[orx-math] Add demo and readme texts.

orx-math/src/jvmDemo/kotlin/linearrange/DemoLinearRange02.kt

@@ -9,6 +9,27 @@ import org.openrndr.shape.Rectangle
 import kotlin.math.cos
 import kotlin.math.sin
 
+/**
+ * Demonstrate how to create a 1D linear range between two instances of a `LinearType`, in this case,
+ * a horizontal `Rectangle` and a vertical one.
+ *
+ * Notice how the `..` operator is used to construct the `LinearRange1D`.
+ *
+ * The resulting `LinearRange1D` provides a `value()` method that takes a normalized
+ * input and returns an interpolated value between the two input elements.
+ *
+ * This example draws a grid of rectangles interpolated between the horizontal and the vertical
+ * triangles. The x and y coordinates and the `seconds` variable are used to specify the
+ * interpolation value for each grid cell.
+ *
+ * One can use the `LinearRange` class to construct
+ * - a `LinearRange2D` out of two `LinearRange1D`
+ * - a `LinearRange3D` out of two `LinearRange2D`
+ * - a `LinearRange4D` out of two `LinearRange3D`
+ *
+ * (not demonstrated here)
+ *
+ */
 fun main() {
     application {
         configure {
@@ -24,7 +45,7 @@ fun main() {
                 for (y in 0 until height step 72) {
                     for (x in 0 until width step 72) {
                         val u = cos(seconds + x * 0.007) * 0.5 + 0.5
-                        val s = sin(seconds*1.03 + y * 0.0075) * 0.5 + 0.5
+                        val s = sin(seconds * 1.03 + y * 0.0075) * 0.5 + 0.5
                         drawer.isolated {
                             drawer.translate(x.toDouble(), y.toDouble())
                             drawer.rectangle(range.value(u * s))