GLhandleARB linkVertexAndFragmentShader(const char* shaderFileName)
{
/* Compile the vertex and fragment shaders: */
GLhandleARB vertexShader=compileVertexShader(shaderFileName);
GLhandleARB fragmentShader=compileFragmentShader(shaderFileName);
/* Link the shader program: */
GLhandleARB shaderProgram=glLinkShader(vertexShader,fragmentShader);
/* Release the compiled shaders (won't get deleted until shader program is released): */
glDeleteObjectARB(vertexShader);
glDeleteObjectARB(fragmentShader);
return shaderProgram;
}
GLhandleARB glLinkShader(size_t numShaderObjects,...)
{
GLhandleARB result=0;
/* Create an argument list and call the actual function: */
va_list ap;
try
{
va_start(ap,numShaderObjects);
result=glLinkShader(numShaderObjects,ap);
va_end(ap);
}
catch(...)
{
/* Clean up and re-throw the exception: */
va_end(ap);
throw;
}
return result;
}
void VolumeRayCasting::initContext(GLContextData& contextData) const
{
DataItem* dataItem=new DataItem();
contextData.addDataItem(this,dataItem);
const char* datasetName = "bin/data/BostonTeapot.raw";
int volumesize = 256*256*256;
/*load sample data*/
std::vector<unsigned char> volumeData;
volumeData.resize(volumesize);
std::ifstream ifs(datasetName, std::ios::binary);
std::cout<<"open dataset file "<<std::endl;
if(!ifs.is_open())
{
/* fail to open dataset file */
std::cout<<"fail to open dataset file: "<<strerror(errno)<<std::endl;
return;
}
ifs.read(reinterpret_cast<char *>(&volumeData.front()), volumesize * sizeof(float));
ifs.close();
/* Select the Volume Rendering texture object: */
glBindTexture(GL_TEXTURE_3D,dataItem->volumeTex);
/* Upload the Volume Rendering texture image: */
glTexImage3D(GL_TEXTURE_3D, 0, GL_R8, 32, 32, 32, 0, GL_RED, GL_UNSIGNED_BYTE, &volumeData.front());
glTexParameteri(GL_TEXTURE_3D,GL_TEXTURE_WRAP_S,GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_3D,GL_TEXTURE_WRAP_T,GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_3D,GL_TEXTURE_WRAP_R,GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_3D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
glTexParameteri(GL_TEXTURE_3D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
/* Protect the Volume Rendering texture object: */
glBindTexture(GL_TEXTURE_3D,0);
//debug
std::cout<<dataItem->volumeTex<<std::endl;
/* Select the Tansfer Function texture object: */
glBindTexture(GL_TEXTURE_2D,dataItem->transferFuncTex);
/* Upload the Tansfer Function texture image: */
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA32F, transFuncData.size(), 1, 0, GL_RGBA, GL_FLOAT, &transFuncData.front());
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S,GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T,GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
/* Protect the Tansfer Function texture object: */
glBindTexture(GL_TEXTURE_2D,0);
//debug
std::cout<<dataItem->transferFuncTex<<std::endl;
glClearColor(0.0, 0.0, 0.0, 0.0);
glEnable(GL_BLEND);
glBlendEquation(GL_FUNC_ADD);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glEnable(GL_CULL_FACE);
glCullFace(GL_FRONT);
glDisable(GL_DEPTH_TEST);
glColorMask(true, true, true, true);
glDepthMask(true);
glEnable(GL_MULTISAMPLE);
if(dataItem->haveShaders)
{
{
GLhandleARB vertexShader=glCompileVertexShaderFromFile("bin/Shaders/VolumeRayCasting.vert");
GLhandleARB fragmentShader=glCompileFragmentShaderFromFile("bin/Shaders/VolumeRayCasting.frag");
dataItem->rayCastingShader=glLinkShader(vertexShader,fragmentShader);
glDeleteObjectARB(vertexShader);
glDeleteObjectARB(fragmentShader);
}
}
std::vector<Vector2f> rectVertices;
rectVertices.push_back(Vector2f(0.0f,0.0f));
rectVertices.push_back(Vector2f(0.0f,1.0f));
rectVertices.push_back(Vector2f(1.0f,1.0f));
rectVertices.push_back(Vector2f(1.0f,0.0f));
glGenBuffersARB(1,&(dataItem->rectVArrayBufferId));
glBindBufferARB(GL_ARRAY_BUFFER, dataItem->rectVArrayBufferId);
glBufferDataARB(GL_ARRAY_BUFFER, rectVertices.size()*sizeof(Vector2f), &rectVertices.front(),GL_STATIC_DRAW);
glBindBufferARB(GL_ARRAY_BUFFER, 0);
GLuint index = glGetAttribLocationARB(dataItem->rayCastingShader, "Vertex");
glGenVertexArrays(1,&(dataItem->rectVerticesArrayId));
glBindVertexArray(dataItem->rectVerticesArrayId);
glBindBufferARB(GL_ARRAY_BUFFER, dataItem->rectVArrayBufferId);
glEnableVertexAttribArrayARB(index);
glVertexAttribPointerARB(index,2, GL_FLOAT,false,0,NULL);
glBindVertexArray(0);
glBindBufferARB(GL_ARRAY_BUFFER, 0);
//debug
std::cout<<"initial 1"<<std::endl;
glNewList(dataItem->displayListIds[0],GL_COMPILE);
glBindVertexArray(dataItem->rectVerticesArrayId);
glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
glBindVertexArray(0);
glEndList();
//debug
std::cout<<"initial finish"<<std::endl;
}
