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authorTavian Barnes <tavianator@gmail.com>2009-11-11 14:26:34 -0500
committerTavian Barnes <tavianator@gmail.com>2009-11-11 14:26:34 -0500
commit98f1ff740af109f99cd35ae44108f3fc5842a4d5 (patch)
treef52fb504f486f313f41b7137ec851edaadd88448 /libdimension
parent5f37c6b3ca7b447ad8a4dc5fd84604342e32e59d (diff)
downloaddimension-98f1ff740af109f99cd35ae44108f3fc5842a4d5.tar.xz
Make dmnsn_illuminate_color() work, with sRGB for now.
Diffstat (limited to 'libdimension')
-rw-r--r--libdimension/color.c27
1 files changed, 7 insertions, 20 deletions
diff --git a/libdimension/color.c b/libdimension/color.c
index 2089326..79def12 100644
--- a/libdimension/color.c
+++ b/libdimension/color.c
@@ -298,28 +298,15 @@ dmnsn_color_mul(double n, dmnsn_color color)
dmnsn_color
dmnsn_color_illuminate(dmnsn_color light, dmnsn_color color)
{
- dmnsn_CIE_Lab Lab1 = dmnsn_Lab_from_color(light, dmnsn_whitepoint);
- dmnsn_CIE_Lab Lab2 = dmnsn_Lab_from_color(color, dmnsn_whitepoint);
+ /* TODO: make this work in a perceptually uniform colorspace */
+ dmnsn_sRGB sRGB1 = dmnsn_sRGB_from_color(light);
+ dmnsn_sRGB sRGB2 = dmnsn_sRGB_from_color(color);
- /*
- * This is derived from the simple illumination equation for RGB color:
- * RGB' = (R_light*R_color, G_light*G_color, B_light*B_color)
- *
- * CIE L*a*b* may be transformed to an RGB colorspace by considering `a'
- * to be the green -> magenta opponent process (from negative to positive),
- * and `b' to be the blue -> yellow opponent process:
- * RGB = (L + a + b, L - a + b, L + a - b)
- *
- * The reverse transformation is:
- * Lab = ((G + B)/2, (R - G)/2, (R - B)/2)
- */
- dmnsn_CIE_Lab Lab = {
- .L = (Lab1.L*Lab2.L + (Lab1.b - Lab1.a)*(Lab2.b - Lab2.a))/100.0,
- .a = (Lab1.a*(Lab2.L + Lab2.b) + Lab2.a*(Lab1.L + Lab1.b))/100.0,
- .b = (Lab1.b*(Lab2.L + Lab2.a) + Lab2.b*(Lab1.L + Lab1.a))/100.0
- };
+ dmnsn_sRGB sRGB = { .R = sRGB1.R*sRGB2.R,
+ .G = sRGB1.G*sRGB2.G,
+ .B = sRGB1.B*sRGB2.B };
- dmnsn_color ret = dmnsn_color_from_Lab(Lab, dmnsn_whitepoint);
+ dmnsn_color ret = dmnsn_color_from_sRGB(sRGB);
ret.filter = color.filter;
ret.trans = color.trans;