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