4 files changed, 14 insertions, 2 deletions
diff --git a/demos/boxes/glbuffers.cpp b/demos/boxes/glbuffers.cpp
index 694d05b..84ab26c 100644
--- a/demos/boxes/glbuffers.cpp
+++ b/demos/boxes/glbuffers.cpp
@@ -42,6 +42,16 @@
 #include "glbuffers.h"
 #include <QtGui/qmatrix4x4.h>
 
+
+void qgluPerspective(GLdouble fovy, GLdouble aspect, GLdouble zNear, GLdouble zFar)
+{
+    const GLdouble ymax = zNear * tan(fovy * M_PI / 360.0);
+    const GLdouble ymin = -ymax;
+    const GLdouble xmin = ymin * aspect;
+    const GLdouble xmax = ymax * aspect;
+    glFrustum(xmin, xmax, ymin, ymax, zNear, zFar);
+}
+
 //============================================================================//
 //                                  GLTexture                                 //
 //============================================================================//
diff --git a/demos/boxes/glbuffers.h b/demos/boxes/glbuffers.h
index 67a4ea6..8c1e209 100644
--- a/demos/boxes/glbuffers.h
+++ b/demos/boxes/glbuffers.h
@@ -58,6 +58,8 @@ if (m_failed || !(assertion)) {
     returnStatement;                                                                        \
 }
 
+void qgluPerspective(GLdouble fovy, GLdouble aspect, GLdouble zNear, GLdouble zFar);
+
 QT_BEGIN_NAMESPACE
 class QMatrix4x4;
 QT_END_NAMESPACE
diff --git a/demos/boxes/qtbox.cpp b/demos/boxes/qtbox.cpp
index 3aaf985..e3a5978 100644
--- a/demos/boxes/qtbox.cpp
+++ b/demos/boxes/qtbox.cpp
@@ -324,7 +324,7 @@ void QtBox::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWi
     glMatrixMode(GL_PROJECTION);
     glPushMatrix();
     glLoadMatrixf(moveToRectMatrix);
-    gluPerspective(60.0, 1.0, 0.01, 10.0);
+    qgluPerspective(60.0, 1.0, 0.01, 10.0);
 
     glMatrixMode(GL_MODELVIEW);
     glPushMatrix();
diff --git a/demos/boxes/scene.cpp b/demos/boxes/scene.cpp
index 97953f2..d65af22 100644
--- a/demos/boxes/scene.cpp
+++ b/demos/boxes/scene.cpp
@@ -922,7 +922,7 @@ void Scene::drawBackground(QPainter *painter, const QRectF &)
     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 
     glMatrixMode(GL_PROJECTION);
-    gluPerspective(60.0, width / height, 0.01, 15.0);
+    qgluPerspective(60.0, width / height, 0.01, 15.0);
 
     glMatrixMode(GL_MODELVIEW);