Add support for cameras

orx-dnk3/src/main/kotlin/Camera.kt

@@ -0,0 +1,32 @@
+package org.openrndr.extra.dnk3
+
+import org.openrndr.math.Matrix44
+import org.openrndr.math.transforms.ortho
+import org.openrndr.math.transforms.perspective
+
+class PerspectiveCamera(var node: SceneNode) : Camera() {
+    override val projectionMatrix: Matrix44
+        get() = perspective(fov, aspectRatio, near, far)
+
+    override val viewMatrix: Matrix44
+        get() = node.worldTransform.inversed
+
+    var aspectRatio: Double = 16.0 / 9.0
+    var fov = 45.0
+    var far = 100.0
+    var near = 0.1
+
+}
+
+class OrthographicCamera(var node: SceneNode) : Camera() {
+    override val projectionMatrix: Matrix44
+        get() = ortho(xMag, yMag, near, far)
+
+    override val viewMatrix: Matrix44
+        get() = node.worldTransform.inversed
+
+    var xMag = 1.0
+    var yMag = 1.0
+    var near = 0.1
+    var far = 100.0
+}

orx-dnk3/src/main/kotlin/Entity.kt

@@ -58,3 +58,7 @@ abstract class Light : Entity() {
     var color: ColorRGBa = ColorRGBa.WHITE
 }
 
+abstract class Camera : Entity() {
+    abstract val projectionMatrix: Matrix44
+    abstract val viewMatrix: Matrix44
+}

orx-dnk3/src/main/kotlin/gltf/Gltf.kt

@@ -28,7 +28,7 @@ class GltfAsset(val generator: String?, val version: String?)
 
 class GltfScene(val nodes: IntArray)
 
-class GltfNode(val name:String,
+class GltfNode(val name: String,
                val children: IntArray?,
                val matrix: DoubleArray?,
                val scale: DoubleArray?,
@@ -36,6 +36,7 @@ class GltfNode(val name:String,
                val translation: DoubleArray?,
                val mesh: Int?,
                val skin: Int?,
+               val camera: Int?,
                val extensions: GltfNodeExtensions?)
 
 class KHRLightsPunctualIndex(val light: Int)
@@ -260,6 +261,11 @@ class KHRLightsPunctual(val lights: List<KHRLightsPunctualLight>)
 
 class GltfExtensions(val KHR_lights_punctual: KHRLightsPunctual?)
 
+class GltfCameraPerspective(val aspectRatio: Double?, val yfov: Double, val zfar: Double?, val znear: Double)
+class GltfCameraOrthographic(val xmag: Double, val ymag: Double, val zfar: Double, val znear: Double)
+
+class GltfCamera(val name: String?, val type: String, val perspective: GltfCameraPerspective?, val orthographic: GltfCameraOrthographic?)
+
 class GltfFile(
         val asset: GltfAsset?,
         val scene: Int?,
@@ -275,7 +281,8 @@ class GltfFile(
         val samplers: List<GltfSampler>?,
         val animations: List<GltfAnimation>?,
         val skins: List<GltfSkin>?,
-        val extensions: GltfExtensions?
+        val extensions: GltfExtensions?,
+        val cameras: List<GltfCamera>?
 ) {
     @Transient
     lateinit var file: File

orx-dnk3/src/main/kotlin/gltf/GltfScene.kt

@@ -259,6 +259,28 @@ fun GltfFile.buildSceneNodes(): GltfSceneData {
         }
     }
 
+    fun GltfCamera.createSceneCamera(sceneNode: SceneNode): Camera {
+        return when (type) {
+            "perspective" -> {
+                PerspectiveCamera(sceneNode).apply {
+                    aspectRatio = perspective?.aspectRatio ?: aspectRatio
+                    far = perspective?.zfar ?: far
+                    near = perspective?.znear ?: near
+                    fov = perspective?.yfov?.let { Math.toDegrees(it) } ?: fov
+                }
+            }
+            "orthographic" -> {
+                OrthographicCamera(sceneNode).apply {
+                    xMag = orthographic?.xmag ?: xMag
+                    yMag = orthographic?.ymag ?: yMag
+                    near = orthographic?.znear ?: near
+                    far = orthographic?.zfar ?: far
+                }
+            }
+            else -> error("unsupported camera type: $type")
+        }
+    }
+
     val scenes = scenes.map { scene ->
         scene.nodes.map { node ->
             val gltfNode = nodes[node]
@@ -271,6 +293,11 @@ fun GltfFile.buildSceneNodes(): GltfSceneData {
             val skin = gltfNode.skin?.let { (skins!!)[it] }
             sceneNode.entities.add(meshes[it].createSceneMesh(skin))
         }
+
+        gltfNode.camera?.let {
+            sceneNode.entities.add(cameras!![it].createSceneCamera(sceneNode))
+        }
+
         gltfNode.extensions?.let { exts ->
             exts.KHR_lights_punctual?.let { lightIndex ->
                 extensions?.KHR_lights_punctual?.lights?.get(lightIndex.light)?.let { light ->