From f599c7edf7e635241e839fc024e4016ae0dcc210 Mon Sep 17 00:00:00 2001
From: Jules Laplace <jules@okfoc.us>
Date: Fri, 31 Oct 2014 16:03:12 -0400
Subject: intersection test 2 - hit-testing on wall structure

---
 .../javascripts/rectangles/models/surface.js       |   9 +
 public/assets/test/intersect2.html                 | 218 +++++++++++++++++++++
 2 files changed, 227 insertions(+)
 create mode 100644 public/assets/test/intersect2.html

diff --git a/public/assets/javascripts/rectangles/models/surface.js b/public/assets/javascripts/rectangles/models/surface.js
index 3a6c449..fc4aae4 100644
--- a/public/assets/javascripts/rectangles/models/surface.js
+++ b/public/assets/javascripts/rectangles/models/surface.js
@@ -154,6 +154,15 @@
 		}
 		return -1
 	}
+	Surface.prototype.face_for_x = function(x, min_i){
+    min_i = min_i || 0
+		for (var i = min_i; i < this.faces.length; i++) {
+			if (this.faces[i].x.contains(x)) {
+				return this.faces[i]
+			}
+		}
+		return null
+	}
 
 	Surface.prototype.bounds_at_index_with_dimensions = function(index, dimensions){
     var faces = this.faces
diff --git a/public/assets/test/intersect2.html b/public/assets/test/intersect2.html
new file mode 100644
index 0000000..fade288
--- /dev/null
+++ b/public/assets/test/intersect2.html
@@ -0,0 +1,218 @@
+<style>
+body,html{margin:0;padding:0;}
+#hud { position: absolute; top: 0; left: 0; pointer-events: none; }
+</style>
+<canvas id="canvas"></canvas>
+<div id="hud"></div>
+
+<script src="/assets/javascripts/util.js"></script>
+<script src="/assets/javascripts/vendor/tube.js"></script>
+<script src="/assets/javascripts/vendor/bower_components/jquery/dist/jquery.min.js"></script>
+<script src="/assets/javascripts/vendor/bower_components/lodash/dist/lodash.min.js"></script>
+<script src="/assets/javascripts/mx/mx.js"></script>
+<script src="/assets/javascripts/mx/extensions/mx.scene.js"></script>
+<script src="/assets/javascripts/rectangles/util/constants.js"></script>
+<script src="/assets/javascripts/rectangles/util/mouse.js"></script>
+<script src="/assets/javascripts/rectangles/util/sort.js"></script>
+<script src="/assets/javascripts/rectangles/util/uid.js"></script>
+<script src="/assets/javascripts/rectangles/models/vec2.js"></script>
+<script src="/assets/javascripts/rectangles/models/rect.js"></script>
+<script src="/assets/javascripts/rectangles/models/room.js"></script>
+<script src="/assets/javascripts/rectangles/models/surface.js"></script>
+<script src="/assets/javascripts/rectangles/models/wall.js"></script>
+<script src="/assets/javascripts/rectangles/models/floor.js"></script>
+<script src="/assets/javascripts/rectangles/engine/rooms/_rooms.js"></script>
+<script src="/assets/javascripts/rectangles/engine/rooms/_walls.js"></script>
+<script src="/assets/javascripts/rectangles/engine/rooms/clipper.js"></script>
+<script src="/assets/javascripts/rectangles/engine/rooms/builder.js"></script>
+<script src="/assets/javascripts/rectangles/engine/rooms/grouper.js"></script>
+<script src="/assets/javascripts/vendor/canvasutilities.js"></script>
+<script>
+
+var ctx = canvas.getContext('2d')
+var scene = new MX.Scene()
+
+var w = canvas.width = window.innerWidth
+var h = canvas.height = window.innerHeight
+
+var cursor = new Rect( 150, 250, 150, 250 )
+var wall_vec = new Rect ( 0, 0, 0, 0 )
+var points = [ cursor.x, cursor.y ]
+
+var origins = new Rect()
+origins.x = cursor.x
+origins.y = wall_vec.x
+
+var radius = 1
+
+var rect       = new Rect( new vec2(100,400), new vec2(100,400) )
+var east       = new Rect( new vec2(200,600), new vec2(100,400) )
+var corner     = new Rect( new vec2(300,700), new vec2(300,700) )
+var peninsula  = new Rect( new vec2(400,600), new vec2(600,800) )
+var peninsula2 = new Rect( new vec2(650,750), new vec2(350,450) )
+
+var rect_room       = new Room({ id: "rect", rect: rect, height: 2 })
+var east_room       = new Room({ id: "east", rect: east, height: 2 })
+var corner_room     = new Room({ id: "corner", rect: corner, height: 2 })
