Does anybody kow how to make a billboard out of one 3D point ? I want to apply a texture that is always facing the camera but I only have one point in 3D space how can I do this? PS I have loads of points so id like to use an opengl function to do it if posssible cus doing all that matrix maths would relly slow my app down

I believe what you are looking for is a point sprite. It''s basically a texture mapped point.

what you need to do is get 2 vectors (per frame) wich is quite inexpensive) from your view matrix

CVECTOR billboardRight=CVECTOR(viewMatrix.entries[0],viewMatrix.entries[4],viewMatrix.entries[8]);
CVECTOR billboardUp=CVECTOR(viewMatrix.entries[1], viewMatrix.entries[5],viewMatrix.entries[9]);

and based on those vectors construct your quad, triangle ,triangle strip or whatever polygon you wish to apply texture to , something like this(for a quad):

m_pVertices[0]=particles.position-billboardRight-billboardUp;
m_pVertices[1]=particles.position+billboardRight-billboardUp;<br>m_pVertices[2]=particles.position+billboardRight+billboardUp;<br>m_pVertices[3]=particles.position-billboardRight+billboardUp;<br><br>this method has an advantage over point sprites , it allows scaling. </i>

If you''re familiar with OpenGL extensions, you should definately take a look at GL_NV_point_sprite and GL_ARB_point_sprite extensions. They have very few limitations and are much more optimized that any matrix-based quad rendering.