Fixes and move to jvmDemo (#286)

orx-jumpflood/src/jvmDemo/kotlin/DemoDistanceField01.kt

@@ -0,0 +1,85 @@
+import org.openrndr.application
+import org.openrndr.color.ColorRGBa
+import org.openrndr.draw.*
+import org.openrndr.extra.jumpfill.DistanceField
+import org.openrndr.extra.noise.simplex
+import org.openrndr.math.Vector2
+import org.openrndr.math.Vector3
+import org.openrndr.shape.Rectangle
+
+/**
+ * Shows how to use the [DistanceField] filter.
+ * Draws moving white shapes on black background,
+ * then applies the DistanceField filter which returns a [ColorBuffer] in which
+ * the red component encodes the distance to the closest black/white edge.
+ * The value is positive when on the black background and negative
+ * when inside white shapes. The sign is used in the [shadeStyle] to choose
+ * between two colors. The inverse of the distance is used to obtain a
+ * non-linear brightness.
+ * Hold down a mouse button to see the raw animation.
+ */
+fun main() = application {
+    configure {
+        width = 1024
+        height = 1024
+    }
+
+    program {
+        val rt = renderTarget(width, height) { colorBuffer() }
+        val distanceField = DistanceField()
+
+        // Needs to be FLOAT32 so we can have negative values
+        val result = colorBuffer(width, height, type = ColorType.FLOAT32)
+        val shader = shadeStyle {
+            fragmentTransform = """
+                float distance = abs(x_fill.r);
+                float bri = 1.0 / (1.0 + 0.03 * distance);
+                
+                // wavy effect
+                // bri *= (1.0 + 0.2 * sin(distance * 0.2));
+                
+                x_fill.rgb = bri * (x_fill.r > 0 ? 
+                    vec3(1.0, 0.0, 0.0) : vec3(0.0, 1.0, 1.0));
+            """
+        }
+
+        extend {
+            // Draw moving white shapes on a black background
+            drawer.isolatedWithTarget(rt) {
+                clear(ColorRGBa.BLACK)
+                stroke = null
+                fill = ColorRGBa.WHITE
+                repeat(10) {
+                    val pos = Vector2.simplex(it, seconds * 0.2) *
+                            bounds.center + bounds.center
+                    val size = (it * it + 5.0) * 2.0
+
+                    isolated {
+                        translate(pos)
+                        if (it % 2 == 0) {
+                            circle(Vector2.ZERO, size)
+                        } else {
+                            rotate(Vector3.UNIT_Z, pos.x)
+                            rectangle(
+                                Rectangle.fromCenter(
+                                    Vector2.ZERO, size, size * 2
+                                )
+                            )
+                        }
+                    }
+                }
+            }
+
+            distanceField.apply(rt.colorBuffer(0), result)
+
+            drawer.isolated {
+                if (mouse.pressedButtons.isEmpty()) {
+                    shadeStyle = shader
+                    image(result)
+                } else {
+                    image(rt.colorBuffer(0))
+                }
+            }
+        }
+    }
+}