intersection test

3 files changed, 348 insertions, 24 deletions

diff --git a/public/assets/javascripts/rectangles/engine/rooms/mover.js b/public/assets/javascripts/rectangles/engine/rooms/mover.js
index 121ecec..8ce00fe 100644
--- a/public/assets/javascripts/rectangles/engine/rooms/mover.js
+++ b/public/assets/javascripts/rectangles/engine/rooms/mover.js
@@ -36,6 +36,18 @@ Rooms.mover = new function(){
 			// check if we've breached one of the walls.. clamp position if so
 			var collision = base.room.collidesDisc(cam, pos, radius)
 
+			if (collision && ! base.noclip) {
+				cam.x = (collision & LEFT_RIGHT) ? base.room.rect.x.clampDisc(pos.x, radius) : pos.x
+				cam.z = (collision & FRONT_BACK) ? base.room.rect.y.clampDisc(pos.z, radius) : pos.z
+				return
+			}
+
+			// in this case, we appear to have left the room..
+			// $(".face.active").removeClass("active")
+			Walls.clearBodyColor()
+			base.room = null
+		}
+
 /*
       var dz = new vec2( cam.z, pos.z )
       dz.normalize()
@@ -43,47 +55,82 @@ Rooms.mover = new function(){
       var dx = new vec2( cam.x, pos.x )
       dx.normalize()
 
+      // first check if the cam-pos movement intersects the wall.
+      // next check if it intersects any of the surface frames
+      // if we can pass through the wall at this point, we do not need to clamp.
+      // otherwise, get the distance along the cam-pos vector where we would hit the wall and clamp to it.
 			Walls.list.forEach(function(wall){
+			  var t = -1
 			  switch (wall.side) {
 			    case FRONT:
+			      if (cam.z >= wall.edge + radius && wall.edge + radius >= pos.z && wall.vec.intersects(dx) ) {
+			        t = check_intersection( front_back_intersection, cam, pos, dx, wall, radius )
+			      }
 			      break
 			    case BACK:
+			      // console.log(cam.z|0, wall.edge-radius, pos.z|0, wall.vec.intersects(dx))
+			      if (cam.z <= wall.edge - radius && wall.edge - radius <= pos.z && wall.vec.intersects(dx) ) {
+			        t = check_intersection( front_back_intersection, cam, pos, dx, wall, -radius )
+			        console.log(t)
+			      }
 			      break
 			    case LEFT:
-			      if (cam.x >= wall.edge + radius && wall.edge + radius >= pos.x && (wall.vec.intersects(dz) ) {
-			        // intersects the wall.. next check if it intersects any of the surface frames
-			        wall.surface.faces.some(function(face, i){
-			          // if we can pass through the wall at this point, we do not need to clamp
-			          if (face.y.a === 0 && face.x.intersects(dz)) {
-			            dz.a = pos.z = face.x.clamp(pos.z)
-			            dz.b = cam.z
-			            dz.normalize()
-			            return true
-			          }
-			        })
+			      if (cam.x >= wall.edge + radius && wall.edge + radius >= pos.x && wall.vec.intersects(dz) ) {
+			        t = check_intersection( left_right_intersection, cam, pos, dz, wall, radius )
 			      }
 			      break
 			    case RIGHT:
-			      if (cam.x <= wall.edge - radius && wall.edge - radius <= pos.x && (wall.vec.contains(cam.z) || wall.vec.contains(pos.z)) ) {
-			        // intersects
+			      if (cam.x <= wall.edge - radius && wall.edge - radius <= pos.x && wall.vec.intersects(dz) ) {
+			        t = check_intersection( left_right_intersection, cam, pos, dz, wall, -radius )
 			      }
 			      break
 			  }
+        if (0 <= t && t <= 1) {
+          pos.x = cam.x + (pos.x - cam.x) * t
+          pos.z = cam.z + (pos.z - cam.z) * t
+
+          dz = new vec2( cam.z, pos.z )
+          dz.normalize()
+
+          dx = new vec2( cam.x, pos.x )
+          dx.normalize()
+        }
       })
-*/
 
