123

Editor/Util/BBox.cpp

@@ -0,0 +1,156 @@
+////////////////////////////////////////////////////////////////////////////
+//
+//  Crytek Engine Source File.
+//  Copyright (C), Crytek Studios, 2002.
+// -------------------------------------------------------------------------
+//  File name:   bbox.cpp
+//  Version:     v1.00
+//  Created:     2/7/2002 by Timur.
+//  Compilers:   Visual Studio.NET
+//  Description: 
+// -------------------------------------------------------------------------
+//  History:
+//
+////////////////////////////////////////////////////////////////////////////
+
+#include "StdAfx.h"
+#include "BBox.h"
+
+typedef unsigned int udword;
+
+// Integer representation of a floating-Vec3 value.
+#define IR(x)	((udword&)x)
+
+///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+/**
+ *	A method to compute a ray-AABB intersection.
+ *	Original code by Andrew Woo, from "Graphics Gems", Academic Press, 1990
+ *	Optimized code by Pierre Terdiman, 2000 (~20-30% faster on my Celeron 500)
+ *	Epsilon value added by Klaus Hartmann. (discarding it saves a few cycles only)
+ *
+ *	Hence this version is faster as well as more robust than the original one.
+ *
+ *	Should work provided:
+ *	1) the integer representation of 0.0f is 0x00000000
+ *	2) the sign bit of the float is the most significant one
+ *
+ *	Report bugs: p.terdiman@codercorner.com
+ *
+ *	\param		aabb		[in] the axis-aligned bounding box
+ *	\param		origin		[in] ray origin
+ *	\param		dir			[in] ray direction
+ *	\param		coord		[out] impact coordinates
+ *	\return		true if ray intersects AABB
+ */
+///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+#define RAYAABB_EPSILON 0.00001f
+bool BBox::IsIntersectRay( const Vec3& vOrigin, const Vec3& vDir, Vec3& pntContact )
+{
+	BOOL Inside = TRUE;
+	float MinB[3] = { min.x,min.y,min.z };
+	float MaxB[3] = { max.x,max.y,max.z };
+	float MaxT[3];
+	MaxT[0]=MaxT[1]=MaxT[2]=-1.0f;
+	float coord[3] = { 0,0,0 };
+
+	float origin[3] = { vOrigin.x,vOrigin.y,vOrigin.z };
+	float dir[3] = { vDir.x,vDir.y,vDir.z };
+
+	// Find candidate planes.
+	for(udword i=0;i<3;i++)
+	{
+		if(origin[i] < MinB[i])
+		{
+			coord[i]	= MinB[i];
+			Inside		= FALSE;
+
+			// Calculate T distances to candidate planes
+			if(IR(dir[i]))	MaxT[i] = (MinB[i] - origin[i]) / dir[i];
+		}
+		else if(origin[i] > MaxB[i])
+		{
+			coord[i]	= MaxB[i];
+			Inside		= FALSE;
+
+			// Calculate T distances to candidate planes
+			if(IR(dir[i]))	MaxT[i] = (MaxB[i] - origin[i]) / dir[i];
+		}
+	}
+
+	// Ray origin inside bounding box
+	if(Inside)
+	{
+		//////////////////////////////////////////////////////////////////////////
+		// Timur: for editor this need to be treated as intersection.
+		//////////////////////////////////////////////////////////////////////////
+		pntContact(origin[0],origin[1],origin[2]);
+		return true;
+	}
+
+	// Get largest of the maxT's for final choice of intersection
+	udword WhichPlane = 0;
+	if(MaxT[1] > MaxT[WhichPlane])	WhichPlane = 1;
+	if(MaxT[2] > MaxT[WhichPlane])	WhichPlane = 2;
+
+	// Check final candidate actually inside box
+	if(IR(MaxT[WhichPlane])&0x80000000) return false;
+
+	for(i=0;i<3;i++)
+	{
+		if(i!=WhichPlane)
+		{
+			coord[i] = origin[i] + MaxT[WhichPlane] * dir[i];
+#ifdef RAYAABB_EPSILON
+			if(coord[i] < MinB[i] - RAYAABB_EPSILON || coord[i] > MaxB[i] + RAYAABB_EPSILON)	return false;
+#else
+			if(coord[i] < MinB[i] || coord[i] > MaxB[i])	return false;
+#endif
+		}
+	}
+
+	pntContact(coord[0],coord[1],coord[2]);
+	return true;	// ray hits box
+}
+
+//////////////////////////////////////////////////////////////////////////
+bool BBox::RayEdgeIntersection( const Vec3 &raySrc,const Vec3 &rayDir,float epsilonDist,float &dist,Vec3 &intPnt )
+{
+	// Check 6 group lines.
+	Vec3 rayTrg = raySrc + rayDir*10000.0f;
+	Vec3 pnt[12];
+
+	float d[12];
+
+	// Near
+	d[0] = RayToLineDistance( raySrc,rayTrg,Vec3(min.x,min.y,max.z),Vec3(max.x,min.y,max.z),pnt[0] );
+	d[1] = RayToLineDistance( raySrc,rayTrg,Vec3(min.x,max.y,max.z),Vec3(max.x,max.y,max.z),pnt[1] );
+	d[2] = RayToLineDistance( raySrc,rayTrg,Vec3(min.x,min.y,max.z),Vec3(min.x,max.y,max.z),pnt[2] );
+	d[3] = RayToLineDistance( raySrc,rayTrg,Vec3(max.x,min.y,max.z),Vec3(max.x,max.y,max.z),pnt[3] );
+
+	// Far
+	d[4] = RayToLineDistance( raySrc,rayTrg,Vec3(min.x,min.y,min.z),Vec3(max.x,min.y,min.z),pnt[4] );
+	d[5] = RayToLineDistance( raySrc,rayTrg,Vec3(min.x,max.y,min.z),Vec3(max.x,max.y,min.z),pnt[5] );
+	d[6] = RayToLineDistance( raySrc,rayTrg,Vec3(min.x,min.y,min.z),Vec3(min.x,max.y,min.z),pnt[6] );
+	d[7] = RayToLineDistance( raySrc,rayTrg,Vec3(max.x,min.y,min.z),Vec3(max.x,max.y,min.z),pnt[7] );
+
+	// Sides.
+	d[8] = RayToLineDistance( raySrc,rayTrg,Vec3(min.x,min.y,min.z),Vec3(min.x,min.y,max.z),pnt[8] );
+	d[9] = RayToLineDistance( raySrc,rayTrg,Vec3(max.x,min.y,min.z),Vec3(max.x,min.y,max.z),pnt[9] );
+	d[10] = RayToLineDistance( raySrc,rayTrg,Vec3(min.x,max.y,min.z),Vec3(min.x,max.y,max.z),pnt[10] );
+	d[11] = RayToLineDistance( raySrc,rayTrg,Vec3(max.x,max.y,min.z),Vec3(max.x,max.y,max.z),pnt[11] );
+
+	dist = FLT_MAX;
+	for (int i = 0; i < 12; i++)
+	{
+		if (d[i] < dist)
+		{
+			dist = d[i];
+			intPnt = pnt[i];
+		}
+	}
+	if (dist < epsilonDist)
+	{
+		return true;
+	}
+	return false;
+}