Added asserts to object absolute transformation, added test.

src/Object.cpp

@@ -50,19 +50,21 @@ Object* Object::setParent(Object* parent) {
 }
 
 Matrix4 Object::absoluteTransformation(Camera* camera) {
-    Matrix4 t = _transformation;
-
     /* Shortcut for absolute transformation of camera relative to itself */
     if(camera == this) return Matrix4();
 
+    Matrix4 t = _transformation;
+
     Object* p = parent();
     while(p != nullptr) {
         t = p->transformation()*t;
 
         /* We got to the scene, multiply with camera matrix */
         if(p->parent() == p) {
-            if(camera && camera->scene() == scene())
+            if(camera) {
+                CORRADE_ASSERT(camera->scene() == scene(), "Object::absoluteTransformation(): the camera is not part of the same scene as object!", t)
                 t = camera->cameraMatrix()*t;
+            }
 
             break;
         }
@@ -70,6 +72,8 @@ Matrix4 Object::absoluteTransformation(Camera* camera) {
         p = p->parent();
     }
 
+    CORRADE_ASSERT(p != nullptr || camera == nullptr, "Object::absoluteTransformation(): the object is not part of camera scene!", t)
+
     return t;
 }
 

src/Object.h

@@ -103,10 +103,9 @@ class MAGNUM_EXPORT Object {
         /**
          * @brief Absolute transformation
          *
-         * If both this object and the camera is part of the same scene,
-         * returns absolute transformation matrix (relative to the camera).
-         * Otherwise returns transformation matrix relative to root object
-         * (in most cases scene of this object).
+         * Returns absolute transformation matrix relative to the camera or
+         * root object, if no camera is specified. If the camera is specified,
+         * it should be part of the same scene as object.
          *
          * Note that the absolute transformation is computed from all parent
          * objects every time it is asked, unless this function is

src/Test/CMakeLists.txt

@@ -1,4 +1,4 @@
-corrade_add_test(ObjectTest ObjectTest.h ObjectTest.cpp Magnum)
+corrade_add_test(ObjectTest ObjectTest.h ObjectTest.cpp MagnumTestLib)
 corrade_add_test(CameraTest CameraTest.h CameraTest.cpp Magnum)
 corrade_add_test(LightTest LightTest.h LightTest.cpp MagnumTestLib)
 corrade_add_test(SceneTest SceneTest.h SceneTest.cpp Magnum)

src/Test/ObjectTest.cpp

@@ -15,9 +15,14 @@
 
 #include "ObjectTest.h"
 #include "Scene.h"
+#include "Camera.h"
 
+#include <sstream>
 #include <QtTest/QTest>
 
+using namespace std;
+using namespace Corrade::Utility;
+
 QTEST_APPLESS_MAIN(Magnum::Test::ObjectTest)
 
 namespace Magnum { namespace Test {
@@ -70,6 +75,45 @@ void ObjectTest::transformation() {
     QVERIFY(o2.transformation() == o.transformation());
 }
 
+void ObjectTest::absoluteTransformationWrongCamera() {
+    stringstream ss;
+    Error::setOutput(&ss);
+
+    Scene s;
+    Object o(&s);
+    o.translate(Vector3::yAxis());
+    Camera c;
+    QVERIFY(o.absoluteTransformation(&c) == Matrix4::translation(Vector3::yAxis()));
+    QVERIFY(ss.str() == "Object::absoluteTransformation(): the camera is not part of the same scene as object!\n");
+
+    ss.str("");
+    Object o2;
+    o2.translate(Vector3::xAxis());
+    QVERIFY(o2.absoluteTransformation(&c) == Matrix4::translation(Vector3::xAxis()));
+    QVERIFY(ss.str() == "Object::absoluteTransformation(): the object is not part of camera scene!\n");
+}
+
+void ObjectTest::absoluteTransformation() {
+    Scene s;
+    Camera c(&s);
+    c.translate(Vector3::zAxis(2.0f));
+    QVERIFY(s.absoluteTransformation() == Matrix4());
+    QVERIFY(c.absoluteTransformation(&c) == Matrix4());
+
+    Object o(&s);
+    o.scale(Vector3(2.0f));
+    Object o2(&o);
+    o.rotate(deg(90.0f), Vector3::yAxis());
+    QVERIFY((o2.absoluteTransformation() ==
+        Matrix4::scaling(Vector3(2.0f))*Matrix4::rotation(deg(90.0f), Vector3::yAxis())));
+    QVERIFY((o2.absoluteTransformation(&c) ==
+        (Matrix4::translation(Vector3::zAxis(2.0f)).inverted())*Matrix4::scaling(Vector3(2.0f))*Matrix4::rotation(deg(90.0f), Vector3::yAxis())));
+
+    Object o3;
+    o3.translate({1.0f, 2.0f, 3.0f});
+    QVERIFY(o3.absoluteTransformation() == Matrix4::translation({1.0f, 2.0f, 3.0f}));
+}
+
 void ObjectTest::scene() {
     Scene scene;
 

src/Test/ObjectTest.h

@@ -27,6 +27,8 @@ class ObjectTest: public QObject {
     private slots:
         void parenting();
         void transformation();
+        void absoluteTransformationWrongCamera();
+        void absoluteTransformation();
         void scene();
         void dirty();
 };