polygon.h

   1 #include <string.h>
   2
   3 template<class Pixel>
   4 struct Bitmap {
   5   int width, height, extra;
   6   Pixel *data;
   7
   8   Bitmap(int e=0) : extra(e), data(0) { };
   9   ~Bitmap() { delete[] data; };
  10
  11   void size(int w,int h) {
  12     delete[] data;
  13     width = w;
  14     height = h;
  15     data = new Pixel[w*h+extra];
  16     clear();
  17   }
  18
  19   void clear() {
  20     memset(data,0,sizeof(Pixel)*(width*height+extra));
  21   }
  22 };
  23
  24 template<class Pixel, class Combiner, int superSampleShift>
  25 struct PolygonEngine : public Bitmap<Pixel> {
  26   PolygonEngine() : Bitmap<Pixel>(1) { }
  27
  28 #define super (1<<superSampleShift)
  29   void apply(Pixel *dest) {
  30     Pixel sum=0;
  31     int count = this->width*this->height;
  32     Pixel *src = this->data;
  33     while(count--) {
  34       sum += *(src++);
  35       if (sum)
  36         *dest = Combiner::combine(sum,*dest);
  37       dest++;
  38     }
  39   }
  40
  41   void add(Pixel color,int x,int y) {
  42     if (y < 0) return;
  43     if (y >= this->height) return;
  44     if (x < 0) x = 0;
  45     if (x > this->width) x = this->width;
  46     this->data[x+y*this->width] += color;
  47   }
  48
  49   /* Color is char[layers] */
  50
  51   //  zwoosh, yknow, it goes... zwoosh an all these bars and lines and
  52   //  crap intersect.
  53   Pixel colorTable[2][super+1];
  54   void pen(Pixel color) {
  55     for(int i=0;i<super+1;i++) {
  56       colorTable[0][i] = color*i;
  57       colorTable[1][i] = -(color*i);
  58     }
  59   }
  60
  61   void line(int x1,int y1,int x2,int y2) {
  62     Pixel *colors;
  63     if (y2 < y1) {
  64       int temp;
  65       temp = x2; x2 = x1; x1 = temp;
  66       temp = y2; y2 = y1; y1 = temp;
  67       colors = colorTable[1];
  68     } else {
  69       if (y1 == y2) return;
  70
  71       colors= colorTable[0];
  72     }
  73
  74     int slope = (x1-x2 << 16)/(y1-y2);
  75     int x = x1<<16, y = y1;
  76     while(y < y2) {
  77       add(colors[super-((x>>16)&(super-1))],
  78           x>>(16+superSampleShift),y>>superSampleShift);
  79       add(colors[(x>>16)&(super-1)],
  80           1+(x>>(16+superSampleShift)),y>>superSampleShift);
  81       x += slope;
  82       y++;
  83     }
  84   }
  85
  86   void icon(double icon[][4],Pixel color,double x,double y,
  87             double scaleX, double scaleY) {
  88     pen(color);
  89     x *= super;
  90     y *= super;
  91     scaleX *= super;
  92     scaleY *= super;
  93     for(int i=0;icon[i][1] != icon[i][3];i++)
  94       line(int(icon[i][0]*scaleX+x),int(icon[i][1]*scaleY+y),
  95            int(icon[i][2]*scaleX+x),int(icon[i][3]*scaleY+y));
  96   }
  97 #undef super
  98 };