// 计算机图形学_实验5_20181017.cpp : 定义应用程序的入口点。
//
#include "计算机图形学_实验5_20181017.h"
#include <graphics.h>
#include <conio.h>
// circle algorithm.cpp : Defines the entry point for the console application.
//
//This program was updated by Ms Huang Jing in Beijing Normal Unbersity Zhuhai Campus
// in Oct 20 in 2012,Contact email: [email protected]
#include "stdafx.h"
#include <glut.h>
//#include <stdio.h>
//#include <stdlib.h>
#include <math.h>
#define N 1000 //maximum line numbers
int cx = 150, cy = 150, radius = 80, ri = 50, ro = 80, n = 3, samples = 1, flag = 1;
int ww, hh; // for display window width and height
int line[N][4], k = 0; //for line's endpoint coordinates and line number
void Myinit(void);
void plotC(int x, int y, int xc, int yc);
void Bresenham_Circle_Algorithm(int cx, int cy, int radius);
void DrawOneLine(int x1, int y1, int x2, int y2);
void NSidedPolygon(int n, int cx, int cy, int radius);
void SampleCircle(int inner, int outer, int samples, int cx, int cy);
void Keyboard(unsigned char key, int x, int y);
void Display(void);
void Reshape(int w, int h);
void Drawlines();
void myMouse(int button, int state, int x, int y);
void myMotion(int x, int y);
void DDA_Drawlines();
void CirPot(int x0, int y0, int x, int y, int color);
void drawCircle();
void MidPoint_Circle(int x0, int y0, double radius, int color);
void Bresenham_line(int xa, int ya, int xb, int yb);
void Bresenham_line2(int xa, int ya, int xb, int yb);
void Bresenham_Drawlines();
int APIENTRY _tWinMain(HINSTANCE hInstance,
HINSTANCE hPrevInstance,
LPTSTR lpCmdLine,
int nCmdShow)
{
UNREFERENCED_PARAMETER(hPrevInstance);
UNREFERENCED_PARAMETER(lpCmdLine);
char *argv[] = { "hello ", " " };
int argc = 2; // must/should match the number of strings in argv
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);
glutCreateWindow("Basic_Primitive_Algorithm");
Myinit(); //初始设置
glutDisplayFunc(Display); //注册绘制响应回调函数
glutKeyboardFunc(Keyboard); //注册键盘响应回调函数
glutReshapeFunc(Reshape); //注册窗口改变回调函数
glutMouseFunc(myMouse); //注册鼠标按钮回调函数
glutMotionFunc(myMotion); //注册鼠标移动回调函数
glutMainLoop();
return 0;
}
void Myinit(void)
{
glClearColor(0.0, 0.0, 0.0, 0.0); //背景色
glLineWidth(4.0); //线宽
}
void Display(void)
{
glClear(GL_COLOR_BUFFER_BIT);
glMatrixMode(GL_MODELVIEW); //设置矩阵模式为模型变换模式，表示在世界坐标系下
glLoadIdentity(); //将当前矩阵设置为单位矩阵
if (flag == 1) //画圆
Bresenham_Circle_Algorithm(cx, cy, radius);
if (flag == 2) //画多边形
NSidedPolygon(n, cx, cy, radius);
if (flag == 3) //画胖圆
SampleCircle(ri, radius, samples, cx, cy);
if (flag == 4) //鼠标划线
Drawlines();
if (flag == 5)
DDA_Drawlines();//DDA画直线
if (flag == 6)
{
drawCircle();//bresenham中心画圆法
}
if (flag == 7)
{
Bresenham_Drawlines();//bresenham画直线
}
glutSwapBuffers();
}
void Keyboard(unsigned char key, int x, int y)
