ID3D11DeviceContext

Overview

The ID3D11DeviceContext interface represents a device context, which is used to issue rendering commands to the GPU. It provides methods for drawing, state management, resource updates, and query handling.

Syntax

interface ID3D11DeviceContext : ID3D11DeviceChild {
    void VSSetConstantBuffers(UINT StartSlot, UINT NumBuffers, ID3D11Buffer *const *ppConstantBuffers);
    void PSSetShaderResources(UINT StartSlot, UINT NumViews, ID3D11ShaderResourceView *const *ppShaderResourceViews);
    // ... many more methods ...
}

Methods

Method	Description
`Draw`	Renders non-indexed, non-instanced primitives.
`DrawIndexed`	Renders indexed primitives.
`DrawInstanced`	Renders instanced primitives.
`DrawIndexedInstanced`	Renders indexed, instanced primitives.

Method	Description
`VSSetShader`	Sets the vertex shader to the device context.
`PSSetShader`	Sets the pixel shader to the device context.
`RSSetViewports`	Sets the viewports for rasterizer stage.
`OMSetRenderTargets`	Sets render targets and depth-stencil view.

Method	Description
`UpdateSubresource`	Copies CPU data to a subresource of a GPU resource.
`CopyResource`	Copies an entire resource.
`CopySubresourceRegion`	Copies a region of one resource to another.

Properties

Device – Retrieves the parent ID3D11Device object.
FeatureLevel – Indicates the highest feature level supported.

Remarks

Device contexts are divided into immediate and deferred contexts. The immediate context executes commands as they are issued, while deferred contexts record command lists for later execution on the immediate context.

Example

// Create device and immediate context
ID3D11Device*           gDevice = nullptr;
ID3D11DeviceContext*    gContext = nullptr;
D3D11CreateDevice(
    nullptr,
    D3D_DRIVER_TYPE_HARDWARE,
    nullptr,
    0,
    nullptr,
    0,
    D3D11_SDK_VERSION,
    &gDevice,
    nullptr,
    &gContext);

// Clear render target
float clearColor[4] = {0.1f, 0.2f, 0.3f, 1.0f};
ID3D11RenderTargetView* rtv = nullptr; // Assume created elsewhere
gContext->ClearRenderTargetView(rtv, clearColor);

// Draw a triangle
gContext->IASetPrimitiveTopology(D3D11_PRIMITIVE_TOPOLOGY_TRIANGLELIST);
gContext->Draw(3, 0);