65 lines
1.8 KiB
Plaintext
65 lines
1.8 KiB
Plaintext
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<HTML>
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<HEAD>
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<TITLE>Whitenoise Procedural Textures</TITLE>
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<LINK type="text/css" rel="stylesheet" href="../webdocs.css">
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</HEAD>
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<BODY>
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<H1>Whitenoise Procedural Textures</H1>
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<P>The whitenoise procedural texture generates random greyscale noise every frame. The effect is similar to static on your television.</P>
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<PRE class="syntax">
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<B>ATD1</B>
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<B>type = whitenoise</B>
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<B>width =</B> <I>integer</I>
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<B>height =</B> <I>integer</I>
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</PRE>
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<H4>Parameters</H4>
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<DL>
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<DT><I>width</I></DT>
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<DD>Width of the texture, must be a power of two.</DD>
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<DT><I>height</I></DT>
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<DD>Height of the texture, must be a power of two.</DD>
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</DL>
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<H4>Remarks</H4>
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<P>The whitenoise algorithm fills a greyscale 8-bit texture with random bits. If requested, a color version of this can be implemented as well. Note that this texture will probably not tile very well. In addition, if you have multiple occurences of this texture in the same room, they will all display exactly the same static at exactly the same time. You can get around this by using different offsets and scale factors in the texture to make each one look a little different. This is better than making separate texture definition files, unless you are using very small texture sizes.</P>
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<H4>Advanced OpenGL parameters</H4>
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<DL>
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<DT><I>internal format</I></DT>
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<DD>GL_LUMINANCE (8-bit greyscale)</DD>
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<DT><I>GL_TEXTURE_MIN_FILTER</I></DT>
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<DD>GL_NEAREST (no mipmapping or interpolation)</DD>
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<DT><I>GL_TEXTURE_MAG_FILTER</I></DT>
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<DD>GL_NEAREST (no interpolation)</DD>
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</DL>
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<H4>Example</H4>
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<PRE class="syntax">
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type = whitenoise
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width = 64
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height = 64
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</PRE>
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<P>Will generate a texture like this:</P>
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<P><IMG src="proc_whitenoise.gif" alt="Example whitenoise image"></P>
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</BODY>
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</HTML>
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