第一课、OpenGL绘制直线等等
//
// 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;
}