On Fri, 02 Mar 2007 03:26:59 -0500 Per Inge Mathisen
<[EMAIL PROTECTED]> wrote:
>On 3/2/07, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote:
>> Before the hardcode of 512, it was change to
>BACKDROP_HACK_WIDTH,
>> and BACKDROP_HACK_HEIGHT (which still is 512).
>>
>> In code below this with
>> glBegin(GL_TRIANGLE_STRIP);
>> glTexCoord2f(0, 0);
>> glVertex2f(0, 0);
>> glTexCoord2f(255, 0);
>> glVertex2f(screenWidth, 0);
>> glTexCoord2f(0, 255);
>> glVertex2f(0, screenHeight);
>> glTexCoord2f(255, 255);
>> glVertex2f(screenWidth, screenHeight);
>> glEnd();
>>
>> should not the 255 be also changed? Why is it 255 in first
>place?
>> if BACKDROP_HACK_HEIGHT = 1024, then it no look right ?
>>
>> Anybody explain why this value used? I think it is mistake?
>
>I believe those are texture coordinates that get translated into
>0.0f
>-> 1.0f. Although I must admit I am a bit mystified about how
>exactly
>this works.
>
> - Per
I find this,
glViewport(0, 0, width, height);
glMatrixMode(GL_PROJECTION);
glPushMatrix();
glLoadIdentity();
glOrtho(0, width, height, 0, 1, -1);
glMatrixMode(GL_TEXTURE);
glScalef(1/256.0, 1/256.0, 1);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glCullFace(GL_FRONT);
glEnable(GL_CULL_FACE);
So we deal with glOrtho to set up coordinates.
Then map coordinates of 0 to width and 0 to height is used yes?
Then mapping should be 0 to width = 0 to 1.0, same for height. If
width=1024, height=768 = 1.0,1.0 I thinks.
glTexCoord2f(255, 255) = 255/256 right because call to
glScalef(1/256.0, 1/256.0, 1) is in the GL_TEXTURE matrix ?
Is logic right?
If yes, then why we scale Texture matrix at all? Is it to save
time from doing division? Why 1/256? Is because original
textures are 256x256?
--
Click for free info on paralegal training and make up to $150K/ year
http://tagline.hushmail.com/fc/CAaCXv1RDFsF40ZrpcjUAfRPfHw0o9Rs/
_______________________________________________
Warzone-dev mailing list
[email protected]
https://mail.gna.org/listinfo/warzone-dev
