I have a 2d game I've made using OpenGL ES. The game contains a large quad that fills the entire screen (as a background image) and many smaller quads that make up a number of balls that bounce across the screen.
To illustrate displaying a ball, I may have a single quad with vertices
(0,0),(0,1),(1,1),(1,0). I then fill this quad with a texture (a colored ball).
I am wondering if I need to perform back-face culling (for performance reasons). Given these 4 vertices, I assume a polygon is drawn to connect them. Is it actually the case that two polygons are drawn? One facing forward and another one facing the back? I'm struggling to understand.
I have tried getting face culling working and I think I've succeeded, but I've not really noticed any difference in rendering times.
Not sure if relevant, but here is my environment setup code:
gl.glEnable(GL10.GL_TEXTURE_2D); gl.glDisable(GL10.GL_DEPTH_TEST); gl.glViewport(0, 0, width, height); gl.glLoadIdentity(); gl.glMatrixMode (GL10.GL_PROJECTION); gl.glLoadIdentity(); gl.glOrthof(0, width, height, 0, 0, 1); gl.glMatrixMode (GL10.GL_MODELVIEW);