From c6e14dd348eb82c80240f9340b75c2aad0e6c0bd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Vladim=C3=ADr=20Vondru=C5=A1?= <mosra@centrum.cz>
Date: Fri, 17 Aug 2012 02:42:34 +0200
Subject: [PATCH] SceneGraph: Initial support for projections with aspect ratio
 != 1:1.

Orthographic projection done, perspective projection needs total rework,
leaving it for later.
---
 src/SceneGraph/Camera.cpp          | 23 +++++++++--------
 src/SceneGraph/Camera.h            | 13 ++++++----
 src/SceneGraph/Test/CameraTest.cpp | 40 ++++++++++++++++++++++++------
 3 files changed, 53 insertions(+), 23 deletions(-)

diff --git a/src/SceneGraph/Camera.cpp b/src/SceneGraph/Camera.cpp
index 32fba23f8..5726e9596 100644
--- a/src/SceneGraph/Camera.cpp
+++ b/src/SceneGraph/Camera.cpp
@@ -24,26 +24,28 @@ namespace Magnum { namespace SceneGraph {
 #ifndef DOXYGEN_GENERATING_OUTPUT
 namespace Implementation {
 
-template<class MatrixType> MatrixType aspectRatioFix(AspectRatioPolicy aspectRatioPolicy, const Math::Vector2<GLsizei>& viewport) {
+template<class MatrixType> MatrixType aspectRatioFix(AspectRatioPolicy aspectRatioPolicy, const Vector2& projectionAspectRatio, const Math::Vector2<GLsizei>& viewport) {
     /* Don't divide by zero / don't preserve anything */
-    if(viewport.x() == 0 || viewport.y() == 0 || aspectRatioPolicy == AspectRatioPolicy::NotPreserved)
+    if(projectionAspectRatio.x() == 0 || projectionAspectRatio.y() == 0 || viewport.x() == 0 || viewport.y() == 0 || aspectRatioPolicy == AspectRatioPolicy::NotPreserved)
         return MatrixType();
 
+    Vector2 relativeAspectRatio = Vector2::from(viewport)/projectionAspectRatio;
+
     /* Extend on larger side = scale larger side down
        Clip on smaller side = scale smaller side up */
     return Camera<MatrixType::Size-1>::aspectRatioScale(
-        (viewport.x() > viewport.y()) == (aspectRatioPolicy == AspectRatioPolicy::Extend) ?
-        Vector2(GLfloat(viewport.y())/viewport.x(), 1.0f) :
-        Vector2(1.0f, GLfloat(viewport.x())/viewport.y()));
+        (relativeAspectRatio.x() > relativeAspectRatio.y()) == (aspectRatioPolicy == AspectRatioPolicy::Extend) ?
+        Vector2(relativeAspectRatio.y()/relativeAspectRatio.x(), 1.0f) :
+        Vector2(1.0f, relativeAspectRatio.x()/relativeAspectRatio.y()));
 }
 
 /* Explicitly instantiate the templates */
-template Matrix4 aspectRatioFix<Matrix4>(AspectRatioPolicy, const Math::Vector2<GLsizei>&);
+template Matrix4 aspectRatioFix<Matrix4>(AspectRatioPolicy, const Vector2&, const Math::Vector2<GLsizei>&);
 
 }
 #endif
 
-template<class MatrixType, class VectorType, class ObjectType, class SceneType, class CameraType> Camera<MatrixType, VectorType, ObjectType, SceneType, CameraType>::Camera(ObjectType* parent): ObjectType(parent), _aspectRatioPolicy(AspectRatioPolicy::Extend) {}
+template<class MatrixType, class VectorType, class ObjectType, class SceneType, class CameraType> Camera<MatrixType, VectorType, ObjectType, SceneType, CameraType>::Camera(ObjectType* parent): ObjectType(parent), projectionAspectRatio(1.0f), _aspectRatioPolicy(AspectRatioPolicy::Extend) {}
 
 template<class MatrixType, class VectorType, class ObjectType, class SceneType, class CameraType> void Camera<MatrixType, VectorType, ObjectType, SceneType, CameraType>::setViewport(const Math::Vector2<GLsizei>& size) {
     Framebuffer::setViewport({0, 0}, size);
@@ -79,18 +81,18 @@ template<class MatrixType, class VectorType, class ObjectType, class SceneType,
     }
 }
 
-void Camera3D::setOrthographic(GLfloat size, GLfloat near, GLfloat far) {
+void Camera3D::setOrthographic(const Vector2& size, GLfloat near, GLfloat far) {
     _near = near;
     _far = far;
 
