[orx-camera] Add demo with content not affected by the camera

orx-camera/src/jvmDemo/kotlin/DemoCamera2D02.kt

@@ -0,0 +1,63 @@
+import org.openrndr.application
+import org.openrndr.color.ColorRGBa
+import org.openrndr.draw.isolatedWithTarget
+import org.openrndr.draw.loadFont
+import org.openrndr.draw.renderTarget
+import org.openrndr.extra.camera.Camera2D
+import org.openrndr.math.Vector2
+import org.openrndr.math.transforms.transform
+import org.openrndr.shape.Rectangle
+import kotlin.math.sin
+
+/**
+ * # Camera2D demo with static elements
+ *
+ * An approach for having certain elements not affected by the camera
+ */
+fun main() = application {
+    program {
+        // Create a renderTarget where to draw things. It will be controlled by the camera.
+        val rt = renderTarget(width, height) {
+            colorBuffer()
+            depthBuffer()
+        }
+        // Create camera and apply an initial transformation
+        // so the origin is no longer in the top left corner.
+        val cam = Camera2D()
+        cam.view *= transform {
+            translate(width * 0.5, height * 1.0)
+            rotate(45.0)
+            scale(2.0)
+        }
+
+        // Add mouse listeners to the camera
+        cam.setup(this)
+
+        val font = loadFont("demo-data/fonts/IBMPlexMono-Regular.ttf", 50.0)
+
+        extend {
+            // Draw onto the renderTarget
+            drawer.isolatedWithTarget(rt) {
+                // Calling ortho required if the size differs from the window size
+                ortho(rt)
+                // Apply the current camera transformation
+                view = cam.view
+                // Clear render target
+                clear(ColorRGBa.TRANSPARENT)
+                // Draw the things affected by the camera (here a rectangle at the origin)
+                rectangle(Rectangle.fromCenter(Vector2.ZERO, 200.0, 100.0 + sin(seconds) * 20.0))
+            }
+
+            drawer.clear(ColorRGBa.PINK)
+
+            // Draw the renderTarget with the camera applied to it
+            drawer.image(rt.colorBuffer(0))
+
+            // Draw things not affected by the camera
+            drawer.fontMap = font
+            drawer.fill = ColorRGBa.PINK.shade(0.5)
+            drawer.text("click and drag mouse", 50.0, 400.0)
+            drawer.text("use mouse wheel", 50.0, 450.0)
+        }
+    }
+}