Cubemapping, what am i doing wrong?

OpenGL OpenGL: Advanced Coding
1

What am i doing wrong or what could be interfering with this code?
The result of this code is that i see absolutely nothing textured.

on startup :

	CUBE_MAPPING_EXTENSION_ENABLE = 1;
	char *ext = (char*)glGetString(GL_EXTENSIONS);
	if( strstr(ext, "EXT_texture_cube_map") == NULL ){
		CUBE_MAPPING_EXTENSION_ENABLE = 0;
		return;
	}
	glDisable(GL_TEXTURE_GEN_S);
	glDisable(GL_TEXTURE_GEN_T);
	glDisable(GL_TEXTURE_GEN_R);

When drawing:

  
	if (!CUBE_MAPPING_EXTENSION_ENABLE) return;
	
	glDisable( GL_TEXTURE_2D );
	glEnable( GL_TEXTURE_CUBE_MAP_EXT );
	
	if (!cubemap->ID){
		glGenTextures(1, &cubemap->ID);
		//ERRORLOG->Add("creating cubemap");
		glBindTexture(GL_TEXTURE_CUBE_MAP_ARB, cubemap->ID);
		
		// create the cubemap.
		if (cubemap->RIGHT)
			glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X_EXT, 0, GL_RGBA, cubemap->RIGHT->WIDTH, cubemap->RIGHT->HEIGHT, 0, GL_RGBA, GL_UNSIGNED_BYTE, cubemap->RIGHT->TEXTURE );
		if (cubemap->LEFT)
			glTexImage2D(GL_TEXTURE_CUBE_MAP_NEGATIVE_X_EXT, 0, GL_RGBA, cubemap->LEFT->WIDTH, cubemap->LEFT->HEIGHT, 0, GL_RGBA, GL_UNSIGNED_BYTE, cubemap->LEFT->TEXTURE );
		if (cubemap->FRONT)
			glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_Y_EXT, 0, GL_RGBA, cubemap->FRONT->WIDTH, cubemap->FRONT->HEIGHT, 0, GL_RGBA, GL_UNSIGNED_BYTE, cubemap->FRONT->TEXTURE );
		if (cubemap->BACK)
			glTexImage2D(GL_TEXTURE_CUBE_MAP_NEGATIVE_Y_EXT, 0, GL_RGBA, cubemap->BACK->WIDTH, cubemap->BACK->HEIGHT, 0, GL_RGBA, GL_UNSIGNED_BYTE, cubemap->BACK->TEXTURE );
		if (cubemap->TOP)
			glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_Z_EXT, 0, GL_RGBA, cubemap->TOP->WIDTH, cubemap->TOP->HEIGHT, 0, GL_RGBA, GL_UNSIGNED_BYTE, cubemap->TOP->TEXTURE );
		if (cubemap->BOTTOM)
			glTexImage2D(GL_TEXTURE_CUBE_MAP_NEGATIVE_Z_EXT, 0, GL_RGBA, cubemap->BOTTOM->WIDTH, cubemap->BOTTOM->HEIGHT, 0, GL_RGBA, GL_UNSIGNED_BYTE, cubemap->BOTTOM->TEXTURE );
	} else  {
		//ERRORLOG->Add("binding cubemap");
		glBindTexture(GL_TEXTURE_CUBE_MAP_ARB, cubemap->ID);
	}
2

Have you tried using glGetError(…) ?

You seem to be confusing the EXT cubemap-extension with the ARB one. You should probably use the latter.

Also, instead of all the

if( cubemap->right )
  • etc., add assertions in the beginning, ie.
#include <assert.h>
.
.
assert( cubemap->right );
assert( cubemap->left );
			glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X_EXT, 0, GL_RGBA, cubemap->RIGHT->WIDTH, cubemap->RIGHT->HEIGHT, 0, GL_RGBA, GL_UNSIGNED_BYTE, cubemap->RIGHT->TEXTURE );
.
.
.
glGetError(..);

At least then you know if you actually upload something. Have you checked that all the parameters for glTexImage2D are valid?

Hope this helps,
\hornet

3

I didn’t know there were two types of cubemaps.
I got what i did from this document which apparently is wrong :
http://webster.fhs-hagenberg.ac.at/staff/haller/cg_20032004/05-Cg%20OpenGL%202.pdf

Anyways, i replaced all EXT’s with ARB’s and the other way around but it still doesn’t do anything. The 3D-model stays plain white.

Do i have to do something to scale the cube of the cubemap or to position it?

4

Did you set min/mag filters for the cubemap?

5

Ah, well now i see something, but it still looks crappy…

This character should be mapped with the NESW image below it mapped on it from all sides :
http://www.gunfight.net/img/misc/problem_03.jpg

6

Looks like you should compute (averaged) per vertex normals, instead of per face. You probably also need to set glShadeModel( GL_SMOOTH ) - and not GL_FLAT… in case you didn’t already :slight_smile:

\hornet

7

Easyer sayed than done.
Since it is a deformable shape, i need to recalculate these normals per frame.
I stored my vertexes in the polygons so i had to rewrite a big chunk of my engine.
Anyways, here’s the result:
http://www.gunfight.net/img/misc/problem_04.jpg

How does it look to you? I think it looks very well, especially when it is moving. It has something metalic about it, which is exactly what i wanted.

I come back to read your replies but thanks already for your help.

8

ARB and EXT both define the same value. Using one or antoher won’t change anything. You can even use GL_TEXTURE_CUBE_MAP alone if you have recent headers.

SeskaPeel