Infinite projection matrix

Hey guys.

I've the last couple of hours tried to implement an infinite projection matrix without succes. So I took a step back to see if I could even make some sense of the "normal" perspective projection matrix used by XNA. Normally I used the CreatePerspectiveFieldOfView() method to create the matrix. Here is what I've tried so far. What is XNA left-handed or right This code works but the view aspect is fu**ed up. Anyone who can clearify or better show how it's in XNA The infinite matrix that is.

float Q = drawParameters.Far / (drawParameters.Near - drawParameters.Far);

float yScale = 1 / (float)Math.Tan((drawParameters.CameraFov) / 2.0f);

float xScale = drawParameters.ViewAspectRatio * yScale;

I need it for a Z-Fail shadow volume implementation. Right now my volume is getting clipped by the farplane. Setting the far plane a huge distance away wouldn't solve the problem when the extruded vertices are pushed back to infinity. Mark Kilgard presented a very elegant solution to this, but I'm having problem getting it to work in XNA.

Any help would be appreciated.

I've gotten the matrix in my problem now but it gives me a funny view distortion as seen in image 1. I'm getting some errors at the farplane as seen in image 2. Any clue why this might be the case

Image 1: http://img126.imageshack.us/img126/4307/distortedrk8.jpg

Image 2: http://img411.imageshack.us/img411/4906/errornu8.jpg

What are you referring to as a distortion in the first image If you are talking about how the shadow for the top of the cylinder is wider than the shadow for the bottom of the cylinder, this is exactly what I would expect to see if the light source is close to the top of the cylinder.

I don't have any idea on the 2nd image. Did you follow an online guide or whitepaper to create the shadow volume code If so, please post a link to the information that you followed.

If you compare the first image to how it is suppose to look using a normal perspective matrix you would see the distortion I'm talking about:

http://img216.imageshack.us/img216/6222/untitledix4.jpg

The "false" shadow is caused by farplane clipping. I havn't found the solution to the clipping artifacts yet though. :(

Got everything working. It turned out that the scaling was done a bit wrong. The farplane clipping was caused by some hardware inprecision. The final matrix looks like this.

// Calculate the infinite matrix used for Z-Fail

float yScale = 1 / (float)Math.Tan((drawParameters.CameraFov) / 2.0f);

float xScale = (1 / drawParameters.ViewAspectRatio) * yScale;

float e = 0.000001f;