Revert "Caching light position relative to camera."

* The light didn't catch camera transformation changes, so it was
   returning wrong position for most of the time.
 * The multiplication was in wrong order, it should be multiplied with
   camera matrix from the left.

I need to find an solution for this, because now it is one redundant
matrix*vector multiplication per object per frame again.

This reverts commit 0443bbe286.

Conflicts:
	src/Light.cpp
	src/Test/LightTest.cpp

src/Light.cpp

@@ -14,26 +14,13 @@
 */
 
 #include "Light.h"
-#include "Camera.h"
 
 namespace Magnum {
 
-Vector3 Light::position(Camera* camera) {
-    CORRADE_ASSERT(scene() && camera->scene() == scene(), "Light: camera and light aren't in the same scene!", Vector3())
-
-    if(camera != _camera) {
-        _camera = camera;
-        setDirty();
-    }
-
-    setClean();
-    return _position;
-}
-
 void Light::clean(const Matrix4& absoluteTransformation) {
     Object::clean(absoluteTransformation);
 
-    _position = (absoluteTransformation*_camera->cameraMatrix())[3].xyz();
+    _position = absoluteTransformation[3];
 }
 
 }

src/Light.h

@@ -34,15 +34,15 @@ class Light: public Object {
          * @brief Constructor
          * @param parent        Parent object
          */
-        inline Light(Object* parent = nullptr): Object(parent), _camera(nullptr) {}
+        inline Light(Object* parent = nullptr): Object(parent) {}
 
         /**
-         * @brief Light position relative to given camera
+         * @brief Light position relative to root object (scene)
-         *
-         * The position is cached until the camera is changed to another or
-         * the light dirty bit is set.
          */
-        Vector3 position(Camera* camera);
+        inline Vector4 position() {
+            setClean();
+            return _position;
+        }
 
     protected:
         /**
@@ -51,8 +51,7 @@ class Light: public Object {
         void clean(const Matrix4& absoluteTransformation);
 
     private:
-        Camera* _camera;
+        Vector4 _position;
-        Vector3 _position;
 };
 
 }

src/Test/CMakeLists.txt

@@ -1,4 +1,3 @@
 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/LightTest.cpp

@@ -1,63 +0,0 @@
-/*
-    Copyright © 2010, 2011, 2012 Vladimír Vondruš <mosra@centrum.cz>
-
-    This file is part of Magnum.
-
-    Magnum is free software: you can redistribute it and/or modify
-    it under the terms of the GNU Lesser General Public License version 3
-    only, as published by the Free Software Foundation.
-
-    Magnum is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-    GNU Lesser General Public License version 3 for more details.
-*/
-
-#include "LightTest.h"
-
-#include <sstream>
-#include <QtTest/QTest>
-
-#include "Camera.h"
-#include "Light.h"
-#include "Scene.h"
-
-QTEST_APPLESS_MAIN(Magnum::Test::LightTest)
-
-using namespace std;
-using namespace Corrade::Utility;
-
-namespace Magnum { namespace Test {
-
-void LightTest::positionWrongCamera() {
-    stringstream ss;
-    Error::setOutput(&ss);
-
-    Camera c;
-    Light l;
-    QVERIFY(l.position(&c) == Vector3());
-    QVERIFY(ss.str() == "Light: camera and light aren't in the same scene!\n");
-}
-
-void LightTest::position() {
-    Scene s;
-
-    Object lightParent(&s);
-    lightParent.translate(Vector3::zAxis(3));
-    Light light(&lightParent);
-
-    Object cameraParent(&s);
-    cameraParent.rotate(deg(90.0f), Vector3::xAxis());
-    Camera camera(&cameraParent);
-
-    QVERIFY(light.position(&camera) == (Matrix4::translation(Vector3::zAxis(3))*
-        Matrix4::rotation(deg(90.0f), Vector3::xAxis()).inverted())[3].xyz());
-
-    /* Set another camera */
-    Camera another(&cameraParent);
-    another.scale(Vector3(3.0f));
-    QVERIFY(light.position(&another) == (Matrix4::translation(Vector3::zAxis(3))*
-        (Matrix4::scaling(Vector3(3.0f))*Matrix4::rotation(deg(90.0f), Vector3::xAxis())).inverted())[3].xyz());
-}
-
-}}

src/Test/LightTest.h

@@ -1,32 +0,0 @@
-#ifndef Magnum_Test_LightTest_h
-#define Magnum_Test_LightTest_h
-/*
-    Copyright © 2010, 2011, 2012 Vladimír Vondruš <mosra@centrum.cz>
-
-    This file is part of Magnum.
-
-    Magnum is free software: you can redistribute it and/or modify
-    it under the terms of the GNU Lesser General Public License version 3
-    only, as published by the Free Software Foundation.
-
-    Magnum is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-    GNU Lesser General Public License version 3 for more details.
-*/
-
-#include <QtCore/QObject>
-
-namespace Magnum { namespace Test {
-
-class LightTest: public QObject {
-    Q_OBJECT
-
-    private slots:
-        void positionWrongCamera();
-        void position();
-};
-
-}}
-
-#endif