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comparison Platforms/WebAssembly/wasm-viewport.js @ 223:d30a10d574ec am

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refactoring continued - not working
author am@osimis.io
date Thu, 14 Jun 2018 10:57:02 +0200
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222:84844649a8fd 223:d30a10d574ec
1 // http://stackoverflow.com/a/28900478/881731
2
3 function WebAssemblyViewport(module, canvasId) {
4 this.module = module;
5
6 // Obtain a reference to the canvas element using its id
7 this.htmlCanvas = document.getElementById(canvasId);
8
9 // Obtain a graphics context on the canvas element for drawing.
10 this.context = htmlCanvas.getContext('2d');
11
12 // ImageData structure that can be used to update the content of the canvas
13 this.imageData = null;
14
15 // Temporary buffer in the WebAssembly heap that is used to render the pixels
16 this.renderingBuffer = null;
17
18 // Get access to the WebAssembly functions
19 this.ViewportSetSize = this.module.cwrap('ViewportSetSize', null, [ 'number', 'number' ]);
20 this.ViewportRender = this.module.cwrap('ViewportRender', 'number', [ 'number', 'number', 'number' ]);
21 this.ViewportMouseDown = this.module.cwrap('ViewportMouseDown', null, [ 'number', 'number', 'number', 'number' ]);
22 this.ViewportMouseMove = this.module.cwrap('ViewportMouseMove', null, [ 'number', 'number' ]);
23 this.ViewportMouseUp = this.module.cwrap('ViewportMouseUp', null, [ ]);
24 this.ViewportMouseEnter = this.module.cwrap('ViewportMouseEnter', null, []);
25 this.ViewportMouseLeave = this.module.cwrap('ViewportMouseLeave', null, []);
26 this.ViewportMouseWheel = this.module.cwrap('ViewportMouseWheel', null, [ 'number', 'number', 'number', 'number' ]);
27 this.ViewportKeyPressed = this.module.cwrap('ViewportKeyPressed', null, [ 'string', 'number', 'number' ]);
28
29 this.Redraw = function() {
30 if (this.imageData === null ||
31 this.renderingBuffer === null ||
32 ViewportRender(this.imageData.width,
33 this.imageData.height,
34 this.renderingBuffer) == 0) {
35 console.log('The rendering has failed');
36 } else {
37 // Create an accessor to the rendering buffer (i.e. create a
38 // "window" above the heap of the WASM module), then copy it to
39 // the ImageData object
40 this.imageData.data.set(new Uint8ClampedArray(
41 this.module.buffer,
42 this.renderingBuffer,
43 this.imageData.width * this.imageData.height * 4));
44
45 this.context.putImageData(imageData, 0, 0);
46 }
47 }
48
49 this.Resize = function() {
50 if (this.imageData != null &&
51 (this.imageData.width != this.window.innerWidth ||
52 this.imageData.height != this.window.innerHeight)) {
53 this.imageData = null;
54 }
55
56 this.htmlCanvas.width = window.innerWidth;
57 this.htmlCanvas.height = window.innerHeight;
58
59 if (this.imageData === null) {
60 this.imageData = context.getImageData(0, 0, this.htmlCanvas.width, this.htmlCanvas.height);
61 ViewportSetSize(this.htmlCanvas.width, this.htmlCanvas.height);
62
63 if (this.renderingBuffer != null) {
64 this.module._free(this.renderingBuffer);
65 }
66
67 renderingBuffer = this.module._malloc(this.imageData.width * this.imageData.height * 4);
68 }
69
70 this.Redraw();
71 }
72
73 // Force the rendering of the viewport for the first time
74 this.Resize();
75
76 // Register an event listener to call the Resize() function
77 // each time the window is resized.