{
switch (key)
{
case 'r':
if ((flag == 1) && (radius>1)) radius--; //画单个圆时半径变小
if ((flag == 3) && (radius>ri)) radius--; //画胖圆时外径变小
break;
case 'R':
if ((radius<ww / 2) && (radius<hh / 2))
radius++; //半径增加
break;
case 'n':
if ((flag == 2) && (n>3)) n--; //多边形边数递减
break;
case 'N':
if (flag == 2) n++; //多边形边数递增
break;
case 'i':
if ((flag == 3) && (ri>1)) ri--; //画胖圆时内径变小
break;
case 'I':
if ((flag == 3) && (ri<radius)) ri++; //画胖圆时内径变大
break;
case 's':
if (samples>1) samples--; //采样数减少
break;
case 'S':
samples++; //采样数增加
break;
case 'a':
//cancel antialias
glDisable(GL_BLEND);
glDisable(GL_LINE_SMOOTH);
glDisable(GL_POINT_SMOOTH);
glDisable(GL_POLYGON_SMOOTH);
break;
case 'A':
//enable antialias
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glEnable(GL_BLEND);
glEnable(GL_POINT_SMOOTH);
glHint(GL_POINT_SMOOTH_HINT, GL_NICEST);
glEnable(GL_LINE_SMOOTH);
glHint(GL_LINE_SMOOTH_HINT, GL_NICEST);
glEnable(GL_POLYGON_SMOOTH);
break;
case '1':
flag = 1; //画圆
break;
case '2':
flag = 2; //画多边形
break;
case '3':
flag = 3; //画胖圆
//cancel antialias
glDisable(GL_BLEND);
glDisable(GL_LINE_SMOOTH);
glDisable(GL_POINT_SMOOTH);
glDisable(GL_POLYGON_SMOOTH);
break;
case '4':
flag = 4; //鼠标划线
for (int i = 0; i <= k; i++)
{
line[i][0] = 0;
line[i][1] = 0;
line[i][2] = 0;
line[i][3] = 0;
}
k = 0;
break;
case '5':
flag = 5;
for (int i = 0; i <= k; i++)
{
line[i][0] = 0;
line[i][1] = 0;
line[i][2] = 0;
line[i][3] = 0;
}
k = 0;
break;
case '6':
flag = 6;
for (int i = 0; i <= k; i++)
{
line[i][0] = 0;
line[i][1] = 0;
line[i][2] = 0;
line[i][3] = 0;
}
k = 0;
break;
case '7':
flag = 7;
for (int i = 0; i <= k; i++)
{
line[i][0] = 0;
line[i][1] = 0;
line[i][2] = 0;
line[i][3] = 0;
}
k = 0;
break;
case 27:
exit(0);
// default:
// return;
}
glutPostRedisplay();
}
void Reshape(int w, int h)
{
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glViewport(0, 0, w, h);
gluOrtho2D(0, w, 0, h);
ww = w;
hh = h;
cx = w / 2;
cy = h / 2;
}
void Bresenham_Circle_Algorithm(int cx, int cy, int radius)
{
/* YOUR CODE HERE ,
Update the followling codes with Bresenham_Circle_Algorithm */
glColor3f(1, 1, 1);
glTranslatef(cx, cy, 0);
glutWireSphere(radius, 40, 40);
}
void NSidedPolygon(int n, int cx, int cy, int radius)
{
int x[100], y[100];
double angle;
angle = 2 * 3.1415926 / n;
glColor3f(1, 1, 1);
for (int i = 0; i <= n; i++)
{
x[i] = (int)(cx + radius*cos(i*angle));
y[i] = (int)(cy + radius*sin(i*angle));
}
for (int i = 0; i <= (n - 1); i++)
{
DrawOneLine(x[i], y[i], x[i + 1], y[i + 1]);
}
}
void DrawOneLine(int xa, int ya, int xb, int yb)
{
/* YOUR CODE HERE */
//update the following codes with DDA line algorithm
glColor3f(1, 1, 1);
glBegin(GL_LINES);
glVertex2f(xa, ya);
glVertex2f(xb, yb);
