Fbm

        texture fbm offset scale H lambda octaves thresh [colormap]
This texture uses "discretized fractional Brownian motion" (see section 8.1 of the Rayshade User's Guide).

The texture scales the surface's colour; if scale is less than 1.0 the surface will be darkened, if greater than 1.0 the surface will brighten. The User's Guide suggests values for the variables.

For details on the (optional) 'colormap', refer to the section on the marble texture.

Figure 7-5

        /*
           fbm.ray
           fbm example
           Stephen Peter 12 Feb 93
        */
        eyep 0 -1 75
        lookp 0 0 0
        light 1 point 40 -40 40
        screen 300 300
        background .9 .9 .9

        surface blue
            ambient  0.2 0.2 0.5
            diffuse  0.1 0.1 0.3
            specular 0.3 0.3 0.6
            specpow 10
            reflect 0.4

        box blue -29   1 -1  -11 29 1
            texture fbm .3 -1 .5 2 5 .1
        box blue  -9   1 -1    9 29 1
            texture fbm .3  0 .5 2 6 .1
        box blue  11   1 -1   29 29 1
            texture fbm .3  1 .5 2 7 .1
        box blue -29 -29 -1  -11 -1 1
            texture fbm .3  2 .5 2 5 .1
        box blue  -9 -29 -1    9 -1 1
            texture fbm .3  3 .5 2 6 .1
        box blue  11 -29 -1   29 -1 1
            texture fbm .3  4 .5 2 7 .1

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Fbmbump.

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THE END - Notes on Rayshade - 7 - Textures - Fbm