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
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
|
<!DOCTYPE html>
<html>
<head>
<title>Canvas3d example</title>
<script src="resources/CanvasMatrix.js"> </script>
<script src="resources/utils3d.js"> </script>
<script id="vshader" type="x-shader/x-vertex">
/*
Copyright (c) 2008 Seneca College
Licenced under the MIT License (http://www.c3dl.org/index.php/mit-license/)
*/
// We need to create our own light structure since we can't access
// the light() function in the 2.0 context.
struct Light
{
vec4 ambient;
vec4 diffuse;
vec4 specular;
vec4 position;
vec3 halfVector;
};
struct Material
{
vec4 emission;
vec4 ambient;
vec4 diffuse;
vec4 specular;
float shininess;
};
//
// vertex attributes
//
attribute vec3 a_normal;
attribute vec4 a_texCoord;
attribute vec4 a_vertex;
// for every model we multiply the projection, view and model matrices
// once to prevent having to do it for every vertex, however we still need
// the view matrix to calculate lighting.
uniform mat4 u_modelViewMatrix;
// we can calculate this once per model to speed up processing done on the js side.
uniform mat4 u_modelViewProjMatrix;
// matrix to transform the vertex normals
uniform mat4 u_normalMatrix;
// custom light structures need to be used since we don't have access to
// light states.
uniform Light u_light;
// material
uniform vec4 u_globalAmbientColor;
uniform Material u_frontMaterial;
uniform Material u_backMaterial;
// passed to fragment shader
varying vec4 v_diffuse, v_specular;
varying vec2 v_texCoord;
/*
Given a reference to the ambient and diffuse lighting variables,
this function will calculate how much each component contributes to the scene.
Light light - the light in view space
vec3 normal -
vec4 ambient -
vec4 diffuse -
*/
void directionalLight(in vec3 normal, inout vec4 ambient, inout vec4 diffuse, inout vec4 specular)
{
vec3 lightDir = normalize(vec3(u_light.position));
ambient += u_light.ambient;
float nDotL = max(dot(normal, lightDir), 0.0);
if (nDotL > 0.0) {
diffuse += u_light.diffuse * nDotL;
float nDotHV = max(dot(normal, u_light.halfVector), 0.0);
nDotHV += 0.3;
vec4 specularColor = u_frontMaterial.specular * u_light.specular;
specular += vec4(specularColor.rgb * pow(nDotHV, u_frontMaterial.shininess), specularColor.a);
}
}
void main()
{
vec3 normal = normalize(u_normalMatrix * vec4(a_normal, 1)).xyz;
vec4 ambient = vec4(0.0, 0.0, 0.0, 1.0);
vec4 diffuse = vec4(0.0, 0.0, 0.0, 1.0);
vec4 specular = vec4(0.0, 0.0, 0.0, 1.0);
// place the current vertex into view space
// ecPos = eye coordinate position.
vec4 ecPos4 = u_modelViewMatrix * a_vertex;
// the current vertex in eye coordinate space
vec3 ecPos = ecPos4.xyz/ecPos4.w;
directionalLight(normal, ambient, diffuse, specular);
ambient = u_frontMaterial.ambient * ambient;
ambient += u_globalAmbientColor * u_frontMaterial.ambient;
diffuse = u_frontMaterial.diffuse * diffuse;
v_diffuse = diffuse;
v_specular = specular + ambient;
gl_Position = u_modelViewProjMatrix * a_vertex;
v_texCoord = a_texCoord.st;
}
</script>
<script id="fshader" type="x-shader/x-fragment">
uniform sampler2D u_sampler2d;
varying vec4 v_diffuse, v_specular;
varying vec2 v_texCoord;
void main()
{
vec4 color = v_diffuse;
gl_FragColor = color + v_specular;
}
</script>
<script>
function setDirectionalLight(ctx, program, eyeVector, direction, ambient, diffuse, specular)
{
var lightString = "u_light.";
ctx.uniform4f(ctx.getUniformLocation(program, lightString+"ambient"),
ambient[0], ambient[1], ambient[2], ambient[3]);
ctx.uniform4f(ctx.getUniformLocation(program, lightString+"diffuse"),
diffuse[0], diffuse[1], diffuse[2], diffuse[3]);
ctx.uniform4f(ctx.getUniformLocation(program, lightString+"specular"),
specular[0], specular[1], specular[2], specular[3]);
ctx.uniform4f(ctx.getUniformLocation(program, lightString+"position"),
direction[0], direction[1], direction[2], direction[3]);
// compute the half vector
var halfVector = [ eyeVector[0] + direction[0], eyeVector[1] + direction[1], eyeVector[2] + direction[2] ];
var length = Math.sqrt(halfVector[0] * halfVector[0] +
halfVector[1] * halfVector[1] +
