Multi-textures and vertex arrays

OpenGL OpenGL: Advanced Coding
1

Right now I use display lists, and want to transition to vertex arrays and VBOs. But I have a question about how to use vertex arrays for multi-texturing. (I don’t have any code problems yet, but need some help getting started. Thus the pseudo code that follows.)

I do the following to send vertex data (I’m using shaders to combine the textures and do surface bump mapping)

// for each vertex…
glNormal3f( nx, ny, nz );                  // normal vector
glTexCoord2f( u,v );                       // base texture coordinates
glMultiTexCoord2f( decal_unit, du, dv );   // decal texture coordinates
glMultiTexCoord3f( tan_unit, tx, ty, tz ); // tanget texture coordinates
glVertex3f( vx, vy, vz );                  // vertex

My question is… is there a vertex array equivalent to glMultiTexCoord, or should I setup the arrays like this…

// setup vertex array…
 EnableClientState ( NORMAL_ARRAY );
  NormalPointer( float, 0, pNormal );

ClientActiveTexture( BaseTextureUnit    );  // << is this the right way to
 EnableClientState ( TEXTURE_COORD_ARRAY);  // << setup multi-texture units
  TexCoordPointer  ( 2, float, pBaseTex );  // << using vertex arrays ?????

ClientActiveTexture( DecalTextureUnit   );  // <<
 EnableClientState ( TEXTURE_COORD_ARRAY);  // <<
  TexCoordPointer  ( 2, float, pDecalTex);  // <<

ClientActiveTexture( TangentTextureUnit );  // <<
 EnableClientState ( TEXTURE_COORD_ARRAY);  // <<
  TexCoordPointer  ( 3, float, pTangents);  // <<

 EnableClientState ( VERTEX_ARRAY );
  VertexPointer( 3, float, 0, pVertex );

 EnableClientState ( INDEX_ARRAY );
  IndexPointer( int, 0, pIndex );



// draw the arrays…
DrawArrays( mode, 0, count );



// clean up…
DisableClientState ( INDEX_ARRAY );
DisableClientState ( NORMAL_ARRAY);
DisableClientState ( VERTEX_ARRAY);

ClientActiveTexture( BaseTextureUnit    );  // << disable each texture unit
 DisableClientState( TEXTURE_COORD_ARRAY);  // << this way ?????

ClientActiveTexture( DecalTextureUnit   );
 DisableClientState( TEXTURE_COORD_ARRAY);

ClientActiveTexture( TangentTextureUnit );
 DisableClientState( TEXTURE_COORD_ARRAY);

Thanks in advance for help. Just need to get my head around how to approach this.

2

Hi!

There is no glMultiTexCoordPointer() or something like this.

So, your way is the only right way to enable multi-texturing. Firstly, glClientActiveTextureARB() tells which unit to use, then, glEnableClientState() and glTexCoordPointer() do what you want. Disabling is right also!

3

Jackis:
[b]There is no glMultiTexCoordPointer() or something like this.

So, your way is the only right way to enable multi-texturing. Firstly, glClientActiveTextureARB() tells which unit to use, then, glEnableClientState() and glTexCoordPointer() do what you want. Disabling is right also! [/b]
Alternatively, use:

glEnableVertexAttribArray(,ARB}
glVertexAttribPointer{,ARB,NV}

4

thanks for the responses. That’s just what I needed.