graphics2d - 如何在一个圆圈中交替颜色,使圆圈看起来像旋转?
问题描述
预期的输出应该是这样的,颜色也会改变它们的位置:
预期输出-:
颜色应该在一个圆圈中改变它们的位置,以便看起来它们在移动而不改变圆圈的位置。
虽然我的代码是用 c/c++ 的代码块编写的,但我很乐意用任何其他编程语言得到答案。
我现在的代码
#include<graphics.h>
#include<stdlib.h>
#include<stdio.h>
#include<conio.h>
#include<math.h>
#include<string.h>
#include<iostream>
using namespace std;
void vvcircle(float xk,float yk,float radius);
int i=0;
int main()
{
float xk,yk,radius;
int gdriver=DETECT,gmode,errorcode;
initgraph(&gdriver,&gmode,"C:\\TURBOC3\\BGI");
// cout<<"enter the value of x, y and radius of circle"<<endl;
//cin>>xk>>yk>>radius;
vvcircle(200,200,100);
getch();
closegraph();
return 0;
}
void vvcircle(float xk,float yk,float radius)
{
int color[60]={0,1,2,3,4,5,6,7,8,9};
while(radius>0)
{
float xo,yo;
float P;
xo=0.0;
yo=radius;
P=1-radius;
/// vvcircle(200,200,100);
for(;xo<=yo;)
{
putpixel(xo+xk,yo+yk,1);
putpixel(yo+xk,xo+yk,1);
putpixel(-yo+xk,xo+yk,2);
putpixel(xo+xk,-yo+yk,2);
putpixel(-yo+xk,-xo+yk,4);
putpixel(-xo+xk,-yo+yk,4);
putpixel(yo+xk,-xo+yk,4);
putpixel(-xo+xk,+yo+yk,4);
if(P<0)
{
xo=xo+1;
yo=yo;
P=P+2*xo+1;
}
else
{
xo=xo+1;
yo=yo-1;
P=P+(2*xo)-(2*yo)+1;
// putpixel(xo,yo,WHITE);
}
}
radius=radius-1;
}
}
当前输出-:
我有很多颜色的同心圆。但我想移动颜色,使它看起来像圆圈在移动,但没有实现。
解决方案
像这样的东西怎么样:
#include <math.h>
void my_circle(int xc,int yc,int r,float a) // center(x,y), radius, animation angle [rad]
{
const int n=4; // segments count
int x,sx,xx,x0,x1,rr=r*r,
y,sy,yy,y0,y1,i,
dx[n+1],dy[n+1], // segments edges direction vectors
c[n]={5,1,2,3}; // segments colors
float da=2.0*M_PI/float(n);
// BBOX
x0=xc-r; x1=xc+r;
y0=yc-r; y1=yc+r;
// compute segments
for (i=0;i<=n;i++,a+=da)
{
dx[i]=100.0*cos(a);
dy[i]=100.0*sin(a);
}
// all pixels in BBOX
for (sx=x0,x=sx-xc;sx<=x1;sx++,x++){ xx=x*x;
for (sy=y0,y=sy-yc;sy<=y1;sy++,y++){ yy=y*y;
// outside circle?
if (xx+yy>rr) continue;
// compute segment
for (i=0;i<n;i++)
if ((x*dy[i ])-(y*dx[i ])>=0)
if ((x*dy[i+1])-(y*dx[i+1])<=0)
break;
// render
putpixel(sx,sy,c[i]);
}}
}
它只是将外接正方形的所有像素循环到您的圆圈,确定像素是否在内部,然后检测它在哪个段中并用段颜色对其进行着色。
段由从圆心到段边缘的方向向量描述。因此,如果像素在内部,则意味着其 CW 到一个边缘,CCW 到另一个边缘,因此在 2D 中检查向量到像素和向量到边缘之间的叉积的 z 坐标将判断像素是否在...
如您所见,我在自己的渲染中没有使用浮点数学,它只需要在渲染之前计算段边缘向量......
我使用了标准的 256 色 VGA 调色板(不确定 BGI 使用的是什么,我期望 16 col),因此您的平台上的颜色可能会有所不同,请在此处预览:
噪音是由于我的 GIF 捕捉工具抖动渲染本身是干净的......
不要忘记以my_circle
不断变化的角度反复调用...
PS。我在没有 BGI 的 BDS2006 中对此进行了编码,因此在不同的编译器中可能存在一些与使用的语言怪癖相关的小语法问题......