-			if (collision && ! base.noclip) {
-				cam.x = (collision & LEFT_RIGHT) ? base.room.rect.x.clampDisc(pos.x, radius) : pos.x
-				cam.z = (collision & FRONT_BACK) ? base.room.rect.y.clampDisc(pos.z, radius) : pos.z
-				return
-			}
+    function check_intersection(intersection_function, cam, pos, cam_pos_vector, wall, radius) {
+      var t = -1
+      wall.surface.faces.some(function(face, i){
+        if (face.y.a == 0 && face.x.intersects(cam_pos_vector)) {
+          t = intersection_function( cam, pos, wall, face, radius )
+          console.log(">>", t)
+          if (0 <= t && t <= 1) {
+            return true
+          }
+          else {
+            t = -1
+          }
+        }
+        return false
+      })
+      return t
+    }
+		function left_right_intersection (cam, pos, wall, face, radius) {
+      var perp_n = (face.x.a - face.x.b) * (wall.edge - cam.z + radius)
+      var perp_d = (face.x.a - face.x.b) * (pos.z - cam.z)
+      if (perp_d == 0) return Infinity
+      return perp_n / perp_d
+    }
+		function front_back_intersection (cam, pos, wall, face, radius) {
+		  // va.vx*vb.vy - va.vy*vb.vx
+      var perp_n = (face.x.b - face.x.a) * (wall.edge - cam.x + radius)
+      var perp_d = (face.x.b - face.x.a) * (pos.x - cam.x)
 
-			// in this case, we appear to have left the room..
-			// $(".face.active").removeClass("active")
-			Walls.clearBodyColor()
-			base.room = null
-		}
+      console.log((pos.x - cam.x), wall.edge - cam.x, radius)
 
