Codeblocks 利用GLUT 画出矩形，直线，三角形，圆形图案并实现翻转，镜像，变色放大缩小等功能

实验要求：开发一个画图程序，用户可以用鼠标绘制线段、矩形、圆和三角形等。通过菜单让用户选择需要绘制的图元。 

注意：一定要加上库否则无法通过编译

#include 
#include 
#include 
#include 
#include 
#ifdef __APPLE__
#include 
#else
#include 
#endif

#define PI 3.1415926


int ww = 500;
int wh = 500;

int need_rotate = 0;//旋转标识
//color 便于修改颜色
float red = 1;
float green = 1;
float blue = 1;
//coordinates
struct cor
{
    float x;
    float y;
};//存储坐标结构体
//3个坐标，用于存储直线（2个）、三角形（3个）、矩形（2个）绘制时的坐标
struct cor cc1;
struct cor cc2;
struct cor cc3;

int mode = 0;//选择绘画模式，line、triangle、rectangle三种，默认为line
int dots_now = 0;//记录已经确定的坐标个数
struct pics
{
    int mode;
    struct cor c1;
    struct cor c2;
    struct cor c3;
};//一个图形所有点的坐标结构体
struct pics saved_cords[100];//可存储100个图形的坐标和绘制模式
int ptr = -1;//如上结构体的计数指针
int reDrawMode =0;//重画模式，用于绘制新图形后，补画之前的图形
int mirrorMode =0;//镜像模式
//func delc
void reDraw();
void draw_one_line(struct cor c1,struct cor c2);
void draw_triangle(struct cor c1,struct cor c2,struct cor c3);
void draw_rectangle(struct cor c1,struct cor c2);
void display();
void main_menu_func(int option);
void sub_menu_draw_mode_func(int option);
void sub_menu_move_func(int option);
void myinit(void);
void mouse_move(int x, int y);
void mouse(int btn, int state, int x, int y);
void myReshape(GLsizei w, GLsizei h);


void draw_one_line(struct cor c1,struct cor c2)
{//绘制直线函数
    if (need_rotate == 1)
    {//平移-旋转-平移操作
        int mid_x = (c1.x + c2.x) / 2;
        int mid_y = (c1.y + c2.y) / 2;
        glTranslated(mid_x, mid_y, 0);
        glRotated(60, 0, 0, 1);
        glTranslated(-mid_x, -mid_y, 0);
        need_rotate = 0;
    }
    if(reDrawMode == 0)
    {//在重画函数调用当前函数时，不需要清除背景
        glClear(GL_COLOR_BUFFER_BIT);
    }
    glColor3f(red, green, blue);
    if(mirrorMode == 0)
    {
        glBegin(GL_LINE_LOOP);
    }
    else
    {//mirror mode，镜像画图，四个象限会对称画图
        glBegin(GL_LINES);//lines，2个2个坐标成对画直线
        glVertex2f(c1.x,-c1.y);//4th
        glVertex2f(c2.x,-c2.y);
        glVertex2f(-c1.x,-c1.y);//3rd
        glVertex2f(-c2.x,-c2.y);
        glVertex2f(-c1.x,c1.y);//2nd
        glVertex2f(-c2.x,c2.y);
    }
    glVertex2f(c1.x, c1.y);
    glVertex2f(c2.x, c2.y);
    glEnd();
    glFlush();
}
void draw_triangle(struct cor c1,struct cor c2,struct cor c3)
{//绘制三角形
    if (need_rotate == 1)
    {//旋转
        int mid_x = (c1.x + c2.x + c3.x) / 3;
        int mid_y = (c1.y + c2.y + c3.y) / 3;
        glTranslated(mid_x, mid_y, 0);
        glRotated(60, 0, 0, 1);
        glTranslated(-mid_x, -mid_y, 0);
        need_rotate = 0;
    }
    if(reDrawMode == 0)
    {
        glClear(GL_COLOR_BUFFER_BIT);
        //reDraw();
    }
    glColor3f(red, green, blue);
    if(mirrorMode == 0)
        glBegin(GL_TRIANGLES);
    else
    {
        glBegin(GL_TRIANGLES);//每3个坐标就能绘制一个三角形
        glVertex2f(c1.x,-c1.y);//4th
        glVertex2f(c2.x,-c2.y);
        glVertex2f(c3.x,-c3.y);

