From 5af44143e29e70dead405653615ac867efef392a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Vladim=C3=ADr=20Vondru=C5=A1?= <mosra@centrum.cz>
Date: Fri, 31 Dec 2010 16:11:41 +0100
Subject: [PATCH] Function for getting absolute object transformation (relative
 to the camera).

Usable for computation of light positions.
---
 src/Object.cpp | 23 +++++++++++++++++++++++
 src/Object.h   | 13 +++++++++++--
 2 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/src/Object.cpp b/src/Object.cpp
index 8ba541163..a1e873d18 100644
--- a/src/Object.cpp
+++ b/src/Object.cpp
@@ -43,6 +43,29 @@ void Object::setParent(Object* parent) {
     _parent = parent;
 }
 
+Matrix4 Object::transformation(bool absolute) {
+    if(!absolute) return _transformation;
+
+    Matrix4 t = _transformation;
+
+    Object* p = parent();
+    while(p != 0) {
+        t = p->transformation()*t;
+
+        /* We got to the scene, multiply with camera matrix */
+        if(p->parent() == p) {
+            Camera* camera = static_cast<Scene*>(p)->camera();
+            if(camera && camera != this) t = camera->cameraMatrix()*t;
+
+            break;
+        }
+
+        p = p->parent();
+    }
+
+    return t;
+}
+
 Object::~Object() {
     /* Remove the object from parent's children */
     setParent(0);
diff --git a/src/Object.h b/src/Object.h
index a6d746ff9..142b5ffb0 100644
--- a/src/Object.h
+++ b/src/Object.h
@@ -72,8 +72,17 @@ class Object {
         /** @brief Set parent object */
         virtual void setParent(Object* parent);
 
-        /** @brief Transformation matrix */
-        inline Matrix4 transformation() const { return _transformation; }
+        /**
+         * @brief Transformation matrix
+         *
+         * If the object is part of an scene and @c absolute is set to true,
+         * returns absolute transformation matrix (thus relative to actual
+         * camera), if the object is not part of an scene, returns
+         * transformation matrix composed of all matrices of parent objects.
+         * If @c absolute is set to false, returns transformation matrix
+         * relative to parent.
+         */
+        virtual Matrix4 transformation(bool absolute = false);
 
         /** @brief Set transformation matrix */
         inline void setTransformation(const Matrix4& transformation) { _transformation = transformation; }