From cb169716fe81dc334a9a902ccf5bd00e0c613106 Mon Sep 17 00:00:00 2001
From: rambetter <rambetter>
Date: Wed, 19 Jan 2011 06:41:33 +0000
Subject: [PATCH] Fixing a 45 degree model clipping problem. Introducing
 Q3MAP2_EXPERIMENTAL_MODEL_CLIPPING_FIX to control the new code, current value
 is 1 (enable the fix). This code fixes the q3map2 regression test
 model_clipping_45_degrees.

git-svn-id: svn://svn.icculus.org/gtkradiant/GtkRadiant/trunk@429 8a3a26a2-13c4-0310-b231-cf6edde360e5
---
 tools/quake3/q3map2/model.c  | 11 +++++++++++
 tools/quake3/q3map2/q3map2.h |  1 +
 2 files changed, 12 insertions(+)

diff --git a/tools/quake3/q3map2/model.c b/tools/quake3/q3map2/model.c
index 4200368b..ef0a0489 100644
--- a/tools/quake3/q3map2/model.c
+++ b/tools/quake3/q3map2/model.c
@@ -431,6 +431,9 @@ void InsertModel( char *name, int frame, m4x4_t transform, remap_t *remap, shade
 					
 					/* copy xyz */
 					VectorCopy( dv->xyz, points[ j ] );
+#if ! Q3MAP2_EXPERIMENTAL_MODEL_CLIPPING_FIX
+					// The code below is totally unneeded regardless of Q3MAP2_EXPERIMENTAL_MODEL_CLIPPING_FIX.
+					// backs is reinitialized further below.  However, the extra code does not hurt anything.
 					VectorCopy( dv->xyz, backs[ j ] );
 					
 					/* find nearest axial to normal and push back points opposite */
@@ -444,6 +447,7 @@ void InsertModel( char *name, int frame, m4x4_t transform, remap_t *remap, shade
 							break;
 						}
 					}
+#endif
 				}
 				
 				/* make plane for triangle */
@@ -461,8 +465,15 @@ void InsertModel( char *name, int frame, m4x4_t transform, remap_t *remap, shade
 						/* find nearest axial to plane normal and push back points opposite */
 						for( k = 0; k < 3; k++ )
 						{
+#if Q3MAP2_EXPERIMENTAL_MODEL_CLIPPING_FIX
+							if( fabs( plane[ k ] ) >= fabs( plane[ (k + 1) % 3 ] ) &&
+								fabs( plane[ k ] ) >= fabs( plane[ (k + 2) % 3 ] ) )
+#else
+							// This code is broken for 45 degree angles where there
+							// is no clear winner.
 							if( fabs( plane[ k ] ) > fabs( plane[ (k + 1) % 3 ] ) &&
 								fabs( plane[ k ] ) > fabs( plane[ (k + 2) % 3 ] ) )
+#endif
 							{
 								backs[ j ][ k ] += plane[ k ] < 0.0f ? 64.0f : -64.0f;
 								break;
diff --git a/tools/quake3/q3map2/q3map2.h b/tools/quake3/q3map2/q3map2.h
index 7b907365..b5b41117 100644
--- a/tools/quake3/q3map2/q3map2.h
+++ b/tools/quake3/q3map2/q3map2.h
@@ -127,6 +127,7 @@ constants
 #define Q3MAP2_EXPERIMENTAL_HIGH_PRECISION_MATH_FIXES	1
 #define Q3MAP2_EXPERIMENTAL_SNAP_NORMAL_FIX		1
 #define Q3MAP2_EXPERIMENTAL_SNAP_PLANE_FIX		1
+#define Q3MAP2_EXPERIMENTAL_MODEL_CLIPPING_FIX		1
 
 /* general */
 #define MAX_QPATH				64
-- 
2.39.2