77 lines
2.0 KiB
HTML
77 lines
2.0 KiB
HTML
<!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
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noise every frame. The effect is similar to static on your
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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
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with random bits. If requested, a color version of this can be
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implemented as well. Note that this texture will probably not
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tile very well. In addition, if you have multiple occurences of
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this texture in the same room, they will all display exactly
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the same static at exactly the same time. You can get around
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this by using different offsets and scale factors in the
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texture to make each one look a little different. This is
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better than making separate texture definition files, unless
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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=
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"Example whitenoise image"></P>
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</BODY>
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</HTML>
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