Window resize aspect ratio glOrtho

Author Mitja Felicijan <mitja.felicijan@gmail.com> 2026-05-11 09:59:55 +0200
Committer Mitja Felicijan <mitja.felicijan@gmail.com> 2026-05-11 09:59:55 +0200
Commit d5430da02bf1004b91b9d75784dba4ccf1ede01a (patch)
-rw-r--r-- main.c 21
1 files changed, 19 insertions, 2 deletions
diff --git a/main.c b/main.c
...
221 
	glEnable(GL_DEPTH_TEST);
 221 
	glEnable(GL_DEPTH_TEST);
222 
	glMatrixMode(GL_PROJECTION);
 222 
	glMatrixMode(GL_PROJECTION);
223 
	glLoadIdentity();
 223 
	glLoadIdentity();
224 
	glOrtho(0.0, 1.0, 0.0, 1.0, -1.0, 1.0);
 224 
  
 
  
 225 
	int w = game.width;
 
  
 226 
	int h = game.height;
 
  
 227 
	if (h == 0) h = 1;
 
  
 228 
	float aspect = (float)w / (float)h;
 
  
 229 
	if (w >= h) {
 
  
 230 
		glOrtho(0.5 - 0.5 * aspect, 0.5 + 0.5 * aspect, 0.0, 1.0, -1.0, 1.0);
 
  
 231 
	} else {
 
  
 232 
		glOrtho(0.0, 1.0, 0.5 - 0.5 / aspect, 0.5 + 0.5 / aspect, -1.0, 1.0);
 
  
 233 
	}
225 
}
 234 
}
226 
  
 235 
  
227 
void handle_mouse_event(int button, int state, int x, int y) {
 236 
void handle_mouse_event(int button, int state, int x, int y) {
...
264 
}
 273 
}
265 
  
 274 
  
266 
void handle_reshape(int w, int h) {
 275 
void handle_reshape(int w, int h) {
 
  
 276 
	if (h == 0) h = 1;
267 
	glViewport (0, 0, (GLsizei) w, (GLsizei) h);
 277 
	glViewport (0, 0, (GLsizei) w, (GLsizei) h);
268 
	glMatrixMode(GL_PROJECTION);
 278 
	glMatrixMode(GL_PROJECTION);
269 
	glLoadIdentity();
 279 
	glLoadIdentity();
270 
	glOrtho(0.0, 1.0, 0.0, 1.0, -1.0, 1.0);
 280 
  
 
  
 281 
	float aspect = (float)w / (float)h;
 
  
 282 
	if (w >= h) {
 
  
 283 
		glOrtho(0.5 - 0.5 * aspect, 0.5 + 0.5 * aspect, 0.0, 1.0, -1.0, 1.0);
 
  
 284 
	} else {
 
  
 285 
		glOrtho(0.0, 1.0, 0.5 - 0.5 / aspect, 0.5 + 0.5 / aspect, -1.0, 1.0);
 
  
 286 
	}
 
  
 287 
  
271 
	glMatrixMode(GL_MODELVIEW);
 288 
	glMatrixMode(GL_MODELVIEW);
272 
	glLoadIdentity();
 289 
	glLoadIdentity();
273 
}
 290 
}
...