Original Post
In my program I want to use a picture as a texture. I load it like this: ///////////////////////////////////////////////////// data=(void*)pData; format = GL_BGRA; type = GL_HALF_FLOAT_NV; glDrawPixels(image_w, image_h, format, type, data);//image_w=4096,image_h=4096 ///////////////////////////////////////////////////////////// In fact,I can only see part of the picture.Most of the data out of screen. after render it ,I want to read the result data. I use glReadPixels(0, 0, image_w, 4096,GL_LUMINANCE, GL_UNSIGNED_BYTE,data1); But I can only get the data on the screen that I can see ,the other part of picture is black. How can it get all the data that I load? thanks.