example: adds SDL3 example (#532)

Author: eloj

README.md

@@ -60,6 +60,7 @@ Examples can be found [in the example directory](/example). Some examples:
     * [GL GLFW](example/c/gl_glfw.c)
     * [GL GLFW On-Demand loading](example/c/gl_glfw_on_demand.c)
     * [GL GLFW Multiple Windows/Contexts](example/c++/multiwin_mx/)
+    * [GL SDL3](example/c/gl_sdl3.c)
     * [GL SDL2](example/c/gl_sdl2.c)
     * [Vulkan GLFW](example/c/vulkan_tri_glfw/)
     * [GLX](example/c/glx.c)

example/c/gl_sdl3.c

@@ -0,0 +1,68 @@
+// gcc $(pkg-config --cflags --libs sdl3) -I${GLAD_PATH}/include example/c/gl_sdl3.c ${GLAD_PATH}/src/gl.c
+#include <stdlib.h>
+#include <stdio.h>
+
+#include <glad/gl.h>
+#include <SDL3/SDL.h>
+#include <SDL3/SDL_main.h>
+
+const GLuint WIDTH = 800, HEIGHT = 600;
+
+int main(void) {
+    // code without checking for errors
+    SDL_Init(SDL_INIT_VIDEO);
+
+    SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
+    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
+    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 2);
+    SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
+
+    SDL_Window *window;
+    SDL_Renderer *renderer;
+
+    SDL_CreateWindowAndRenderer(
+        "[glad] GL with SDL3",
+        WIDTH, HEIGHT,
+        SDL_WINDOW_OPENGL,
+        &window, &renderer
+    );
+
+    SDL_GLContext context = SDL_GL_CreateContext(window);
+
+    int version = gladLoadGL((GLADloadfunc) SDL_GL_GetProcAddress);
+    printf("GL %d.%d\n", GLAD_VERSION_MAJOR(version), GLAD_VERSION_MINOR(version));
+
+    int exit = 0;
+    while(!exit) {
+        SDL_Event event;
+        while (SDL_PollEvent(&event)) {
+            switch(event.type) {
+                case SDL_EVENT_WINDOW_CLOSE_REQUESTED:
+                    /* fallthrough */
+                case SDL_EVENT_QUIT:
+                    exit = 1;
+                    break;
+                case SDL_EVENT_KEY_DOWN:
+                    if (event.key.key == SDLK_ESCAPE) {
+                        exit = 1;
+                    }
+                    break;
+                default:
+                    break;
+            }
+        }
+
+        glClearColor(0.7f, 0.9f, 0.1f, 1.0f);
+        glClear(GL_COLOR_BUFFER_BIT);
+
+        SDL_GL_SwapWindow(window);
+        SDL_Delay(1);
+    }
+
+    SDL_GL_DestroyContext(context);
+    SDL_DestroyRenderer(renderer);
+    SDL_DestroyWindow(window);
+    SDL_Quit();
+
+    return 0;
+}