VAO

class demosys.opengl.vao.VAO(name, mode=4)

Represents a vertex array object. A name must be provided for debug puporses. The default draw mode is moderngl.TRIANGLES

Methods

VAO.buffer(buffer, buffer_format:str, attribute_names, per_instance=False)

Register a buffer/vbo for the VAO. This can be called multiple times. adding multiple buffers (interleaved or not)

Parameters:
  • buffer – The buffer object. Can be ndarray or Buffer
  • buffer_format – The format of the buffer (‘f’, ‘u’, ‘i’)
Returns:

The buffer object
VAO.index_buffer(buffer, index_element_size=4)

Set the index buffer for this VAO

Parameters:
  • buffer – Buffer object or ndarray
  • index_element_size – Byte size of each element. 1, 2 or 4
VAO.instance(program:Program) → VertexArray

Obtain the moderngl.VertexArray instance for the program

Returns:moderngl.VertexArray
VAO.render(program:Program, mode=None, vertices=-1, first=0, instances=1)

Render the VAO.

Parameters:
  • program – The program to draw with
  • mode – Override the draw mode (TRIANGLES etc)
  • vertices – The number of vertices to transform
  • first – The index of the first vertex to start with
  • instances – The number of instances
VAO.render_indirect(program:Program, buffer, mode=None, count=-1, first=0)

The render primitive (mode) must be the same as the input primitive of the GeometryShader. The draw commands are 5 integers: (count, instanceCount, firstIndex, baseVertex, baseInstance).

Parameters:
  • program – (Buffer) Indirect drawing commands.
  • buffer – (Buffer) Indirect drawing commands.
  • mode – (int) By default TRIANGLES will be used.
  • count – (int) The number of draws.
  • first – (int) The index of the first indirect draw command.
VAO.transform(program:Program, buffer:Buffer, mode=None, vertices=-1, first=0, instances=1)

Transform vertices. Stores the output in a single buffer.

Parameters:
  • program – The program
  • buffer – The buffer to store the output
  • mode – Draw mode (for example POINTS
  • vertices – The number of vertices to transform
  • first – The index of the first vertex to start with
  • instances – The number of instances
VAO.release(buffer=True)

Destroy the vao object

Parameters:buffers – (bool) also release buffers