Big bang

src/arc_ball_camera.h

@@ -0,0 +1,65 @@
+#ifndef ARCBALLCAMERA_H
+#define ARCBALLCAMERA_H
+
+#include <Magnum/SceneGraph/AbstractTranslationRotation3D.h>
+#include <Magnum/SceneGraph/Camera.h>
+#include <Magnum/SceneGraph/Object.h>
+#include <Magnum/SceneGraph/Scene.h>
+#include "arc_ball.h"
+
+using namespace Magnum;
+
+/* Arcball camera implementation integrated into the SceneGraph */
+class ArcBallCamera : public ArcBall {
+public:
+  template <class Transformation>
+  ArcBallCamera(SceneGraph::Scene<Transformation> &scene,
+                const Vector3 &cameraPosition, const Vector3 &viewCenter,
+                const Vector3 &upDir, Deg fov, const Vector2i &windowSize,
+                const Vector2i &viewportSize)
+      : ArcBall{cameraPosition, viewCenter, upDir, fov, windowSize} {
+    /* Create a camera object of a concrete type */
+    auto *cameraObject = new SceneGraph::Object<Transformation>{&scene};
+    (*(m_camera = new SceneGraph::Camera3D{*cameraObject}))
+        .setAspectRatioPolicy(SceneGraph::AspectRatioPolicy::Extend)
+        .setProjectionMatrix(Matrix4::perspectiveProjection(
+            fov, Vector2{windowSize}.aspectRatio(), 0.01f, 100.0f))
+        .setViewport(viewportSize);
+
+    /* Save the abstract transformation interface and initialize the
+       camera position through that */
+    (*(m_cameraObject = cameraObject))
+        .rotate(transformation().rotation())
+        .translate(transformation().translation());
+  }
+
+  /* Update screen and viewport size after the window has been resized */
+  void reshape(const Vector2i &windowSize, const Vector2i &viewportSize) {
+    m_windowSize = windowSize;
+    m_camera->setViewport(viewportSize);
+  }
+
+  /* Update the SceneGraph camera if arcball has been changed */
+  bool update() {
+    /* call the internal update */
+    if (!updateTransformation())
+      return false;
+
+    (*m_cameraObject)
+        .resetTransformation()
+        .rotate(transformation().rotation())
+        .translate(transformation().translation());
+    return true;
+  }
+
+  /* Draw objects using the internal scenegraph camera */
+  void draw(SceneGraph::DrawableGroup3D &drawables) {
+    m_camera->draw(drawables);
+  }
+
+private:
+  SceneGraph::AbstractTranslationRotation3D *m_cameraObject{};
+  SceneGraph::Camera3D *m_camera{};
+};
+
+#endif