Version: 2022.3
LanguageEnglish
  • C#
Experimental: this API is experimental and might be changed or removed in the future.

RayTracingAccelerationStructure.AddInstance

Suggest a change

Success!

Thank you for helping us improve the quality of Unity Documentation. Although we cannot accept all submissions, we do read each suggested change from our users and will make updates where applicable.

Close

Submission failed

For some reason your suggested change could not be submitted. Please <a>try again</a> in a few minutes. And thank you for taking the time to help us improve the quality of Unity Documentation.

Close

Cancel

Declaration

public void AddInstance(Renderer targetRenderer, RayTracingSubMeshFlags[] subMeshFlags, bool enableTriangleCulling, bool frontTriangleCounterClockwise, uint mask, uint id);
Obsolete This AddInstance method has been deprecated and will be removed in a future version. Please use the alternate method for adding Renderers to the acceleration structure.

Declaration

public void AddInstance(Renderer targetRenderer, bool[] subMeshMask, bool[] subMeshTransparencyFlags, bool enableTriangleCulling, bool frontTriangleCounterClockwise, uint mask, uint id);
Obsolete This AddInstance method has been deprecated and will be removed in a future version. Please use the alternate method for adding procedural geometry (AABBs) to the acceleration structure.

Declaration

public void AddInstance(GraphicsBuffer aabbBuffer, uint numElements, Material material, bool isCutOff, bool enableTriangleCulling, bool frontTriangleCounterClockwise, uint mask, bool reuseBounds, uint id);
Obsolete This AddInstance method has been deprecated and will be removed in a future version. Please use the alternate method for adding procedural geometry (AABBs) to the acceleration structure.

Declaration

public void AddInstance(GraphicsBuffer aabbBuffer, uint numElements, Material material, Matrix4x4 instanceTransform, bool isCutOff, bool enableTriangleCulling, bool frontTriangleCounterClockwise, uint mask, bool reuseBounds, uint id);

Parameters

targetRenderer The Renderer to add to the RayTracingAccelerationStructure.
subMeshMask A bool array of any size that indicates whether or not to add a sub-mesh to the RayTracingAccelerationStructure. For a Renderer with multiple sub-meshes, if subMeshMask[i] = true, Unity adds the sub-mesh to the RayTracingAccelerationStructure. For a Renderer with only one sub-mesh, you may pass an uninitialized array as a default value.
subMeshTransparencyFlags A bool array of any size that indicates whether a given sub-mesh is transparent or opaque. For a Renderer with multiple sub-meshes, if subMeshTransparencyFlag[i] = true, Unity marks that sub-mesh as transparent. For a Renderer with only one sub-mesh, pass an array with a single initialized entry to indicate whether or not the one sub-mesh is transparent. When a ray-triangle intersection test succeeds for a sub-meshes that is marked as transparent, the GPU invokes an any hit shader.
enableTriangleCulling A bool that indicates whether front/back face culling for this ray tracing instance is enabled. The culling takes place when the GPU performs a ray-triangle intersection test. Culling is enabled (true) by default.
frontTriangleCounterClockwise A bool that indicates whether to flip the way triangles face in this ray tracing instance. If this is set to true, front-facing triangles will become back-facing and vice versa. Set to false by default.
mask An 8-bit mask you can use to selectively intersect the ray tracing instance associated with the target Renderer with rays that only pass the mask. All rays are enabled (0xff) by default.
aabbBuffer A GraphicsBuffer that defines a number of axis-aligned bounding boxes (AABBs). An AABB can be defined by a list of bounds, written as floats in the following order: minX, minY, minZ, maxX, maxY, maxZ.
numElements The number of axis-aligned bounding boxes defined in the given GraphicsBuffer.
material The Material to apply to an instance defined by axis-aligned bounding boxes in a GraphicsBuffer.
instanceTransform The object to world matrix to apply to an instance defined by axis-aligned bounding boxes in a GraphicsBuffer. This is optional, and takes the value of a Matrix4x4.identity by default.
isCutOff A bool that indicates whether the Material applied to a GraphicsBuffer instance has cutoff transparency.
reuseBounds A bool that indicates whether Unity reuses the AABBs defined in the GraphicsBuffer without change. If the exact same bounds can be used across multiple acceleration structures or multiple frames, set this to true. This is false by default.
subMeshFlags A list of flags that control the shader execution behaviour when a ray intersects a sub-mesh geometry. See RayTracingSubMeshFlags for additional information.
id An optional instance ID value that can be accessed using InstanceID() HLSL function.

