My opengl program on OSX renders a 3D scene to texture using FBO, reads from the FBO using glReadPixels and transmits the data over IP to an iPhone app using OpenGL ES 1.1. Since OpenglES does not support glDrawPixels, I am using glTexSubImage instead to upload texture. I dont do any modifications to the buffer in which data was captured, but I verify that the data is correct (I can convert it to a UIImage and display it). But when I use it in an opegl view I am not able to get it to work. Any pointers/suggestions are appreciated. Are there any exmaples available?