From c86fea11dc593287394d9d8c4ff727de23a841dd Mon Sep 17 00:00:00 2001
From: ejcoumans <ejcoumans@08e121b0-ae19-0410-a57b-3be3395fd4fd>
Date: Thu, 24 Jan 2008 01:35:34 +0000
Subject: [PATCH] use btHullShape/btConvexHull to reduce vertices in a convex
 hull. Perhaps we always use this, to avoid convex objects with too many
 vertices...?

---
 .../ConvexDecompositionDemo.cpp               | 41 ++++++++++++++++---
 Demos/OpenGL/GL_ShapeDrawer.cpp               |  6 +--
 2 files changed, 39 insertions(+), 8 deletions(-)

diff --git a/Demos/ConvexDecompositionDemo/ConvexDecompositionDemo.cpp b/Demos/ConvexDecompositionDemo/ConvexDecompositionDemo.cpp
index a0d1fa55b..6ec0f46aa 100644
--- a/Demos/ConvexDecompositionDemo/ConvexDecompositionDemo.cpp
+++ b/Demos/ConvexDecompositionDemo/ConvexDecompositionDemo.cpp
@@ -21,7 +21,7 @@ subject to the following restrictions:
 #include "LinearMath/btQuickprof.h"
 #include "LinearMath/btIDebugDraw.h"
 #include "LinearMath/btGeometryUtil.h"
-
+#include "BulletCollision/CollisionShapes/btShapeHull.h"
 
 //#define USE_PARALLEL_DISPATCHER 1
 #ifdef USE_PARALLEL_DISPATCHER
@@ -143,7 +143,7 @@ void ConvexDecompositionDemo::initPhysics(const char* filename)
 				btVector3 localScaling(6.f,6.f,6.f);
 
 				//export data to .obj
-				printf("ConvexResult\n");
+				printf("ConvexResult. ");
 				if (mOutputFile)
 				{
 					fprintf(mOutputFile,"## Hull Piece %d with %d vertices and %d triangles.\r\n", mHullCount, result.mHullVcount, result.mHullTcount );
@@ -284,7 +284,8 @@ void ConvexDecompositionDemo::initPhysics(const char* filename)
 
 		btVector3 localScaling(6.f,6.f,6.f);
 		
-		for (int i=0;i<wo.mTriCount;i++)
+		int i;
+		for ( i=0;i<wo.mTriCount;i++)
 		{
 			int index0 = wo.mIndices[i*3];
 			int index1 = wo.mIndices[i*3+1];
@@ -301,7 +302,37 @@ void ConvexDecompositionDemo::initPhysics(const char* filename)
 			trimesh->addTriangle(vertex0,vertex1,vertex2);
 		}
 
-		btCollisionShape* convexShape = new btConvexTriangleMeshShape(trimesh);
+		
+		btConvexShape* tmpConvexShape = new btConvexTriangleMeshShape(trimesh);
+	
+		printf("old numTriangles= %d\n",wo.mTriCount);
+		printf("old numIndices = %d\n",wo.mTriCount*3);
+		printf("old numVertices = %d\n",wo.mVertexCount);
+		
+		printf("reducing vertices by creating a convex hull\n");
+
+		//create a hull approximation
+		btShapeHull* hull = new btShapeHull(tmpConvexShape);
+		btScalar margin = tmpConvexShape->getMargin();
+		hull->buildHull(margin);
+		tmpConvexShape->setUserPointer(hull);
+		
+		
+		printf("new numTriangles = %d\n", hull->numTriangles ());
+		printf("new numIndices = %d\n", hull->numIndices ());
+		printf("new numVertices = %d\n", hull->numVertices ());
+		
+		btConvexHullShape* convexShape = new btConvexHullShape();
+		for (i=0;i<hull->numVertices();i++)
+		{
+			convexShape->addPoint(btPoint3(hull->getVertexPointer()[i]));	
+		}
+
+		delete tmpConvexShape;
+		delete hull;
+
+
+
 		m_collisionShapes.push_back(convexShape);
 
 		float mass = 1.f;
@@ -337,7 +368,7 @@ void ConvexDecompositionDemo::initPhysics(const char* filename)
 		unsigned int maxv  = 16;
 		float skinWidth    = 0.0;
 
-		printf("WavefrontObj num triangles read %i",tcount);
+		printf("WavefrontObj num triangles read %i\n",tcount);
 		ConvexDecomposition::DecompDesc desc;
 		desc.mVcount       =	wo.mVertexCount;
 		desc.mVertices     = wo.mVertices;
diff --git a/Demos/OpenGL/GL_ShapeDrawer.cpp b/Demos/OpenGL/GL_ShapeDrawer.cpp
index ab0549eaa..df14dca1f 100644
--- a/Demos/OpenGL/GL_ShapeDrawer.cpp
+++ b/Demos/OpenGL/GL_ShapeDrawer.cpp
@@ -476,9 +476,9 @@ void GL_ShapeDrawer::drawOpenGL(btScalar* m, const btCollisionShape* shape, cons
 							convexShape->setUserPointer(hull);
 
 							
-							printf("numTriangles = %d\n", hull->numTriangles ());
-							printf("numIndices = %d\n", hull->numIndices ());
-							printf("numVertices = %d\n", hull->numVertices ());
+						//	printf("numTriangles = %d\n", hull->numTriangles ());
+						//	printf("numIndices = %d\n", hull->numIndices ());
+						//	printf("numVertices = %d\n", hull->numVertices ());
 							
 
 						}