Create an array buffer object (VBO).
Creates a VBO using input data, usually as a ndarray or list. Attributes common to one vertex should occupy a single row of the data array.
data (array_like) – A 2D array of values to write to the array buffer. The data type of the VBO is inferred by the type of the array. If the input is a Python list or tuple type, the data type of the array will be GL_FLOAT.
target (int) – Target used when binding the buffer (e.g. GL_VERTEX_ARRAY or
GL_ELEMENT_ARRAY_BUFFER). Default is GL_VERTEX_ARRAY.
dataType (Glenum, optional) – Data type of array. Input data will be recast to an appropriate type if necessary. Default is GL_FLOAT.
usage (GLenum or int, optional) – Usage type for the array (i.e. GL_STATIC_DRAW).
A descriptor with vertex buffer information.
Examples
Creating a vertex buffer object with vertex data:
# vertices of a triangle
verts = [[ 1.0, 1.0, 0.0], # v0
[ 0.0, -1.0, 0.0], # v1
[-1.0, 1.0, 0.0]] # v2
# load vertices to graphics device, return a descriptor
vboDesc = createVBO(verts)
Drawing triangles or quads using vertex buffer data:
nIndices, vSize = vboDesc.shape # element size
bindVBO(vboDesc)
setVertexAttribPointer(
GL_VERTEX_ARRAY, vSize, vboDesc.dataType, legacy=True)
enableVertexAttribArray(GL_VERTEX_ARRAY, legacy=True)
if vSize == 3:
drawMode = GL_TRIANGLES
elif vSize == 4:
drawMode = GL_QUADS
glDrawArrays(drawMode, 0, nIndices)
glFlush()
disableVertexAttribArray(GL_VERTEX_ARRAY, legacy=True)
unbindVBO()
Custom data can be associated with this vertex buffer by specifying userData:
myVBO = createVBO(data)
myVBO.userData['startIdx'] = 14 # first index to draw with
# use it later
nIndices, vSize = vboDesc.shape # element size
startIdx = myVBO.userData['startIdx']
endIdx = nIndices - startIdx
glDrawArrays(GL_TRIANGLES, startIdx, endIdx)
glFlush()