Add source-atop and destination-atop

orx-fx/README.md

@@ -32,8 +32,10 @@ Blend filters take two inputs ("source" and "destination"), they are intended to
 #### Porter-Duff blends
  - `SourceIn`, Porter-Duff source-in blend, intersect source and destination opacity and keep source colors
  - `SourceOut`, Porter-Duff source-out blend, subtract destination from source opacity and keep source colors
+ - `SourceAtop`, Porter-Duff source-atop blend, uses destination opacity, layers source on top and keeps both colors
  - `DestinationIn`, Porter-Duff destination-in blend, intersect source and destination opacity and keep source colors
  - `DestinationOut`, Porter-Duff destination-out blend, subtract destination from source opacity and keep destination colors
+ - `DestinationAtop`, Porter-Duff destination-atop blend, uses source opacity, layers destination on top and keeps both colors
  - `Xor`, Porter-Duff xor blend, picks colors from input with highest opacity or none with opacities are equal
 
 #### Various blends

orx-fx/src/main/kotlin/blend/BlendFilters.kt

@@ -89,8 +89,10 @@ class Screen : Filter(Shader.createFromCode(Filter.filterVertexCode, filterFragm
 
 class SourceIn : Filter(Shader.createFromCode(Filter.filterVertexCode, filterFragmentCode("blend/source-in.frag")))
 class SourceOut : Filter(Shader.createFromCode(Filter.filterVertexCode, filterFragmentCode("blend/source-out.frag")))
+class SourceAtop : Filter(Shader.createFromCode(Filter.filterVertexCode, filterFragmentCode("blend/source-atop.frag")))
 class DestinationIn : Filter(Shader.createFromCode(Filter.filterVertexCode, filterFragmentCode("blend/destination-in.frag")))
 class DestinationOut : Filter(Shader.createFromCode(Filter.filterVertexCode, filterFragmentCode("blend/destination-out.frag")))
+class DestinationAtop : Filter(Shader.createFromCode(Filter.filterVertexCode, filterFragmentCode("blend/destination-atop.frag")))
 class Xor : Filter(Shader.createFromCode(Filter.filterVertexCode, filterFragmentCode("blend/xor.frag")))
 
 class MultiplyContrast : Filter(Shader.createFromCode(Filter.filterVertexCode, filterFragmentCode("blend/multiply-contrast.frag")))

orx-fx/src/main/resources/org/openrndr/extra/fx/gl3/blend/destination-atop.frag

@@ -0,0 +1,17 @@
+#version 330
+
+in vec2 v_texCoord0;
+uniform sampler2D tex0;
+uniform sampler2D tex1;
+
+out vec4 o_color;
+
+void main() {
+    vec4 src = texture(tex0, v_texCoord0);
+    vec4 dest = texture(tex1, v_texCoord0);
+
+    float lsrc = src.a * (1.0 - dest.a);
+    float lboth = src.a * dest.a;
+
+    o_color = src * lsrc + dest * 0.0 + dest * lboth;
+}

orx-fx/src/main/resources/org/openrndr/extra/fx/gl3/blend/destination-in.frag

@@ -7,9 +7,10 @@ uniform sampler2D tex1;
 out vec4 o_color;
 
 void main() {
-    vec4 a = texture(tex0, v_texCoord0);
+    vec4 src = texture(tex0, v_texCoord0);
-    vec4 b = texture(tex1, v_texCoord0);
+    vec4 dest = texture(tex1, v_texCoord0);
 
-    vec3 na = a.a == 0.0 ? vec3(0.0): a.rgb / a.a;
+    float lboth = src.a * dest.a;
-    o_color = vec4(na, 1.0) * b.a * a.a;
+
+    o_color = dest * lboth;
 }

orx-fx/src/main/resources/org/openrndr/extra/fx/gl3/blend/destination-out.frag

@@ -6,9 +6,10 @@ uniform sampler2D tex1;
 
 out vec4 o_color;
 void main() {
-    vec4 a = texture(tex0, v_texCoord0);
+    vec4 src = texture(tex0, v_texCoord0);
-    vec4 b = texture(tex1, v_texCoord0);
+    vec4 dest = texture(tex1, v_texCoord0);
 