78 window.addEventListener('resize', this.Resize, false);
79
80 var that = this;
81
82 this.htmlCanvas.addEventListener('contextmenu', function(event) {
83 // Prevent right click on the canvas
84 event.preventDefault();
85 }, false);
86
87 this.htmlCanvas.addEventListener('mouseleave', function(event) {
88 that.ViewportMouseLeave();
89 });
90
91 this.htmlCanvas.addEventListener('mouseenter', function(event) {
92 that.ViewportMouseEnter();
93 });
94
95 this.htmlCanvas.addEventListener('mousedown', function(event) {
96 var x = event.pageX - this.offsetLeft;
97 var y = event.pageY - this.offsetTop;
98 that.ViewportMouseDown(event.button, x, y, 0 /* TODO */);
99 });
100
101 this.htmlCanvas.addEventListener('mousemove', function(event) {
102 var x = event.pageX - this.offsetLeft;
103 var y = event.pageY - this.offsetTop;
104 that.ViewportMouseMove(x, y);
105 });
106
107 this.htmlCanvas.addEventListener('mouseup', function(event) {
108 that.ViewportMouseUp();
109 });
110
111 window.addEventListener('keydown', function(event) {
112 that.ViewportKeyPressed(event.key, event.shiftKey, event.ctrlKey, event.altKey);
113 });
114
115 this.htmlCanvas.addEventListener('wheel', function(event) {
116 var x = event.pageX - this.offsetLeft;
117 var y = event.pageY - this.offsetTop;
118 that.ViewportMouseWheel(event.deltaY, x, y, event.ctrlKey);
119 event.preventDefault();
120 });
121
122
123 // Touch events
124 this.touchTranslation = false;
125 this.touchZoom = false;
126
127 this.ResetTouch = function() {
128 if (this.touchTranslation ||
129 this.touchZoom) {
130 this.ViewportMouseUp();
131 }
132
133 this.touchTranslation = false;
134 this.touchZoom = false;
135 }
136
137 this.GetTouchTranslation = function(event) {
138 var touch = event.targetTouches[0];
139 return [
140 touch.pageX,
141 touch.pageY
142 ];
143 }
144
145 this.GetTouchZoom = function(event) {
146 var touch1 = event.targetTouches[0];
147 var touch2 = event.targetTouches[1];
148 var dx = (touch1.pageX - touch2.pageX);
149 var dy = (touch1.pageY - touch2.pageY);
150 var d = Math.sqrt(dx * dx + dy * dy);
151 return [
152 (touch1.pageX + touch2.pageX) / 2.0,
153 (touch1.pageY + touch2.pageY) / 2.0,
154 d
155 ];
156 }
157
158 this.htmlCanvas.addEventListener('touchstart', function(event) {
159 ResetTouch();
160 });
161
162 this.htmlCanvas.addEventListener('touchend', function(event) {
163 ResetTouch();
164 });
165
166 this.htmlCanvas.addEventListener('touchmove', function(event) {
167 if (that.touchTranslation.length == 2) {
168 var t = GetTouchTranslation(event);
169 that.ViewportMouseMove(t[0], t[1]);
170 }
171 else if (that.touchZoom.length == 3) {
172 var z0 = that.touchZoom;
173 var z1 = GetTouchZoom(event);
174 that.ViewportMouseMove(z0[0], z0[1] - z0[2] + z1[2]);
175 }
176 else {
177 // Realize the gesture event
178 if (event.targetTouches.length == 1) {
179 // Exactly one finger inside the canvas => Setup a translation
180 that.touchTranslation = GetTouchTranslation(event);
181 that.ViewportMouseDown(1 /* middle button */,
182 that.touchTranslation[0],
183 that.touchTranslation[1], 0);
184 } else if (event.targetTouches.length == 2) {
185 // Exactly 2 fingers inside the canvas => Setup a pinch/zoom
186 that.touchZoom = GetTouchZoom(event);
187 var z0 = that.touchZoom;
188 that.ViewportMouseDown(2 /* right button */,
189 z0[0],
190 z0[1], 0);
191 }
192 }
193 });
194
195 return this;
196 }
197