     /* Scale the volume down so it fits in (-1, 1) in all directions */
-    GLfloat xyScale = 2/size;
     GLfloat zScale = 2/(far-near);
-    rawProjectionMatrix = Matrix4::scaling({xyScale, xyScale, -zScale});
+    rawProjectionMatrix = Matrix4::scaling({2.0f/size, -zScale});
 
     /* Move the volume on z into (-1, 1) range */
     rawProjectionMatrix = Matrix4::translation(Vector3::zAxis(-1-near*zScale))*rawProjectionMatrix;
 
+    projectionAspectRatio = size;
     fixAspectRatio();
 }
 
@@ -116,6 +118,7 @@ void Camera3D::setPerspective(GLfloat fov, GLfloat near, GLfloat far) {
     /* And... another magic */
     rawProjectionMatrix[3][3] = 0;
 
+    projectionAspectRatio = Vector2(xyScale);
     fixAspectRatio();
 }
 
diff --git a/src/SceneGraph/Camera.h b/src/SceneGraph/Camera.h
index 96f71cef4..36a4c8d06 100644
--- a/src/SceneGraph/Camera.h
+++ b/src/SceneGraph/Camera.h
@@ -38,10 +38,10 @@ namespace Implementation {
 
     template<size_t dimensions> class Camera {};
 
-    template<class MatrixType> MatrixType aspectRatioFix(AspectRatioPolicy aspectRatioPolicy, const Math::Vector2<GLsizei>& viewport);
+    template<class MatrixType> MatrixType aspectRatioFix(AspectRatioPolicy aspectRatioPolicy, const Vector2& projectionAspectRatio, const Math::Vector2<GLsizei>& viewport);
 
     /* These templates are instantiated in source file */
-    extern template SCENEGRAPH_EXPORT Matrix4 aspectRatioFix<Matrix4>(AspectRatioPolicy, const Math::Vector2<GLsizei>&);
+    extern template SCENEGRAPH_EXPORT Matrix4 aspectRatioFix<Matrix4>(AspectRatioPolicy, const Vector2&, const Math::Vector2<GLsizei>&);
 }
 #endif
 
@@ -130,9 +130,10 @@ template<class MatrixType, class VectorType, class ObjectType, class SceneType,
 
         #ifndef DOXYGEN_GENERATING_OUTPUT
         inline void fixAspectRatio() {
-            _projectionMatrix = Implementation::aspectRatioFix<MatrixType>(_aspectRatioPolicy, _viewport)*rawProjectionMatrix;
+            _projectionMatrix = Implementation::aspectRatioFix<MatrixType>(_aspectRatioPolicy, projectionAspectRatio, _viewport)*rawProjectionMatrix;
         }
 
+        Vector2 projectionAspectRatio;
         MatrixType rawProjectionMatrix;
         AspectRatioPolicy _aspectRatioPolicy;
         #endif
@@ -172,20 +173,22 @@ class SCENEGRAPH_EXPORT Camera3D: public Camera<Matrix4, Vector3, Object3D, Scen
 
         /**
          * @brief Set orthographic projection
-         * @param size      Size of (square) view
+         * @param size      Size of the view
          * @param near      Near clipping plane
          * @param far       Far clipping plane
          *
          * The volume of given size will be scaled down to range @f$ [-1; 1] @f$
          * on all directions.
          */
-        void setOrthographic(GLfloat size, GLfloat near, GLfloat far);
+        void setOrthographic(const Vector2& size, GLfloat near, GLfloat far);
 
         /**
          * @brief Set perspective projection
          * @param fov       Field of view angle
          * @param near      Near clipping plane
          * @param far       Far clipping plane
+         *
+         * @todo Aspect ratio
          */
         void setPerspective(GLfloat fov, GLfloat near, GLfloat far);
 
diff --git a/src/SceneGraph/Test/CameraTest.cpp b/src/SceneGraph/Test/CameraTest.cpp
index 2a72ac5a9..d2c514b09 100644
--- a/src/SceneGraph/Test/CameraTest.cpp
+++ b/src/SceneGraph/Test/CameraTest.cpp
@@ -28,35 +28,50 @@ CameraTest::CameraTest() {
 }
 