+      if (perp_d == 0) return Infinity
+      return perp_n / perp_d
+    }
+*/
 		// collision test failed, so update position
 		cam.x = pos.x
 		cam.z = pos.z
diff --git a/public/assets/javascripts/vendor/canvasutilities.js b/public/assets/javascripts/vendor/canvasutilities.js
new file mode 100644
index 0000000..011ebb0
--- /dev/null
+++ b/public/assets/javascripts/vendor/canvasutilities.js
@@ -0,0 +1,145 @@
+var drawArrow = function(ctx, x1, y1, x2, y2, style, which, angle, d) {
+  'use strict';
+  // Ceason pointed to a problem when x1 or y1 were a string, and concatenation
+  // would happen instead of addition
+  if (typeof(x1) == 'string') x1 = parseInt(x1);
+  if (typeof(y1) == 'string') y1 = parseInt(y1);
+  if (typeof(x2) == 'string') x2 = parseInt(x2);
+  if (typeof(y2) == 'string') y2 = parseInt(y2);
+  style = typeof(style) != 'undefined' ? style : 3;
+  which = typeof(which) != 'undefined' ? which : 1; // end point gets arrow
+  angle = typeof(angle) != 'undefined' ? angle : Math.PI / 8;
+  d = typeof(d) != 'undefined' ? d : 10;
+  // default to using drawHead to draw the head, but if the style
+  // argument is a function, use it instead
+  var toDrawHead = typeof(style) != 'function' ? drawHead : style;
+
+  // For ends with arrow we actually want to stop before we get to the arrow
+  // so that wide lines won't put a flat end on the arrow.
+  //
+  var dist = Math.sqrt((x2 - x1) * (x2 - x1) + (y2 - y1) * (y2 - y1));
+  var ratio = (dist - d / 3) / dist;
+  var tox, toy, fromx, fromy;
+  if (which & 1) {
+    tox = Math.round(x1 + (x2 - x1) * ratio);
+    toy = Math.round(y1 + (y2 - y1) * ratio);
+  } else {
+    tox = x2;
+    toy = y2;
+  }
+  if (which & 2) {
+    fromx = x1 + (x2 - x1) * (1 - ratio);
+    fromy = y1 + (y2 - y1) * (1 - ratio);
+  } else {
+    fromx = x1;
+    fromy = y1;
+  }
+
+  // Draw the shaft of the arrow
+  ctx.beginPath();
+  ctx.moveTo(fromx, fromy);
+  ctx.lineTo(tox, toy);
+  ctx.stroke();
+
+  // calculate the angle of the line
+  var lineangle = Math.atan2(y2 - y1, x2 - x1);
+  // h is the line length of a side of the arrow head
+  var h = Math.abs(d / Math.cos(angle));
+
+  if (which & 1) { // handle far end arrow head
+    var angle1 = lineangle + Math.PI + angle;
+    var topx = x2 + Math.cos(angle1) * h;
+    var topy = y2 + Math.sin(angle1) * h;
+    var angle2 = lineangle + Math.PI - angle;
+    var botx = x2 + Math.cos(angle2) * h;
+    var boty = y2 + Math.sin(angle2) * h;
+    toDrawHead(ctx, topx, topy, x2, y2, botx, boty, style);
+  }
+  if (which & 2) { // handle near end arrow head
+    var angle1 = lineangle + angle;
+    var topx = x1 + Math.cos(angle1) * h;
+    var topy = y1 + Math.sin(angle1) * h;
+    var angle2 = lineangle - angle;
+    var botx = x1 + Math.cos(angle2) * h;
+    var boty = y1 + Math.sin(angle2) * h;
+    toDrawHead(ctx, topx, topy, x1, y1, botx, boty, style);
+  }
+}
+
+var drawHead = function(ctx, x0, y0, x1, y1, x2, y2, style) {
+  'use strict';
+  if (typeof(x0) == 'string') x0 = parseInt(x0);
+  if (typeof(y0) == 'string') y0 = parseInt(y0);
+  if (typeof(x1) == 'string') x1 = parseInt(x1);
+  if (typeof(y1) == 'string') y1 = parseInt(y1);
+  if (typeof(x2) == 'string') x2 = parseInt(x2);
+  if (typeof(y2) == 'string') y2 = parseInt(y2);
+  var radius = 3;
+  var twoPI = 2 * Math.PI;
+
+  // all cases do this.
+  ctx.save();
+  ctx.beginPath();
+  ctx.moveTo(x0, y0);
+  ctx.lineTo(x1, y1);
+  ctx.lineTo(x2, y2);
+  switch (style) {
+    case 0:
+      // curved filled, add the bottom as an arcTo curve and fill
+      var backdist = Math.sqrt(((x2 - x0) * (x2 - x0)) + ((y2 - y0) * (y2 - y0)));
+      ctx.arcTo(x1, y1, x0, y0, .55 * backdist);
+      ctx.fill();
+      break;
+    case 1:
