-
Notifications
You must be signed in to change notification settings - Fork 228
/
draft6.html
272 lines (230 loc) · 6.19 KB
/
draft6.html
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
<!doctype>
<html>
<head>
<style>
body{
margin:0;
background: #eee;
}
#canvas{
width:640px;
height:360px;
background: #000;
}
</style>
</head>
<body>
<canvas id="canvas" width="640" height="360"></canvas>
</body>
</html>
<script>
// Find intersection of RAY & SEGMENT
function getIntersection(ray,segment){
// RAY in parametric: Point + Delta*T1
var r_px = ray.a.x;
var r_py = ray.a.y;
var r_dx = ray.b.x-ray.a.x;
var r_dy = ray.b.y-ray.a.y;
// SEGMENT in parametric: Point + Delta*T2
var s_px = segment.a.x;
var s_py = segment.a.y;
var s_dx = segment.b.x-segment.a.x;
var s_dy = segment.b.y-segment.a.y;
// Are they parallel? If so, no intersect
var r_mag = Math.sqrt(r_dx*r_dx+r_dy*r_dy);
var s_mag = Math.sqrt(s_dx*s_dx+s_dy*s_dy);
if(r_dx/r_mag==s_dx/s_mag && r_dy/r_mag==s_dy/s_mag){
// Unit vectors are the same.
return null;
}
// SOLVE FOR T1 & T2
// r_px+r_dx*T1 = s_px+s_dx*T2 && r_py+r_dy*T1 = s_py+s_dy*T2
// ==> T1 = (s_px+s_dx*T2-r_px)/r_dx = (s_py+s_dy*T2-r_py)/r_dy
// ==> s_px*r_dy + s_dx*T2*r_dy - r_px*r_dy = s_py*r_dx + s_dy*T2*r_dx - r_py*r_dx
// ==> T2 = (r_dx*(s_py-r_py) + r_dy*(r_px-s_px))/(s_dx*r_dy - s_dy*r_dx)
var T2 = (r_dx*(s_py-r_py) + r_dy*(r_px-s_px))/(s_dx*r_dy - s_dy*r_dx);
var T1 = (s_px+s_dx*T2-r_px)/r_dx;
// Must be within parametic whatevers for RAY/SEGMENT
if(T1<0) return null;
if(T2<0 || T2>1) return null;
// Return the POINT OF INTERSECTION
return {
x: r_px+r_dx*T1,
y: r_py+r_dy*T1,
param: T1
};
}
function getSightPolygon(sightX,sightY){
// Get all unique points
var points = (function(segments){
var a = [];
segments.forEach(function(seg){
a.push(seg.a,seg.b);
});
return a;
})(segments);
var uniquePoints = (function(points){
var set = {};
return points.filter(function(p){
var key = p.x+","+p.y;
if(key in set){
return false;
}else{
set[key]=true;
return true;
}
});
})(points);
// Get all angles
var uniqueAngles = [];
for(var j=0;j<uniquePoints.length;j++){
var uniquePoint = uniquePoints[j];
var angle = Math.atan2(uniquePoint.y-sightY,uniquePoint.x-sightX);
uniquePoint.angle = angle;
uniqueAngles.push(angle-0.00001,angle,angle+0.00001);
}
// RAYS IN ALL DIRECTIONS
var intersects = [];
for(var j=0;j<uniqueAngles.length;j++){
var angle = uniqueAngles[j];
// Calculate dx & dy from angle
var dx = Math.cos(angle);
var dy = Math.sin(angle);
// Ray from center of screen to mouse
var ray = {
a:{x:sightX,y:sightY},
b:{x:sightX+dx,y:sightY+dy}
};
// Find CLOSEST intersection
var closestIntersect = null;
for(var i=0;i<segments.length;i++){
var intersect = getIntersection(ray,segments[i]);
if(!intersect) continue;
if(!closestIntersect || intersect.param<closestIntersect.param){
closestIntersect=intersect;
}
}
// Intersect angle
if(!closestIntersect) continue;
closestIntersect.angle = angle;
// Add to list of intersects
intersects.push(closestIntersect);
}
// Sort intersects by angle
