FPS problem

OpenGL OpenGL: Basic Coding
1

Hello everyone.

I recently decided to continue work on my old project (game). So I installed MSVC++ 6.0 (OS = Vista), opened the project and compiled it without a problem.

Now here is the problem:

I draw a grid of quads 32*32 by using GL_QUADS (4 vertices per quad, no shared vertices) and everything works fast as it should. Each quad is drawn seperately.

Then I tried to draw 256256 grid and my FPS dropped down to 10-12 frames per second. I find this strange since I can play games such as Doom 3, Far Cry 2, Gothic 3 with max quality without a problem and I’m sure that these games show much more triangles than this 256256 quad grid.

I tought the problem might be in vista, but fps drop down in Win XP too. Could the problem be in MSVC++ 6.0? Here is a pseudo code for the drawing:


for(x = 0; x < 256; x++) {
   for(z = 0; z < 256; z++) {
      glBindTexture(GL_TEXTURE_2D, some_tex);
      glBegin(GL_QUADS);
        // draw the quad here. 1 normal per quad
        // 4 vertices using x and z values, y = 0 and texture 
        // coorinate for each vertex
      glEnd();
   }
}

Any suggestions?

2

Very similar problem, solved here :
http://www.opengl.org/discussion_boards/ubbthreads.php?ubb=showflat&Number=251247

3

Okay, thanks for the quick answer. I’ll look into this later when I’m home. I tought it might be something with all those immidiate calls. I’m not really new to OpenGL but It’s been few years since I used it in any application. Looks like I’ll have to read that OpenGl bible again :wink:

4

Spot on. The thread ZbuffeR refers to will show you the ‘correct solution™’.
But as a quick fix you can just move the glBegin/glEnd out of the for-loops, which should give you at least a little speed boost.

If you don’t have a very recent version, there is no gain. :slight_smile:

5

Well I found some tutorials on the net about the VBOs and now it works now with the super speed :smiley:

I haven’t check the OGL Bible yet, but I have SAMS OpenGL Super Bible 3rd edition (2004). And yes, as I remeber there’s nothing about VBO’s there. I might be wrong though.