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Member Since 24 Jun 2010
Offline Last Active Nov 26 2014 08:45 AM

Topics I've Started

DirectXMath / DirectXCollision BoundingFrustum

06 May 2013 - 01:25 PM

Hi guys,
I'm trying to do some frustum culling using DirectXMath' BoundingFrustum and BoundingBox classes.
Construction of the BoundingBoxes is looking good. I'm using DirectXTK's PrimitiveBatch to do some debug Output. Projection and View matrices are looking right too, because the rendering of the scene ist fine.
I've tried to different ways to construct the frustum:
BoundingFrustum frustum( XMLoadFloat4x4A(&proj) );
frustum.Transform(frustum, XMLoadFloat4x4A(&view) );
and the other one is
BoundingFrustum frustum( XMMatrixMultiply( XMLoadFloat4x4A(&view), XMLoadFloat4x4A(&proj) ) );

The matrices are both Left-Handed as DirectXCollision is LH only. To be sure I tried RH matrices too but it doesn't change the result (I'm able to Switch using preprocessor directives).
To check the BoundingBox I'm using the Intersects-Method of the BoundingFrustum class.
When using the first approach to construct the frustum nothing is displayed at all because all boxes are culled.
When using the second approach everything looks fine until I move the camera. When camera is moved the view Matrix is recalculated and after that the BoundingFrustum too. I've checked this in the Debugger. When rotating the camera it looks like the left and right sides are on the wrong side. When rotation approx. 45° around the Y-Axis everything is culled.
Has someone used the BoundingFrustum class to do frustum culling? Does someone know what I'm doing wrong?
Thanks in advance...

Signed Distance Field Direction

26 February 2012 - 05:26 AM

Hi guys,

I have created a signed distance field (two dimensional) which contains the nearest distance to the boundary like in PixelJunk Shooter (described here: http://fumufumu.q-ga.../shooterGDC.pdf; pages 44 to 46). Now I want to calculate the direction to the nearest boundary for any given point. In the PixelJunk Shooter presentation they talk about gradients and four sample points around the given point, but I'm not very good with calculus.

Is there anyone who can easily explain how to do that? Some pseudo-code would be great :-)

Thanks in advance.