clamping

1 files changed, 69 insertions, 1 deletions

diff --git a/public/assets/javascripts/rectangles/models/surface.js b/public/assets/javascripts/rectangles/models/surface.js
index 448722b..171376f 100644
--- a/public/assets/javascripts/rectangles/models/surface.js
+++ b/public/assets/javascripts/rectangles/models/surface.js
@@ -71,8 +71,9 @@
 	Surface.prototype.bounds = function(index){
 		var bounds = faces[index].clone()
 		var height = faces[index].height()
+		bounds.first = bounds.last = index
 
-		for (var i = index-1; i > 0; i--) {
+		for (var i = index-1; i >= 0; i--) {
 			var face = faces[i]
 			if (face.y.length() < height) {
 				continue
@@ -84,6 +85,7 @@
 				continue
 			}
 			bounds.x.a = bounds.x.a
+			bounds.first = i
 		}
 		
 		for (var i = index+1; i < faces.length; i++) {
@@ -98,9 +100,75 @@
 				continue
 			}
 			bounds.x.b = bounds.x.b
+			bounds.last = i
 		}
 		return bounds
 	}
+	Surface.prototype.clamp = function (bounds, dimension, position, dx, dy) {
+		// we start out with a set of boundaries where we know the object should fall
+		// we then check if we've moved the box off any edge of the bounds
+		// if so, check if the new position is valid with respect to the surface.
+		// for horizontal movement, this means checking the height and boundaries of
+		//   faces with adjacent indexes
+		var p = position.clone(), nextIndex, nextFace, newBounds
+		p.a += dx
+		p.b += dy
+
+		// left edge
+		if (p.a < bounds.x.a) {
+			if (bounds.first == 0) {
+				p.a = bounds.x.a
+			}
+			else {
+				nextIndex = bounds.first - 1
+				nextFace = this.faces[nextIndex]
+				if (nextFace.y.a <= p.b && p.b + dimension.b <= nextFace.y.b) {
+					// it appears the div to the left will accomodate this element
+				}
+				else {
+					p.a = bounds.x.a
+				}
+			}
+		}
+		// right edge
+		else if (p.a + dimension.a > bounds.x.b) {
+			if (bounds.last == this.faces.length-1) {
+				p.a = bounds.x.b - dimension.a
+			}
+			else {
+				nextIndex = bounds.last + 1
+				nextFace = this.faces[nextIndex]
+				if (nextFace.y.a <= p.b && p.b + dimension.b <= nextFace.y.b) {
+					// it appears the div to the right will accomodate this element
+				}
+				else {
+					p.a = bounds.x.b - dimension.a
+				}
+			}
+		}
+		
+		// for vertical movement, this means checking the height and boundaries of
+		//   elements in the set of bounds' indexes
+		if (p.b < bounds.y.a) {
+			for (var i = Math.min(nextIndex, bounds.first), last = Math.max(nextIndex, bounds.last); i < last; i++) {
+				face = this.faces[i]
+				// loop over each of the faces in the list
+				// given a face, figure out if the new top-left is in its bounds
+				// if so, find which one contains its right edge
+				// get the lowest height of this set
+				// then clamp to that lowest height
+				// additionally, this is the new center-index
+				// recalculate the bounds
+// 				if (face.x.b < p.
+// 				for (var j = bounds.first+1; j < bounds.last
+			}
+		}
+		// bottom edge, so we can clamp here trivially
+		else if (p.b + dimension.b > bounds.y.b) {
+			p.b = bounds.y.b - dimension.b
+		}
+		// if we're able to move out of bounds in that direction, recalculate the bounds
+	}
 	
 	if ('window' in this) {
 		window.Surface = Surface