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
|
#include <iostream>
#include <osg/Array>
#include <osg/BoundingSphere>
#include <osg/BufferIndexBinding>
#include <osg/BufferObject>
#include <osg/Group>
#include <osg/Math>
#include <osg/MatrixTransform>
#include <osg/Program>
#include <osg/Shader>
#include <osgDB/ReadFile>
#include <osgDB/WriteFile>
#include <osgUtil/Optimizer>
#include <osgViewer/Viewer>
#include <osgViewer/ViewerEventHandlers>
using namespace std;
using namespace osg;
// This example is based on the sample code in the
// ARB_uniform_buffer_object extension specification.
GLfloat colors1[] = {
// block
0.45,0.45,1,1,
0.45,0.45,1,1,
0.75,0.75,0.75,1,
0.0,0.0,1.0,1,
0.0,1.0,0.0,1
};
GLfloat colors2[] = {
// block
0.45,0.45,1,1,
0.45,0.45,1,1,
0.75,0.75,0.75,1,
1.0,0.0,0.0,1,
0.0,1.0,0.0,1,
};
char vertexShaderSource[] =
"// Vertex shader for Gooch shading\n"
"// Author: Randi Rost\n"
"// Copyright (c) 2002-2006 3Dlabs Inc. Ltd.\n"
"// See 3Dlabs-License.txt for license information\n"
"vec3 LightPosition = vec3(0.0, 10.0, 4.0); \n"
"varying float NdotL;\n"
"varying vec3 ReflectVec;\n"
"varying vec3 ViewVec;\n"
"void main(void)\n"
"{\n"
"vec3 ecPos = vec3 (gl_ModelViewMatrix * gl_Vertex);\n"
"vec3 tnorm = normalize(gl_NormalMatrix * gl_Normal);\n"
"vec3 lightVec = normalize(LightPosition - ecPos);\n"
"ReflectVec = normalize(reflect(-lightVec, tnorm));\n"
"ViewVec = normalize(-ecPos);\n"
"NdotL = (dot(lightVec, tnorm) + 1.0) * 0.5;\n"
"gl_Position = ftransform();\n"
"}\n";
char fragmentShaderSource[] =
"// Fragment shader for Gooch shading, adapted for ARB_uniform_buffer_object\n"
"#extension GL_ARB_uniform_buffer_object : enable\n"
"layout(std140) uniform colors0\n"
"{\n"
"float DiffuseCool;\n"
"float DiffuseWarm;\n"
"vec3 SurfaceColor;\n"
"vec3 WarmColor;\n"
"vec3 CoolColor;\n"
"};\n"
"varying float NdotL;\n"
"varying vec3 ReflectVec;\n"
"varying vec3 ViewVec;\n"
"void main (void)\n"
"{\n"
"vec3 kcool = min(CoolColor + DiffuseCool * SurfaceColor, 1.0);\n"
"vec3 kwarm = min(WarmColor + DiffuseWarm * SurfaceColor, 1.0); \n"
"vec3 kfinal = mix(kcool, kwarm, NdotL);\n"
"vec3 nreflect = normalize(ReflectVec);\n"
"vec3 nview = normalize(ViewVec);\n"
"float spec = max(dot(nreflect, nview), 0.0);\n"
"spec = pow(spec, 32.0);\n"
"gl_FragColor = vec4 (min(kfinal + spec, 1.0), 1.0);\n"
"}\n";
// Callback for animating the WarmColor
class UniformCallback : public StateAttributeCallback
{
public:
void operator() (StateAttribute* attr, NodeVisitor* nv)
{
UniformBufferBinding* ubb = static_cast<UniformBufferBinding*>(attr);
UniformBufferObject* ubo
= static_cast<UniformBufferObject*>(ubb->getBufferObject());
FloatArray* array = static_cast<FloatArray*>(ubo->getBufferData(0));
double time = nv->getFrameStamp()->getSimulationTime();
double frac = fmod(time, 1.0);
Vec4f warmColor = (Vec4f(0.0, 0.0, 1.0 ,1) * frac
+ Vec4f(1.0, 0.0, 0.0, 1) * (1 - frac));
// Since we're using the std140 layout, we know where the
// warmColor variable is located in the buffer.
