From d43e18a741f07cdc6e68b475b9a2dbaede108799 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Vladim=C3=ADr=20Vondru=C5=A1?= <mosra@centrum.cz>
Date: Thu, 16 Aug 2012 15:39:01 +0200
Subject: [PATCH] Initial support for 2D scene graph.

---
 src/SceneGraph/Camera.cpp | 10 ++++++++++
 src/SceneGraph/Camera.h   | 29 +++++++++++++++++++++++++++
 src/SceneGraph/Object.cpp |  1 +
 src/SceneGraph/Object.h   | 41 +++++++++++++++++++++++++++++++++++++++
 src/SceneGraph/Scene.h    |  3 +++
 5 files changed, 84 insertions(+)

diff --git a/src/SceneGraph/Camera.cpp b/src/SceneGraph/Camera.cpp
index 5726e9596..5ab0c81b8 100644
--- a/src/SceneGraph/Camera.cpp
+++ b/src/SceneGraph/Camera.cpp
@@ -40,6 +40,7 @@ template<class MatrixType> MatrixType aspectRatioFix(AspectRatioPolicy aspectRat
 }
 
 /* Explicitly instantiate the templates */
+template Matrix3 aspectRatioFix<Matrix3>(AspectRatioPolicy, const Vector2&, const Math::Vector2<GLsizei>&);
 template Matrix4 aspectRatioFix<Matrix4>(AspectRatioPolicy, const Vector2&, const Math::Vector2<GLsizei>&);
 
 }
@@ -81,6 +82,14 @@ template<class MatrixType, class VectorType, class ObjectType, class SceneType,
     }
 }
 
+void Camera2D::setProjection(const Vector2& size) {
+    /* Scale the volume down so it fits in (-1, 1) in all directions */
+    rawProjectionMatrix = Matrix3::scaling(2.0f/size);
+
+    projectionAspectRatio = size;
+    fixAspectRatio();
+}
+
 void Camera3D::setOrthographic(const Vector2& size, GLfloat near, GLfloat far) {
     _near = near;
     _far = far;
@@ -123,6 +132,7 @@ void Camera3D::setPerspective(GLfloat fov, GLfloat near, GLfloat far) {
 }
 
 /* Explicitly instantiate the templates */
+template class Camera<Matrix3, Vector2, Object2D, Scene2D, Camera2D>;
 template class Camera<Matrix4, Vector3, Object3D, Scene3D, Camera3D>;
 
 }}
diff --git a/src/SceneGraph/Camera.h b/src/SceneGraph/Camera.h
index 36a4c8d06..cf6ba0c4b 100644
--- a/src/SceneGraph/Camera.h
+++ b/src/SceneGraph/Camera.h
@@ -147,9 +147,16 @@ template<class MatrixType, class VectorType, class ObjectType, class SceneType,
 
 #ifndef DOXYGEN_GENERATING_OUTPUT
 /* These templates are instantiated in source file */
+extern template class SCENEGRAPH_EXPORT Camera<Matrix3, Vector2, Object2D, Scene2D, Camera2D>;
 extern template class SCENEGRAPH_EXPORT Camera<Matrix4, Vector3, Object3D, Scene3D, Camera3D>;
 
 namespace Implementation {
+    template<> class Camera<2> {
+        public:
+            inline constexpr static Matrix3 aspectRatioScale(const Vector2& scale) {
+                return Matrix3::scaling({scale.x(), scale.y()});
+            }
+    };
     template<> class Camera<3> {
         public:
             inline constexpr static Matrix4 aspectRatioScale(const Vector2& scale) {
@@ -159,6 +166,28 @@ namespace Implementation {
 }
 #endif
 
+/** @brief %Camera for two-dimensional scenes */
+class SCENEGRAPH_EXPORT Camera2D: public Camera<Matrix3, Vector2, Object2D, Scene2D, Camera2D> {
+    public:
+        /**
+         * @brief Constructor
+         * @param parent    Parent object
+         *
+         * Sets orthographic projection to the default OpenGL cube (range @f$ [-1; 1] @f$ in all directions).
+         * @see setOrthographic()
+         */
+        inline Camera2D(Object2D* parent = nullptr): Camera(parent) {}
+
+        /**
+         * @brief Set projection
+         * @param size      Size of the view
+         *
+         * The area of given size will be scaled down to range @f$ [-1; 1] @f$
+         * on all directions.
+         */
+        void setProjection(const Vector2& size);
+};
+
 /** @brief %Camera for three-dimensional scenes */
 class SCENEGRAPH_EXPORT Camera3D: public Camera<Matrix4, Vector3, Object3D, Scene3D, Camera3D> {
     public:
diff --git a/src/SceneGraph/Object.cpp b/src/SceneGraph/Object.cpp
index 386cf86e9..f74602bb1 100644
--- a/src/SceneGraph/Object.cpp
+++ b/src/SceneGraph/Object.cpp
@@ -152,6 +152,7 @@ template<class MatrixType, class VectorType, class ObjectType, class SceneType,
 }
 