我用这个伪造了putpixel
:
void putpixel(int x,int y,BYTE c)
{
static const DWORD pal[256]=
{
0x00000000,0x000000A8,0x0000A800,0x0000A8A8,0x00A80000,0x00A800A8,0x00A85400,0x00A8A8A8,
0x00545454,0x005454FC,0x0054FC54,0x0054FCFC,0x00FC5454,0x00FC54FC,0x00FCFC54,0x00FCFCFC,
0x00000000,0x00101010,0x00202020,0x00343434,0x00444444,0x00545454,0x00646464,0x00747474,
0x00888888,0x00989898,0x00A8A8A8,0x00B8B8B8,0x00C8C8C8,0x00DCDCDC,0x00ECECEC,0x00FCFCFC,
0x000000FC,0x004000FC,0x008000FC,0x00BC00FC,0x00FC00FC,0x00FC00BC,0x00FC0080,0x00FC0040,
0x00FC0000,0x00FC4000,0x00FC8000,0x00FCBC00,0x00FCFC00,0x00BCFC00,0x0080FC00,0x0040FC00,
0x0000FC00,0x0000FC40,0x0000FC80,0x0000FCBC,0x0000FCFC,0x0000BCFC,0x000080FC,0x000040FC,
0x008080FC,0x009C80FC,0x00BC80FC,0x00DC80FC,0x00FC80FC,0x00FC80DC,0x00FC80BC,0x00FC809C,
0x00FC8080,0x00FC9C80,0x00FCBC80,0x00FCDC80,0x00FCFC80,0x00DCFC80,0x00BCFC80,0x009CFC80,
0x0080FC80,0x0080FC9C,0x0080FCBC,0x0080FCDC,0x0080FCFC,0x0080DCFC,0x0080BCFC,0x00809CFC,
0x00B8B8FC,0x00C8B8FC,0x00DCB8FC,0x00ECB8FC,0x00FCB8FC,0x00FCB8EC,0x00FCB8DC,0x00FCB8C8,
0x00FCB8B8,0x00FCC8B8,0x00FCDCB8,0x00FCECB8,0x00FCFCB8,0x00ECFCB8,0x00DCFCB8,0x00C8FCB8,
0x00B8FCB8,0x00B8FCC8,0x00B8FCDC,0x00B8FCEC,0x00B8FCFC,0x00B8ECFC,0x00B8DCFC,0x00B8C8FC,
0x00000070,0x001C0070,0x00380070,0x00540070,0x00700070,0x00700054,0x00700038,0x0070001C,
0x00700000,0x00701C00,0x00703800,0x00705400,0x00707000,0x00547000,0x00387000,0x001C7000,
0x00007000,0x0000701C,0x00007038,0x00007054,0x00007070,0x00005470,0x00003870,0x00001C70,
0x00383870,0x00443870,0x00543870,0x00603870,0x00703870,0x00703860,0x00703854,0x00703844,
0x00703838,0x00704438,0x00705438,0x00706038,0x00707038,0x00607038,0x00547038,0x00447038,
0x00387038,0x00387044,0x00387054,0x00387060,0x00387070,0x00386070,0x00385470,0x00384470,
0x00505070,0x00585070,0x00605070,0x00685070,0x00705070,0x00705068,0x00705060,0x00705058,
0x00705050,0x00705850,0x00706050,0x00706850,0x00707050,0x00687050,0x00607050,0x00587050,
0x00507050,0x00507058,0x00507060,0x00507068,0x00507070,0x00506870,0x00506070,0x00505870,
0x00000040,0x00100040,0x00200040,0x00300040,0x00400040,0x00400030,0x00400020,0x00400010,
0x00400000,0x00401000,0x00402000,0x00403000,0x00404000,0x00304000,0x00204000,0x00104000,
0x00004000,0x00004010,0x00004020,0x00004030,0x00004040,0x00003040,0x00002040,0x00001040,
0x00202040,0x00282040,0x00302040,0x00382040,0x00402040,0x00402038,0x00402030,0x00402028,
0x00402020,0x00402820,0x00403020,0x00403820,0x00404020,0x00384020,0x00304020,0x00284020,
0x00204020,0x00204028,0x00204030,0x00204038,0x00204040,0x00203840,0x00203040,0x00202840,
0x002C2C40,0x00302C40,0x00342C40,0x003C2C40,0x00402C40,0x00402C3C,0x00402C34,0x00402C30,
0x00402C2C,0x0040302C,0x0040342C,0x00403C2C,0x0040402C,0x003C402C,0x0034402C,0x0030402C,
0x002C402C,0x002C4030,0x002C4034,0x002C403C,0x002C4040,0x002C3C40,0x002C3440,0x002C3040,
0x00000000,0x00000000,0x00000000,0x00000000,0x00000000,0x00000000,0x00000000,0x00000000,
};
if ((x<0)||(x>=Main->xs)) return;
if ((y<0)||(y>=Main->ys)) return;
Main->pyx[y][x]=pal[c];
}
Main->xs, Main->ys
我的窗口分辨率在哪里,Main->pyx
是直接像素访问其画布的更多信息,请参阅:
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