本文整理汇总了C++中gl::GlslProg::getAttribLocation方法的典型用法代码示例。如果您正苦于以下问题：C++ GlslProg::getAttribLocation方法的具体用法？C++ GlslProg::getAttribLocation怎么用？C++ GlslProg::getAttribLocation使用的例子？那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类gl::GlslProg的用法示例。
在下文中一共展示了GlslProg::getAttribLocation方法的1个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的C++代码示例。
示例1: initializeBuffer
void HexagonMirrorApp::initializeBuffer()
{
// To pass the model matrix for each instance, we will use
// a custom vertex shader attribute. Using an attribute will
// give us more freedom and more storage capacity than using
// a uniform buffer, which often has a capacity limit of 64KB
// or less, which is just enough for 1024 instances.
//
// Because we want the attribute to stay the same for all
// vertices of an instance, we set the divisor to '1' instead
// of '0', so the attribute will only change after all
// vertices of the instance have been drawn.
//
// See for more information: http://ogldev.atspace.co.uk/www/tutorial33/tutorial33.html
// initialize transforms for every instance
std::vector< Matrix44f > matrices;
matrices.reserve( NUM_INSTANCES );
for(size_t i=0; i<NUM_INSTANCES; ++i)
{
// determine position for this hexagon
float x = math<float>::fmod( float(i), INSTANCES_PER_ROW );
float y = math<float>::floor( float(i) / INSTANCES_PER_ROW );
// create transform matrix, then rotate and translate it
Matrix44f model;
model.translate( Vec3f( 3.0f * x + 1.5f * math<float>::fmod( y, 2.0f ) , 0.866025f * y, 0.0f ) );
matrices.push_back( model );
}
// retrieve attribute location from the shader
// (note: make sure the shader is loaded and compiled before calling this function)
GLint ulocation = mShaderInstanced.getAttribLocation( "model_matrix" );
// if found...
if( ulocation != -1 )
{
// create vertex array object to hold our buffer
// (note: this is required for OpenGL 3.1 and above)
glGenVertexArrays(1, &mVAO);
glBindVertexArray(mVAO);
// create array buffer to store model matrices
mBuffer = gl::Vbo( GL_ARRAY_BUFFER );
// setup the buffer to contain space for all matrices.
// we need 4 attributes to contain the 16 floats of a single matrix,
// because the maximum size of an attribute is 4 floats (16 bytes).
// When adding a 'mat4' attribute, OpenGL will make sure that
// the attribute locations are sequential, e.g.: 3, 4, 5 and 6
mBuffer.bind();
for (unsigned int i = 0; i < 4 ; i++) {
glEnableVertexAttribArray(ulocation + i);
glVertexAttribPointer( ulocation + i, 4, GL_FLOAT, GL_FALSE, sizeof(Matrix44f), (const GLvoid*) (4 * sizeof(GLfloat) * i) );
// get the next matrix after each instance, instead of each vertex
glVertexAttribDivisor( ulocation + i, 1 );
}
// fill the buffer with our data
mBuffer.bufferData( matrices.size() * sizeof(Matrix44f), &matrices.front(), GL_STATIC_READ );
mBuffer.unbind();
// unbind the VAO
glBindVertexArray(0);
}
}