[orx-shapes] BezierPatch: add missing user uniforms, demo (#366)

orx-shapes/src/commonMain/kotlin/bezierpatches/BezierPatchDrawer.kt

@@ -34,6 +34,7 @@ class BezierPatchDrawer {
         return ("""
             |// BezierPatchDrawer.kt / fsGenerator            
             |${drawerUniforms()}
+            |${structure.uniforms ?: ""}
             |${structure.varyingIn.orEmpty()}
 
             |out vec4 o_color;
@@ -53,6 +54,7 @@ class BezierPatchDrawer {
             |${drawerUniforms()}
             |${ColorPhraseBook.oklabToLinearRgb.phrase}
             |${ColorPhraseBook.linearRgbToSRgb.phrase}
+            |${structure.uniforms ?: ""}
             |${structure.varyingIn.orEmpty()}
             |out vec4 o_color;
             |void main() {

orx-shapes/src/jvmDemo/kotlin/bezierpatch/DemoBezierPatch06.kt

@@ -0,0 +1,55 @@
+package bezierpatch
+
+import org.openrndr.application
+import org.openrndr.color.ColorRGBa
+import org.openrndr.draw.loadImage
+import org.openrndr.draw.shadeStyle
+import org.openrndr.extra.shapes.bezierpatches.bezierPatch
+import org.openrndr.math.Polar
+import org.openrndr.shape.LineSegment
+import org.openrndr.shape.Segment2D
+
+/**
+ * Shows how to
+ * - create a [bezierPatch] out of 4 curved Segment2D instances
+ * - apply an image texture to the patch using a shadeStyle
+ *
+ */
+fun main() = application {
+    configure {
+        width = 800
+        height = 800
+    }
+    program {
+        fun offset(n: Int) = Polar(n * 107.0, 100.0).cartesian
+
+        // Take the window bounds, shift it inwards, then take 4 horizontal
+        // LineSegment instances from that Rectangle
+        val lineSegments = List(4) {
+            drawer.bounds.offsetEdges(-100.0).horizontal(1.0 - it * 0.333)
+        }
+        // Map the 4 LineSegment instances to curved Segment2D instances by
+        // offsetting 4 points in each.
+        val bentSegments = lineSegments.mapIndexed { i, seg ->
+            Segment2D(
+                seg.position(0.0) + offset(i * 4 + 1),
+                seg.position(0.333) + offset(i * 4 + 2),
+                seg.position(0.666) + offset(i * 4 + 3),
+                seg.position(1.0) + offset(i * 4 + 4)
+            )
+        }
+
+        val bp = bezierPatch(bentSegments[0], bentSegments[1], bentSegments[2], bentSegments[3])
+
+        val tex = loadImage("demo-data/images/peopleCity01.jpg")
+        val style = shadeStyle {
+            fragmentTransform = "x_fill = texture(p_tex, va_texCoord0.xy);"
+            parameter("tex", tex)
+        }
+        extend {
+            drawer.shadeStyle = style
+            drawer.clear(ColorRGBa.PINK)
+            drawer.bezierPatch(bp)
+        }
+    }
+}