21. Scissor Test

• We won't be using this in our code, but:

  • Used to increase performance

  • Updates only the portion within a defined area

  • Doesn't update anything outside of the area

• By default, scissor test is the size of the window

• Use glScissor()

  
      glScissor(int x, int y, int width, int height);
  
  

  call to enable:

  
      glEnable( GL_SCISSOR_TEST );
      glScissor( 100, 100, 600, 400 );  // render in that area only