[orx-fx] Refactor CMYKHalftone to support customizable elements/colors

orx-fx/src/commonMain/kotlin/dither/CMYKHalftone.kt

@@ -2,14 +2,31 @@
 
 package org.openrndr.extra.fx.dither
 
+import org.openrndr.color.ColorRGBa
 import org.openrndr.draw.Filter1to1
+import org.openrndr.draw.filterShaderFromCode
 import org.openrndr.extra.fx.fx_cmyk_halftone
-import org.openrndr.extra.fx.mppFilterShader
+import org.openrndr.extra.parameters.ColorParameter
 import org.openrndr.extra.parameters.Description
 import org.openrndr.extra.parameters.DoubleParameter
+import org.openrndr.extra.shaderphrases.sdf.sdCirclePhrase
 
 @Description("CMYK Halftone")
-class CMYKHalftone: Filter1to1(mppFilterShader(fx_cmyk_halftone, "cmyk-halftone")) {
+class CMYKHalftone(
+    domainWarpFunction: String = "vec2 domainWarp(vec2 p) { return p; }",
+    elementFunction: String = """
+    $sdCirclePhrase
+    float element(in vec2 p, float v) {
+        return sdCircle(p, v * dotSize);
+    }""".trimIndent()
+) : Filter1to1(
+    filterShaderFromCode(
+        fx_cmyk_halftone.split("#pragma INSERT_PHRASES").let {
+            listOf(it[0], elementFunction, domainWarpFunction, it[1])
+        }.joinToString("\n"),
+        "cmyk-halftone"
+    )
+) {
     @DoubleParameter("scale", 1.0, 30.0, precision = 4)
     var scale: Double by parameters
 
@@ -19,9 +36,45 @@ class CMYKHalftone: Filter1to1(mppFilterShader(fx_cmyk_halftone, "cmyk-halftone"
     @DoubleParameter("rotation", -180.0, 180.0)
     var rotation: Double by parameters
 
+    @DoubleParameter("cyan rotation", -180.0, 180.0, precision = 4)
+    var cyanRotation: Double by parameters
+
+    @DoubleParameter("magenta rotation", -180.0, 180.0, precision = 4)
+    var magentaRotation: Double by parameters
+
+    @DoubleParameter("yellow rotation", -180.0, 180.0, precision = 4)
+    var yellowRotation: Double by parameters
+
+    @DoubleParameter("black rotation", -180.0, 180.0, precision = 4)
+    var blackRotation: Double by parameters
+
+    @ColorParameter("cyan color")
+    var cyanColor: ColorRGBa by parameters
+
+    @ColorParameter("magenta color")
+    var magentaColor: ColorRGBa by parameters
+
+    @ColorParameter("yellow color")
+    var yellowColor: ColorRGBa by parameters
+
+    @ColorParameter("black color")
+    var blackColor: ColorRGBa by parameters
+
+    var phase: Double by parameters
+
     init {
+        blackRotation = 45.0
+        magentaRotation = 75.0
+        cyanRotation = 15.0
+        yellowRotation = 0.0
+        cyanColor = ColorRGBa.CYAN
+        magentaColor = ColorRGBa.MAGENTA
+        yellowColor = ColorRGBa.YELLOW
+        blackColor = ColorRGBa.BLACK
+
         scale = 3.0
         rotation = 0.0
-        dotSize = 1.0
+        dotSize = 0.9
+        phase = 0.0
     }
 }

orx-fx/src/shaders/glsl/dither/cmyk-halftone.frag

@@ -1,17 +1,27 @@
 /*  Based on CMYK Halftone by tsone https://www.shadertoy.com/view/Mdf3Dn */
 uniform float dotSize;
 
-#define SST 0.888
-#define SSQ 0.288
-
 uniform float scale;
 uniform float rotation;
+uniform float phase;
+
+uniform float blackRotation;
+uniform float yellowRotation;
+uniform float magentaRotation;
+uniform float cyanRotation;
+
+uniform vec4 blackColor;
+uniform vec4 yellowColor;
+uniform vec4 magentaColor;
+uniform vec4 cyanColor;
 
 in vec2 v_texCoord0;
 uniform sampler2D tex0;
 
 out vec4 o_color;
 
