第一课、OpenGL绘制直线等等

第一课、OpenGL绘制直线等等

分类： 【开发技术】OpenGL 2012-01-18 14:59 5217人阅读 评论(0) 收藏 举报

buffer图形c

//

//  main.c

//  opengl_ animationRect_0002

//

//  Created by  ch_soft on 12-1-16.

//  Copyright (c) 2012年 __MyCompanyName__. All rights reserved.

//

#include<stdio.h>

#include<GLUT/glut.h>

#include<OpenGL/gl.h>

#include<OpenGL/glu.h>

//用于绘制窗口需要的图形

void RenderScene()

{

//清除颜色缓冲区，即窗口的背景色

glClear(GL_COLOR_BUFFER_BIT);

//设置当前绘图使用的颜色

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

//使用当前的颜色来绘制一个矩形

//    glRectf(100.0f, 150.0f, 150.0f, 100.0f);

//   1.画点

GLfloat sizesPoint[2];//保存线宽的尺寸范围

GLfloat stepPoint;//保存线宽度尺寸的最小间隔

GLfloat curSizePoint;

glGetFloatv(GL_POINT_SIZE_RANGE,sizesPoint);

glGetFloatv(GL_POINT_SIZE_GRANULARITY,&stepPoint);

curSizePoint=sizesPoint[0];

for (int i=0;i<25;i++) {

glPointSize(curSizePoint);

glBegin(GL_POINTS);

glVertex3f(25.0+i*8,200.0f,0.0f);

glEnd();

curSizePoint +=stepPoint*2;

}

//  2. 画直线

//    GLfloat sizesLine[2];//保存线宽的尺寸范围

//    GLfloat stepLine;//保存线宽度尺寸的最小间隔

GLfloat curSizeLine=5;

//    glGetFloatv(GL_LINE_WIDTH_RANGE,sizesLine);

//    glGetFloatv(GL_LINE_WIDTH_GRANULARITY,&stepLine);

glLineWidth(curSizeLine);

glBegin(GL_LINES);

glVertex3f(25.0f,160.0f,0.0f);

glVertex3f(225.0f,160.0f,0.0f);

glEnd();

//   3.画连续的直线

glBegin(GL_LINE_STRIP);

glVertex3f(25.0f,150.0f,0.0f);

glVertex3f(100.0f,150.0f,0.0f);

glVertex3f(100.0f,130.0f,0.0f);

glEnd();

glBegin(GL_LINE_STRIP);

glVertex3f(0.0f,0.0f,0.0f);

glVertex3f(10.0f,10.0f,0.0f);

glVertex3f(20.0f,5.0f,0.0f);

glEnd();

//   4.画封闭式直线

glBegin(GL_LINE_LOOP);

glVertex3f(125.0f,150.0f,0.0f);

glVertex3f(200.0f,150.0f,0.0f);

glVertex3f(200.0f,130.0f,0.0f);

glEnd();

//   画虚线

glEnable(GL_LINE_STIPPLE);

glLineStipple(1,0x00FF);//第一个参数是倍数，第二个参数是一个十六进制数，用来表示如何显示的

glBegin(GL_LINES);

glVertex3f(25.0f,120.0f,0.0f);

glVertex3f(225.0f,120.0f,0.0f);

glEnd();

glLineWidth(3);

glLineStipple(1,0xFF0C);

glBegin(GL_LINES);

glVertex3f(25.0f,80.0f,0.0f);

glVertex3f(225.0f,80.0f,0.0f);

glEnd();

glLineStipple(4,0xFF0C);

glBegin(GL_LINES);

glVertex3f(25.0f,40.0f,0.0f);

glVertex3f(225.0f,40.0f,0.0f);

glEnd();

glDisable(GL_LINE_STIPPLE);

//刷新opengl命令队列

glFlush();

}

//改变大小时调用的函数

void ChangeSize(GLsizei w,GLsizei h)

{

if (h==0) {

h=1;

}

//设置视区尺寸

glViewport(0,
0, w, h);

//重置坐标系统，使用投影变换复位

glMatrixMode(GL_PROJECTION);

glLoadIdentity();

if (w<=h) {

glOrtho (0.0f,250.0f,
0.0f,250.0f*h/w,
1.0f, -1.0f);

}else

{

glOrtho (0.0f,250.0f*w/h,
0.0f,250.0f,
1.0f, -1.0f);

}

glMatrixMode(GL_MODELVIEW);

glLoadIdentity();

}

//用于初始化，常用来设置场景的渲染状态

void SetupRC(void)

{

glClearColor(1.0f,1.0f,
1.0f,1.0f);

}

int main(int argc,char** argv)

{

//    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);

//    glutCreateWindow("GLRect");

glutInit(&argc, argv);

//初始化GLUT库OpenGL窗口的显示模式

glutInitDisplayMode (GLUT_SINGLE |GLUT_RGB
|GLUT_DEPTH);

glutInitWindowSize (500,500);

glutInitWindowPosition (100,100);

glutCreateWindow (argv[0]);

glutDisplayFunc(RenderScene);

glutReshapeFunc(ChangeSize);

SetupRC();

glutMainLoop();

return 0;

}