 /* Explicitly instantiate the templates */
+template class Object<Matrix3, Vector2, Object2D, Scene2D, Camera2D>;
 template class Object<Matrix4, Vector3, Object3D, Scene3D, Camera3D>;
 
 }}
diff --git a/src/SceneGraph/Object.h b/src/SceneGraph/Object.h
index b86f48d20..691baf688 100644
--- a/src/SceneGraph/Object.h
+++ b/src/SceneGraph/Object.h
@@ -241,15 +241,56 @@ template<class MatrixType, class VectorType, class ObjectType, class SceneType,
 template<class MatrixType, class VectorType, class ObjectType, class SceneType, class CameraType> inline void Object<MatrixType, VectorType, ObjectType, SceneType, CameraType>::draw(const MatrixType&, CameraType*) {}
 template<class MatrixType, class VectorType, class ObjectType, class SceneType, class CameraType> inline void Object<MatrixType, VectorType, ObjectType, SceneType, CameraType>::clean(const MatrixType&) { dirty = false; }
 
+class Camera2D;
 class Camera3D;
+class Object2D;
 class Object3D;
+typedef Scene<Matrix3, Vector2, Object2D, Camera2D> Scene2D;
 typedef Scene<Matrix4, Vector3, Object3D, Camera3D> Scene3D;
 
 #ifndef DOXYGEN_GENERATING_OUTPUT
 /* These templates are instantiated in source file */
+extern template class SCENEGRAPH_EXPORT Object<Matrix3, Vector2, Object2D, Scene2D, Camera2D>;
 extern template class SCENEGRAPH_EXPORT Object<Matrix4, Vector3, Object3D, Scene3D, Camera3D>;
 #endif
 
+/** @brief Two-dimensional object */
+class SCENEGRAPH_EXPORT Object2D: public Object<Matrix3, Vector2, Object2D, Scene2D, Camera2D> {
+    public:
+        /** @copydoc Object::Object */
+        inline Object2D(Object2D* parent = nullptr): Object(parent) {}
+
+        /**
+         * @brief Translate object
+         *
+         * Same as calling multiplyTransformation() with Matrix3::translation().
+         */
+        inline Object2D* translate(const Vector2& vec, Transformation type = Transformation::Global) {
+            multiplyTransformation(Matrix3::translation(vec), type);
+            return this;
+        }
+
+        /**
+         * @brief Scale object
+         *
+         * Same as calling multiplyTransformation() with Matrix3::scaling().
+         */
+        inline Object2D* scale(const Vector2& vec, Transformation type = Transformation::Global) {
+            multiplyTransformation(Matrix3::scaling(vec), type);
+            return this;
+        }
+
+        /**
+         * @brief Rotate object
+         *
+         * Same as calling multiplyTransformation() with Matrix3::rotation().
+         */
+        inline Object2D* rotate(GLfloat angle, Transformation type = Transformation::Global) {
+            multiplyTransformation(Matrix3::rotation(angle), type);
+            return this;
+        }
+};
+
 /** @brief Three-dimensional object */
 class SCENEGRAPH_EXPORT Object3D: public Object<Matrix4, Vector3, Object3D, Scene3D, Camera3D> {
     public:
diff --git a/src/SceneGraph/Scene.h b/src/SceneGraph/Scene.h
index 35b36e501..73e3793f0 100644
--- a/src/SceneGraph/Scene.h
+++ b/src/SceneGraph/Scene.h
@@ -42,6 +42,9 @@ template<class MatrixType, class VectorType, class ObjectType, class CameraType>
         inline void draw(const MatrixType&, CameraType*) {}
 };
 
+/** @brief Two-dimensional scene */
+typedef Scene<Matrix3, Vector2, Object2D, Camera2D> Scene2D;
+
 /** @brief Three-dimensional scene */
 typedef Scene<Matrix4, Vector3, Object3D, Camera3D> Scene3D;