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Slow Program

Started by TheShadow Apr 17, 2003 at 10:01 PM 15 replies 550+ views

Original Post

Apr 17, 2003 at 10:01 PM

Im having trouble on drawing quads ... im drawing them into the screen very slowly... I previously thought my texturing was the problem but no... it runs the same with textures (just a bit slower but nothing really so significant) but without textures my quad drawing makes my player quad move slow... See here is my code

  

int draw_tiles(GLvoid)
{
  int tile;
   glLoadIdentity();
  for (int y = 0; y < MAP_SIZEY; y++)
  {
    for (int x = 0; x < MAP_SIZEX; x++)
    {
	
    tile = map[y][x];

  glBindTexture(GL_TEXTURE_2D, texture[tile]);
  glBegin(GL_QUADS);

    glTexCoord2f(0.0f, 1.0f); glVertex2f(tiles[x][y].tlVertex_x, tiles[x][y].tlVertex_y);
    glTexCoord2f(1.0f, 1.0f); glVertex2f(tiles[x][y].trVertex_x, tiles[x][y].trVertex_y);
    glTexCoord2f(1.0f, 0.0f); glVertex2f(tiles[x][y].blVertex_x, tiles[x][y].blVertex_y);
    glTexCoord2f(0.0f, 0.0f); glVertex2f(tiles[x][y].brVertex_x, tiles[x][y].brVertex_y );
   
	glEnd();
    }
	
  }
   

  return (1);
}

And here is where i have calculated previously my coordinates

  

void PrecalcTileCoords(GLvoid)
{
	for (int y = 0; y < MAP_SIZEY; y++)
  {
    for (int x = 0; x < MAP_SIZEX; x++)
    {
	tiles[x][y].tlVertex_x = float(x)*50;
	tiles[x][y].tlVertex_y = float(y)*50;
	tiles[x][y].trVertex_x = float(x+1)*50;
	tiles[x][y].trVertex_y = float(y)*50;
	tiles[x][y].blVertex_x = float(x+1)*50;
	tiles[x][y].blVertex_y = float(y+1)*50;
	tiles[x][y].brVertex_x = float(x) * 50;
	tiles[x][y].brVertex_y = float(y + 1) * 50;
    
    }
	
  }
}

My player movement function is A-OK for now because without the map drawing the player quad moves very smoothly Mecha Engineer (Making Real Humanoid Suits)

TheShadow

Author

TheShadow

Apr 17, 2003 at 10:22 PM

C:\Program Files\Microsoft Visual Studio\MyProjects\mge\glEngine.cpp(47) : error C2296: ''<<'' : illegal, left operand has type ''float''

that''s what shifting gave me

Mecha Engineer (Making Real Humanoid Suits)

cowsarenotevil

478

cowsarenotevil

Apr 17, 2003 at 10:23 PM

quote:
Original post by TheShadow
C:\Program Files\Microsoft Visual Studio\MyProjects\mge\glEngine.cpp(47) : error C2296: ''<<'' : illegal, left operand has type ''float''

that''s what shifting gave me

Mecha Engineer (Making Real Humanoid Suits)

I think you can only shift integers.

-~-The Cow of Darkness-~-

TheShadow

Author

TheShadow

Apr 17, 2003 at 10:25 PM

Yeah im going to use typecasting

(GLfloat)((x) << 5) + ((x) << 4) + ((x) << 1);

Mecha Engineer (Making Real Humanoid Suits)

[edited by - TheShadow on April 17, 2003 11:28:52 PM]

TheShadow

Author

TheShadow

Apr 17, 2003 at 10:28 PM

Nope no improvement... same thing

Mecha Engineer (Making Real Humanoid Suits)

noixtirdoe

Apr 17, 2003 at 10:48 PM

you''re right; sorry.

-noix-

In this world gone mad, we won''t spank the monkey; the monkey will spank us.

TheShadow

Author

TheShadow

Apr 17, 2003 at 11:10 PM

I scaled my program and got a better speed... even though its still slow because of quad drawing... they are barely 100

kdogg

Apr 18, 2003 at 2:11 AM

You might want to try taking out all your calls to glBegin and glEnd. Just call glbegin before your loop and glend after your loop.

Do you have to calculate the tile coordinates before every call to draw_tiles?

Luke Philpot

Apr 18, 2003 at 2:17 AM

glBegin/glEnd is expensive. I''d use vertex arrays if I were you, or at least display lists.

Ilici

205

Ilici

Apr 18, 2003 at 2:23 PM

hope u have a main loop with
do
{

} while (running);

not windows message stuff

and i dont think u need to precalculate texcoords

ah and dont bind the texture every time

[edited by - Ilici on April 18, 2003 3:27:55 PM]

higherspeed

Apr 18, 2003 at 3:14 PM

How wide is your grid? If it was about 100, then that would be 20000 polys. But if by 100, you mean 10 by 10 then that''s nothing. 20000 polys can really slow it down on older computers, I must admit I don''t know of any figures. Finally, isn''t that a strange way of drawing tiles, wouldn''t it be far easier to draw one quad for your whole level and tile the texture. Unless you''re going to expand the program and make a rough surface. Or am I missing the point somewhere?

kdogg

Apr 18, 2003 at 3:16 PM

Another thing to consider is drawing all the quads with the same texture at the same time instead of having to bind a texture for each quad, but i don''t know how your program''s setup.

TheShadow

Author

TheShadow

Apr 18, 2003 at 4:19 PM

Well i cant really texture all my quads with the same texture because its a tile engine... that would be nonsense... but about texturing only one big quad... with different textures inside it? that would be interesting... i'm new to ogl so i didn't know that could be done... could you initiate me in that? Even though my player quad moves at the same speed when i use a one 10*10 quad then when i use 100 1*1 quads

[edited by - TheShadow on April 18, 2003 5:21:36 PM]

Luctus

Apr 18, 2003 at 6:36 PM

quote:
Original post by TheShadow
... but about texturing only one big quad... with different textures inside it? that would be interesting... i''m new to ogl so i didn''t know that could be done...

Nope, can''t be done.

quote:
Original post by Ilici
hope u have a main loop with
do
{
} while (running);
not windows message stuff

AP: I don''t think he meant you should throw out windows message processing, just that you shouldn''t use the message pump as game loop.

What you want to do is:
1) Sort the tiles by texture so you set one texture, and then draw all tiles that uses that texture, then set next texture, draw all tiles using that texture..and so on. Setting textures are VERY performance expensive.

2) Use vertex arrays to gain some serious speed, or at least try to get rid of as many glBegin/glEnd as possible.

Instead of doing:


for ( ... )
{
glBegin( GL_QUADS );
  glVertex2f(...);
  glVertex2f(...);
  glVertex2f(...);
  glVertex2f(...);
glEnd();
}

you do:


glBegin( GL_QUADS );
for ( ... )
{
  glVertex2f(...);
  glVertex2f(...);
  glVertex2f(...);
  glVertex2f(...);
}
glEnd();

3) Only draw those tiles that are visible

Most of this has already been said..but..

-Luctus
Codito, Ergo Sum (Courtesy of ThinkGeek)

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