halfVector[2] * halfVector[2]);
if (length == 0)
halfVector = [ 0, 0, 1 ];
else {
halfVector[0] /= length;
halfVector[1] /= length;
halfVector[2] /= length;
}
ctx.uniform3f(ctx.getUniformLocation(program, lightString+"halfVector"),
halfVector[0], halfVector[1], halfVector[2]);
}
function setMaterial(ctx, program, emission, ambient, diffuse, specular, shininess)
{
var matString = "u_frontMaterial.";
ctx.uniform4f(ctx.getUniformLocation(program, matString+"emission"),
emission[0], emission[1], emission[2], emission[3]);
ctx.uniform4f(ctx.getUniformLocation(program, matString+"ambient"),
ambient[0], ambient[1], ambient[2], ambient[3]);
ctx.uniform4f(ctx.getUniformLocation(program, matString+"diffuse"),
diffuse[0], diffuse[1], diffuse[2], diffuse[3]);
ctx.uniform4f(ctx.getUniformLocation(program, matString+"specular"),
specular[0], specular[1], specular[2], specular[3]);
ctx.uniform1f(ctx.getUniformLocation(program, matString+"shininess"), shininess);
}
function init()
{
var gl = initWebGL("example", "vshader", "fshader",
[ "a_normal", "a_texCoord", "a_vertex"],
[ 0, 0, 0, 1 ], 10000);
gl.uniform1i(gl.getUniformLocation(gl.program, "u_sampler2d"), 0);
gl.uniform4f(gl.getUniformLocation(gl.program, "u_globalAmbientColor"), 0.2, 0.2, 0.2, 1);
setDirectionalLight(gl, gl.program,
[ 0, 0, 1 ], // eyeVector
[0, 0, 1, 1], // position
[0.1, 0.1, 0.1, 1], // ambient
[1, 1, 1, 1], // diffuse
[1, 1, 1, 1]); // specular
setMaterial(gl, gl.program,
[ 0, 0, 0, 0 ], // emission
[ 0.1, 0.1, 0.1, 1 ], // ambient
[ 0.8, 0.2, 0, 1 ], // diffuse
[ 0, 0, 1, 1 ], // specular
32); // shininess
obj = loadObj(gl, "resources/teapot.obj");
mvMatrix = new CanvasMatrix4();
normalMatrix = new CanvasMatrix4();
return gl;
}
width = -1;
height = -1;
loaded = false;
function reshape(ctx)
{
var canvas = document.getElementById('example');
if (canvas.clientWidth == width && canvas.clientHeight == height)
return;
width = canvas.clientWidth;
height = canvas.clientHeight;
ctx.viewport(0, 0, width, height);
ctx.perspectiveMatrix = new CanvasMatrix4();
ctx.perspectiveMatrix.lookat(0,0,50, 0, 0, 0, 0, 1, 0);
ctx.perspectiveMatrix.perspective(30, width/height, 1, 10000);
}
function drawPicture(ctx)
{
var startRenderTime = new Date().getTime();
reshape(ctx);
ctx.clear(ctx.COLOR_BUFFER_BIT | ctx.DEPTH_BUFFER_BIT);
if (!loaded && obj.loaded) {
loaded = true;
ctx.enableVertexAttribArray(0);
ctx.enableVertexAttribArray(1);
ctx.enableVertexAttribArray(2);
ctx.bindBuffer(ctx.ARRAY_BUFFER, obj.normalObject);
ctx.vertexAttribPointer(0, 3, ctx.FLOAT, false, 0, 0);
ctx.bindBuffer(ctx.ARRAY_BUFFER, obj.texCoordObject);
ctx.vertexAttribPointer(1, 2, ctx.FLOAT, false, 0, 0);
ctx.bindBuffer(ctx.ARRAY_BUFFER, obj.vertexObject);
ctx.vertexAttribPointer(2, 3, ctx.FLOAT, false, 0, 0);
ctx.bindBuffer(ctx.ELEMENT_ARRAY_BUFFER, obj.indexObject);
}
if (!loaded)
return;
// generate the model-view matrix
mvMatrix.makeIdentity();
mvMatrix.rotate(currentAngle, 0, 1, 0);
mvMatrix.rotate(10, 1,0,0);
ctx.uniformMatrix4fv(ctx.getUniformLocation(ctx.program, "u_modelViewMatrix"), false, mvMatrix.getAsCanvasFloatArray());
// construct the normal matrix from the model-view matrix
normalMatrix.load(mvMatrix);
normalMatrix.invert();
normalMatrix.transpose();
ctx.uniformMatrix4fv(ctx.getUniformLocation(ctx.program, "u_normalMatrix"), false, normalMatrix.getAsCanvasFloatArray());
mvMatrix.multRight(ctx.perspectiveMatrix);
ctx.uniformMatrix4fv(ctx.getUniformLocation(ctx.program, "u_modelViewProjMatrix"), false, mvMatrix.getAsCanvasFloatArray());
ctx.drawElements(ctx.TRIANGLES, obj.numIndices, ctx.UNSIGNED_SHORT, 0);
ctx.flush();
framerate.snapshot();
currentAngle += incAngle;
if (currentAngle > 360)
currentAngle -= 360;
}
function start()
{
var ctx = init();
currentAngle = 0;
incAngle = 0.2;
framerate = new Framerate("framerate");
var f = function() { drawPicture(ctx) };
setInterval(f, 10);
}
</script>
<style type="text/css">
canvas {
border: 2px solid black;
width:90%;
height:90%;
}
</style>
</head>
<body onload="start()">
<canvas id="example">
There is supposed to be an example drawing here, but it's not important.
</canvas>
<div id="framerate"></div>
</body>
</html>
|
