Fixed Timestep Interpolation: MultiMesh

Adds fixed timestep interpolation to multimeshes.

Co-authored-by: lawnjelly <lawnjelly@gmail.com>

1 files changed, 29 insertions, 0 deletions

diff --git a/doc/classes/MultiMesh.xml b/doc/classes/MultiMesh.xml
index 529912171c..e99694c3f0 100644
--- a/doc/classes/MultiMesh.xml
+++ b/doc/classes/MultiMesh.xml
@@ -51,6 +51,24 @@
 				Returns the [Transform2D] of a specific instance.
 			</description>
 		</method>
+		<method name="reset_instance_physics_interpolation">
+			<return type="void" />
+			<param index="0" name="instance" type="int" />
+			<description>
+				When using [i]physics interpolation[/i], this function allows you to prevent interpolation on an instance in the current physics tick.
+				This allows you to move instances instantaneously, and should usually be used when initially placing an instance such as a bullet to prevent graphical glitches.
+			</description>
+		</method>
+		<method name="set_buffer_interpolated">
+			<return type="void" />
+			<param index="0" name="buffer_curr" type="PackedFloat32Array" />
+			<param index="1" name="buffer_prev" type="PackedFloat32Array" />
+			<description>
+				An alternative to setting the [member buffer] property, which can be used with [i]physics interpolation[/i]. This method takes two arrays, and can set the data for the current and previous tick in one go. The renderer will automatically interpolate the data at each frame.
+				This is useful for situations where the order of instances may change from physics tick to tick, such as particle systems.
+				When the order of instances is coherent, the simpler alternative of setting [member buffer] can still be used with interpolation.
+			</description>
+		</method>
 		<method name="set_instance_color">
 			<return type="void" />
 			<param index="0" name="instance" type="int" />
@@ -109,6 +127,11 @@
 			[Mesh] resource to be instanced.
 			The looks of the individual instances can be modified using [method set_instance_color] and [method set_instance_custom_data].
 		</member>
+		<member name="physics_interpolation_quality" type="int" setter="set_physics_interpolation_quality" getter="get_physics_interpolation_quality" enum="MultiMesh.PhysicsInterpolationQuality" default="0">
+			Choose whether to use an interpolation method that favors speed or quality.
+			When using low physics tick rates (typically below 20) or high rates of object rotation, you may get better results from the high quality setting.
+			[b]Note:[/b] Fast quality does not equate to low quality. Except in the special cases mentioned above, the quality should be comparable to high quality.
+		</member>
 		<member name="transform_2d_array" type="PackedVector2Array" setter="_set_transform_2d_array" getter="_get_transform_2d_array" deprecated="Accessing this property is very slow. Use [method set_instance_transform_2d] and [method get_instance_transform_2d] instead.">
 			Array containing each [Transform2D] value used by all instances of this mesh, as a [PackedVector2Array]. Each transform is divided into 3 [Vector2] values corresponding to the transforms' [code]x[/code], [code]y[/code], and [code]origin[/code].
 		</member>
@@ -135,5 +158,11 @@
 		<constant name="TRANSFORM_3D" value="1" enum="TransformFormat">
 			Use this when using 3D transforms.
 		</constant>
+		<constant name="INTERP_QUALITY_FAST" value="0" enum="PhysicsInterpolationQuality">
+			Always interpolate using Basis lerping, which can produce warping artifacts in some situations.
+		</constant>
+		<constant name="INTERP_QUALITY_HIGH" value="1" enum="PhysicsInterpolationQuality">
+			Attempt to interpolate using Basis slerping (spherical linear interpolation) where possible, otherwise fall back to lerping.
+		</constant>
 	</constants>
 </class>