openGL线型和线宽以及线的抗锯齿

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>

四、线型代码

<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

免分源码工程

end

多多指教！