+#pragma INSERT_PHRASES
+
 vec4 rgb2cmyki(in vec3 c)
 {
     float k = max(max(c.r, c.g), c.b);
@@ -31,10 +41,10 @@ vec3 u(vec4 c) {
 
 }
 vec4 cmyki2rgba(in vec4 cmyk) {
-    vec4 c = vec4(0.0, 1.0, 1.0, 1.0)*(1.0-cmyk.r);
-    vec4 m = vec4(1.0, 0.0, 1.0, 1.0)*(1.0-cmyk.g);
-    vec4 y = vec4(1.0, 1.0, 0.0, 1.0)*(1.0-cmyk.b);
-    vec4 k = vec4(0.0, 0.0, 0.0, 1.0)*(1.0-cmyk.a);
+    vec4 c = cyanColor * (1.0 - cmyk.r);
+    vec4 m = magentaColor * (1.0 - cmyk.g);
+    vec4 y = yellowColor * (1.0 - cmyk.b);
+    vec4 k = blackColor * (1.0 - cmyk.a);
 
     vec4 f = c;
     f = (1.0 - f.a) * m + f.a * vec4(u(f) * u(m), 1.0) * m.a + (1.0 - m.a) * f;
@@ -56,43 +66,46 @@ vec2 grid(in vec2 px)
 
 vec4 ss(in vec4 v)
 {
-    return smoothstep(vec4(SST-SSQ), vec4(SST+SSQ), v);
+    vec4 vw = fwidth(v);
+    return smoothstep(vec4(-vw), vec4(vw), v);
 }
 
-vec4 halftone(in vec2 fc,in mat2 m)
+
+float halftone(in vec2 fc, in mat2 m, int channel)
 {
     vec2 smp = (grid(m * fc) + 0.5 * scale) * m;
-    float s = min(length(fc-smp) / (dotSize*0.5*scale), 1.0);
+
+    float s = length(fc - smp) / (dotSize * 2.0 * scale);
+    vec2 d2 = m * ((fc) - smp) / (dotSize * 0.5 * scale);
     vec3 texc = texture(tex0, px2uv(smp + vec2(textureSize(tex0, 0)) / 2.0)).rgb;
-    vec4 c = rgb2cmyki(texc);
-    return c+s;
+    float c = 1.0 - rgb2cmyki(texc)[channel];
+    return element(d2, c);
 }
 
-mat2 rotm(in float r)
-{
+mat2 rotm(in float r) {
     float cr = cos(r);
     float sr = sin(r);
-    return mat2(
-    cr,-sr,
-    sr,cr
-    );
+    return mat2(cr, -sr, sr, cr);
 }
 
 void main() {
-    vec2 fc = v_texCoord0 * vec2(textureSize(tex0, 0)) - vec2(textureSize(tex0, 0))/2.0;
+    vec2 fc = (v_texCoord0 - vec2(0.5)) * vec2(textureSize(tex0, 0));
+    fc = domainWarp(fc);
 
-    mat2 mc = rotm(rotation + radians(15.0));
-    mat2 mm = rotm(rotation + radians(75.0));
-    mat2 my = rotm(rotation);
-    mat2 mk = rotm(rotation + radians(45.0));
+    mat2 mc = rotm(rotation + radians(cyanRotation));
+    mat2 mm = rotm(rotation + radians(magentaRotation));
+    mat2 my = rotm(rotation + radians(yellowRotation));
+    mat2 mk = rotm(rotation + radians(blackRotation));
 
-    float k = halftone(fc, mk).a;
-    vec4 c = cmyki2rgba(ss(vec4(
-    halftone(fc, mc).r,
-    halftone(fc, mm).g,
-    halftone(fc, my).b,
-    halftone(fc, mk).a
-    )));
+    vec4 c = cmyki2rgba(
+        ss(vec4(
+           halftone(fc, mc, 0),
+           halftone(fc, mm, 1),
+           halftone(fc, my, 2),
+           halftone(fc, mk, 3)
+           )
+        )
+    );
 
     o_color = c;
 }