e5a9eaa711
A few things remain to do: * The binding between a uniform block in a shader program and a buffer indexed target number is fixed, like a vertex attribute binding. This is too restrictive because that binding can be changed without relinking the program. This mapping should be done by name in the same way that uniform values are handled i.e., like a pseudo state attribute; * There's no direct way yet to query for the offset of uniforms in uniform block, so only the std140 layout is really usable. A helper class that implemented the std140 rules would be quite helpful for setting up uniform blocks without having to link a program first; * There's no direct support for querying parameters such as the maximum block length, minimum offset alignment, etc. Having that information available outside of the draw thread would make certain instancing techniques easier to implement."
207 lines
6.9 KiB
C++
207 lines
6.9 KiB
C++
#include <iostream>
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#include <osg/Array>
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#include <osg/BoundingSphere>
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#include <osg/BufferIndexBinding>
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#include <osg/BufferObject>
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#include <osg/Group>
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#include <osg/Math>
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#include <osg/MatrixTransform>
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#include <osg/Program>
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#include <osg/Shader>
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#include <osgDB/ReadFile>
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#include <osgDB/WriteFile>
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#include <osgUtil/Optimizer>
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#include <osgViewer/Viewer>
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#include <osgViewer/ViewerEventHandlers>
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using namespace std;
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using namespace osg;
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// This example is based on the sample code in the
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// ARB_uniform_buffer_object extension specification.
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GLfloat colors1[] = {
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// block
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0.45,0.45,1,1,
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0.45,0.45,1,1,
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0.75,0.75,0.75,1,
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0.0,0.0,1.0,1,
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0.0,1.0,0.0,1
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};
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GLfloat colors2[] = {
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// block
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0.45,0.45,1,1,
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0.45,0.45,1,1,
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0.75,0.75,0.75,1,
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1.0,0.0,0.0,1,
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0.0,1.0,0.0,1,
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};
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char vertexShaderSource[] =
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"// Vertex shader for Gooch shading\n"
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"// Author: Randi Rost\n"
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"// Copyright (c) 2002-2006 3Dlabs Inc. Ltd.\n"
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"// See 3Dlabs-License.txt for license information\n"
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"vec3 LightPosition = vec3(0.0, 10.0, 4.0); \n"
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"varying float NdotL;\n"
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"varying vec3 ReflectVec;\n"
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"varying vec3 ViewVec;\n"
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"void main(void)\n"
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"{\n"
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"vec3 ecPos = vec3 (gl_ModelViewMatrix * gl_Vertex);\n"
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"vec3 tnorm = normalize(gl_NormalMatrix * gl_Normal);\n"
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"vec3 lightVec = normalize(LightPosition - ecPos);\n"
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"ReflectVec = normalize(reflect(-lightVec, tnorm));\n"
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"ViewVec = normalize(-ecPos);\n"
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"NdotL = (dot(lightVec, tnorm) + 1.0) * 0.5;\n"
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"gl_Position = ftransform();\n"
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"}\n";
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char fragmentShaderSource[] =
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"// Fragment shader for Gooch shading, adapted for ARB_uniform_buffer_object\n"
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"#extension GL_ARB_uniform_buffer_object : enable\n"
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"layout(std140) uniform colors0\n"
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"{\n"
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"float DiffuseCool;\n"
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"float DiffuseWarm;\n"
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"vec3 SurfaceColor;\n"
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"vec3 WarmColor;\n"
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"vec3 CoolColor;\n"
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"};\n"
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"varying float NdotL;\n"
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"varying vec3 ReflectVec;\n"
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"varying vec3 ViewVec;\n"
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"void main (void)\n"
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"{\n"
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"vec3 kcool = min(CoolColor + DiffuseCool * SurfaceColor, 1.0);\n"
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"vec3 kwarm = min(WarmColor + DiffuseWarm * SurfaceColor, 1.0); \n"
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"vec3 kfinal = mix(kcool, kwarm, NdotL);\n"
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"vec3 nreflect = normalize(ReflectVec);\n"
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"vec3 nview = normalize(ViewVec);\n"
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"float spec = max(dot(nreflect, nview), 0.0);\n"
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"spec = pow(spec, 32.0);\n"
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"gl_FragColor = vec4 (min(kfinal + spec, 1.0), 1.0);\n"
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"}\n";
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// Callback for animating the WarmColor
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class UniformCallback : public StateAttributeCallback
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{
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public:
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void operator() (StateAttribute* attr, NodeVisitor* nv)
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{
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UniformBufferBinding* ubb = static_cast<UniformBufferBinding*>(attr);
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UniformBufferObject* ubo
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= static_cast<UniformBufferObject*>(ubb->getBufferObject());
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FloatArray* array = static_cast<FloatArray*>(ubo->getBufferData(0));
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double time = nv->getFrameStamp()->getSimulationTime();
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double frac = fmod(time, 1.0);
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Vec4f warmColor = (Vec4f(0.0, 0.0, 1.0 ,1) * frac
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+ Vec4f(1.0, 0.0, 0.0, 1) * (1 - frac));
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// Since we're using the std140 layout, we know where the
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// warmColor variable is located in the buffer.
