Add orx-shade-styles demo

orx-shade-styles/build.gradle

@@ -1,3 +1,18 @@
+sourceSets {
+    demo {
+        java {
+            srcDirs = ["src/demo/kotlin"]
+            compileClasspath += main.getCompileClasspath()
+            runtimeClasspath += main.getRuntimeClasspath()
+        }
+    }
+}
 dependencies {
     api project(":orx-parameters")
+
+    demoImplementation("org.openrndr:openrndr-core:$openrndrVersion")
+    demoRuntimeOnly("org.openrndr:openrndr-gl3:$openrndrVersion")
+    demoRuntimeOnly("org.openrndr:openrndr-gl3-natives-$openrndrOS:$openrndrVersion")
+    demoImplementation(sourceSets.getByName("main").output)
+
 }

orx-shade-styles/src/demo/kotlin/DemoRadialGradient01.kt

@@ -0,0 +1,20 @@
+import org.openrndr.application
+import org.openrndr.color.ColorRGBa
+
+import org.openrndr.extra.shadestyles.radialGradient
+import kotlin.math.cos
+
+fun main() {
+    application {
+        program {
+            extend {
+                drawer.shadeStyle = radialGradient(
+                        ColorRGBa.PINK,
+                        ColorRGBa.PINK.toHSVa().shiftHue(180.0).scaleValue(0.5).toRGBa(),
+                        exponent = cos(seconds)*0.5+0.5
+                )
+                drawer.rectangle(120.0, 40.0, 400.0, 400.0)
+            }
+        }
+    }
+}