Subtle OpenGL Projection Matrix Difference Between iPhone Simulator and Device

Anthony Caliendo, Tuesday, December 2, 2008 @ 6:27 pm

If you are deploying to the iPhone simulator instead of to a device, you can get away with not loading the identity matrix for the projection matrix so long as you do not want to draw over any bound textures which are drawn.  However, on an iPhone device, you will notice some serious artifacting if you attempt this.  The artifacts will be related to the last drawn textures, even if they were drawn from a different application (except if the phone was turned off in the interim, in which case you will get a black strobe effect).

This implies that the simulator loads the identity matrix automatically for GL_PROJECTION when loading your application, where as the iPhone itself will maintain the matrix's state between applications.

agile ajax

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