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for (int i = 0; i < 4; ++i)
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(*array)[12 + i] = warmColor[i];
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array->dirty();
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}
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};
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int main(int argc, char** argv)
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{
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osg::ArgumentParser arguments(&argc,argv);
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osgViewer::Viewer viewer(arguments);
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if (arguments.argc() <= 1) {
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cerr << "Need a scene.\n";
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return 1;
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}
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osg::ref_ptr<osg::Node> loadedModel = osgDB::readNodeFiles(arguments);
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if (!loadedModel) {
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cerr << "couldn't load " << argv[1] << "\n";
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return 1;
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}
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osgUtil::Optimizer optimizer;
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optimizer.optimize(loadedModel.get());
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const BoundingSphere bound = loadedModel->getBound();
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const float displacement = 2.25 * bound.radius();
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Group* scene = new Group;
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StateSet* rootSS = scene->getOrCreateStateSet();
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Shader* vertexShader = new Shader(Shader::VERTEX);
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vertexShader->setShaderSource(vertexShaderSource);
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Shader* fragmentShader = new Shader(Shader::FRAGMENT);
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fragmentShader->setShaderSource(fragmentShaderSource);
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Program* prog = new Program;
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prog->addShader(vertexShader);
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prog->addShader(fragmentShader);
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prog->addBindUniformBlock("colors0", 0);
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rootSS->setAttributeAndModes(prog, StateAttribute::ON);
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// Place 3 instances of the loaded model with different uniform
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// blocks for each.
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//
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// The blocksize is known because of the std140 format.
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const unsigned blockSize = 20 * sizeof(GLfloat);
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ref_ptr<FloatArray> colorArray
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= new FloatArray(&colors1[0],
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&colors1[sizeof(colors1) / sizeof(GLfloat)]);
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ref_ptr<UniformBufferObject> ubo = new UniformBufferObject;
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colorArray->setBufferObject(ubo.get());
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Group* group1 = new Group;
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StateSet* ss1 = group1->getOrCreateStateSet();
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group1->addChild(loadedModel.get());
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scene->addChild(group1);
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ref_ptr<UniformBufferBinding> ubb1
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= new UniformBufferBinding(0, ubo.get(), 0, blockSize);
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ss1->setAttributeAndModes(ubb1.get(), StateAttribute::ON);
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ref_ptr<FloatArray> colorArray2
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= new FloatArray(&colors2[0],
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&colors2[sizeof(colors2) / sizeof(GLfloat)]);
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ref_ptr<UniformBufferObject> ubo2 = new UniformBufferObject;
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colorArray2->setBufferObject(ubo2.get());
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MatrixTransform* group2 = new MatrixTransform;
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Matrix mat2 = Matrix::translate(-displacement, 0.0, 0.0);
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group2->setMatrix(mat2);
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StateSet* ss2 = group2->getOrCreateStateSet();
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group2->addChild(loadedModel.get());
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scene->addChild(group2);
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ref_ptr<UniformBufferBinding> ubb2
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= new UniformBufferBinding(0, ubo2.get(), 0, blockSize);
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ss2->setAttributeAndModes(ubb2.get(), StateAttribute::ON);
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ref_ptr<FloatArray> colorArray3
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= new FloatArray(&colors2[0],
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&colors2[sizeof(colors2) / sizeof(GLfloat)]);
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ref_ptr<UniformBufferObject> ubo3 = new UniformBufferObject;
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colorArray3->setBufferObject(ubo3.get());
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MatrixTransform* group3 = new MatrixTransform;
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Matrix mat3 = Matrix::translate(displacement, 0.0, 0.0);
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group3->setMatrix(mat3);
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StateSet* ss3 = group3->getOrCreateStateSet();
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group3->addChild(loadedModel.get());
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scene->addChild(group3);
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ref_ptr<UniformBufferBinding> ubb3
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= new UniformBufferBinding(0, ubo3.get(), 0, blockSize);
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ubb3->setUpdateCallback(new UniformCallback);
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ubb3->setDataVariance(Object::DYNAMIC);
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ss3->setAttributeAndModes(ubb3.get(), StateAttribute::ON);
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viewer.setSceneData(scene);
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viewer.realize();
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return viewer.run();
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}
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