Moved shader creation code out of main

src/main.c

@@ -1,68 +1,29 @@
 #include <GL/glew.h>
 #include <SDL3/SDL.h>
 #include <stdlib.h>
-#include <time.h>
 
 #include "SDL3/SDL_events.h"
 #include "SDL3/SDL_keycode.h"
 #include "camera.h"
+#include "shader.h"
 #include "window.h"
 
-// settings
-const unsigned int SCR_WIDTH = 800;
-const unsigned int SCR_HEIGHT = 600;
-
 int main(int argc, char *argv[]) {
 
   wn_window window = {0};
   if (!wn_window_init(&window)) {
     SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't initialize wn_window");
+    return EXIT_FAILURE;
   }
+  wn_shader_code_location shader_code_location = {
+      .vertex_shader_source_path = "shaders/vert.glsl",
+      .fragment_shader_source_path = "shaders/frag.glsl"};
 
-  const char *vertexShaderSource = SDL_LoadFile("shaders/vert.glsl", NULL);
-  const char *fragmentShaderSource = SDL_LoadFile("shaders/frag.glsl", NULL);
-
-  // vertex shader
-  unsigned int vertexShader = glCreateShader(GL_VERTEX_SHADER);
-  glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
-  glCompileShader(vertexShader);
-  // check for shader compile errors
-  int success;
-  char infoLog[512];
-  glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
-  if (!success) {
-    glGetShaderInfoLog(vertexShader, 512, NULL, infoLog);
-    SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
-                 "Failed to compile vertex shader: %s", infoLog);
+  wn_shader shader = wn_shader_init(shader_code_location);
+  if (shader.success == false) {
+    SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't initialize shader");
+    return EXIT_FAILURE;
   }
-  // fragment shader
-  unsigned int fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
-  glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
-  glCompileShader(fragmentShader);
-  // check for shader compile errors
-  glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
-  if (!success) {
-    glGetShaderInfoLog(fragmentShader, 512, NULL, infoLog);
-    SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
-                 "Failed to compile fragment shader: %s", infoLog);
-  }
-  // Free source code memory
-  SDL_free((void *)vertexShaderSource);
-  SDL_free((void *)fragmentShaderSource);
-  // link shaders
-  unsigned int shaderProgram = glCreateProgram();
-  glAttachShader(shaderProgram, vertexShader);
-  glAttachShader(shaderProgram, fragmentShader);
-  glLinkProgram(shaderProgram);
-  // check for linking errors
-  glGetProgramiv(shaderProgram, GL_LINK_STATUS, &success);
-  if (!success) {
-    glGetProgramInfoLog(shaderProgram, 512, NULL, infoLog);
-    SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
-                 "Failed to link shader program: %s", infoLog);
-  }
-  glDeleteShader(vertexShader);
-  glDeleteShader(fragmentShader);
 
   // set up vertex data (and buffer(s)) and configure vertex attributes
   float vertices[] = {
@@ -134,7 +95,8 @@ int main(int argc, char *argv[]) {
     mat4 mvp;
     camera_calc_mvp(&mvp, &camera);
     // glm_mat4_print(mvp,stdout);
-    int mvp_uniform_location = glGetUniformLocation(shaderProgram, "MVP");
+    int mvp_uniform_location =
+        glGetUniformLocation(shader.shaderProgram, "MVP");
     glUniformMatrix4fv(mvp_uniform_location, 1, GL_FALSE, &mvp[0][0]);
 
     // render
@@ -142,7 +104,7 @@ int main(int argc, char *argv[]) {
     glClear(GL_COLOR_BUFFER_BIT);
 
     // draw our first triangle
-    glUseProgram(shaderProgram);
+    glUseProgram(shader.shaderProgram);
     glBindVertexArray(
         VAO); // seeing as we only have a single VAO there's no need to bind it
               // every time, but we'll do so to keep things a bit more organized
@@ -156,8 +118,8 @@ int main(int argc, char *argv[]) {
   glDeleteVertexArrays(1, &VAO);
   glDeleteBuffers(1, &VBO);
   glDeleteBuffers(1, &EBO);
-  glDeleteProgram(shaderProgram);
 
+  wn_shader_deinit(shader);
   wn_window_deinit(&window);
 
   return EXIT_SUCCESS;

src/shader.c

@@ -0,0 +1,70 @@
+#include "shader.h"
+#include "SDL3/SDL_iostream.h"
+#include "SDL3/SDL_log.h"
+#include <GLES2/gl2.h>
+
+wn_shader wn_shader_init(wn_shader_code_location shader_code_location) {
+  wn_shader shader = {.shaderProgram = 0, .success = false};
+
+  const char *vertexShaderSource =
+      SDL_LoadFile(shader_code_location.vertex_shader_source_path, NULL);
+  const char *fragmentShaderSource =
+      SDL_LoadFile(shader_code_location.fragment_shader_source_path, NULL);
+
+  // vertex shader
+  unsigned int vertexShader = glCreateShader(GL_VERTEX_SHADER);
+  glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
+  glCompileShader(vertexShader);
+  // check for shader compile errors
+  int success;
+  char infoLog[512];
+  glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
+  if (!success) {
+    glGetShaderInfoLog(vertexShader, 512, NULL, infoLog);
+    SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
+                 "Failed to compile vertex shader: %s", infoLog);
+    return shader;
+  }
+
+  // fragment shader
+  unsigned int fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
+  glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
+  glCompileShader(fragmentShader);
+  // check for shader compile errors
+  glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
+  if (!success) {
+    glGetShaderInfoLog(fragmentShader, 512, NULL, infoLog);
+    SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
+                 "Failed to compile fragment shader: %s", infoLog);
+    return shader;
+  }
+
+  // Free source code memory
+  SDL_free((void *)vertexShaderSource);
+  SDL_free((void *)fragmentShaderSource);
+
+  // link shaders
+  unsigned int shaderProgram = glCreateProgram();
+  glAttachShader(shaderProgram, vertexShader);
+  glAttachShader(shaderProgram, fragmentShader);
+  glLinkProgram(shaderProgram);
+
+  // check for linking errors
+  glGetProgramiv(shaderProgram, GL_LINK_STATUS, &success);
+  if (!success) {
+    glGetProgramInfoLog(shaderProgram, 512, NULL, infoLog);
+    SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
+                 "Failed to link shader program: %s", infoLog);
+    return shader;
+  }
+  glDeleteShader(vertexShader);
+  glDeleteShader(fragmentShader);
+
+  shader.shaderProgram = shaderProgram;
+  shader.success = true;
+  return shader;
+}
+
+void wn_shader_deinit(wn_shader shader) {
+  glDeleteProgram(shader.shaderProgram);
+}

src/shader.h

@@ -1,5 +1,7 @@
 #pragma once
 
+#include <stdbool.h>
+
 typedef struct {
   const char *vertex_shader_source_path;
   const char *fragment_shader_source_path;
@@ -7,6 +9,7 @@ typedef struct {
 
 struct wn_shader_s {
   unsigned int shaderProgram;
+  bool success;
 };
 typedef struct wn_shader_s wn_shader;