-    vec3 na = a.a == 0.0 ? vec3(0.0): a.rgb / a.a;
+    float ldest = dest.a * (1.0 - src.a);
-    o_color = vec4(na, 1.0) * max(a.a - b.a, 0.0);
+
+    o_color = dest * ldest;
 }

orx-fx/src/main/resources/org/openrndr/extra/fx/gl3/blend/source-atop.frag

@@ -0,0 +1,17 @@
+#version 330
+
+in vec2 v_texCoord0;
+uniform sampler2D tex0;
+uniform sampler2D tex1;
+
+out vec4 o_color;
+
+void main() {
+    vec4 src = texture(tex0, v_texCoord0);
+    vec4 dest = texture(tex1, v_texCoord0);
+
+    float ldest = dest.a * (1.0 - src.a);
+    float lboth = src.a * dest.a;
+
+    o_color = dest * ldest + src * lboth;
+}

orx-fx/src/main/resources/org/openrndr/extra/fx/gl3/blend/source-in.frag

@@ -6,9 +6,10 @@ uniform sampler2D tex1;
 
 out vec4 o_color;
 void main() {
-    vec4 a = texture(tex0, v_texCoord0);
+    vec4 src = texture(tex0, v_texCoord0);
-    vec4 b = texture(tex1, v_texCoord0);
+    vec4 dest = texture(tex1, v_texCoord0);
 
-    vec3 nb = b.a == 0.0 ? vec3(0.0): b.rgb / b.a;
+    float lboth = src.a * dest.a;
-    o_color = vec4(nb, 1.0) * a.a * b.a;
+
+    o_color = src * lboth;
 }

orx-fx/src/main/resources/org/openrndr/extra/fx/gl3/blend/source-out.frag

@@ -6,9 +6,10 @@ uniform sampler2D tex1;
 
 out vec4 o_color;
 void main() {
-    vec4 a = texture(tex0, v_texCoord0);
+    vec4 src = texture(tex0, v_texCoord0);
-    vec4 b = texture(tex1, v_texCoord0);
+    vec4 dest = texture(tex1, v_texCoord0);
 
-    vec3 nb = b.a == 0.0 ? vec3(0.0): b.rgb / b.a;
+    float lsrc = src.a * (1.0 - dest.a);
-    o_color = vec4(nb, 1.0) * max(b.a - a.a, 0.0);
+
+    o_color = src * lsrc;
 }

orx-fx/src/main/resources/org/openrndr/extra/fx/gl3/blend/xor.frag

@@ -6,19 +6,11 @@ uniform sampler2D tex1;
 
 out vec4 o_color;
 void main() {
-    vec4 a = texture(tex0, v_texCoord0);
+    vec4 src = texture(tex0, v_texCoord0);
-    vec4 b = texture(tex1, v_texCoord0);
+    vec4 dest = texture(tex1, v_texCoord0);
-    vec4 color = vec4(0.0);
 
-    vec3 na = a.a == 0.0 ? vec3(0.0) : a.rgb/a.a;
+    float lsrc = src.a * (1.0 - dest.a);
-    vec3 nb = b.a == 0.0 ? vec3(0.0) : b.rgb/b.a;
+    float ldest = dest.a * (1.0 - src.a);
-    if (a.a > b.a) {
-        color = vec4(na, 1.0) * (b.a == 0.0? a.a : (1.0-b.a));
-    }
 
-    if (b.a > a.a) {
+    o_color = src * lsrc + dest * ldest;
-        color = vec4(nb, 1.0) * (a.a == 0.0? b.a : (1.0-a.a));
-    }
-
-    o_color = color;
 }