glEnd();
}
void Drawlines()
{
for (int i = 0; i <= k; i++) //********
{
DrawOneLine(line[i][0], line[i][1], line[i][2], line[i][3]);
}
}
void SampleCircle(int inner, int outer, int samples, int cx, int cy)
{
float r2, ro2, ri2; //r2为子像素的半径
int x, y, nx, ny; //x,y 为胖圆内的一点
float color_value; //颜色亮度
int count; //计数合格的子像素
//######### Calculate outer radius's square and inner's square
ro2 = outer*outer; //胖圆外径平方
ri2 = inner*inner; //胖圆内径平方
//######### for each pixel(x,y), testing its sample
//1/4胖圆内的点测试
for (x = 0; x<outer; x++)
for (y = 0; y <= outer; y++)
{
//######## count available subpixels for each pixel
count = 0;
//每个点切分成smaples*samples个子像素
//判断子像素是否在胖圆内
for (nx = 0; nx <= samples; nx++)
for (ny = 0; ny <= samples; ny++)
{
r2 = (x + (float)nx / (float)samples)*(x + (float)nx / (float)samples);
r2 = r2 + (y + (float)ny / (float)samples)*(y + (float)ny / (float)samples);
if ((r2 <= ro2) && (r2 >= ri2)) count++; //计数合格的子像素
}
//########## calculate color gray level for each pixel
color_value = ((float)count) / (((float)samples + 1.0)*((float)samples + 1.0));
//########## draw pixel by using the color calculated above
glColor3f(color_value, color_value, color_value);
//对称画点
glBegin(GL_POINTS);
glVertex2f(cx + x, cy + y);
glVertex2f(cx + x, cy - y);
glVertex2f(cx - x, cy + y);
glVertex2f(cx - x, cy - y);
glEnd();
}
}
//鼠标按钮响应事件..
void myMouse(int button, int state, int x, int y)
{
if (button == GLUT_LEFT_BUTTON&&state == GLUT_DOWN)
{
line[k][0] = x; //线段起点x坐标
line[k][1] = hh - y; //线段起点y坐标
}
if (button == GLUT_LEFT_BUTTON&&state == GLUT_UP)
{
line[k][2] = x; //线段终点x坐标
line[k][3] = hh - y; //线段终点y坐标
k++;
glutPostRedisplay();
}
}
//鼠标移动时获得鼠标移动中的坐标-----------------------------------------------------
void myMotion(int x, int y)
{
//get the line's motion point
line[k][2] = x; //动态终点的x坐标
line[k][3] = hh - y; //动态终点的y坐标
glutPostRedisplay();
}
//DDA画直线算法
void DDA_line(int xa, int ya, int xb, int yb)
{
int dx = xb - xa;
int dy = yb - ya;
float xIncrement, yIncrement, steps, x = xa, y = ya;
if (abs(dx) > abs(dy))
{
steps = abs(dx);
}
else
{
steps = abs(dy);
}
xIncrement = (float)(dx) / steps;
yIncrement = (float)(dy) / steps;
for (int k = 0; k < steps; k++)
{
glBegin(GL_POINTS);
glVertex2i((int)(x + 0.5), (int)(y + 0.5));
glEnd();
x += xIncrement;
y += yIncrement;
}
}
void DDA_Drawlines()
{
glColor3f(1, 1, 1);
for (int i = 0; i <= k; i++) //********
{
DDA_line(line[i][0], line[i][1], line[i][2], line[i][3]);
}
}
void Bresenham_Drawlines()
{
glColor3f(1, 1, 1);
for (int i = 0; i <= k; i++) //********
{
Bresenham_line2(line[i][0], line[i][1], line[i][2], line[i][3]);
}
}
//DDA画直线算法
void Bresenham_line(int x0, int y0, int x1, int y1)
{
if (x0 - x1 < 0 && y0 - y1 < 0)
{
int dx = abs(x0 - x1);
