openGL线型和线宽以及线的抗锯齿
Posted cartzhang
tags:
篇首语：本文由小常识网(cha138.com)小编为大家整理，主要介绍了openGL线型和线宽以及线的抗锯齿相关的知识，希望对你有一定的参考价值。
openGL线型和线宽以及线抗锯齿
一、 线宽
Opengl的线宽设置：glLineWidth(width); width为float类型值，在0~10.0，大于10以上按10来处理。
若开启线的反走样glEnable(GL_LINE_SMOOTH);，设置小数值才起作用，否则就四舍五入的处理整数了。
二、 线型
函数为glLineStipple(factor, Pattern[PatternMode]);
其中pattern值可以是任意的你想要的，把01转换为16进制的值就可以了。Factor为缩放因子。
pattern参数是由1或0组成的16位序列，它们根据需要进行重复，对一条特定的直线进行点画处理。从这个模式的低位开始，一个像素一个像素的进行处理。如果模式中对应的位是1，就绘制这个像素，否则就不绘制。模式可以使用factor参数（表示重复因子）进行扩展，它与1和0的连续子序列相乘。因此，如果模式中出现了3个1，并且factor是2，那么它们就扩展为6个连续的1。必须以GL_LINE_STIPPLE为参数调用glEnable()才能启用直线点画功能。
三、线宽代码
<span style="font-size:14px;">void show_width_lines(int width,float red,float green,float blue)
glColor3f(red,green,blue);
width = 1.0f;
float PI = 3.1415926;
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glColor3f(red,green,blue);
//禁用反走样
glDisable(GL_BLEND);
glDisable(GL_LINE_SMOOTH);
// line_1
for (int i = 0; i < 8;i++ )
glLineWidth(width);
glBegin(GL_LINE_STRIP);
glVertex3f(5,5*(i+1), 0.0);
glVertex3f(100,5*(i+1)-qingxie_,0.0);
glEnd();
//直线宽度增加0.5
width += 2.0;
//启用反走样
glEnable(GL_BLEND);
glEnable(GL_LINE_SMOOTH);
glHint(GL_LINE_SMOOTH_HINT, GL_FASTEST); // Antialias the lines
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
//初始化直线宽度
width=1.0;
// line_2
glColor4f(0,green,0,1.0);
for (int i = 0; i < 8;i++ )
glLineWidth(width);
glBegin(GL_LINE_STRIP);
glVertex3f(5, 50+1*(i+1), 0.0);
//glVertex3f(50,50+2*(i+1)-qingxie_, 0.0);
glVertex3f(80,50+3*(i+1)+qingxie_, 0.0);
//glVertex3f(100,50+4*(i+1)-qingxie_, 0.0);
glVertex3f(120,50+5*(i+1)+qingxie_, 0.0);
glEnd();
//宽度累加
width += 2.0;
glFlush();
</span>
<span style="font-size:14px;">void show_dot_lines(int width,float red,float green,float blue)
int PatternMode = 0; //线型模式
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glColor3f(red,green,blue);
int Pattern[6]= //定义了6种线型
//点线 1000100010001000, 表示实际画线的点，反序后转换成16进制就是0x1111 dotted
//. . . . . . . . . . . . . .
//0x1111,
0x0101,
//点划线 1111111111100100 dot dash
//____ . ____ . _____ . _____. _____
0x27FF,
//0x1C47,
//中心线 1111111111001100 centre line
//_____ _ _____ _ _____ _ _____ _ _____
0x33FF,
//虚线 1111110011111100 dashed
//____ ____ ____ ____ ____ ____ ____
0x3F3F,
//双点划线 1111111100100100 double dot dash
// ____ . . ____ . . ____ . . ____ . . ____
0x24FF,
//三点划线 111111110101010 tri_dot_dash
// ____ . . ____ . . ____ . . ____ . . ____
0x55FF
;
static float angle = 0.0;
glEnable(GL_BLEND);
glEnable(GL_LINE_SMOOTH);
glEnable(GL_LINE_STIPPLE);
//初始化直线宽度
width=2.0;
// line_2
glColor3f(0,0,blue);
for (int i = 0; i<6; i++)
int PatternMode = i;
glLineStipple(1, Pattern[PatternMode]);
glLineWidth(width);
glBegin(GL_LINES);
glVertex3f(1,23+i*5, 0.0);
glVertex3f(50,23+i*5-qingxie_, 0.0);
glEnd();
width = 1.0;
glColor3f(red,0,0);
for (int i = 0; i<6; i++)
int PatternMode = i;
glLineStipple(1, Pattern[PatternMode]);
glLineWidth(width);
glBegin(GL_LINES);
glVertex3f(20,50+i*5, 0.0);
glVertex3f(50,50+i*5-qingxie_, 0.0);
glEnd();
glDisable(GL_LINE_STIPPLE);
glFlush();
</span>五、结果
线的线宽
很明显，绿色线开启反走样，而淡红色的没有。
线型--点划线的实现效果
开启的反走样，为fastest. 当然你可以根据你效果与效率之间选择自己需要的。
六、全部实现代码和工程
<span style="font-size:14px;">
#include <Windows.h>
#include "glew.h"
#pragma comment(lib,"opengl32.lib")
#pragma comment(lib,"glu32.lib")
#pragma comment(lib,"./glew32.lib")
#include <math.h>
//
#include "glut.h"
#include<stdio.h>
#include<stdlib.h>
#define drawOneLine(x1,y1,x2,y2) glBegin(GL_LINES);glVertex3f((x1),(y1),0); glVertex3f((x2),(y2),0);glEnd();
#define qingxie_ 2.0
// function declear
void init (void)
glClearColor (1.0, 1.0, 1.0, 0.0); // Set display-window color to white.
