2D tile drawing

If you are sure that this is the cause for the slowdown then you should render all the tiles that use the same texture in one go. I never checked it but I guess that calling glBindTexture 10,000 times might be a bit slow...

HTH.

Another way to save glBindTexture calls would be to pack all of your tile textures into one big texture atlas and use texture coordinates to select the right part of the big texture for each tile.

Hm.. you present an interesting idea.. I'm loading the textures as one big image to begin with anyway. Thanks (both of you)

What's the size of the texture? (Height and width)

The "large" image is 1024x1024, each tile is 64x64

Further problems.. I've been trying to put the texture atlas idea to work, but I ran into a strange problem. As I move my sprites, or zoom the camera out, the textures on the map change. ONLY when I move one and or the other.. I'm rather tired, so I may have just done something stupid.. but I've been wracking my brain for quite some time without any headway. Here is the code as it is now;

---------MAP.CPP----------------
void RSMAP::Draw(const float scale)
{
float zvalue = -2.0;
int lx, ly, tmpid;
float texx, texy;

glEnable(GL_TEXTURE_2D);

if (scale ==0) {allegro_message("Warning! Map scale is zero!");}

glBindTexture(GL_TEXTURE_2D, Tileset);
glBegin(GL_QUADS);
for (ly=0;ly<=MAPW;ly++)
{
for (lx=0;lx<=MAPH;lx++)
{

tmpid =0;
texy =1;
while (tmpid != Tile[lx][ly].TileID)
{
if (texx >= 1)
{
texx=0;
texy-=TILESIZE;
}
else texx +=TILESIZE;

if (texy <=0) texy=1;

tmpid++;
}


glColor3f(1.0, 1.0, 1.0);
glTexCoord2f( texx , texy ); glVertex3f(lx , ly , zvalue);
glTexCoord2f( texx+TILESIZE, texy ); glVertex3f(lx +scale, ly , zvalue);
glTexCoord2f( texx+TILESIZE, texy+TILESIZE); glVertex3f(lx +scale, ly +scale, zvalue);
glTexCoord2f( texx , texy+TILESIZE); glVertex3f(lx , ly +scale, zvalue);
}
}

glEnd();

}
--------------------------


and just in case you need to see my main loop..

--------MAIN.CPP-------------
while (!key[KEY_ESC])
{
tmptimer = Tick;

// This is just a test blurb. Has nothing to do with the map at all
if (key[KEY_SPACE])
if (Sprite[0].Binding.isbound == 0)
Sprite[0].Binding.isbound = 1;
else Sprite[0].Binding.isbound =0;

// very VERY basic, half assed camera...
if (key[KEY_PGUP]) zoom += 0.05;
if (key[KEY_PGDN]) zoom -= 0.05;
if (key[KEY_HOME]) zoom =0;
if (zoom >= 1) zoom -=0.05;;
//if (zoom <= -0.15) zoom = -0.15;

glPushMatrix();

glTranslatef(0,0 ,zoom);

Update_sprites();
TestMap.Draw(1);


allegro_gl_flip();
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glPopMatrix();
while (Tick == tmptimer) rest(0);

}
return 0;
}

-----------------------------



TILESIZE is a define 1/16 (as I have a 16x16 tile texturemap). I'm also pretty new to the whole texture coordinate thing, but this is what I came up with after reading the OpenGL superbible's take on the subject.. so I hope I got it right. Any help would be appreciated.

Thanks


Arith

Nevermind.... I did something stupid..
I didn't initialize "texx". Sorry, heh. Told you I was tired :D

Have a look at my engine here if you want to see how I handle 2D tiling in OpenGL (look in ArcEngine/Layer.cs)