Include PolyCubeMapped models in your application
It is very easy to include in your application a model textured with a PolyCubeMap.
Basically
it is as easy as to include a standard texture mapped model.
Just follow three steps:
To let you test PolyCubeMap right away, we included a few downloadable examples of PolyCubeMapped models at the bottom of this page.
If anything is going wrong, you may check the troubleshooting section.
[back to main PolyCubeMap page]
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void ParameterizeShader(int textSizeX,
int textSizeY,
int squareletSize) {
double
d0x = 1.0 / textSizeX ,
d0y = 1.0 / textSizeY ,
d1x = 255.0 * squareletSize / textSizeX ,
d1y = 255.0 * squareletSize / textSizeY ,
d2x = 1.0 * squareletSize / textSizeX ,
d2y = 1.0 * squareletSize / textSizeY ;
glProgramEnvParameter4dARB( GL_FRAGMENT_PROGRAM_ARB, 0, d0x,d0y,0,0 );
glProgramEnvParameter4dARB( GL_FRAGMENT_PROGRAM_ARB, 1, d1x,d1y,0,0 );
glProgramEnvParameter4dARB( GL_FRAGMENT_PROGRAM_ARB, 2, d2x,d2y,1,0 );
glProgramEnvParameter4dARB( GL_FRAGMENT_PROGRAM_ARB, 3, d2x,d2y,1,1 );
};
And don't forget to enable the fragment program: glEnable(GL_FRAGMENT_PROGRAM_ARB);
Note that there are four alternative endings in the fragment program above.
Select the one suiting your tastes, uncommenting it.
The first one (on by default) is a plain copy of the final texture value on the screen - useful for example
when the texture maps encodes pre-shaded gray levels. The second one blends the texel color
with the original fragment color (that may encode for example the shading).
The last two are just for illustration purposes: the third blends in a color that codes the current cell
configuration, and the fourth also highlights cell borders.
Of course there are much more things that you may want to do with the final texel value. Just to name one, in a normal-map polycube maps the texel would encode a normal value, that must be shaded accordingly, and so on. Implementing these is up to you...
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You load the PolyCubeMap image in the same way you load any other texture image. We provide here some example PolyCubeMap images and models. Get them at the bottom of this page. Remember, a PolyCubeMap is stored in the texture memory as a flattened polycube 2D image, that stores the final texture values, plus a tiny lookup table that in practices stores the polycube layout. The latter can optionally be serialized and kept in a subpart of the former (instead of keeping it in a tiny separate texture). This is the case for the texture images provided here (and the fragment shader above knows about this). So all you have to do is to load the a single png image and store it in texture space as normal. Don't forget to bind the texture and to activate it. Also, remember to set both the minification and magnification filters to a plain CLOSEST, leave that to the shader. |
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Just be sure to send, along with each vertex, its 3D texture coordinates (actually, the possibility to set them uniquely per-vertex is one of the neat feature of PolyCubeMaps). For example, to send a single textured triangle of a mesh, just use:
glBegin(GL_TRIANGLES);
glTexCoord3dv( tc[i] );
glVertex3dv( v[i] );
glTexCoord3dv( tc[j] );
glVertex3dv( v[j] );
glTexCoord3dv( tc[k] );
glVertex3dv( v[k] );
glEnd();
Below, you will find some triangle meshes that can be used as a test. Each of them has one (or more) corresponding PolyCubeMaps images.
The format, an ascii ply file, should be quite self explanatory: after the header, you will find a plain series of vertices, followed by a series of faces. Each separate vertex or face is on a single line. A vertices is represented by it position (three real numbers), followed by its texture coordinates (other three real numbers). A face is plainly a number of sides (always "3" here, they are triangle meshes) followed by the three indexes of the vertices of that face.
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If you are experiencing any problems, you can check this list:
Meshes
Texture
Texture
Texture
Texture