Re: [pygame] Python - Pygame - PyOpenGL performance

["RB[0]" <roebros@xxxxxxxxx>]

Well, most likely your main speed down is looping through all those sprites as it is - trying just looping through them and calling a dummy function instead of the opengl one - and see what happens - otherwise, that seems quite odd to me, I haven't run into that before (are you using psyco, perhaps?)

On Thu, Feb 26, 2009 at 1:04 PM, Zack Schilling <zack.schilling@xxxxxxxxx> wrote:

I know the PyOpenGL mailing list might be a better place to ask this question, but I've had a lot of luck talking to the experienced people here so I figured I'd try it first.

I'm trying to migrate a game I created from using the Pygame / SDL software rendering to OpenGL. Before attempting the massive and complex conversion involved with moving the whole game, I decided to make a little test program while I learned OpenGL.

In this test, I set up OpenGL to work in 2D and began loading images into texture objects and drawing textured quads as sprites. I created a little glSprite class to handle the drawing and translation. At first its draw routine looked like this:

       glPushMatrix()
       glTranslate(self.positionx,self.positiony,0)
       glBindTexture(GL_TEXTURE_2D, self.texture)
       glBegin(GL_QUADS)
       glTexCoord2f(0, 1)
       glVertex2f(0, 0)
       glTexCoord2f(1, 1)
       glVertex2f(w, 0)
       glTexCoord2f(1, 0)
       glVertex2f(w, h)
       glTexCoord2f(0, 0)
       glVertex2f(0, h)
       glEnd()
       glPopMatrix()

Note: self.texture is a texture ID of a loaded OpenGL texture object. My sprite class keeps a dictionary cache and only loads the sprite's image into a texture if it needs to.

I'd get maybe 200 identical sprites (same texture) onscreen and my CPU would hit 100% load from Python execution. I looked into what could be causing this and found out that it's probably function call overhead. That's 14 external library function calls per sprite draw.

The next thing I tried was to create a display list at each sprite's initialization. Then my code looked like this:
       glPushMatrix()
       glTranslate(self.positionx,self.positiony,0)
       glCallList(self.displist)
       glPopMatrix()

Well, that's nice, down to 4 calls per draw. I was able to push ~500 sprites per frame using this method before the CPU tapped out. I need more speed than this. My game logic uses 30-40% of the CPU alone and I'd like to push at least 1000 sprites. What can I do? I've looked into passing sprites as a matrix with vertex arrays, but forming a proper vertex array with numpy can sometimes be more trouble than it's worth. Plus, I can't swap out textures easily mid-draw, so it makes things much more complex than the simple way I'm doing things now.

Is there any design pattern I could follow that will get me more speed without sending me off the deep end with complexity.

Thanks,

Zack