int dy = abs(y0 - y1);
int h = 2 * dy - dx;
int x = x0;
int y = y0;
glColor3f(1, 1, 1);
glBegin(GL_POINTS);
glVertex2i(x, y);
glEnd();
while (x < x1)
{
if (h < 0)
{
h += 2 * dy;
}
else
{
h += 2 * (dy - dx);
y++;
}
glBegin(GL_POINTS);
glVertex2i(x, y);
glEnd();
x++;
}
}
else if (x0 - x1 > 0 && y0 - y1 > 0)
{
int dx = abs(x0 - x1);
int dy = abs(y0 - y1);
int h = (2 * dy - dx);
int x = x0;
int y = y0;
glColor3f(1, 1, 1);
glBegin(GL_POINTS);
glVertex2i(x, y);
glEnd();
while (x > x1)
{
if (h < 0)
{
h += 2 * dy;
}
else
{
h += 2 * (dy - dx);
y--;
}
glBegin(GL_POINTS);
glVertex2i(x, y);
glEnd();
x--;
}
}
}
/*
-------------------- -
作者：谛听 -
来源：CSDN
原文：https ://blog.csdn.net/u012319493/article/details/53289132
版权声明：本文为博主原创文章，转载请附上博文链接！
*/
void Bresenham_line2(int x0, int y0, int x1, int y1)
{
int dx = abs(x1 - x0);
int dy = abs(y1 - y0);
int x = x0;
int y = y0;
int stepX = 1;
int stepY = 1;
if (x0 > x1) //从右向左画
stepX = -1;
if (y0 > y1)
stepY = -1;
if (dx > dy) //沿着最长的那个轴前进
{
int e = dy * 2 - dx;
for (int i = 0; i <= dx; i++)
{
glColor3f(1, 1, 1);
glBegin(GL_POINTS);
glVertex2i(x, y);
glEnd();
x += stepX;
e += 2*dy;
if (e >= 0)
{
y += stepY;
e -= 2*dx;
}
}
}
else
{
int e = 2 * dx - dy;
for (int i = 0; i <= dy; i++)
{
glColor3f(1, 1, 1);
glBegin(GL_POINTS);
glVertex2i(x, y);
glEnd();
y += stepY;
e += dx;
if (e >= 0)
{
x += stepX;
e -= dy;
}
}
}
}
void drawCircle()
{
//glColor3f(1, 1, 1);
double radius;
for(int i = 0; i <=k; i++)
{
radius = sqrt((double)((line[i][0] - line[i][2])*(line[i][0] - line[i][2])+ (line[i][1] - line[i][3])*(line[i][1] - line[i][3])));
//glColor3f(1.0f, 0.0f, 0.0f);
//glRasterPos2f(line[i][0], line[i][1]);
//glutBitmapCharacter(GLUT_BITMAP_9_BY_15,'A');
MidPoint_Circle(line[i][0], line[i][1], radius, 1);
}
}
void MidPoint_Circle(int x0, int y0, double radius, int color)
{
//参数x0,y0 表示圆心坐标, radius表示圆的半径，color表示圆的绘制颜色
int x, y, h;
x = 0; y = int(radius); h = 1 - int(radius);
CirPot(x0, y0, x, y, color);
while (x<y)
{
if (h<0) h += 2 * x + 3;
else { h += 2 * (x - y) + 5; y--; }
x++;
CirPot(x0, y0, x, y, color);
}
}
void CirPot(int x0, int y0, int x, int y, int color)
{
//根据圆的对称性绘出8个对称点
glBegin(GL_POINTS);
glColor3f(1, 1, 1);
glVertex2i(x0 + x, y0 + y);
glVertex2i(x0 + x, y0 - y);
glVertex2i(x0 - x, y0 + y);
glVertex2i(x0 - x, y0 - y);
glVertex2i(x0 + y, y0 + x);
glVertex2i(x0 + y, y0 - x);
glVertex2i(x0 - y, y0 + x);
glVertex2i(x0 - y, y0 - x);
glEnd();
//putpixel(x0 + x, y0 + y, color); //用color颜色在x0+x,y0+y处绘制一点
//putpixel(x0 + x, y0 - y, color);
//putpixel(x0 - x, y0 + y, color);
//putpixel(x0 - x, y0 - y, color);
//putpixel(x0 + y, y0 + x, color);
//putpixel(x0 + y, y0 - x, color);
//putpixel(x0 - y, y0 + x, color);
//putpixel(x0 - y, y0 - x, color);
}