lod.cpp

用VC++与OPENGL研发的粒子系统的模拟程序

// Lod.cpp: implementation of the CLod class.
//
//////////////////////////////////////////////////////////////////////

#include "stdafx.h"
#include "MyLOD.h"
#include "Lod.h"
#include "LandTex.h"
#include <math.h>

#ifdef _DEBUG
#undef THIS_FILE
static char THIS_FILE[]=__FILE__;
#define new DEBUG_NEW
#endif

//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////
extern int quadtree[];
extern int location[];
extern int lod_level;
extern CLandTex lt;
extern COLOUR *colour_map; 
extern int *y;
CLod::CLod()
{

}

CLod::~CLod()
{

}

void CLod::reset_quad_tree(void) 
{
	int i;
	
   for(i=0; i<(QUAD_MAP * QUAD_MAP); i++) 
   {
      quadtree[i] = UNKNOWN;
   }
}

void CLod::setup_quadtree(int x, int z, int width) 
{
   int width2;
   int v1[3];
	
   v1[0] = x;
   v1[2] = z;
	
   width2 = width / 2;
	
   if((width > 1) && DISTANCE(v1, location) < width * lod_level) 
   {
      quadtree[IX_QT(x, z)] = NODE_POINT;
      quadtree[IX_QT(x - width2, z - width2)] = EDGE_POINT;
      quadtree[IX_QT(x + width2, z - width2)] = EDGE_POINT;
      quadtree[IX_QT(x - width2, z + width2)] = EDGE_POINT;
      quadtree[IX_QT(x + width2, z + width2)] = EDGE_POINT;
		
      setup_quadtree(x - width2, z - width2, width2);
      setup_quadtree(x + width2, z - width2, width2);
      setup_quadtree(x - width2, z + width2, width2);
      setup_quadtree(x + width2, z + width2, width2);
   }
   else 
   {
      quadtree[IX_QT(x, z)] = EDGE_POINT;
   }
}

void CLod::draw(int x, int z, int width, int direction) 
{
	int width2;
	if(width > 1) 
	{
		if(width > 16) 
		{
			glBindTexture(GL_TEXTURE_2D, lt.texture_name[(int)((x) / 64)][(int)((z) / 64)]);
		}

		width2 = width / 2;
		if(quadtree[IX_QT(x, z)] == NODE_POINT) 
		{
			// NORTH
			if(quadtree[IX_QT(x - width2, z - width2)] == EDGE_POINT &&
				quadtree[IX_QT(x + width2, z - width2)] == EDGE_POINT) 
			{
				if(quadtree[IX_QT(x, z - width*2)] == NODE_POINT || (z-width)%MAP==0)
				{
					draw_point(x, z, width, NORTH_L);
					draw_point(x, z, width, NORTH_R);
				}
				else
				{
					draw_point(x, z, width, NORTH);
				}
			}
			else if(quadtree[IX_QT(x - width2, z - width2)] == EDGE_POINT) 
			{
				draw_point(x, z, width, NORTH_L);
			}
			else if(quadtree[IX_QT(x + width2, z - width2)] == EDGE_POINT) 
			{
				draw_point(x, z, width, NORTH_R);
			}
			// SOUTH
			if(quadtree[IX_QT(x - width2, z + width2)] == EDGE_POINT &&
				quadtree[IX_QT(x + width2, z + width2)] == EDGE_POINT) 
			{
				if(quadtree[IX_QT(x, z + width*2)] == NODE_POINT || (z+width)%MAP==0)
				{
					draw_point(x, z, width, SOUTH_L);
					draw_point(x, z, width, SOUTH_R);
				}
				else
				{
					draw_point(x, z, width, SOUTH);
				}
			}
			else if(quadtree[IX_QT(x - width2, z + width2)] == EDGE_POINT) 
			{
				draw_point(x, z, width, SOUTH_L);
			}
			else if(quadtree[IX_QT(x + width2, z + width2)] == EDGE_POINT) 
			{
				draw_point(x, z, width, SOUTH_R);
			}
			// EAST
			if(quadtree[IX_QT(x + width2, z - width2)] == EDGE_POINT &&
				quadtree[IX_QT(x + width2, z + width2)] == EDGE_POINT) 
			{
				
				if(quadtree[IX_QT(x + width*2, z)] == NODE_POINT || (x+width)%MAP==0) 
				{
					draw_point(x, z, width, EAST_T);
					draw_point(x, z, width, EAST_B);
				}
				else 
				{
					draw_point(x, z, width, EAST);
				}
			}
			else if(quadtree[IX_QT(x + width2, z - width2)] == EDGE_POINT) 
			{
				draw_point(x, z, width, EAST_T);
			}
			else if(quadtree[IX_QT(x + width2, z + width2)] == EDGE_POINT) 
			{
				draw_point(x, z, width, EAST_B);
			}
			