+var peninsula_room  = new Room({ id: "peninsula", rect: peninsula, height: 3 })
+var peninsula2_room = new Room({ id: "peninsula2", rect: peninsula2, height: 3 })
+
+Rooms.add( rect_room )
+Rooms.add( east_room )
+Rooms.add( corner_room )
+Rooms.add( peninsula_room )
+Rooms.add( peninsula2_room )
+
+Rooms.clipper.update()
+Rooms.builder.build()
+Rooms.grouper.build()
+
+var r = 4
+
+var intersect = new vec2 ()
+
+var dragging = false, dragging_a, dragging_b
+var delta = new vec2( 0, 0 )
+
+var mymouse = new mouse({
+  el: canvas,
+  down: function(e, cursor){
+    points.some(function(p){
+      if (-cursor.x.a > p.a - r && -cursor.x.a < p.a + r &&
+           cursor.y.a > p.b - r &&  cursor.y.a < p.b + r) {
+        dragging_a = p.a
+        dragging_b = p.b
+        dragging = p
+        return true
+      }
+    })
+  },
+  drag: function(e, cursor){
+    if (! dragging) return
+    delta = cursor.delta()
+    delta.a = - delta.a
+    dragging.a = dragging_a + delta.a
+    dragging.b = dragging_b + delta.b
+  },
+  up: function(e, cursor, new_cursor){
+    delta.zero()
+    dragging.dragging = false
+    dragging = false
+  },
+})
+
+function draw () {
+  ctx.fillStyle = "#fff"
+  ctx.fillRect(0,0,w,h)
+
+  Rooms.forEach(function(room, i){
+    ctx.fillStyle = "#eee"
+    ctx.fillRect(room.rect.x.a, room.rect.y.a, room.rect.width(), room.rect.height())
+  })
+  
+  ctx.fillStyle = "#333"
+  points.forEach(drawPoint)
+  
+  drawLine(cursor.x, cursor.y, "#f00")
+  hud.innerHTML = ""
+  Walls.list.forEach(function(wall, i){
+    if (wall.side & LEFT_RIGHT) {
+      wall_vec.x.a = wall.edge
+      wall_vec.x.b = wall.vec.a
+      wall_vec.y.a = wall.edge
+      wall_vec.y.b = wall.vec.b
+    }
+    else {
+      wall_vec.x.a = wall.vec.a
+      wall_vec.x.b = wall.edge
+      wall_vec.y.a = wall.vec.b
+      wall_vec.y.b = wall.edge
+    }
+    drawLine(wall_vec.x, wall_vec.y, "#888", true)
+    drawLine(origins.x, origins.y, "rgba(0,0,0,0.1)")
+
+    var t = perp(origins, wall_vec) / ( perp(cursor, wall_vec) || 0.0000001 )
+    intersect.a = cursor.x.a + ( cursor.y.a - cursor.x.a ) * t
+    intersect.b = cursor.x.b + ( cursor.y.b - cursor.x.b ) * t
+
+    var collinear = is_collinear( intersect, wall_vec )
+    var long_enough_to_intersect = 0 <= t && t <= 1
+    var actually_intersects = false
+    var intersecting_face
+    var msg
+  
+    if (long_enough_to_intersect && collinear) {
+      if (wall.side & LEFT_RIGHT) {
+        intersecting_face = wall.surface.face_for_x(intersect.b)
+      }
+      else {
+        intersecting_face = wall.surface.face_for_x(intersect.a)
+      }
+      actually_intersects = !! (intersecting_face && intersecting_face.y.a == 0)
+    }
+    
+    if (actually_intersects) {
+      ctx.fillStyle = "#f00"
+      msg = "through"
+    }
+    else if (collinear) {
+      ctx.fillStyle = "#0f0"
+      msg = "to"
+    }
+    else {
+      ctx.fillStyle = "rgba(0,0,0,0.1)"
+      msg = "off"
+    }
+    
+    drawPoint(intersect)
+    if (intersecting_face) {
+      hud.innerHTML += intersecting_face.y.a + "<br>"
+    }
+  })
+
+}
+function drawLine (pa, pb, color, headless) {
+  ctx.fillStyle = color
+  ctx.strokeStyle = color
+  var x1 = pa.a
+  var y1 = pa.b
+  var x2 = pb.a
+  var y2 = pb.b
+  drawArrow(ctx, x1, y1, x2, y2, 3, headless ? 0 : 1)
+}
+function drawPoint (p) {
+  var x = p.a - r
+  var y = p.b - r
+  ctx.fillRect(x, y, r*2, r*2)
+}
+function perp (va, vb) {
+  return (va.y.a - va.x.a) * (vb.y.b - vb.x.b) - (va.y.b - va.x.b) * (vb.y.a - vb.x.a)
+}
+function is_collinear (p, vec) {
+  var on_x, on_y
+  var pa = round(p.a), pb = round(p.b)
+  
+  if (vec.x.a < vec.y.a) {
+    on_x = vec.x.a <= pa && pa <= vec.y.a
+  }
+  else {
+    on_x = vec.x.a >= pa && pa >= vec.y.a
+  }
+  
+  if (vec.x.b < vec.y.b) {
+    on_y = vec.x.b <= pb && pb <= vec.y.b
+  }
+  else {
+    on_y = vec.x.b >= pb && pb >= vec.y.b
+  }
+
+  return !! (on_x && on_y)
+}
+
+function animate(){
+  requestAnimationFrame(animate)
+  draw()
+}
+animate()
+
+</script>
-- 
cgit v1.2.3-70-g09d2