Question

我试图用OpenGL和Objective C绘制Sierpinski三角形分形。我得到了三角形的大部分，但似乎有一个我无法弄清楚的错误。在图像中是我得到的输出。请注意，右半边的三角形出错了。

#import "Fractals.h"
#include <math.h>
#include <OpenGL/gl.h>
//the points for the initial equilateral triangle
const float ox1 = 0, ox2 = 1.0, ox3 = 0.5, oy1 = 0, oy2 = 0, oy3 = 0.866025404;

void drawSubTriangle(float x1, float x2, float x3, float y1, float y2, float y3)
{
//set the colors
//0, 0 , 0 is black
glColor3f(0, 0, 0);
//draw triangles with midpoints of the original triangle
glBegin(GL_TRIANGLES);

{

    glVertex3f( (x1+x3)/2, (y1+y3)/2, 0.0);

    glVertex3f( (x2+x3)/2, (y2+y3)/2, 0.0);

    glVertex3f( (x2+x1)/2, (y2+y1)/2, 0.0);

}

glEnd();
}

void drawFractals(float x1, float x2, float x3, float y1, float y2, float y3)
{
drawSubTriangle(x1, x2, x3, y1, y2, y3);
//ensure that the size of the triangles is not too small
//distance formula is in the if condition
if(pow((pow((x2-x1),2) + pow((y2-y1),2)),0.5) > 0.0625)
{
    drawFractals((x1+x3)/2, (x3+x2)/2, x3, (y1+y3)/2, (y3+y1)/2, y3); //top triangle
    drawFractals(x1, (x1+x2)/2, (x1+x3)/2, y1, (y1+y2)/2, (y1+y3)/2); //left triangle
    drawFractals((x2+x3)/2, x2, (x1+x2)/2, (y2+y3)/2, y2, (y1+y2)/2); //right triangle
}
}

@implementation MyOpenGLView
-(void) drawRect: (NSRect) bounds

{

glClearColor(0, 0, 0, 0);

glClear(GL_COLOR_BUFFER_BIT);

glColor3f(1.0f, 1.0f, 1.0f);

glBegin(GL_TRIANGLES);

{

    glVertex3f( ox1, oy1, 0.0);

    glVertex3f( ox2, oy2, 0.0);

    glVertex3f( ox3, oy3, 0.0);

}

glEnd();

drawFractals(ox1, ox2, ox3, oy1, oy2, oy3);

glFlush();

}

@end

output from the program

Answer 1

我发现了这个错误。在递归函数中传递值时出错了... 我从

改变了它

drawFractals((x2+x3)/2, x2, (x1+x2)/2, (y2+y3)/2, y2, (y1+y2)/2); //right triangle

到

drawFractals((x1+x3)/2, x2, (x3+x2)/2, (y1+y3)/2, y2, (y3+y2)/2); //right triangle

OpenGL中的Sierpinski Triangle和使用递归的Objective C

1 个答案: