects, Vertex Array Objects */
-    const char *vertexShaderSource, *fragmentShaderSource;
+    char *vertexShaderSource, *fragmentShaderSource;
     unsigned int vertexShader, fragmentShader, shaderProgram;
     int success;
     char infoLog[512];
@@ -54,6 +58,7 @@ int main (void) {
         glfwTerminate();
 
     glfwSetErrorCallback(&glfwPrintError);
+    glfwSetFramebufferSizeCallback(win, framebufferSizeCallback);
     glfwMakeContextCurrent(win);
 
     if((err = glewInit())) {
@@ -63,9 +68,9 @@ int main (void) {
 
     /*  Vertex Input (or Vertex Data)  */
     float vertices[] = {
-        -0.5f, -0.5f, 0.0f,
-         0.5f, -0.5f, 0.0f,
-         0.0f,  0.5f, 0.0f,
+        -0.5f, -0.5f,
+         0.5f, -0.5f,
+         0.0f,  0.5f,
     };
 
     /* Generate an unique ID to VBO */
@@ -91,7 +96,7 @@ int main (void) {
     }
 
     vertexShader = glCreateShader(GL_VERTEX_SHADER);
-    glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
+    glShaderSource(vertexShader, 1, (char const* const*)&vertexShaderSource, NULL);
     glCompileShader(vertexShader);
 
     /* Check if the Vertex Shader compiled succesfully */
@@ -110,7 +115,7 @@ int main (void) {
     }
 
     fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
-    glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
+    glShaderSource(fragmentShader, 1, (char const* const*)&fragmentShaderSource, NULL);
     glCompileShader(fragmentShader);
 
     /* Check if the Fragment Shader compiled succesfully */
@@ -143,12 +148,14 @@ int main (void) {
     glBindVertexArray(VAO);
 
     /* Linking Vertex attributes */
-    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE,
-            3 * sizeof(float), (void *)0);
+    glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE,
+            2 * sizeof(float), (void *)0);
+
     glEnableVertexAttribArray(0);
     glUseProgram(shaderProgram);
     glBindVertexArray(VAO);
 
+    /* main loop */
     while (!glfwWindowShouldClose(win)) {
         glClear(GL_COLOR_BUFFER_BIT);
 
@@ -160,6 +167,12 @@ int main (void) {
 
     free(vertexShaderSource);
     free(fragmentShaderSource);
+
+    glDeleteVertexArrays(1, &VAO);
+    glDeleteBuffers(1, &VBO);
+    glDeleteProgram(shaderProgram);
+
+    glfwDestroyWindow(win);
     glfwTerminate();
     return 0;
 }
diff --git a/main.frag b/main.frag
@@ -1,4 +1,4 @@
-#version 410 core
+#version 330 core
 out vec4 fragColor;
 
 void main() {
diff --git a/main.vert b/main.vert
@@ -1,6 +1,6 @@
-#version 410 core
-layout (location = 0) in vec3 aPos;
+#version 330 core
+layout (location = 0) in vec2 pos;
 
 void main() {
-    gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);
+    gl_Position = vec4(pos.x, pos.y, 0.0, 1.0);
 }