glMatrixMode (GL_PROJECTION); // Set projection parameters.
gluOrtho2D (0.0, 200.0, 0.0, 150.0);
void show_width_lines(int width,float red,float green,float blue)
glColor3f(red,green,blue);
width = 1.0f;
float PI = 3.1415926;
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glColor3f(red,green,blue);
//禁用反走样
glDisable(GL_BLEND);
glDisable(GL_LINE_SMOOTH);
// line_1
for (int i = 0; i < 8;i++ )
glLineWidth(width);
glBegin(GL_LINE_STRIP);
glVertex3f(5,5*(i+1), 0.0);
glVertex3f(100,5*(i+1)-qingxie_,0.0);
glEnd();
//直线宽度增加0.5
width += 2.0;
//启用反走样
glEnable(GL_BLEND);
glEnable(GL_LINE_SMOOTH);
glHint(GL_LINE_SMOOTH_HINT, GL_FASTEST); // Antialias the lines
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
//初始化直线宽度
width=1.0;
// line_2
glColor4f(0,green,0,1.0);
for (int i = 0; i < 8;i++ )
glLineWidth(width);
glBegin(GL_LINE_STRIP);
glVertex3f(5, 50+1*(i+1), 0.0);
//glVertex3f(50,50+2*(i+1)-qingxie_, 0.0);
glVertex3f(80,50+3*(i+1)+qingxie_, 0.0);
//glVertex3f(100,50+4*(i+1)-qingxie_, 0.0);
glVertex3f(120,50+5*(i+1)+qingxie_, 0.0);
glEnd();
//宽度累加
width += 2.0;
glFlush();
void Line3f(GLfloat fromX, GLfloat fromY, GLfloat fromZ,
GLfloat toX, GLfloat toY, GLfloat toZ)
glBegin(GL_LINES);
glVertex3f(fromX, fromY, fromZ);
glVertex3f(toX, toY, toZ);
glEnd();
void show_dot_lines(int width,float red,float green,float blue)
int PatternMode = 0; //线型模式
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glColor3f(red,green,blue);
int Pattern[6]= //定义了6种线型
//点线 1000100010001000, 表示实际画线的点，反序后转换成16进制就是0x1111 dotted
//. . . . . . . . . . . . . .
//0x1111,
0x0101,
//点划线 1111111111100100 dot dash
//____ . ____ . _____ . _____. _____
0x27FF,
//0x1C47,
//中心线 1111111111001100 centre line
//_____ _ _____ _ _____ _ _____ _ _____
0x33FF,
//虚线 1111110011111100 dashed
//____ ____ ____ ____ ____ ____ ____
0x3F3F,
//双点划线 1111111100100100 double dot dash
// ____ . . ____ . . ____ . . ____ . . ____
0x24FF,
//三点划线 111111110101010 tri_dot_dash
// ____ . . ____ . . ____ . . ____ . . ____
0x55FF
;
static float angle = 0.0;
glEnable(GL_BLEND);
glEnable(GL_LINE_SMOOTH);
glHint(GL_LINE_SMOOTH_HINT, GL_FASTEST); // 反走样的fastest效果，也可以根据需要选择GL_NICEST.etc.
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glEnable(GL_LINE_STIPPLE);
//初始化直线宽度
width=5.0;
// line_2
glColor3f(0,0,blue);
for (int i = 0; i<6; i++)
int PatternMode = i;
glLineStipple(i, Pattern[PatternMode]);
glLineWidth(width);
glBegin(GL_LINES);
glVertex3f(1,23+i*5, 0.0);
glVertex3f(50,23+i*5-qingxie_, 0.0);
glEnd();
width = 1.0;
glColor3f(red,0,0);
for (int i = 0; i<6; i++)
int PatternMode = i;
glLineStipple(i, Pattern[PatternMode]);
glLineWidth(width);
glBegin(GL_LINES);
glVertex3f(2,50+i*5, 0.0);
glVertex3f(50,50+i*5-qingxie_, 0.0);
glEnd();
glDisable(GL_LINE_STIPPLE);
glDisable(GL_BLEND);
glFlush();
void pointFun()
float red = 1.0,green = 0.5,blue = 0.5;
glClear (GL_COLOR_BUFFER_BIT);
// 去掉注释就可以看线宽效果了。
//show_width_lines(5,red,green,blue);
show_dot_lines(5,red,green,blue);
glFlush();
int main (int argc, char** argv)
glutInit (&argc, argv); // Initialize GLUT.
glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB); // Set display mode.
glutInitWindowPosition (50, 100); // Set top-left display-window position.
glutInitWindowSize (1000, 800); // Set display-window width and height.
//glutFullScreen();
glutCreateWindow ("An Example OpenGL Program By Qiu"); // Create display window.
init(); // Execute initialization procedure.
// draw position.
glTranslatef(50.0f, 50.0f,0.0f);
glutDisplayFunc (pointFun); // Send graphics to display window.
glutMainLoop ( );// Send graphics to display window. // Display everything and wait.
return 0;
</span>
工程下载地址:http://download.csdn.net/detail/cartzhang/7648119
end
多多指教！
以上是关于openGL线型和线宽以及线的抗锯齿的主要内容，如果未能解决你的问题，请参考以下文章