MultiMesh

Provides high-performance mesh instancing.

MultiMesh provides low-level mesh instancing. Drawing thousands of nodes can be slow, since each object is submitted to the GPU then drawn individually.

MultiMesh is much faster as it can draw thousands of instances with a single draw call, resulting in less API overhead.

As a drawback, if the instances are too far away of each other, performance may be reduced as every single instance will always rendered (they are spatially indexed as one, for the whole object).

Since instances may have any behavior, the AABB used for visibility must be provided by the user.

Tutorials

• Animating thousands of fish with MultiMeshInstance

Methods

enum TransformFormat:

• TRANSFORM_2D = 0 —- Use this when using 2D transforms.

enum ColorFormat:

• COLOR_NONE = 0 —- Use when you are not using per-instance Colors.
• COLOR_8BIT = 1 —- Compress data into 8 bits when passing to shader. This uses less memory and can be faster, but the Color loses precision.
• COLOR_FLOAT = 2 —- The passed into set_instance_color will use 4 floats. Use this for highest precision .

enum CustomDataFormat:

• CUSTOM_DATA_NONE = 0 —- Use when you are not using per-instance custom data.
• CUSTOM_DATA_8BIT = 1 —- Compress custom_data into 8 bits when passing to shader. This uses less memory and can be faster, but loses precision and range. Floats packed into 8 bits can only represent values between 0 and 1, numbers outside that range will be clamped.
• CUSTOM_DATA_FLOAT = 2 —- The Color passed into will use 4 floats. Use this for highest precision.

Property Descriptions

• ColorFormat color_format

• custom_data_format

Format of custom data in custom data array that gets passed to shader.

• int instance_count

Number of instances that will get drawn. This clears and (re)sizes the buffers. By default, all instances are drawn but you can limit this with .

• Mesh mesh

Mesh to be drawn.

Format of transform used to transform mesh, either 2D or 3D.

• visible_instance_count

Limits the number of instances drawn, -1 draws all instances. Changing this does not change the sizes of the buffers.

• AABB get_aabb ( ) const

Returns the visibility axis-aligned bounding box in local space. See also .

• Color get_instance_color ( instance ) const

Gets a specific instance’s color.

• Color get_instance_custom_data ( instance ) const

Returns the custom data that has been set for a specific instance.

• Transform get_instance_transform ( instance ) const

• Transform2D get_instance_transform_2d ( instance ) const

Returns the Transform2D of a specific instance.

• void set_as_bulk_array ( array )

Sets all data related to the instances in one go. This is especially useful when loading the data from disk or preparing the data from GDNative.

All data is packed in one large float array. An array may look like this: Transform for instance 1, color data for instance 1, custom data for instance 1, transform for instance 2, color data for instance 2, etc…

Transform is stored as 12 floats, is stored as 8 floats, / CUSTOM_DATA_8BIT is stored as 1 float (4 bytes as is) and COLOR_FLOAT / CUSTOM_DATA_FLOAT is stored as 4 floats.

• void set_instance_color ( int instance, color )

Sets the color of a specific instance by multiplying the mesh’s existing vertex colors.

For the color to take effect, ensure that color_format is non-null on the and is true on the material.

• void set_instance_custom_data ( int instance, custom_data )

Sets custom data for a specific instance. Although Color is used, it is just a container for 4 floating point numbers. The format of the number can change depending on the used.

• void set_instance_transform ( int instance, transform )

Sets the Transform for a specific instance.