+      // straight filled, add the bottom as a line and fill.
+      ctx.beginPath();
+      ctx.moveTo(x0, y0);
+      ctx.lineTo(x1, y1);
+      ctx.lineTo(x2, y2);
+      ctx.lineTo(x0, y0);
+      ctx.fill();
+      break;
+    case 2:
+      // unfilled head, just stroke.
+      ctx.stroke();
+      break;
+    case 3:
+      //filled head, add the bottom as a quadraticCurveTo curve and fill
+      var cpx = (x0 + x1 + x2) / 3;
+      var cpy = (y0 + y1 + y2) / 3;
+      ctx.quadraticCurveTo(cpx, cpy, x0, y0);
+      ctx.fill();
+      break;
+    case 4:
+      //filled head, add the bottom as a bezierCurveTo curve and fill
+      var cp1x, cp1y, cp2x, cp2y, backdist;
+      var shiftamt = 5;
+      if (x2 == x0) {
+        // Avoid a divide by zero if x2==x0
+        backdist = y2 - y0;
+        cp1x = (x1 + x0) / 2;
+        cp2x = (x1 + x0) / 2;
+        cp1y = y1 + backdist / shiftamt;
+        cp2y = y1 - backdist / shiftamt;
+      } else {
+        backdist = Math.sqrt(((x2 - x0) * (x2 - x0)) + ((y2 - y0) * (y2 - y0)));
+        var xback = (x0 + x2) / 2;
+        var yback = (y0 + y2) / 2;
+        var xmid = (xback + x1) / 2;
+        var ymid = (yback + y1) / 2;
+
+        var m = (y2 - y0) / (x2 - x0);
+        var dx = (backdist / (2 * Math.sqrt(m * m + 1))) / shiftamt;
+        var dy = m * dx;
+        cp1x = xmid - dx;
+        cp1y = ymid - dy;
+        cp2x = xmid + dx;
+        cp2y = ymid + dy;
+      }
+
+      ctx.bezierCurveTo(cp1x, cp1y, cp2x, cp2y, x0, y0);
+      ctx.fill();
+      break;
+  }
+  ctx.restore();
+}
diff --git a/public/assets/test/intersect.html b/public/assets/test/intersect.html
new file mode 100644
index 0000000..3f6d110
--- /dev/null
+++ b/public/assets/test/intersect.html
@@ -0,0 +1,132 @@
+<canvas id="canvas"></canvas>
+
+<script src="/assets/javascripts/util.js"></script>
+<script src="/assets/javascripts/vendor/tube.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/models/vec2.js"></script>
+<script src="/assets/javascripts/rectangles/models/rect.js"></script>
+<script src="/assets/javascripts/vendor/canvasutilities.js"></script>
+<script>
+
+var ctx = canvas.getContext('2d')
+
+var w = canvas.width = 600
+var h = canvas.height = 400
+
+var vec_a = new Rect( 100, 120, 50, 100 )
+var vec_b = new Rect( 20, 200, 120, 120 )
+var vecs = [ vec_a, vec_b ]
+var points = [ vec_a.x, vec_a.y, vec_b.x, vec_b.y ]
+var r = 4
+
+var vec_c = new Rect()
+vec_c.x = vec_a.x
+vec_c.y = vec_b.x
+
+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)
+  
+  ctx.fillStyle = "#bbb"
+  points.forEach(drawPoint)
+  
+  drawLine(vec_a.x, vec_a.y, "#f00")
+  drawLine(vec_b.x, vec_b.y, "#00f")
+  drawLine(vec_a.x, vec_b.x, "#080")
+
+  var t = perp(vec_c, vec_b) / ( perp(vec_a, vec_b) || 0.0000001 )
+  intersect.a = vec_a.x.a + ( vec_a.y.a - vec_a.x.a ) * t
+  intersect.b = vec_a.x.b + ( vec_a.y.b - vec_a.x.b ) * t
+  
+  var collinear = is_collinear( intersect.b, vec_b )
+  var long_enough_to_intersect = 0 <= t && t <= 1
+  
+  if (long_enough_to_intersect && collinear) {
+    ctx.fillStyle = "#f00"
+  }
+  else if (is_on_line) {
+    ctx.fillStyle = "#0f0"
+  }
+  else {
+    ctx.fillStyle = "#000"
+  }
+  
+  drawPoint(intersect)
+}
+function drawLine (pa, pb, color) {
+  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)
+}
+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 (n, vec) {
+  var on_x, on_y
+  
+  if (vec.x.a < vec.y.a) {
+    on_x = vec.x.a <= n && n <= vec.y.a
+  }
+  else {
+    on_x = vec.x.a >= n && n >= vec.y.a
+  }
+  
+  if (vec.x.b < vec.y.b) {
+    on_y = vec.x.b <= n && n <= vec.y.b
+  }
+  else {
+    on_y = vec.x.b >= n && n >= vec.y.b
+  }
+  
+  return !! (on_x && on_y)
+}
+
+function animate(){
+  requestAnimationFrame(animate)
+  draw()
+}
+animate()
+
+</script>