        glVertex2f(-c1.x,-c1.y);//3rd
        glVertex2f(-c2.x,-c2.y);
        glVertex2f(-c3.x,-c3.y);

        glVertex2f(-c1.x,c1.y);//2nd
        glVertex2f(-c2.x,c2.y);
        glVertex2f(-c3.x,c3.y);
    }

    glVertex2f(c1.x, c1.y);
    glVertex2f(c2.x, c2.y);
    glVertex2f(c3.x, c3.y);
    glEnd();
    glFlush();

}
void draw_rectangle(struct cor c1,struct cor c2)
{//绘制矩形，用两个点绘制，分别是左上和右下点
    if (need_rotate == 1)
    {//旋转
        int mid_x = (c1.x + c2.x) / 2;
        int mid_y = (c1.y + c2.y) / 2;
        glTranslated(mid_x, mid_y, 0);
        glRotated(60, 0, 0, 1);
        glTranslated(-mid_x, -mid_y, 0);
        need_rotate = 0;
    }
    if(reDrawMode == 0)
    {
        glClear(GL_COLOR_BUFFER_BIT);
        //reDraw();
    }
    glColor3f(red, green, blue);
    if(mirrorMode == 0)
        glBegin(GL_QUADS);
    else
    {
        glBegin(GL_QUADS);//每4个坐标就能绘制出一个矩形
        glVertex2f(c1.x,-c1.y);//4th
        glVertex2f(c1.x,-c2.y);
        glVertex2f(c2.x,-c2.y);
        glVertex2f(c2.x,-c1.y);

        glVertex2f(-c1.x,-c1.y);//3rd
        glVertex2f(-c1.x,-c2.y);
        glVertex2f(-c2.x,-c2.y);
        glVertex2f(-c2.x,-c1.y);

        glVertex2f(-c1.x,c1.y);//2nd
        glVertex2f(-c1.x, c2.y);
        glVertex2f(-c2.x, c2.y);
        glVertex2f(-c2.x, c1.y);
    }
        // glBegin(GL_LINE_LOOP);
    glVertex2f(c1.x, c1.y);
    glVertex2f(c1.x, c2.y);
    glVertex2f(c2.x, c2.y);
    glVertex2f(c2.x, c1.y);
    glEnd();
    glFlush();
}
void draw_cycle(struct cor c1,struct cor c2)
{//绘制圆形，用两个点绘制，分别是圆心和圆周上一点
    glBegin(GL_POLYGON);
    float R= sqrt(float((c1.x-c2.x)*(c1.x-c2.x)+(c1.y-c2.y)*(c1.y-c2.y))) / 2;
    float dx = (c1.x+c2.x) / 2;
    float dy = (c1.y+c2.y) / 2;
    int n=100;
    for(int i=0;i

实验结果截图及功能实现

主菜单：

 

 

Draw中有:line,triangle,rectangle,cycle四种选择，分别代表直线，三角形，矩形和圆形。

 

画图：

2.Move功能：

 

可实现对已经画出所有图形的上下左右的移动。

3.Set new color

可改变已经画出所有图形的颜色的改变。

1. Zoom in 和Zoom out 放大缩小函数

 

1. Rotate 旋转函数

1. mirror 镜像函数

 

实验反思

在实验中，首先是C++中库的问题，添加上了库,否则无法通过编译。

在设计重画之前已经存在的函数时没有考虑充分，遇到了许多bug，比如在画三角形以及矩形时会出现画圆时出现的界面。