164 lines
4.0 KiB
C++
Executable File
164 lines
4.0 KiB
C++
Executable File
///////////////////////////////////////////////////////////////////////////////
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//
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// Name: Bound.cpp
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// Author: Rich Cross
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// Contact: rich@wildfiregames.com
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//
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///////////////////////////////////////////////////////////////////////////////
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#include "precompiled.h"
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// necessary includes
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#include <assert.h>
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#include <float.h>
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#include "Bound.h"
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///////////////////////////////////////////////////////////////////////////////
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// operator+=: extend this bound to include given bound
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CBound& CBound::operator+=(const CBound& b)
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{
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for (int i=0;i<3;++i) {
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if (b[0][i]<m_Data[0][i])
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m_Data[0][i]=b[0][i];
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if (b[1][i]>m_Data[1][i])
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m_Data[1][i]=b[1][i];
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}
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return *this;
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}
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///////////////////////////////////////////////////////////////////////////////
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// operator+=: extend this bound to include given point
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CBound& CBound::operator+=(const CVector3D& pt)
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{
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for (int i=0;i<3;++i) {
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if (pt[i]<m_Data[0][i])
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m_Data[0][i]=pt[i];
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else if (pt[i]>m_Data[1][i])
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m_Data[1][i]=pt[i];
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}
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return *this;
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}
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///////////////////////////////////////////////////////////////////////////////
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// RayIntersect: intersect ray with this bound; return true
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// if ray hits (and store entry and exit times), or false
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// otherwise
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// note: incoming ray direction must be normalised
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bool CBound::RayIntersect(const CVector3D& origin,const CVector3D& dir,
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float& tmin,float& tmax) const
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{
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float t1,t2;
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float tnear,tfar;
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if (dir[0]==0) {
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if (origin[0]<m_Data[0][0] || origin[0]>m_Data[1][0])
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return false;
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else {
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tnear=(float) FLT_MIN;
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tfar=(float) FLT_MAX;
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}
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} else {
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t1=(m_Data[0][0]-origin[0])/dir[0];
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t2=(m_Data[1][0]-origin[0])/dir[0];
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if (dir[0]<0) {
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tnear = t2;
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tfar = t1;
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} else {
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tnear = t1;
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tfar = t2;
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}
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if (tfar<0)
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return false;
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}
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if (dir[1]==0 && (origin[1]<m_Data[0][1] || origin[1]>m_Data[1][1]))
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return false;
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else {
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t1=(m_Data[0][1]-origin[1])/dir[1];
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t2=(m_Data[1][1]-origin[1])/dir[1];
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if (dir[1]<0) {
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if (t2>tnear)
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tnear = t2;
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if (t1<tfar)
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tfar = t1;
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} else {
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if (t1>tnear)
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tnear = t1;
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if (t2<tfar)
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tfar = t2;
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}
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if (tnear>tfar || tfar<0)
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return false;
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}
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if (dir[2]==0 && (origin[2]<m_Data[0][2] || origin[2]>m_Data[1][2]))
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return false;
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else {
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t1=(m_Data[0][2]-origin[2])/dir[2];
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t2=(m_Data[1][2]-origin[2])/dir[2];
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if (dir[2]<0) {
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if (t2>tnear)
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tnear = t2;
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if (t1<tfar)
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tfar = t1;
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} else {
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if (t1>tnear)
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tnear = t1;
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if (t2<tfar)
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tfar = t2;
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}
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if (tnear>tfar || tfar<0)
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return false;
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}
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tmin=tnear;
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tmax=tfar;
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return true;
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}
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///////////////////////////////////////////////////////////////////////////////
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// SetEmpty: initialise this bound as empty
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void CBound::SetEmpty()
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{
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m_Data[0]=CVector3D(FLT_MAX,FLT_MAX,FLT_MAX);
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m_Data[1]=CVector3D(FLT_MIN,FLT_MIN,FLT_MIN);
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}
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///////////////////////////////////////////////////////////////////////////////
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// Transform: transform this bound by given matrix; return transformed bound
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// in 'result' parameter - slightly modified version of code in Graphic Gems
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// (can't remember which one it was, though)
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void CBound::Transform(const CMatrix3D& m,CBound& result) const
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{
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assert(this!=&result);
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for (int i=0;i<3;++i) {
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// handle translation
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result[0][i]=result[1][i]=m(i,3);
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// Now find the extreme points by considering the product of the
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// min and max with each component of matrix
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for(int j=0;j<3;j++) {
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float a=m(j,i)*m_Data[0][j];
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float b=m(j,i)*m_Data[1][j];
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if (a<b) {
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result[0][i]+=a;
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result[1][i]+=b;
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} else {
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result[0][i]+=b;
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result[1][i]+=a;
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}
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}
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}
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}
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