camera->pan = 0;
camera->tilt = -90;
camera->roll = -90;
...
vecMouse.x = mouse_pos.x - ( screen_size.x / 2 );
vecMouse.y = ( screen_size.y / 2 ) - mouse_pos.y;
vecCameraOffset.x = player.x + vecMouse.x*0.8;
vecCameraOffset.y = player.y + vecMouse.y*0.8;
camera.x += (vecCameraOffset.x-camera.x) * time_step * 0.1;
camera.y += (vecCameraOffset.y-camera.y) * time_step * 0.1;