add cmyk warping planes gimmick to decals

renders the decal 4 times one planes, and applies domain warping to each
plane. Requires a 4-channel (RGBA) noise texture.

1 files changed, 37 insertions, 0 deletions

diff --git a/math.cginc b/math.cginc
index f2b64fa..8ada893 100644
--- a/math.cginc
+++ b/math.cginc
@@ -246,4 +246,41 @@ void calcNormalInScreenSpace(inout float3 normal, float3 objPos) {
   normal = normalize(cross(ddy(objPos), ddx(objPos)));

 }

 

+// Formulae from here: https://www.rapidtables.com/convert/color/rgb-to-cmyk.html

+float4 rgbToCmyk(float3 rgb) {

+  float4 cmyk;

+  cmyk[3] = 1 - max(rgb.r, max(rgb.g, rgb.b));

+  cmyk[0] = (1 - rgb.r - cmyk[3]) / (1 - cmyk[3]);

+  cmyk[1] = (1 - rgb.g - cmyk[3]) / (1 - cmyk[3]);

+  cmyk[2] = (1 - rgb.b - cmyk[3]) / (1 - cmyk[3]);

+  return cmyk;

+}

+

+float rgbToCmyk_C(float3 rgb) {

+  float k = 1 - max(rgb.r, max(rgb.g, rgb.b));

+  float c = (1 - rgb.r - k) / (1 - k);

+  return c;

+}

+float rgbToCmyk_M(float3 rgb) {

+  float k = 1 - max(rgb.r, max(rgb.g, rgb.b));

+  float m = (1 - rgb.g - k) / (1 - k);

+  return m;

+}

+float rgbToCmyk_Y(float3 rgb) {

+  float k = 1 - max(rgb.r, max(rgb.g, rgb.b));

+  float y = (1 - rgb.b - k) / (1 - k);

+  return y;

+}

+float rgbToCmyk_K(float3 rgb) {

+  float k = 1 - max(rgb.r, max(rgb.g, rgb.b));

+  return k;

+}

+

+float3 cmykToRgb(float4 cmyk) {

+  return float3(

+    (1 - cmyk[0]) * (1 - cmyk[3]),

+    (1 - cmyk[1]) * (1 - cmyk[3]),

+    (1 - cmyk[2]) * (1 - cmyk[3]));

+}

+

 #endif  // __MATH_INC