Imagination PowerVR SDK Blog

glTranslatef with negative values not drawing



I am rendering a scene with the viewport/project setup to mimic 2D. So I have something like:

glLoadIdentity ();

glMatrixMode (GL_PROJECTION);

glLoadIdentity ();

glViewport(0, 0, width, height);

glOrthof (0, width, height, 0, 0, 1);

glMatrixMode (GL_MODELVIEW);

glTranslatef(trans_x, trans_y, 0);

If I draw textures or triangles in this method things work fine. However if I change my trans_x or trans_y to a negative value then nothing renders. I can for example draw a texture with (vertex) x=-20 then things work fine. However if I draw with x=0 and the trans_x at -20 the texture does not display. Also positive values for translation work as expected.

Thanks for any help,



Sorry I should have mentioned that I am testing this with the WindowsPC SDK running on a Windows 7 laptop.