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GLSL shader "light going through objects"

Started by overflowsc Apr 15, 2012 at 8:31 AM 1 replies 3.2k views

Original Post

Apr 15, 2012 at 8:31 AM

I, before asking any questions, i would like to thank everyone posting on this forum. It has really helpful since I started my OpenGL project.

I have a problem with my glsl shader. In fact I just don't know how to prevent any of it to happend. As you can see on the picture, the light from the red spotlight is "going through" the table.
[attachment=8239:example.jpg]

How can i test is the path between the pixel being drawn and the light source is "free".

Thank you

Hodgman

Apr 15, 2012 at 8:46 AM

Short answer - you need to implement a shadow technique.

The two main categories of techniques are shadow mapping and shadow volumes (AKA stencil shadows). Shadow mapping is the more popular one these days, and there are literally hundreds of variations upon the basic technique, which involves rendering a depth-buffer from the light's point-of-view, and using this depth-texture in your lighting shader to determine if a pixel is in light or shadow.

overflowsc

Apr 15, 2012 at 8:54 AM

Thank you Hodgman, I'll try this out.

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