Back before development was started on POV-Ray 3.7.1, it was pointed out
that poly_wave 2.2 can be used to achieve non-linear gradients with
assumed_gamma 1. Alas, while trying to adapt Warp's wood texture to
linear color, I realized that poly_wave only gives the desired result
for the very simplest of gradients.
The attached montage compares poly_wave 2.2 with blend modes 1 to 3,
blend_gamma 2.2, for a variety of color maps on gradient x. The color
maps are, left to right, top to bottom:
[0.0 Red] [1.0 Green]
[0.0 Red] [1.0 Yellow]
[0.0 Yellow] [1.0 Red]
[0.0 Red] [1.0 Black]
[0.0 Black] [1.0 Red]
[0.5 Red] [1.0 Green]
[0.0 Red] [0.5 Green]
[0.5 Red] [1.0 Yellow]
[0.0 Red] [0.5 Yellow]
[0.5 Yellow] [1.0 Red]
[0.0 Yellow] [0.5 Red]
[0.5 Red] [1.0 Black]
[0.0 Red] [0.5 Black]
[0.5 Black] [1.0 Red]
[0.0 Black] [0.5 Red]
[1/3 Red] [2/3 Green]
[1/3 Red] [2/3 Yellow]
[1/3 Yellow] [2/3 Red]
[1/3 Red] [2/3 Black]
[1/3 Black] [2/3 Red]
The issue is that poly_wave does not adjust the colors themselves; it
adjusts their positions within the gradient. If you want traditional
gamma 2.2 gradients without mathematically micromanaging the color map,
you'll need to use POV-Ray 3.8.
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Attachments:
Download 'blend_v_poly-pbi.png' (15 KB)
Preview of image 'blend_v_poly-pbi.png'
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