I wrote a sample on iOS, use OpenGL ES 2.0, then encountered a problem about shaders.
In a simply scene, I do the following
Code :
GLuint shaderProgramA;
GLuint shaderProgramB;
- (void) render
  gluseProgram( shaderProgramA );
  // render something
  gluseProgram( shaderProgramB );
  // render something else

Run the sample, I found all object render at a same position Can anybody tell me what's wrong with it?