for (int i = 0; i < 4; ++i)
(*array)[12 + i] = warmColor[i];
array->dirty();
}
};
int main(int argc, char** argv)
{
osg::ArgumentParser arguments(&argc,argv);
osgViewer::Viewer viewer(arguments);
if (arguments.argc() <= 1) {
cerr << "Need a scene.\n";
return 1;
}
osg::ref_ptr<osg::Node> loadedModel = osgDB::readNodeFiles(arguments);
if (!loadedModel) {
cerr << "couldn't load " << argv[1] << "\n";
return 1;
}
osgUtil::Optimizer optimizer;
optimizer.optimize(loadedModel.get());
const BoundingSphere bound = loadedModel->getBound();
const float displacement = 2.25 * bound.radius();
Group* scene = new Group;
StateSet* rootSS = scene->getOrCreateStateSet();
Shader* vertexShader = new Shader(Shader::VERTEX);
vertexShader->setShaderSource(vertexShaderSource);
Shader* fragmentShader = new Shader(Shader::FRAGMENT);
fragmentShader->setShaderSource(fragmentShaderSource);
Program* prog = new Program;
prog->addShader(vertexShader);
prog->addShader(fragmentShader);
prog->addBindUniformBlock("colors0", 0);
rootSS->setAttributeAndModes(prog, StateAttribute::ON);
// Place 3 instances of the loaded model with different uniform
// blocks for each.
//
// The blocksize is known because of the std140 format.
const unsigned blockSize = 20 * sizeof(GLfloat);
ref_ptr<FloatArray> colorArray
= new FloatArray(&colors1[0],
&colors1[sizeof(colors1) / sizeof(GLfloat)]);
ref_ptr<UniformBufferObject> ubo = new UniformBufferObject;
colorArray->setBufferObject(ubo.get());
Group* group1 = new Group;
StateSet* ss1 = group1->getOrCreateStateSet();
group1->addChild(loadedModel.get());
scene->addChild(group1);
ref_ptr<UniformBufferBinding> ubb1
= new UniformBufferBinding(0, ubo.get(), 0, blockSize);
ss1->setAttributeAndModes(ubb1.get(), StateAttribute::ON);
ref_ptr<FloatArray> colorArray2
= new FloatArray(&colors2[0],
&colors2[sizeof(colors2) / sizeof(GLfloat)]);
ref_ptr<UniformBufferObject> ubo2 = new UniformBufferObject;
colorArray2->setBufferObject(ubo2.get());
MatrixTransform* group2 = new MatrixTransform;
Matrix mat2 = Matrix::translate(-displacement, 0.0, 0.0);
group2->setMatrix(mat2);
StateSet* ss2 = group2->getOrCreateStateSet();
group2->addChild(loadedModel.get());
scene->addChild(group2);
ref_ptr<UniformBufferBinding> ubb2
= new UniformBufferBinding(0, ubo2.get(), 0, blockSize);
ss2->setAttributeAndModes(ubb2.get(), StateAttribute::ON);
ref_ptr<FloatArray> colorArray3
= new FloatArray(&colors2[0],
&colors2[sizeof(colors2) / sizeof(GLfloat)]);
ref_ptr<UniformBufferObject> ubo3 = new UniformBufferObject;
colorArray3->setBufferObject(ubo3.get());
MatrixTransform* group3 = new MatrixTransform;
Matrix mat3 = Matrix::translate(displacement, 0.0, 0.0);
group3->setMatrix(mat3);
StateSet* ss3 = group3->getOrCreateStateSet();
group3->addChild(loadedModel.get());
scene->addChild(group3);
ref_ptr<UniformBufferBinding> ubb3
= new UniformBufferBinding(0, ubo3.get(), 0, blockSize);
ubb3->setUpdateCallback(new UniformCallback);
ubb3->setDataVariance(Object::DYNAMIC);
ss3->setAttributeAndModes(ubb3.get(), StateAttribute::ON);
viewer.setSceneData(scene);
viewer.realize();
return viewer.run();
}
|
