//By wysaid
//blog: http://wysaid.org
#define _CRT_SECURE_NO_WARNINGS
#include <graphics.h>
#include <vector>
#include <cmath>
using namespace std;
struct Point
{
Point() : x(0), y(0), dx(0), dy(0) {}
Point(float vx, float vy) : x(vx), y(vy), dx(0), dy(0) {}
float x, y;
float dx, dy;
};
class Net
{
public:
Net() : m_index(0), m_intensity(0.2f), m_lastIndex(-1) {}
~Net() {}
bool initNet(int w, int h)
{
if(w < 2 || h < 2)
return false;
m_
width = w;
m_height = h;
m_vec[0].resize(w * h);
m_vec[1].resize(w * h);
float
widthStep = 1.0f / (w - 1);
float heightStep = 1.0f / (h - 1);
for(int i = 0; i != h; ++i)
{
const float heightI = i * heightStep;
int index = w * i;
for(int j = 0; j != w; ++j)
{
const float
widthJ = j *
widthStep;
m_vec[0][index] = Point(
widthJ, heightI);
m_vec[1][index] = Point(
widthJ, heightI);
++index;
}
}
return true;
}
void update()
{
const float
widthStep = 1.0f / (m_
width - 1.0f);
const float heightStep = 1.0f / (m_height - 1.0f);
int index = (m_index + 1) % 2;
for(int i = 1; i < m_height - 1; ++i)
{
//const float heightI = i * heightStep;
const int k = m_
width * i;
for(int j = 1; j < m_
width - 1; ++j)
{
const int h = k + j;
float dx, dy;
dx = (m_vec[m_index][h - 1].x + m_vec[m_index][h + 1].x - m_vec[m_index][h].x * 2.0f);
dy = (m_vec[m_index][h - 1].y + m_vec[m_index][h + 1].y - m_vec[m_index][h].y * 2.0f);
dx += (m_vec[m_index][h - m_
width].x + m_vec[m_index][h + m_
width].x - m_vec[m_index][h].x * 2.0f);
dy += (m_vec[m_index][h - m_
width].y + m_vec[m_index][h + m_
width].y - m_vec[m_index][h].y * 2.0f);
//模拟能量损失， 当加速度方向与速度方向相反时，加快减速
if(((unsigned&)dx >> 31) != ((unsigned&)m_vec[m_index][h].dx >> 31))
dx *= 1.0f + m_intensity;
if(((unsigned&)dy >> 31) != ((unsigned&)m_vec[m_index][h].dy >> 31))
dy *= 1.0f + m_intensity;
m_vec[m_index][h].dx += dx * m_intensity;
m_vec[m_index][h].dy += dy * m_intensity;
m_vec[index][h].dx = m_vec[m_index][h].dx;
m_vec[index][h].dy = m_vec[m_index][h].dy;
m_vec[index][h].x = m_vec[m_index][h].x + m_vec[index][h].dx;
m_vec[index][h].y = m_vec[m_index][h].y + m_vec[index][h].dy;
}
}
m_index = index;
}
void catchPoint(float x, float y)
{
int index;
if(m_lastIndex < 0)
{
float mdis = 1e9f;
for(int i = 1; i < m_height - 1; ++i)
{
const int k = m_
width * i;
for(int j = 1; j < m_
width - 1; ++j)
{
const int h = k + j;
const float dis = fabsf(x - m_vec[m_index][h].x) + fabsf(y - m_vec[m_index][h].y);
if(dis < mdis)
{
index = h;
mdis = dis;
}
}
}
m_lastIndex = index;
}
else
index = m_lastIndex;
m_vec[0][index].x = x;
m_vec[0][index].y = y;
m_vec[1][index].x = x;
m_vec[1][index].y = y;
m_vec[0][index].dx = 0.0f;
m_vec[0][index].dy = 0.0f;
m_vec[1][index].dx = 0.0f;
m_vec[1][index].dy = 0.0f;
}
void releasePoint()
{
m_lastIndex = -1;
}
void drawNet(float
width, float height)
{
auto &v = m_vec[m_index];
for(int i = 0; i != m_height; ++i)
{
const int k = i * m_
width;
for(int j = 1; j != m_
width; ++j)
{
const int h = k + j;
ege_line(v[h - 1].x *
width, v[h - 1].y * height, v[h].x *
width, v[h].y * height);
}
}
for(int i = 0; i != m_
width; ++i)
{
for(int j = 1; j != m_height; ++j)
{
const int h2 = j * m_
width + i;
const int h1 = (j - 1) * m_
width + i;
ege_line(v[h1].x *
width, v[h1].y * height, v[h2].x *
width, v[h2].y * height);
}
}
}
void intensityInc(float f)
{
m_intensity += f;
if(m_intensity > 0.3f)
m_intensity = 0.3f;
}
void intensityDec(float f)
{
m_intensity -= f;
if(m_intensity < 0.001f)
m_intensity = 0.001f;
}
float getIntensity()
{
return m_intensity;
}
private:
vector<Point> m_vec[2];
int m_index;
int m_
width, m_height;
float m_intensity;
int m_lastIndex;
};
int main()
{
initgraph(800, 600, INIT_RENDERMANUAL);
setcaption("EGE网格 By wysaid");
Net net;
char buffer[1024];
sprintf(buffer, "当前网格强度：%g", net.getIntensity());
net.initNet(80, 60);
for(; is_run(); delay_fps(60))
{
cleardevice();
if(keystate(key_mouse_l))
{
int x, y;
mousepos(&x, &y);
net.catchPoint(x / 800.0f, y / 600.0f);
}
else
net.releasePoint();
if(kbhit())
{
switch(getch())
{
case '+':
net.intensityInc(0.005f);
break;
case '-':
net.intensityDec(0.005f);
break;
case 27:
exit(0);
}
flushkey();
sprintf(buffer, "当前网格强度：%g", net.getIntensity());
}
setcolor(GREEN);
net.drawNet(800, 600);
net.update();
setcolor(0x00ff0000);
outtextxy(10, 10, "按'+'或者'-'可以增大或者减小网格弹力！这个版本由wysaid制作， 参见: http://blog.wysaid.org");
outtextxy(10, 30, buffer);
}
closegraph();
return 0;
}为什么在小熊猫dev3.3.1上D:/Backup/Documents/untitled2.cpp 0 -1 In member function 'void Net::update()':
D:/Backup/Documents/untitled2.cpp 55 15 [警告] unused variable '
widthStep' [-Wunused-variable]
D:/Backup/Documents/untitled2.cpp 56 15 [警告] unused variable 'heightStep' [-Wunused-variable]
D:/Backup/Documents/untitled2.cpp 0 -1 In function 'int main()':
D:/Backup/Documents/untitled2.cpp 191 2 [错误] 'sprintf' was not declared in this scope
D:/Backup/Documents/untitled2.cpp 8 1 [说明] 'sprintf' is defined in header '<cstdio>'; did you forget to '#include <cstdio>'?
本文详细介绍了图像处理中widthStep的概念及其作用。widthStep指存储一行像素所需的字节数，必须为4的倍数以实现字节对齐，这对于提高图像处理速度至关重要。通过具体例子解释了如何计算一个图像的widthStep。
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