From 7b9de3ad9132b31dde433e1ef5778ffe01e46464 Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Thu, 21 Aug 2003 09:51:25 +0000
Subject: [PATCH] From Marco Jez, improvement to the handling of coordinates
 frame in CubeMapGenerator.

---
 src/osgUtil/CubeMapGenerator.cpp | 43 ++++++++++++++++----------------
 1 file changed, 22 insertions(+), 21 deletions(-)

diff --git a/src/osgUtil/CubeMapGenerator.cpp b/src/osgUtil/CubeMapGenerator.cpp
index 5839eccf1..84e748dcf 100644
--- a/src/osgUtil/CubeMapGenerator.cpp
+++ b/src/osgUtil/CubeMapGenerator.cpp
@@ -13,6 +13,8 @@
 #include <osgUtil/CubeMapGenerator>
 #include <stdlib.h>
 
+#include <osg/Matrix>
+
 using namespace osgUtil;
 
 CubeMapGenerator::CubeMapGenerator(int texture_size)
@@ -41,29 +43,28 @@ CubeMapGenerator::CubeMapGenerator(const CubeMapGenerator &copy, const osg::Copy
 
 void CubeMapGenerator::generateMap(bool use_osg_system)
 {
-    const float duv = 2.0f/(texture_size_-1);
+	osg::Matrix M;
+	
+	if (use_osg_system) {
+		M = osg::Matrix::rotate(osg::PI_2, osg::Vec3(1, 0, 0));
+	} else {
+		M = osg::Matrix::identity();
+	}
+
+    const float dst = 2.0f/(texture_size_-1);
     
-    float v = 1;
+    float t = -1;
     for (int i=0; i<texture_size_; ++i) {
-        float u = 1;
-        for (int j=0; j<texture_size_; ++j) {            
-            if (use_osg_system) {
-                set_pixel(0, j, i, compute_color(osg::Vec3(1, -u, v)));
-                set_pixel(1, j, i, compute_color(osg::Vec3(-1, u, v)));
-                set_pixel(2, j, i, compute_color(osg::Vec3(-u, v, 1)));
-                set_pixel(3, j, i, compute_color(osg::Vec3(-u, -v, -1)));
-                set_pixel(4, j, i, compute_color(osg::Vec3(-u, -1, v)));
-                set_pixel(5, j, i, compute_color(osg::Vec3(u, 1, v)));
-            } else {
-                set_pixel(0, j, i, compute_color(osg::Vec3(1, v, -u)));
-                set_pixel(1, j, i, compute_color(osg::Vec3(-1, v, u)));
-                set_pixel(2, j, i, compute_color(osg::Vec3(-u, 1, v)));
-                set_pixel(3, j, i, compute_color(osg::Vec3(-u, -1, -v)));
-                set_pixel(4, j, i, compute_color(osg::Vec3(-u, v, -1)));
-                set_pixel(5, j, i, compute_color(osg::Vec3(u, v, 1)));
-            }
-            u -= duv;
+        float s = -1;
+        for (int j=0; j<texture_size_; ++j) {
+			set_pixel(0, j, i, compute_color(osg::Vec3(1, -t, -s)  * M));
+            set_pixel(1, j, i, compute_color(osg::Vec3(-1, -t, s)  * M));
+            set_pixel(2, j, i, compute_color(osg::Vec3(s, 1, t)    * M));
+            set_pixel(3, j, i, compute_color(osg::Vec3(s, -1, -t)  * M));
+            set_pixel(4, j, i, compute_color(osg::Vec3(s, -t, 1)   * M));
+            set_pixel(5, j, i, compute_color(osg::Vec3(-s, -t, -1) * M));
+            s += dst;
         }
-        v -= duv;
+        t += dst;
     }
 }