Version: 2021.3
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Graphics.DrawProceduralIndirect

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Declaration

public static void DrawProceduralIndirect(Material material, Bounds bounds, MeshTopology topology, GraphicsBuffer bufferWithArgs, int argsOffset, Camera camera, MaterialPropertyBlock properties, Rendering.ShadowCastingMode castShadows, bool receiveShadows, int layer);

Declaration

public static void DrawProceduralIndirect(Material material, Bounds bounds, MeshTopology topology, ComputeBuffer bufferWithArgs, int argsOffset, Camera camera, MaterialPropertyBlock properties, Rendering.ShadowCastingMode castShadows, bool receiveShadows, int layer);

Parameters

material Material to use.
bounds The bounding volume surrounding the instances you intend to draw.
topology Topology of the procedural geometry.
camera If null (default), the mesh will be drawn in all cameras. Otherwise it will be rendered in the given Camera only.
bufferWithArgs Buffer with draw arguments.
argsOffset Byte offset where in the buffer the draw arguments are.
properties Additional material properties to apply onto material just before this mesh will be drawn. See MaterialPropertyBlock.
castShadows Determines whether the mesh can cast shadows.
receiveShadows Determines whether the mesh can receive shadows.
layer Layer to use.

Description

Draws procedural geometry on the GPU.

This function only works on platforms that support compute shaders.

DrawProceduralIndirect does a draw call on the GPU, without any vertex or index buffers. If the shader requires vertex buffers one of the following occurs depending on platform: If the vertex buffer is declared but compiler can optimize it away then the normal DrawProcedural call will occur. If the compiler is not able to optimize the vertex buffer declaration away then this will be converted into a normal mesh drawing call with emulated vertexbuffers injected. The latter option has performance overhead so it is recommended not to declare vertex inputs in shaders when using DrawProceduralIndirect. The amount of geometry to draw is read from a ComputeBuffer. Typical use case is generating an arbitrary amount of data from a ComputeShader and then rendering that, without requiring a readback to the CPU.

This is mainly useful on Shader Model 4.5 level hardware where shaders can read arbitrary data from ComputeBuffer buffers.

Buffer with arguments, bufferWithArgs, has to have four integer numbers at given argsOffset offset: vertex count per instance, instance count, start vertex location, and start instance location. This maps to Direct3D11 DrawInstancedIndirect and equivalent functions on other graphics APIs. On OpenGL versions before 4.2 and all OpenGL ES versions that support indirect draw, the last argument is reserved and therefore must be zero.

There's also similar functionality in CommandBuffers, see CommandBuffer.DrawProceduralIndirect.

Additional resources: Graphics.DrawProcedural, ComputeBuffer.CopyCount, SystemInfo.supportsComputeShaders.


Declaration

public static void DrawProceduralIndirect(Material material, Bounds bounds, MeshTopology topology, GraphicsBuffer indexBuffer, GraphicsBuffer bufferWithArgs, int argsOffset, Camera camera, MaterialPropertyBlock properties, Rendering.ShadowCastingMode castShadows, bool receiveShadows, int layer);

Declaration

public static void DrawProceduralIndirect(Material material, Bounds bounds, MeshTopology topology, GraphicsBuffer indexBuffer, ComputeBuffer bufferWithArgs, int argsOffset, Camera camera, MaterialPropertyBlock properties, Rendering.ShadowCastingMode castShadows, bool receiveShadows, int layer);

Parameters

material Material to use.
bounds The bounding volume surrounding the instances you intend to draw.
topology Topology of the procedural geometry.
indexBuffer Index buffer used to submit vertices to the GPU.
camera If null (default), the mesh will be drawn in all cameras. Otherwise it will be rendered in the given Camera only.
bufferWithArgs Buffer with draw arguments.
argsOffset Byte offset where in the buffer the draw arguments are.
properties Additional material properties to apply onto material just before this mesh will be drawn. See MaterialPropertyBlock.
castShadows Determines whether the mesh can cast shadows.
receiveShadows Determines whether the mesh can receive shadows.
layer Layer to use.

Description

Draws procedural geometry on the GPU.

DrawProceduralIndirect does a draw call on the GPU, without a vertex buffer. The amount of geometry to draw is read from a ComputeBuffer. Typical use case is generating an arbitrary amount of data from a ComputeShader and then rendering that, without requiring a readback to the CPU.

This is mainly useful on Shader Model 4.5 level hardware where shaders can read arbitrary data from ComputeBuffer buffers.

Buffer with arguments, bufferWithArgs, has to have five integer numbers at given argsOffset offset: index count per instance, instance count, start index location, base vertex location, and start instance location. This maps to Direct3D11 DrawIndexedInstancedIndirect and equivalent functions on other graphics APIs. On OpenGL versions before 4.2 and all OpenGL ES versions that support indirect draw, the last argument is reserved and therefore must be zero.

There's also similar functionality in CommandBuffers, see CommandBuffer.DrawProceduralIndirect.

Additional resources: Graphics.DrawProcedural, ComputeBuffer.CopyCount, SystemInfo.supportsComputeShaders.