Add AxisHelper to orx-camera

* Rename Debug3D to GridHelper

orx-camera/src/main/kotlin/AxisHelper.kt

@@ -0,0 +1,88 @@
+package org.openrndr.extras.camera
+
+import org.openrndr.Extension
+import org.openrndr.Program
+import org.openrndr.color.ColorRGBa
+import org.openrndr.draw.*
+import org.openrndr.math.Matrix33
+import org.openrndr.math.Matrix44
+import org.openrndr.math.Vector3
+
+
+@Suppress("unused")
+class AxisHelper(var size: Int = 80) : Extension {
+    override var enabled: Boolean = true
+
+    val fbo = renderTarget(size, size) {
+        colorBuffer()
+        depthBuffer()
+    }
+    val side = size.toDouble()
+    val axisLength = size / 2.0
+    val planeLength = axisLength + 10.0
+
+    override fun afterDraw(drawer: Drawer, program: Program) {
+        draw(drawer)
+    }
+
+    fun draw(drawer: Drawer) {
+        val viewMatrix = drawer.view
+        val projMatrix = drawer.projection
+        val x = drawer.width - (size + 5.0)
+        val y = 5.0
+
+        drawer.isolatedWithTarget(fbo) {
+            drawer.view = Matrix44.IDENTITY
+            drawer.model = Matrix44.IDENTITY
+            drawer.drawStyle.depthTestPass = DepthTestPass.ALWAYS
+
+            drawer.ortho(0.0, side, 0.0, side, -1.0, 1.0)
+
+            drawer.background(ColorRGBa.TRANSPARENT)
+            drawer.stroke = null
+            drawer.fill = ColorRGBa.PINK.opacify(0.7)
+            drawer.circle(axisLength, axisLength, axisLength)
+
+            drawer.ortho(-planeLength, planeLength, -planeLength, planeLength, -planeLength, planeLength)
+            drawer.view = getRotation(viewMatrix)
+            drawer.strokeWeight = 0.6
+
+            drawer.fill = ColorRGBa.RED
+            drawer.stroke = ColorRGBa.RED
+            drawer.lineSegment(Vector3.ZERO, Vector3.UNIT_X * axisLength)
+
+            drawer.fill = ColorRGBa.GREEN
+            drawer.stroke = ColorRGBa.GREEN
+            drawer.lineSegment(Vector3.ZERO, Vector3.UNIT_Y * axisLength)
+
+            drawer.fill = ColorRGBa.BLUE
+            drawer.stroke = ColorRGBa.BLUE
+            drawer.lineSegment(Vector3.ZERO, Vector3.UNIT_Z * axisLength)
+        }
+
+        drawer.view = Matrix44.IDENTITY
+        drawer.model = Matrix44.IDENTITY
+        drawer.ortho()
+
+        drawer.isolated {
+            val cb = fbo.colorBuffer(0)
+            drawer.image(cb, x, y, side, side)
+        }
+
+        drawer.view = viewMatrix
+        drawer.projection = projMatrix
+    }
+}
+
+internal fun getRotation(mat: Matrix44): Matrix44 {
+    val mat3 = mat.matrix33 // without translation
+    val c0 = mat3[0].length
+    val c1 = mat3[1].length
+    val c2 = mat3[2].length
+
+    return Matrix33(
+            mat3.c0r0 / c0, mat3.c1r0 / c1, mat3.c2r0 / c2,
+            mat3.c0r1 / c0, mat3.c1r1 / c1, mat3.c2r1 / c2,
+            mat3.c0r2 / c0, mat3.c1r2 / c1, mat3.c2r2 / c2
+    ).matrix44
+}

orx-camera/src/main/kotlin/GridHelper.kt

@@ -7,7 +7,7 @@ import org.openrndr.draw.*
 import org.openrndr.math.Vector3
 
 @Suppress("unused")
-class Debug3D(val size: Int = 10, val divisions: Int = 10) : Extension {
+class GridHelper(val size: Int = 10, val divisions: Int = 10) : Extension {
     override var enabled: Boolean = true
     private val step = size / divisions.toDouble()