[orx-temporal-blur] Add gain and color matrix controls

orx-temporal-blur/src/demo/kotlin/DemoBasic01.kt

@@ -0,0 +1,22 @@
+import org.openrndr.applicationSynchronous
+import org.openrndr.extensions.SingleScreenshot
+import org.openrndr.extra.temporalblur.TemporalBlur
+import org.openrndr.math.Polar
+
+fun main() = applicationSynchronous {
+    program {
+        if (System.getProperty("takeScreenshot") == "true") {
+            extend(SingleScreenshot()) {
+                this.outputFile = System.getProperty("screenshotPath")
+            }
+        }
+        extend(TemporalBlur()) {
+            samples = 10
+            duration = 0.9
+        }
+
+        extend {
+            drawer.circle(Polar(seconds * 360.0, 200.0).cartesian + drawer.bounds.center, 50.0)
+        }
+    }
+}

orx-temporal-blur/src/demo/kotlin/DemoColorShift01.kt

@@ -0,0 +1,38 @@
+import org.openrndr.applicationSynchronous
+import org.openrndr.color.ColorRGBa
+import org.openrndr.draw.tint
+import org.openrndr.extensions.SingleScreenshot
+import org.openrndr.extra.temporalblur.TemporalBlur
+import org.openrndr.math.Polar
+import kotlin.math.cos
+
+fun main() = applicationSynchronous {
+    program {
+        if (System.getProperty("takeScreenshot") == "true") {
+            extend(SingleScreenshot()) {
+                this.outputFile = System.getProperty("screenshotPath")
+            }
+        }
+        extend(TemporalBlur()) {
+            samples = 100
+            duration = 10.0
+            colorMatrix = {
+                // `it` is 0.0 at start of frame, 1.0 at end of frame
+                tint(ColorRGBa.WHITE.mix(ColorRGBa.BLUE, it))
+            }
+            gain = 1.2
+        }
+
+        extend {
+            for (i in 0 until 10) {
+                drawer.circle(
+                    Polar(
+                        seconds * 760.0 + i * 30,
+                        140.0 + cos(i + seconds) * 40.0
+                    ).cartesian + drawer.bounds.center,
+                    50.0
+                )
+            }
+        }
+    }
+}