intersects = intersects.sort(function(a,b){
return a.angle-b.angle;
});
// Polygon is intersects, in order of angle
return intersects;
}
///////////////////////////////////////////////////////
// DRAWING
var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");
function draw(){
// Clear canvas
ctx.clearRect(0,0,canvas.width,canvas.height);
// Draw segments
ctx.strokeStyle = "#999";
for(var i=0;i<segments.length;i++){
var seg = segments[i];
ctx.beginPath();
ctx.moveTo(seg.a.x,seg.a.y);
ctx.lineTo(seg.b.x,seg.b.y);
ctx.stroke();
}
// Sight Polygons
var fuzzyRadius = 10;
var polygons = [getSightPolygon(Mouse.x,Mouse.y)];
for(var angle=0;angle<Math.PI*2;angle+=(Math.PI*2)/10){
var dx = Math.cos(angle)*fuzzyRadius;
var dy = Math.sin(angle)*fuzzyRadius;
polygons.push(getSightPolygon(Mouse.x+dx,Mouse.y+dy));
};
// DRAW AS A GIANT POLYGON
for(var i=1;i<polygons.length;i++){
drawPolygon(polygons[i],ctx,"rgba(255,255,255,0.2)");
}
drawPolygon(polygons[0],ctx,"#fff");
// Draw red dots
ctx.fillStyle = "#dd3838";
ctx.beginPath();
ctx.arc(Mouse.x, Mouse.y, 2, 0, 2*Math.PI, false);
ctx.fill();
for(var angle=0;angle<Math.PI*2;angle+=(Math.PI*2)/10){
var dx = Math.cos(angle)*fuzzyRadius;
var dy = Math.sin(angle)*fuzzyRadius;
ctx.beginPath();
ctx.arc(Mouse.x+dx, Mouse.y+dy, 2, 0, 2*Math.PI, false);
ctx.fill();
}
}
function drawPolygon(polygon,ctx,fillStyle){
ctx.fillStyle = fillStyle;
ctx.beginPath();
ctx.moveTo(polygon[0].x,polygon[0].y);
for(var i=1;i<polygon.length;i++){
var intersect = polygon[i];
ctx.lineTo(intersect.x,intersect.y);
}
ctx.fill();
}
// LINE SEGMENTS
var segments = [
// Border
{a:{x:0,y:0}, b:{x:640,y:0}},
{a:{x:640,y:0}, b:{x:640,y:360}},
{a:{x:640,y:360}, b:{x:0,y:360}},
{a:{x:0,y:360}, b:{x:0,y:0}},
// Polygon #1
{a:{x:100,y:150}, b:{x:120,y:50}},
{a:{x:120,y:50}, b:{x:200,y:80}},
{a:{x:200,y:80}, b:{x:140,y:210}},
{a:{x:140,y:210}, b:{x:100,y:150}},
// Polygon #2
{a:{x:100,y:200}, b:{x:120,y:250}},
{a:{x:120,y:250}, b:{x:60,y:300}},
{a:{x:60,y:300}, b:{x:100,y:200}},
// Polygon #3
{a:{x:200,y:260}, b:{x:220,y:150}},
{a:{x:220,y:150}, b:{x:300,y:200}},
{a:{x:300,y:200}, b:{x:350,y:320}},
{a:{x:350,y:320}, b:{x:200,y:260}},
// Polygon #4
{a:{x:340,y:60}, b:{x:360,y:40}},
{a:{x:360,y:40}, b:{x:370,y:70}},
{a:{x:370,y:70}, b:{x:340,y:60}},
// Polygon #5
{a:{x:450,y:190}, b:{x:560,y:170}},
{a:{x:560,y:170}, b:{x:540,y:270}},
{a:{x:540,y:270}, b:{x:430,y:290}},
{a:{x:430,y:290}, b:{x:450,y:190}},
// Polygon #6
{a:{x:400,y:95}, b:{x:580,y:50}},
{a:{x:580,y:50}, b:{x:480,y:150}},
{a:{x:480,y:150}, b:{x:400,y:95}}
];
// DRAW LOOP
window.requestAnimationFrame = window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || window.msRequestAnimationFrame;
var updateCanvas = true;
function drawLoop(){
requestAnimationFrame(drawLoop);
if(updateCanvas){
draw();
updateCanvas = false;
}
}
window.onload = function(){
drawLoop();
};
// MOUSE
var Mouse = {
x: canvas.width/2,
y: canvas.height/2
};
canvas.onmousemove = function(event){
Mouse.x = event.clientX;
Mouse.y = event.clientY;
updateCanvas = true;
};
</script>