Bresenham圆弧绘制算法OpenGL版

今天一时高兴，改进了以前在OpenGL中做的一个360度画圆的函数，完成个Bresenham圆弧画法，发在此处，供各位参考。

这个是用的OpenGL控制台形式，采用了那个半官方库glut。

//cnsGLArc.cpp : Defines the entry point for the console application.



//Filename:cnsGLArc.cpp

//Function:Draw arc by Bresenham

//Author:9Cat

//OS:WindowsXP Sp2

//Development Tool:Visual C++ 2005

//Other refrence:OpenGL

//First Create Time:2008-07-13	18:37

//Last Modify Time:2008-07-13	22:38



#pragma once

#pragma comment(linker,"/subsystem:/"windows/" /entry:/"mainCRTStartup/"")



#define WIN32_LEAN_AND_MEAN



#include<tchar.h>

#include<stdlib.h>

#include<windows.h>



#include<gl/glut.h>



#include<cmath>

#include<iostream>



using namespace std;



const int iXSTART=200;

const int iYSTART=100;

const int iWIDTH=500;

const int iHEIGHT=400;



const float fORG=0.0f;

const float fTX=0.8f;

const float fTY=0.7f;



const float fR=0.4f;



const float fDIFFER=0.001f;



//点结构体定义

struct mypoint

{

	float x;

	float y;

};

//点坐标的xy坐标赋值与初始化函数

void proInitp(struct mypoint *,float,float);



//单位升降级函数

float flaUpUnit(float,int);

float flaDownUnit(float,int);



//直线测试函数的声明

void proLine(struct mypoint *,struct mypoint *);

//画点函数的声明

void proPoint(struct mypoint *);

//Bresenham画圆算法的声明

void proBresenArc(struct mypoint *,float);





//主渲染函数实现

void renderscene(void)

{

	glClear(GL_COLOR_BUFFER_BIT);

	

	//主要绘图操作在该部分实现

	//绘制直线 

	struct mypoint stuA,stuB,*stpA,*stpB;;

	stpA=&stuA;

	stpB=&stuB;

	proInitp(stpA,fORG,fORG);

	proInitp(stpB,fTX,fTY);

	proLine(stpA,stpB);



	//绘制圆弧

	struct mypoint stuCent,*stpCent;

	stpCent=&stuCent;

	proInitp(stpCent,fORG,fORG);

	

	proBresenArc(stpCent,fR);

	



	//glutSwapBuffers();

}



//环境设置函数实现

void setuprc(void)

{

	glClearColor(0.0f, 0.0f, 0.0f,0.1f);

}



//程序主函数

int main()

{

	glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);

    

	//双缓冲模式需配合renderscene中的glutSwapBuffers使用

	//glutInitDisplayMode(GLUT_DOUBLE|GLUT_RGB);

	

	glutCreateWindow("Draw arc by bresenham");

	

	glutPositionWindow(iXSTART,iYSTART);

	glutReshapeWindow(iWIDTH,iHEIGHT);



	glutDisplayFunc(renderscene);

	setuprc();

    

	glutMainLoop();

	

	return 0;

}



//*************各函数定义过程**************

//初始化点结构的横纵坐标

void proInitp(struct mypoint *myp,float x,float y)

{

	myp->x=x;

	myp->y=y;

}



//单位变换函数的实现

float flaUpUnit(float flaVar,int intTimes)

{

	flaVar=flaVar*intTimes;

	return flaVar;

}

float flaDownUnit(float flaVar,int intTimes)

{

	flaVar=flaVar/intTimes;

	return flaVar;

}



//直线测试函数的实现

void proLine(struct mypoint *stpStart,struct mypoint *stpEnd)

{

	glBegin(GL_LINES);

    glColor3f(1.0f, 1.0f, 1.0f);

	glVertex2f(stpStart->x,stpStart->y);

	glColor3f(1.0f, 1.0f, 0.0f);

	glVertex2f(stpEnd->x,stpEnd->y);

   

	glEnd();

	

	glFlush();



}



//画点函数的实现

void proPoint(struct mypoint *stpPoint)

{

	glBegin(GL_POINTS);

	glColor3f(1.0f,1.0f,1.0f);

	glVertex2f(stpPoint->x,stpPoint->y);

	glEnd();

	glFlush();

}



//Bresenham画圆算法的实现

void proBresenArc(struct mypoint *stpCenter,float flaR)

{

	float flaX,flaY,flaDis;

	struct mypoint stuPB,*stpPB;

	stpPB=&stuPB;

	

	flaX=0.0f;

	flaY=flaR;



	flaX=flaUpUnit(flaX,iWIDTH/2);

	flaY=flaUpUnit(flaY,iHEIGHT/2);

	flaR=flaUpUnit(flaR,iWIDTH/2);



	stpCenter->x=flaUpUnit(stpCenter->x,iWIDTH/2);

	stpCenter->y=flaUpUnit(stpCenter->y,iHEIGHT/2);



	flaDis=3-2*flaR;

	

	while(flaX<flaY)

	{

		stpPB->x=(flaX+stpCenter->x);

		stpPB->y=(flaY+stpCenter->y);



		stpPB->x=flaDownUnit(stpPB->x,iWIDTH/2);

		stpPB->y=flaDownUnit(stpPB->y,iHEIGHT/2);

		proPoint(stpPB);



		if(flaDis<0)

		{

			flaDis=flaDis+4*flaX+6;

		}

		else

		{

			flaDis=flaDis+4*(flaX-flaY)+10;

			flaY=flaY-1;

		}

		flaX=flaX+1;

	}



	if((flaX-flaY)<=fDIFFER)

	{	

		stpPB->x=(flaX+stpCenter->x);

		stpPB->y=(flaY+stpCenter->y);

		

		stpPB->x=flaDownUnit(stpPB->x,iWIDTH/2);

		stpPB->y=flaDownUnit(stpPB->y,iHEIGHT/2);

		proPoint(stpPB);

	}



}