Description

Adds a ray tracing instance associated with a Renderer to the RayTracingAccelerationStructure.

Ray tracing instances in the acceleration structure contain an 8-bit user defined instance mask. The TraceRay() HLSL function has an 8-bit input parameter, InstanceInclusionMask which gets ANDed with the instance mask from any ray tracing instance that is a candidate for intersection during acceleration structure traversal on the GPU. If the result of the AND operation is zero, the intersection is ignored.

When you have added all required instances, use RayTracingAccelerationStructure.Build or CommandBuffer.BuildRayTracingAccelerationStructure to build the acceleration structure on the GPU.

Additional resources: RayTracingAccelerationStructure.RemoveInstance, RayTracingSubMeshFlags.


Declaration

public int AddInstance(GraphicsBuffer aabbBuffer, uint aabbCount, bool dynamicData, Matrix4x4 matrix, Material material, bool opaqueMaterial, MaterialPropertyBlock properties, uint mask, uint id);

Parameters

aabbBuffer A GraphicsBuffer that defines a number of axis-aligned bounding boxes (AABBs). An AABB can be defined by a list of float values written in the following order: minX, minY, minZ, maxX, maxY, maxZ.
aabbCount The number of AABBs to consider when building the acceleration stucture for this ray tracing instance.
dynamicData Whether the data in the aabbBuffer is dynamic or not. If the data is dynamic, then Unity will rebuild the acceleration structure of the ray tracing instance every frame.
matrix The transformation matrix of the ray tracing instance.
material The Material to apply to the ray tracing instance.
opaqueMaterial Whether material is considered opaque or not. If the material is opaque then anyhit shaders, if present, will be disabled and the GPU will not execute them.
properties Additional material properties to apply onto material. This is useful for setting up individual shader parameters for each ray tracing instance. See MaterialPropertyBlock.
mask An 8-bit mask you can use to selectively intersect the ray tracing instance with rays that only pass the mask. All rays are enabled (0xff) by default.
id An optional instance ID value that can be accessed using InstanceID() HLSL function.

Returns

int A value representing a handle that can be used to perform later actions (e.g. RemoveInstance, UpdateInstancePropertyBlock or UpdateInstanceTransform).

Description

Adds a ray tracing instance associated with a list of axis-aligned bounding boxes (AABBs) to the RayTracingAccelerationStructure for procedural geometry generation using intersection shaders.

The AABB list is defined in a GraphicsBuffer which Unity uses to build an acceleration structure for this ray tracing instance.

The AABBs are defined in local space and can be transformed using the matrix argument. Use RayTracingAccelerationStructure.UpdateInstanceTransform to update the transformation of the ray tracing instance at a later time.

The MaterialPropertyBlock contents are copied into the ray tracing instance when this function is called. Any subsequent changes to the MaterialPropertyBlock object that was passed as argument are not taken into account. Use RayTracingAccelerationStructure.UpdateInstancePropertyBlock to updated the properties again at a later time.

When a ray intersects one of the AABBs in the list during a ray tracing dispatch, an intersection shader is invoked. The index of a discrete AABB in the acceleration structure can be retrieved in shader code using PrimitiveIndex() HLSL function.

When you have added all required instances, use RayTracingAccelerationStructure.Build or CommandBuffer.BuildRayTracingAccelerationStructure to build the acceleration structure on the GPU.

Additional resources: RayTracingAccelerationStructure.RemoveInstance, RayTracingShader.Dispatch.