DirectCompute Compute Shader Functions

DirectCompute exposes a set of intrinsic functions that can be used directly within your HLSL compute shaders. These functions provide low-level access to GPU hardware capabilities, enabling optimized parallel processing.

Core Compute Shader Functions

`Dispatch(x, y, z)`

Dispatches a grid of thread groups for execution on the GPU.

void Dispatch(uint3 groupCountX, uint3 groupCountY, uint3 groupCountZ);

`GetGroupThreadID()`

Returns the unique thread ID within the current thread group.

uint3 GetGroupThreadID();

`GetGroupID()`

Returns the unique ID of the current thread group within the dispatch grid.

uint3 GetGroupID();

`GetGroupSize()`

Returns the dimensions (number of threads) of the current thread group.

uint3 GetGroupSize();

`Load(address)`

Loads data from a structured buffer or texture at a specific memory address.

T Load(StructuredBuffer buffer, uint index);

`Store(address, value)`

Stores data to a structured buffer or texture at a specific memory address.

void Store(StructuredBuffer buffer, uint index, T value);

`InterlockedAdd()`

Performs an atomic addition operation on a memory location.

uint InterlockedAdd(inout uint dest, uint value, out uint original_dest);

`InterlockedExchange()`

Performs an atomic exchange operation on a memory location.

uint InterlockedExchange(inout uint dest, uint value, out uint original_dest);

`SyncThread()`

Synchronizes threads within a thread group, ensuring all previous memory operations are visible to subsequent operations.

void SyncThreads();

`WaveReadLaneFirst()`

Reads a value from the first active lane in the current wavefront.

uint WaveReadLaneFirst(uint value);

Resource Access Functions

These functions are crucial for interacting with various GPU resources like buffers and textures.

`Texture2D.Load()`

Loads a texel from a 2D texture at a specified coordinate.

float4 Texture2D.Load(int2 location);

`RWTexture2D.Write()`

Writes a value to a read/write 2D texture at a specified coordinate.

void RWTexture2D.Write(float4 value, int2 location);

`Buffer.Load()`

Loads data from a raw buffer at a specific byte offset.

uint Buffer.Load(uint offset);

`RWBuffer.Store()`

Stores data to a read/write raw buffer at a specific byte offset.

void RWBuffer.Store(uint offset, uint value);

Mathematical Functions

Standard mathematical operations are also available for complex calculations within shaders.

`dot(a, b)`

Calculates the dot product of two vectors.

float dot(float2 a, float2 b);

`length(v)`

Calculates the magnitude (length) of a vector.

float length(float3 v);

`normalize(v)`

Returns a normalized version of a vector (length 1).

float3 normalize(float3 v);

`lerp(a, b, t)`

Performs linear interpolation between two values.

float lerp(float a, float b, float t);

`sin(x), cos(x), tan(x)`

Trigonometric functions.

float sin(float angle);