OpenGL中Bresenham画线算法，就是画不出东西。麻烦大神帮忙看看

2015-12-17 09:37:23 169 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

bresenham直线，画圆算法（附OpenGL代码）我们在电脑上看到的图像时由一个个像素点拼接而成，当你放大图像就可以观察到这点。以下是一条直线：它是由这些像素点一个一个拼接而成，那么问题来了，怎样选取这些点，使我们看到的更像是一条直线呢？我们的主要思路就是，谁靠近直线我们就选谁，近水楼台先得月。如下图，因为,所以我们选择直线下面的黄点作为画直线的点。依照这个原则，直到终点。这样一条线就出来了。所以我们得比较这两个值的大小。我们只阅读详情

//------------Bresenham画线算法---------------------

//--------------by D_Viking-------------------------

#include<stdio.h>

#include<stdlib.h>

#include<math.h>

#include<GL/glut.h>







/*Bresenham line-drawing procedure for |m|<1.0 */

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, 550.0, 0.0, 550.0);	

}



void setPixel(GLint x, GLint y){

	glClear(GL_COLOR_BUFFER_BIT | GL_COLOR_BUFFER_BIT);

	

	

	glBegin(GL_POINTS);

	    glColor3f(1, 0, 0);//Set line segment color to green.

	    glVertex2i(x, y);

		glPointSize(9);//绘制前设置点的大小和颜色

	glEnd();

	glFlush();

}



void lineBres(){

	int x0, y0, xEnd, yEnd;

	//scanf_s("%d", &x0); scanf_s("%d", &xEnd); scanf_s("%d", &y0); scanf_s("%d", ¥d);

	x0 = 60; y0 = 300; xEnd = 100; yEnd = 400;

	glClear(GL_COLOR_BUFFER_BIT);//Clear display window.

	

	glColor3f(1, 0, 0);//Set line segment color to green.

	int dx = (int)fabs((float)xEnd - x0), dy = (int)fabs((float)yEnd - y0);

	int p = 2 * dy - dx;

	int twoDy = 2 * dy, twoDyMinusDx = 2 * (dy - dx);

	int x, y;

	/*Determine which endpoint to use as start position.*/



	if (x0 > xEnd){

		x = xEnd;

		y = yEnd;

		xEnd = x0;

	}

	else

	{

		x = x0;

		y = y0;

	}

	setPixel(x, y);

	while (x < xEnd){

		x++;

		if (p < 0)

			p += twoDy;

		else

		{

			y++;

			p += twoDyMinusDx;

		}

		setPixel(x, y);

	}

}



void 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(400, 300);//Set display-window width and height.

	glutCreateWindow("Bresenham画线算法");//Create display window.



	init();//Execute initialization procedure.

	glutDisplayFunc(lineBres);//Send graphics to display window.

	

	glutMainLoop();//Display everything and wait.

}