From: Koichi KAMICHI <kamichi@fonts.jp>
Date: Wed, 15 Oct 2008 06:22:28 +0000 (+0000)
Subject: Initial revision
X-Git-Url: http://git.chise.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ad1a1c8a5ef45c1fede2c3e5493c6570323a9a08;p=chise%2Fkage.git

Initial revision
---

diff --git a/engine/2d.js b/engine/2d.js
new file mode 100644
index 0000000..864f22f
--- /dev/null
+++ b/engine/2d.js
@@ -0,0 +1,129 @@
+// Reference : http://www.cam.hi-ho.ne.jp/strong_warriors/teacher/chapter0{4,5}.html
+
+function point(x, y){
+  this.x = x;
+  this.y = y;
+}
+
+function getCrossPoint(x11, y11, x12, y12, x21, y21, x22, y22){ // point
+  var a1 = y12 - y11;
+  var b1 = x11 - x12;
+  var c1 = -1 * a1 * x11 - b1 * y11;
+  var a2 = y22 - y21;
+  var b2 = x21 - x22;
+  var c2 = -1 * a2 * x21 - b2 * y21;
+  
+  var temp = b1 * a2 - b2 * a1;
+  if(temp == 0){ // parallel
+    return false;
+  }
+  return new point((c1 * b2 - c2 * b1) / temp, (a1 * c2 - a2 * c1) / temp);
+}
+
+function isCross(x11, y11, x12, y12, x21, y21, x22, y22){ // boolean
+  var temp = getCrossPoint(x11, y11, x12, y12, x21, y21, x22, y22);
+  if(!temp){ return false; }
+  if(x11 < x12 && (temp.x < x11 || x12 < temp.x) ||
+     x11 > x12 && (temp.x < x12 || x11 < temp.x) ||
+     y11 < y12 && (temp.y < y11 || y12 < temp.y) ||
+     y11 > y12 && (temp.y < y12 || y11 < temp.y)
+     ){
+    return false;
+  }
+  if(x21 < x22 && (temp.x < x21 || x22 < temp.x) ||
+     x21 > x22 && (temp.x < x22 || x21 < temp.x) ||
+     y21 < y22 && (temp.y < y21 || y22 < temp.y) ||
+     y21 > y22 && (temp.y < y22 || y21 < temp.y)
+     ){
+    return false;
+  }
+  return true;
+}
+
+function isCrossBox(x1, y1, x2, y2, bx1, by1, bx2, by2){ // boolean
+  if(isCross(x1, y1, x2, y2, bx1, by1, bx2, by1)){ return true; }
+  if(isCross(x1, y1, x2, y2, bx2, by1, bx2, by2)){ return true; }
+  if(isCross(x1, y1, x2, y2, bx1, by2, bx2, by2)){ return true; }
+  if(isCross(x1, y1, x2, y2, bx1, by1, bx1, by2)){ return true; }
+  return false;
+}
+
+function isCrossBoxWithOthers(strokesArray, i, bx1, by1, bx2, by2){ // boolean
+  for(var j = 0; j < strokesArray.length; j++){
+    if(i == j){ continue; }
+    switch(strokesArray[j][0]){
+    case 0:
+    case 8:
+    case 9:
+      break;
+    case 6:
+    case 7:
+      if(isCrossBox(strokesArray[j][7],
+                    strokesArray[j][8],
+                    strokesArray[j][9],
+                    strokesArray[j][10],
+                    bx1, by1, bx2, by2)){
+        return true;
+      }
+    case 2:
+    case 12:
+    case 3:
+      if(isCrossBox(strokesArray[j][5],
+                    strokesArray[j][6],
+                    strokesArray[j][7],
+                    strokesArray[j][8],
+                    bx1, by1, bx2, by2)){
+        return true;
+      }
+    default:
+      if(isCrossBox(strokesArray[j][3],
+                    strokesArray[j][4],
+                    strokesArray[j][5],
+                    strokesArray[j][6],
+                    bx1, by1, bx2, by2)){
+        return true;
+      }
+    }
+  }
+  return false;
+}
+
+function isCrossWithOthers(strokesArray, i, bx1, by1, bx2, by2){ // boolean
+  for(var j = 0; j < strokesArray.length; j++){
+    if(i == j){ continue; }
+    switch(strokesArray[j][0]){
+    case 0:
+    case 8:
+    case 9:
+      break;
+    case 6:
+    case 7:
+      if(isCross(strokesArray[j][7],
+                 strokesArray[j][8],
+                 strokesArray[j][9],
+                 strokesArray[j][10],
+                 bx1, by1, bx2, by2)){
+        return true;
+      }
+    case 2:
+    case 12:
+    case 3:
+      if(isCross(strokesArray[j][5],
+                 strokesArray[j][6],
+                 strokesArray[j][7],
+                 strokesArray[j][8],
+                 bx1, by1, bx2, by2)){
+        return true;
+      }
+    default:
+      if(isCross(strokesArray[j][3],
+                 strokesArray[j][4],
+                 strokesArray[j][5],
+                 strokesArray[j][6],
+                 bx1, by1, bx2, by2)){
+        return true;
+      }
+    }
+  }
+  return false;
+}