WhyCan Forum(哇酷开发者社区)

//画 虚线 ，点线，通过glLineStipple设置虚线模型，然后enable GL_LINE_STIPPLE开关
glLineStipple(2, 0x5555);
glEnable(GL_LINE_STIPPLE);

glBegin(GL_LINES);
glVertex3f(0.25,0.85,0.6);
glVertex3f(0.75,0.85,0.6);
glEnd();

//结束画虚线
glDisable(GL_LINE_STIPPLE);

#include <stdio.h>
#include <Windows.h>
#include <gl/glut.h>

/*
 功能描述：使用OpenGL简单画一个虚心水壶
 缩放变换函数glScalef
 */

//输出模式，0-单缓存模式；非0双缓存模式
#define OUTPUT_MODE 1

float scale = 0.0;
bool add = true;

unsigned char axle = 'x';

void init(void)
{
    //glClearColor函数设置好清除颜色，glClear利用glClearColor函数设置好的当前清除颜色设置窗口颜色
    glClearColor(1.0, 1.0, 0.8, 1.0);
}

void display(void)
{
    printf("scale=%f, axle=%c\n", scale, axle);
    glClear(GL_COLOR_BUFFER_BIT);

    //配置缩放比例大小scale
    scale = (add ? scale + 0.1 : scale - 0.1);
    if (scale >= 2.0)
    {
        add = false;
    } else if (scale <= 0.0) {
        add = true;
    }
    //开始绘画
    glPushMatrix();
    {
        if (axle == 'x') {
            glScalef(scale, 1, 1);
        } else if (axle == 'y') {
            glScalef(1, scale, 1);
        } else if (axle == 'z') {
            glScalef(1, 1, scale);
        } else {
            glScalef(scale, scale, scale);
        }
        glColor3f (1.0, 0.0, 1.0); //画笔梅红色
        glBegin(GL_POLYGON);
        glVertex2f(-0.2, -0.2);
        glVertex2f(-0.2, 0.2);
        glVertex2f(0.2, 0.2);
        glVertex2f(0.2, -0.2);
        glEnd();
    }
    glPopMatrix();

    glLoadIdentity();  //加载单位矩阵
    glColor3f (0.0, 0.0, 1.0); //画笔蓝色
    //--------画直线START--------
    //画直线
    glBegin(GL_LINES);
    glVertex2f(-0.5, 0);
    glVertex2f(0.5, 0);
    glVertex2f(0, 0.5);
    glVertex2f(0, -0.5);
    glEnd();
    //--------画直线E N D--------

    if (OUTPUT_MODE == 0) {
        glFlush();//单缓存GLUT_SINGLE时使用
    } else {
        glutSwapBuffers();//因为使用的是双缓存GLUT_DOUBLE，所以这里必须要交换缓存才会显示
    }

    Sleep(50);
}

void reshape(int w, int h)
{
    int offset = 50;
    int dis = (w > h ? h : w) - offset * 2;

    //配置显示物体屏幕的大小
    glViewport(offset, offset, (GLsizei)dis, (GLsizei)dis);
    printf("reshape: w=%d, h=%d, dis=%d\n", w, h, dis);

    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();

    glOrtho(-1.5, 1.5, -1.5, 1.5, 0, 10);
    //gluOrtho2D(-1.5, 1.5, -1.5, 1.5);

    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
}

void keyboard(unsigned char key, int x, int y)
{
    switch (key) {
        case 'x':
        case 'X':
            axle = 'x';
            glutPostRedisplay();
            break;
        case 'y':
        case 'Y':
            axle = 'y';
            glutPostRedisplay();
            break;
        case 'z':
        case 'Z':
            axle = 'z';
            glutPostRedisplay();
            break;
        case 'a':
        case 'A':
            axle = 'a';
            glutPostRedisplay();
            break;
        default:
            break;
    }
    printf("按键%c\n", key);
}

int main(int argc, char *argv[])
{
    printf("可通过按键xyza控制图形按哪一轴缩放\n");
    glutInit(&argc, argv);

    glutInitDisplayMode(GLUT_RGB | (OUTPUT_MODE == 0 ? GLUT_SINGLE : GLUT_DOUBLE));
    glutInitWindowPosition(100, 100);
    glutInitWindowSize(400, 400);
    glutCreateWindow("第一个 OpenGL 程序");

    init();
    glutDisplayFunc(&display);
    glutIdleFunc(display);  //设置不断调用显示函数
    glutReshapeFunc(reshape);
    glutKeyboardFunc(keyboard);
    glutMainLoop();
    return 0;
}

		//画一个蓝色的点
		glPointSize(20);
		glBegin(GL_POINTS);
		glColor3f(0.0f, 0.0f, 1.0f);
		glVertex2f(hit_pos_x, hit_pos_y);
		glEnd();