opengl.vao.VAO¶
-
moderngl_window.opengl.vao.
VAO
[source]¶ Represents a vertex array object.
This is a wrapper class over
moderngl.VertexArray
to make interactions with programs/shaders simpler. Named buffers are added correspoding with attribute names in a vertex shader. When rendering the VAO an internal`moderngl.VertextArray
is created by automatically creating a buffer mapping compatible with the supplied program. This program is cached internally.The shader program doesn’t need to use all the buffers registered in this wrapper. When a subset is used only the used buffers are mapped and the approproate padding is calculated when iterleaved data is used.
There is no requirements to use this class, but most methods in the system creating vertexbuffers will return this type. You can obtain a single
`moderngl.VertexBuffer
instance by callingVAO.instance()
method if you prefer to work directly on moderngl instances.Example:
# Separate buffers vao = VAO(name="test", mode=moderngl.POINTS) vao.buffer(positions, '3f', ['in_position']) vao.buffer(velocities, '3f', ['in_velocities']) # Interleaved vao = VAO(name="test", mode=moderngl.POINTS) vao.buffer(interleaved_data, '3f 3f', ['in_position', 'in_velocities'])
# GLSL vertex shader in attributes in vec3 in_position; in vec3 in_velocities;
Methods¶
-
VAO.
__init__
(name='', mode=4)[source]¶ Create and empty VAO with a name and default render mode.
Example:
VAO(name="cube", mode=moderngl.TRIANGLES)
Keyword Arguments: - name (str) – Optional name for debug purposes
- mode (int) – Default draw mode
-
VAO.
render
(program: moderngl.program.Program, mode=None, vertices=-1, first=0, instances=1)[source]¶ Render the VAO.
An internal
moderngl.VertexBuffer
with compatible buffer bindings is automatically created on the fly and cached internally.Parameters: program – The
moderngl.Program
Keyword Arguments: - mode – Override the draw mode (
TRIANGLES
etc) - vertices (int) – The number of vertices to transform
- first (int) – The index of the first vertex to start with
- instances (int) – The number of instances
- mode – Override the draw mode (
-
VAO.
render_indirect
(program: moderngl.program.Program, buffer, mode=None, count=-1, *, first=0)[source]¶ 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 – The
moderngl.Program
- buffer – The
moderngl.Buffer
containing indirect draw commands
Keyword Arguments: - mode (int) – By default
TRIANGLES
will be used. - count (int) – The number of draws.
- first (int) – The index of the first indirect draw command.
- program – The
-
VAO.
transform
(program: moderngl.program.Program, buffer: moderngl.buffer.Buffer, mode=None, vertices=-1, first=0, instances=1)[source]¶ Transform vertices. Stores the output in a single buffer.
Parameters: - program – The
moderngl.Program
- buffer – The
moderngl.buffer
to store the output
Keyword Arguments: - mode – Draw mode (for example
moderngl.POINTS
) - vertices (int) – The number of vertices to transform
- first (int) – The index of the first vertex to start with
- instances (int) – The number of instances
- program – The
-
VAO.
buffer
(buffer, buffer_format: str, attribute_names: List[str])[source]¶ Register a buffer/vbo for the VAO. This can be called multiple times. adding multiple buffers (interleaved or not).
Parameters: - buffer – The buffer data. Can be
numpy.array
,moderngl.Buffer
orbytes
. - buffer_format (str) – The format of the buffer. (eg.
3f 3f
for interleaved positions and normals). - attribute_names – A list of attribute names this buffer should map to.
Returns: The
moderngl.Buffer
instance object. This is handy when providingbytes
andnumpy.array
.- buffer – The buffer data. Can be
-
VAO.
index_buffer
(buffer, index_element_size=4)[source]¶ Set the index buffer for this VAO.
Parameters: buffer – moderngl.Buffer
,numpy.array
orbytes
Keyword Arguments: index_element_size (int) – Byte size of each element. 1, 2 or 4
-
VAO.
instance
(program: moderngl.program.Program) → moderngl.vertex_array.VertexArray[source]¶ Obtain the
moderngl.VertexArray
instance for the program.The instance is only created once and cached internally.
Parameters: program (moderngl.Program) – The program Returns: instance Return type: moderngl.VertexArray
-
VAO.
release
(buffer=True)[source]¶ Destroy all iternally cached vaos and release all buffers.
Keyword Arguments: buffers (bool) – also release buffers
-
VAO.
get_buffer_by_name
(name: str) → moderngl_window.opengl.vao.BufferInfo[source]¶ Get the BufferInfo associated with a specific attribute name
If no buffer is associated with the name None will be returned.
Parameters: name (str) – Name of the mapped attribute Returns: BufferInfo instance Return type: BufferInfo