像OpenGL中的游戏制造商一样以2D绘制顺序

Question

I have the following:

while(1){
  ...    
  object1.draw();
  object2.draw();
}

Of course the second object is drawn on first. My question is if the object 1 can be drawn on the object 2 without changing the order in which they appear in the main loop.

I can do something similar as the program game maker where the depth function is used?

I use OpenGL without shaders.

Answer 1

I'm not familiar with Game Maker, but you can to use glFrustrum to achieve what you want in opengl.

https://www.opengl.org/sdk/docs/man2/xhtml/glFrustum.xml

set the near and far clipping planes to 0, and 100 or some other arbitrarily large number. then when you draw them specify a z-value where the second z-value is less than, ie closer to the camera, than the first objects z-value.