1 files changed, 42 insertions, 0 deletions
diff --git a/src/jogl/classes/jogamp/graph/curve/opengl/shader/functions.glsl b/src/jogl/classes/jogamp/graph/curve/opengl/shader/functions.glsl
new file mode 100644
index 000000000..eeab54ebf
--- /dev/null
+++ b/src/jogl/classes/jogamp/graph/curve/opengl/shader/functions.glsl
@@ -0,0 +1,42 @@
+// Copyright 2023 JogAmp Community. All rights reserved.
+
+#ifndef functions_glsl
+#define functions_glsl
+
+/** Returns product of components. */
+float v_mul( vec2 v ) {
+    return v.x * v.y;
+}
+/** Returns component wise logical 'or' as float '0' or '1' using the components product and clamp. */ 
+float v_or( vec2 v ) {
+    return clamp(v.x * v.y, 0, 1);
+}
+
+/** Returns sum of components. */
+float v_sum( vec2 v ) {
+    return v.x + v.y;
+}
+/** Returns component wise logical 'and' as float '0' or '1' using the components sum  and clamp. */
+float v_and( vec2 v ) {
+    return clamp(v.x + v.y, 0, 1);
+}
+
+/**
+ * Branch-less clipping function.
+ * <p>
+ * Returns either 'col_in' if the 'coord' is within ['low'..'high'] range,
+ * otherwise 'col_ex'.
+ * </p>
+ * <p>
+ * This is achieved via the build-in 'step' and 'mix' function 
+ * as well as our own 'v_mul' and v_and' function, 
+ * which flattens a 'vec2' to one float suitable to be used as the 'mix' criteria.
+ * </p>
+ */
+vec4 clip_coord(vec4 col_in, vec4 col_ex, vec2 coord, vec2 low, vec2 high) {
+    vec4 c = mix( col_ex, col_in, v_mul( step(low,  coord) ));
+    return   mix( c,      col_ex, v_and( step(high, coord) ));    
+}
+
+#endif // functions_glsl
+