# Fixes to the line segment frustum test.

This was SVN commit r4245.

source/graphics/Frustum.cpp

@@ -17,6 +17,7 @@
 
 #include "Frustum.h"
 #include "maths/Bound.h"
+#include "maths/MathUtil.h"
 
 CFrustum::CFrustum ()
 {
@@ -52,13 +53,22 @@ bool CFrustum::IsPointVisible (const CVector3D &point) const
 
 	return true;
 }
-bool CFrustum::DoesSegmentIntersect(const CVector3D& start, const CVector3D &end)
+bool CFrustum::DoesSegmentIntersect(const CVector3D& startRef, const CVector3D &endRef)
 {
+	CVector3D start = startRef;
+	CVector3D end = endRef;
+
+	if(IsPointVisible(start) || IsPointVisible(end))
+		return true;
+
 	CVector3D intersect;
 	for ( int i = 0; i<m_NumPlanes; ++i )
 	{
 		if ( m_aPlanes[i].FindLineSegIntersection(start, end, &intersect) )
-			return true;
+		{
+			if ( IsPointVisible( intersect ) )
+				return true;
+		}
 	}
 	return false;
 }

source/maths/Plane.cpp

@@ -14,6 +14,7 @@
 #include "precompiled.h"
 
 #include "Plane.h"
+#include "MathUtil.h"
 
 CPlane::CPlane ()
 {
@@ -74,9 +75,11 @@ PLANESIDE CPlane::ClassifyPoint (const CVector3D &point) const
 		   m_Norm.Z * point.Z +
 		   m_Dist;
 
-	if (Dist > 0.0f)
+	const float EPS = 0.001f;
+
+	if (Dist > EPS)
 		return PS_FRONT;
-	else if (Dist < 0.0f)
+	else if (Dist < -EPS)
 		return PS_BACK;
 
 	return PS_ON;
@@ -99,31 +102,14 @@ float CPlane::DistanceToPlane (const CVector3D &point) const
 //plane. Returns false if there is no intersection
 bool CPlane::FindLineSegIntersection (const CVector3D &start, const CVector3D &end, CVector3D *intsect)
 {
-	PLANESIDE StartS, EndS;
-	CVector3D Dir;
-	float Length;
-	
-	//work out where each point is
-	StartS = ClassifyPoint (start);
-	EndS = ClassifyPoint (end);
+	float dist1 = DistanceToPlane( start );
+	float dist2 = DistanceToPlane( end );
 
-	//if they are not on opposite sides of the plane return false
-	if (StartS == EndS)
+	if( (dist1 < 0 && dist2 < 0) || (dist1 >= 0 && dist2 >= 0) )
 		return false;
 
-	//work out a normalized vector in the direction start to end
-	Dir = end - start;
-	Dir.Normalize ();
-
-	//a bit of algebra to work out how much we need to scale
-	//this direction vector to get to the plane
-	Length = -m_Norm.Dot(start)/m_Norm.Dot(Dir);
-
-	//scale it by this amount
-	Dir *= Length;
-
-	//workout actual position vector of impact
-	*intsect = start + Dir;
+	float t = (-dist1) / (dist2-dist1);
+	*intsect = Interpolate( start, end, t );
 
 	return true;
 }

source/simulation/TerritoryManager.cpp

@@ -214,13 +214,13 @@ void CTerritoryManager::renderTerritories()
 	std::vector<CTerritory*>::iterator terr=m_Territories.begin();
 	glEnable(GL_LINE_SMOOTH);
 	glLineWidth(1.4f);
+	glColor3f(1.0f, 1.0f, 1.0f);
 
 	for ( ; terr != m_Territories.end(); ++terr )
 	{
 		std::vector<CVector2D>::iterator it=(*terr)->boundary.begin()+1;
-		const SPlayerColour& col = (*terr)->owner->GetColour();
-		glColor3f(col.r, col.g, col.b);
-		glBegin(GL_LINE_STRIP);
+		//const SPlayerColour& col = (*terr)->owner->GetColour();
+		//glColor3f(col.r, col.g, col.b);
 	
 		for ( ; it != (*terr)->boundary.end(); ++it )
 		{
@@ -229,6 +229,7 @@ void CTerritoryManager::renderTerritories()
 			if ( !frustum.DoesSegmentIntersect(prev, front) )
 				continue;
 			
+			glBegin(GL_LINE_STRIP);
 			float iterf = (front - prev).GetLength() / TERRITORY_PRECISION_STEP;
 			for ( float i=0; i<iterf; i+= TERRITORY_PRECISION_STEP )
 			{
@@ -236,6 +237,7 @@ void CTerritoryManager::renderTerritories()
 				glVertex3f(pos.x, pTerrain->getExactGroundLevel(pos)+.25f, pos.y); 
 			}
 			glVertex3f(front.X, pTerrain->getExactGroundLevel(front.X, front.Z)+.25f, front.Z); 
+			glEnd();
 		}
 		//Loop around
 		CVector2D first2D((*terr)->boundary.front()), back2D((*terr)->boundary.back());
@@ -243,10 +245,9 @@ void CTerritoryManager::renderTerritories()
 		CVector3D back(back2D.x, pTerrain->getExactGroundLevel(back2D), back2D.y);
 
 		if ( !frustum.DoesSegmentIntersect(back, first) )
-		{
-			glEnd();
 			continue;
-		}
+		
+		glBegin(GL_LINE_STRIP);
 		float iterf = (first - back).GetLength() / TERRITORY_PRECISION_STEP;
 		for ( float i=0; i<iterf; i+= TERRITORY_PRECISION_STEP )
 		{
@@ -254,9 +255,8 @@ void CTerritoryManager::renderTerritories()
 			glVertex3f(pos.x, pTerrain->getExactGroundLevel(pos)+.25f, pos.y); 
 		}
 		glVertex3f(first.X, pTerrain->getExactGroundLevel(first2D)+.25f, first.Z); 
-	
 		glEnd();
 	}
 	glDisable(GL_LINE_SMOOTH);
-	glLineWidth(1.0f);	
+	glLineWidth(1.0f);
 }

source/simulation/TerritoryManager.h

@@ -20,7 +20,7 @@
 class CUnit;
 class CPlayer;
 
-const float TERRITORY_PRECISION_STEP = 1.0f / 6;
+const float TERRITORY_PRECISION_STEP = 1.0f;
 
 class CTerritory
 {