 void CameraTest::fixAspectRatio() {
+    Vector2 projectionSize(2, 3);
+    Math::Vector2<GLsizei> size(400, 300);
+
     /* Division by zero */
+    Vector2 projectionSizeZeroY(2, 0);
+    Vector2 projectionSizeZeroX(0, 2);
     Math::Vector2<GLsizei> sizeZeroY(400, 0);
     Math::Vector2<GLsizei> sizeZeroX(0, 300);
-    CORRADE_COMPARE(Implementation::aspectRatioFix<Matrix4>(Implementation::AspectRatioPolicy::Clip, sizeZeroY), Matrix4());
-    CORRADE_COMPARE(Implementation::aspectRatioFix<Matrix4>(Implementation::AspectRatioPolicy::Extend, sizeZeroX), Matrix4());
-
-    Math::Vector2<GLsizei> size(400, 300);
+    CORRADE_COMPARE(Implementation::aspectRatioFix<Matrix4>(Implementation::AspectRatioPolicy::Clip, projectionSizeZeroX, size), Matrix4());
+    CORRADE_COMPARE(Implementation::aspectRatioFix<Matrix4>(Implementation::AspectRatioPolicy::Clip, projectionSizeZeroY, size), Matrix4());
+    CORRADE_COMPARE(Implementation::aspectRatioFix<Matrix4>(Implementation::AspectRatioPolicy::Clip, projectionSize, sizeZeroY), Matrix4());
+    CORRADE_COMPARE(Implementation::aspectRatioFix<Matrix4>(Implementation::AspectRatioPolicy::Extend, projectionSize, sizeZeroX), Matrix4());
 
     /* Not preserved */
-    CORRADE_COMPARE(Implementation::aspectRatioFix<Matrix4>(Implementation::AspectRatioPolicy::NotPreserved, size), Matrix4());
+    CORRADE_COMPARE(Implementation::aspectRatioFix<Matrix4>(Implementation::AspectRatioPolicy::NotPreserved, projectionSize, size), Matrix4());
 
     /* Clip */
     Matrix4 expectedClip(1.0f, 0.0f,      0.0f, 0.0f,
                          0.0f, 4.0f/3.0f, 0.0f, 0.0f,
                          0.0f, 0.0f,      1.0f, 0.0f,
                          0.0f, 0.0f,      0.0f, 1.0f);
-    CORRADE_COMPARE(Implementation::aspectRatioFix<Matrix4>(Implementation::AspectRatioPolicy::Clip, size), expectedClip);
+    CORRADE_COMPARE(Implementation::aspectRatioFix<Matrix4>(Implementation::AspectRatioPolicy::Clip, Vector2(2.0f), size), expectedClip);
+    Matrix4 expectedClipRectangle(1.0f, 0.0f, 0.0f, 0.0f,
+                                  0.0f, 2.0f, 0.0f, 0.0f,
+                                  0.0f, 0.0f, 1.0f, 0.0f,
+                                  0.0f, 0.0f, 0.0f, 1.0f);
+    CORRADE_COMPARE(Implementation::aspectRatioFix<Matrix4>(Implementation::AspectRatioPolicy::Clip, projectionSize, size), expectedClipRectangle);
 
     /* Extend */
     Matrix4 expectedExtend(3.0f/4.0f, 0.0f, 0.0f, 0.0f,
                            0.0f,      1.0f, 0.0f, 0.0f,
                            0.0f,      0.0f, 1.0f, 0.0f,
                            0.0f,      0.0f, 0.0f, 1.0f);
-    CORRADE_COMPARE(Implementation::aspectRatioFix<Matrix4>(Implementation::AspectRatioPolicy::Extend, size), expectedExtend);
+    CORRADE_COMPARE(Implementation::aspectRatioFix<Matrix4>(Implementation::AspectRatioPolicy::Extend, Vector2(2.0f), size), expectedExtend);
+    Matrix4 expectedExtendRectangle(0.5f, 0.0f, 0.0f, 0.0f,
+                                    0.0f, 1.0f, 0.0f, 0.0f,
+                                    0.0f, 0.0f, 1.0f, 0.0f,
+                                    0.0f, 0.0f, 0.0f, 1.0f);
+    CORRADE_COMPARE(Implementation::aspectRatioFix<Matrix4>(Implementation::AspectRatioPolicy::Extend, projectionSize, size), expectedExtendRectangle);
 }
 
 void CameraTest::orthographic() {
     Camera3D camera;
-    camera.setOrthographic(5, 1, 9);
+    camera.setOrthographic(Vector2(5), 1, 9);
 
     Matrix4 a(0.4f,   0.0f,   0.0f,       0.0f,
               0.0f,   0.4f,   0.0f,       0.0f,
@@ -64,6 +79,15 @@ void CameraTest::orthographic() {
               0.0f,   0.0f,   -1.25f,     1.0f);
 
     CORRADE_COMPARE(camera.projectionMatrix(), a);
+
+    camera.setOrthographic(Vector2(5.0f, 4.0f), 1, 9);
+
+    Matrix4 rectangle(0.4f,   0.0f,   0.0f,       0.0f,
+                      0.0f,   0.5f,   0.0f,       0.0f,
+                      0.0f,   0.0f,   -0.25f,     0.0f,
+                      0.0f,   0.0f,   -1.25f,     1.0f);
+
+    CORRADE_COMPARE(camera.projectionMatrix(), rectangle);
 }
 
 void CameraTest::perspective() {