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// FrustumCull.cpp: implementation of the CFrustumCull class. 
// 
////////////////////////////////////////////////////////////////////// 
 
#include "stdafx.h" 
#include "FrustumCull.h" 
#include  
 
#ifdef _DEBUG 
#undef THIS_FILE 
static char THIS_FILE[]=__FILE__; 
#define new DEBUG_NEW 
#endif 
 
////////////////////////////////////////////////////////////////////// 
// Construction/Destruction 
////////////////////////////////////////////////////////////////////// 
 
CFrustumCull::CFrustumCull() 
{   
	m_HalfFOV=40; 
	m_ViewerRotate=0; 
	m_ViewDistance=30; 
    m_ViewerX=m_ViewerZ=0; 
	m_ViewLeftX=m_ViewLeftZ=0; 
	m_ViewRightX=m_ViewRightZ=0; 
    m_FarFoucsX=m_FarFoucsZ=0; 
	m_BackLeftX=m_BackLeftZ=0; 
	m_BackRightX=m_BackRightZ=0; 
 
    m_MaxX=m_MaxZ=0; 
	m_MinX=m_MinZ=256; 
	 
	for(int i=0;i<128;i++) 
	{ 
		m_LeftArray[i]=0; 
		m_RightArray[i]=0; 
	} 
 
} 
void CFrustumCull::InitFrustumCull(int halfFOV,int distance) 
{ 
	m_HalfFOV=halfFOV; 
	m_ViewDistance=distance; 
	if(m_ViewDistance>125)m_ViewDistance=125; 
} 
CFrustumCull::~CFrustumCull() 
{ 
 
} 
 
void CFrustumCull::UpdateFrustumCull(float angle) 
{ 
	/////////////update viewer rotate ////// 
    m_ViewerRotate=angle; 
    ///////////////////////////////////////////// 
    ///////////// Calculate Frustum ///////////// 
    ///////////////////////////////////////////// 
	///////////////get view back,left and right 
    m_BackLeftX =-int(4*sinf((m_ViewerRotate+150)*0.01745329f)); 
    m_BackLeftZ =-int(4*cosf((m_ViewerRotate+150)*0.01745329f)); 
 
    m_BackRightX=-int(4*sinf((m_ViewerRotate-150)*0.01745329f)); 
    m_BackRightZ=-int(4*cosf((m_ViewerRotate-150)*0.01745329f)); 
 
    m_FarFoucsX =-int(m_ViewDistance*sinf(m_ViewerRotate*0.01745329f)); 
	m_FarFoucsZ =-int(m_ViewDistance*cosf(m_ViewerRotate*0.01745329f)); 
 
    m_ViewLeftX =-int(m_ViewDistance*sinf((m_ViewerRotate+m_HalfFOV)*0.01745329f)); 
    m_ViewLeftZ =-int(m_ViewDistance*cosf((m_ViewerRotate+m_HalfFOV)*0.01745329f)); 
 
    m_ViewRightX=-int(m_ViewDistance*sinf((m_ViewerRotate-m_HalfFOV)*0.01745329f)); 
    m_ViewRightZ=-int(m_ViewDistance*cosf((m_ViewerRotate-m_HalfFOV)*0.01745329f)); 
	////////////////get Rectangle boundary 
    m_MaxX=m_MaxZ=0; 
	m_MinX=m_MinZ=256; 
 
    if(m_ViewLeftX>m_MaxX)m_MaxX=m_ViewLeftX; 
    if(m_ViewLeftZ>m_MaxZ)m_MaxZ=m_ViewLeftZ; 
    if(m_ViewRightX>m_MaxX)m_MaxX=m_ViewRightX; 
    if(m_ViewRightZ>m_MaxZ)m_MaxZ=m_ViewRightZ; 
    if(m_FarFoucsX>m_MaxX)m_MaxX=m_FarFoucsX; 
    if(m_FarFoucsZ>m_MaxZ)m_MaxZ=m_FarFoucsZ; 
    if(m_BackLeftX>m_MaxX)m_MaxX=m_BackLeftX; 
    if(m_BackLeftZ>m_MaxZ)m_MaxZ=m_BackLeftZ; 
    if(m_BackRightX>m_MaxX)m_MaxX=m_BackRightX; 
    if(m_BackRightZ>m_MaxZ)m_MaxZ=m_BackRightZ; 
 
    if(m_ViewLeftXstartx) 
	{ 
		dx=endx-startx; 
		SignX=1; 
	} 
	else 
	{ 
		dx=startx-endx; 
		SignX=-1; 
	} 
	if(endz>startz) 
	{ 
		dz=endz-startz; 
		SignZ=1; 
	} 
	else 
	{ 
		dz=startz-endz;	 
		SignZ=-1; 
	} 
    x=startx; 
	z=startz; 
	if(dz>dx) 
	{ 
		int temp; 
 		temp=dx; dx=dz;dz=temp; 
		bChange=true; 
        pArray[124]=dx+1;      //存储个数 
        pArray[125]=startz;  //起始 
        pArray[126]=endz;    //结束 
        pArray[127]=1;       //Z轴加 
	} 
	else 
	{ 
		bChange=false; 
        pArray[124]=dx+1;      //存储个数 
        pArray[125]=startx;  //起始 
        pArray[126]=endx;    //结束 
        pArray[127]=0;       //X轴加 
	} 
	d=2*dz-dx; 
	//////////////////////// 
	for(int i=0;i=0) 
		{ 
			if(bChange) x+=SignX; 
			else z+=SignZ; 
			d=d-dx*2; 
		} 
        if(bChange)z+=SignZ; 
		else x+=SignX; 
		d=d+dz*2; 
	} 
 
}