			// WEST
			if(quadtree[IX_QT(x - width2, z - width2)] == EDGE_POINT &&
				quadtree[IX_QT(x - width2, z + width2)] == EDGE_POINT) 
			{
				
				if(quadtree[IX_QT(x - width*2, z)] == NODE_POINT || (x-width)%MAP==0) 
				{
					draw_point(x, z, width, WEST_T);
					draw_point(x, z, width, WEST_B);
				}
				else 
				{
					draw_point(x, z, width, WEST);
				}
			}
			else if(quadtree[IX_QT(x - width2, z - width2)] == EDGE_POINT) 
			{
				draw_point(x, z, width, WEST_T);
			}
			else if(quadtree[IX_QT(x - width2, z + width2)] == EDGE_POINT) 
			{
				draw_point(x, z, width, WEST_B);
			}
						
		}
		else 
		{
			return;
		}
		
		draw(x - width2, z - width2, width2, NW);
		draw(x + width2, z - width2, width2, NE);
		draw(x - width2, z + width2, width2, SW);
		draw(x + width2, z + width2, width2, SE);
	}
}
// 纹理形式的三角形绘制函数
void CLod::triangle1(int x1, int z1, int x2, int z2, int x3, int z3) 
{
	glBegin(GL_TRIANGLES);
	glTexCoord2f(x1/(texScale), z1/(texScale));
	setColor(x1, z1);
	setVertex(x1, z1);
	
	glTexCoord2f(x2/(texScale), z2/(texScale));
	setColor(x2, z2);
	setVertex(x2, z2);
	
	glTexCoord2f(x3/(texScale), z3/(texScale));
	setColor(x3, z3);
	setVertex(x3, z3);
	glEnd();
}
// 线框形式的三角形绘制函数
void CLod::triangle2(int x1, int z1, int x2, int z2, int x3, int z3) 
{
	glBegin(GL_LINE_LOOP);
	setVertex(x1, z1);
	setVertex(x2, z2);
	setVertex(x3, z3);
	glEnd();
}

void CLod::draw_point(int x, int z, int width, int direction) 
{
	
	switch(direction) {
	case NORTH:
		if(m_bFlag)
			triangle1(x, z, x + width, z - width, x - width, z - width);
		else
			triangle2(x, z, x + width, z - width, x - width, z - width);
		return;
	case SOUTH:
		if(m_bFlag)
			triangle1(x, z, x - width, z + width, x + width, z + width);
		else
			triangle2(x, z, x - width, z + width, x + width, z + width);
		return;
	case EAST:
		if(m_bFlag)
			triangle1(x, z, x + width, z + width, x + width, z - width);
		else
			triangle2(x, z, x + width, z + width, x + width, z - width);
		return;
	case WEST:
		if(m_bFlag)
			triangle1(x, z, x - width, z - width, x - width, z + width);
		else
			triangle2(x, z, x - width, z - width, x - width, z + width);
		return; 
	case NORTH_L:
		if(m_bFlag)
			triangle1(x, z, x, z - width, x - width, z - width);
		else
			triangle2(x, z, x, z - width, x - width, z - width);
		return;
	case NORTH_R:
		if(m_bFlag)
			triangle1(x, z, x + width, z - width, x, z - width);
		else
			triangle2(x, z, x + width, z - width, x, z - width);
		return;
		
	case SOUTH_L:
		if(m_bFlag)
			triangle1(x, z, x - width, z + width, x, z + width);
		else
			triangle2(x, z, x - width, z + width, x, z + width);
		return;
	case SOUTH_R:
		if(m_bFlag)
			triangle1(x, z, x, z + width, x + width, z + width);
		else
			triangle2(x, z, x, z + width, x + width, z + width);
		return;
		
	case EAST_T:
		if(m_bFlag)
			triangle1(x, z, x + width, z, x + width, z - width);
		else
			triangle2(x, z, x + width, z, x + width, z - width);
		return;
	case EAST_B:
		if(m_bFlag)
			triangle1(x, z, x + width, z + width, x + width, z);
		else
			triangle2(x, z, x + width, z + width, x + width, z);
		return;
		
	case WEST_T:
		if(m_bFlag)
			triangle1(x, z, x - width, z - width, x - width, z);
		else
			triangle2(x, z, x - width, z - width, x - width, z);
		return;
	case WEST_B:
		if(m_bFlag)
			triangle1(x, z, x - width, z, x - width, z + width);
		else
			triangle2(x, z, x - width, z, x - width, z + width);
		return;
	default:
		break;
	};
}


void CLod::setColor(int x, int z) 
{
	glColor3ub(colour_map[IX(x, z)].r, colour_map[IX(x, z)].g, colour_map[IX(x, z)].b);
}

void CLod::setVertex(int x, int z) 
{
	glVertex3f((x << SHIFT), y[IX(x, z)] * 8, (z << SHIFT));
}