Содержание

Header
Initialization
Simple drawing
Sorting
Alpha blending
Custom render states
Pixel centers
Custom pixel shaders
Custom vertex shaders
Custom transform
Custom clipping
Applications

Feature Level Notes
Threading model
Orientation
State management
Xbox One
Further reading

DirectXTK

This is a native Direct3D 11 implementation of the SpriteBatch helper from XNA Game Studio 4 (Microsoft.Xna.Framework.Graphics.SpriteBatch), providing the same functionality and API.

Header

#include <SpriteBatch.h>

Initialization

The SpriteBatch class requires a Direct3D 11 device context for drawing.

std::unique_ptr<SpriteBatch> spriteBatch;
spriteBatch = std::make_unique<SpriteBatch>(deviceContext);

For exception safety, it is recommended you make use of the C++ RAII pattern and use a std::unique_ptr or std::shared_ptr

Simple drawing

spriteBatch->Begin();
spriteBatch->Draw(texture, XMFLOAT2(x, y));
spriteBatch->End();

The Draw method has many overloads with parameters controlling:

Specify screen position as XMFLOAT2, XMVECTOR or RECT (in units of pixels if using default transformation)
Optional source rectangle (in units of pixels) for drawing just part of a texture (i.e. a sprite sheet)
Tint color (defaults to 1,1,1,1 which means 'no tinting')
Rotation (in radians)
Origin point (in units of pixels if using the default transformation): position, scaling and rotation are relative to this point. This defaults to (0,0) which is the upper-left of the sprite image. If you want to use the center of the sprite, for example, set the origin to (width / 2), (height / 2).
Scale
SpriteEffects enum (for horizontal or vertical mirroring)
Layer depth (for sorting)

The source rectangle is used to compute the texture coordinates for the sprite on the texture. The position, rotation, origin, and scale are used to compute the sprite triangle's drawing location.

Sorting

The first parameter to SpriteBatch::Begin is a SpriteSortMode enum. For most efficient rendering, use SpriteSortMode_Deferred (which batches up sprites, then submits them all to the GPU during the End call), and manually draw everything in texture order. If it is not possible to draw in texture order, the second most efficient approach is to use SpriteSortMode_Texture, which will automatically sort on your behalf.

When drawing scenes with multiple depth layers, SpriteSortMode_BackToFront or SpriteSortMode_FrontToBack will sort by the layerDepth parameter specified to each Draw call.

SpriteSortMode_Immediate disables all batching, submitting a separate Direct3D draw call for each sprite. This is expensive, but convenient in rare cases when you need to set shader constants differently per sprite.

Multiple SpriteBatch instances are lightweight. It is reasonable to create several, Begin them at the same time with different sort modes, submit sprites to different batches in arbitrary orders as you traverse a scene, then End the batches in whatever order you want these groups of sprites to be drawn.

SpriteBatch and SpriteSortMode
SpriteBatch sorting part 2
Return of the SpriteBatch: sorting part 3
SpriteSortMode.Immediate in XNA Game Studio 4.0

Alpha blending

Alpha blending defaults to using premultiplied alpha. To make use of 'straight' alpha textures, provide a blend state object to Begin.

m_states = std::make_unique<CommonStates>(device);

spriteBatch->Begin(SpriteSortMode_Deferred, m_states->NonPremultiplied() );

If you need to provide custom blend factors or sample mask, use the setCustomShaders callback to call the device context's OMSetBlendState directly instead.

SpriteFont is designed to work with premultiplied alpha, so if you need to draw both text and straight-alpha content, you should submit them in two different Begin / End batches. Alternatively, you can use MakeSpriteFont to generate 'straight-alpha' .spritefont files using the /NoPremultiply switch.

Custom render states

By default SpriteBatch uses premultiplied alpha blending, no depth buffer, counter clockwise culling, and linear filtering with clamp texture addressing. You can change this by passing custom state objects to SpriteBatch::Begin.

void Begin(SpriteSortMode sortMode,
    ID3D11BlendState* blendState,
    ID3D11SamplerState* samplerState,
    ID3D11DepthStencilState* depthStencilState,
    ID3D11RasterizerState* rasterizerState,
    std::function<void> setCustomShaders,
    FXMMATRIX transformMatrix);

Pass null for any parameters that should use their default value.

spriteBatch->Begin(SpriteSortMode_Deferred, nullptr, nullptr, nullptr, nullptr, [=]
{
   deviceContext->...
});

Pixel centers

In Direct3D 11, the 'pixel center' is at the '.5, .5' coordinate rather than Direct3D 9's integer coordinates being considered the pixel center. If doing 'nearest-point' filtering (such as CommonStates::PointClamp or CommonStates::PointWrap), then the sampled pixel is going to be the one that touces the pixel center based on the sprite location. This means that the position has to move from, say, "1.5" to "1.6" to get the pixel sample to change.

If you want to achieve something more like Direct3D 9's integer coordinates are pixel centers, then you should use DirectMath (or SimpleMath) to adjust your positions provided to SpriteBatch accordingly.

XMVECTOR pos = XMLoadFloat2(&m_position);

static const XMVECTORF32 s_half = { { { 0.5f, 0.5f, 0.f, 0.f } } };

pos = XMVectorAdd(XMVectorTruncate(pos), s_half);

m_spriteBatch->( ..., pos, ...)

Custom pixel shaders

To use SpriteBatch with a custom pixel shader (handy for 2D postprocessing effects such as bloom or blur), use the setCustomShaders parameter to specify a state setting callback function:

spriteBatch->Begin(SpriteSortMode_Immediate,
    nullptr, nullptr, nullptr, nullptr, [=]
{
    deviceContext->PSSetShader(...);
    deviceContext->PSSetConstantBuffers(...);
    deviceContext->PSSetShaderResources(...);
});

SpriteBatch automatically sets pixel shader resource #0 and sampler slot 0 for the texture specified by each Draw call, so you only need to call PSSetResources for any additional textures required by your shader.

To write a custom sprite batch pixel shader in HLSL, make sure it matches the following signature

Texture2D<float4> Texture : register(t0);
sampler TextureSampler : register(s0);

float4 MySpritePixelShader(float4 color : COLOR0,
    float2 texCoord : TEXCOORD0) : SV_Target0
{
    // TODO
}

Custom vertex shaders

To use a custom vertex shader with SpriteBatch, you'll need to create an input layout for your shader that uses VertexPositionColorTexture.

The vertex position x, y coordinates are generated from position, rotation, origin, and scale SpriteBatch::Draw parameters.
The vertex position z coordinate is the layerDepth SpriteBatch::Draw parameter, which defaults to 0.
The vertex u, v coordinates are generated.
The vertex color is the tint color SpriteBatch::Draw parameter, which defaults to White (1,1,1,1).

Here's an example using Effects.

void const* shaderByteCode;
size_t byteCodeLength;

effect->GetVertexShaderBytecode(&shaderByteCode, &byteCodeLength);

device->CreateInputLayout(VertexPositionColorTexture::InputElements,
                          VertexPositionColorTexture::InputElementCount,
                          shaderByteCode, byteCodeLength,
                          pInputLayout);

...

spriteBatch->Begin(SpriteSortMode_Deferred,
    nullptr, nullptr, nullptr, nullptr, [=]
{
    effect->Apply( deviceContext );
    deviceContext->IASetInputLayout( pInputLayout );
});

Remember that the pixel shader input signature must match the vertex shader output signature, so it's easiest to provide both if you are going to override the standard sprite vertex shader.

Custom transform

SpriteBatch::Begin also has a transformMatrix parameter, which can be used for global transforms such as scaling or translation of an entire scene. It otherwise defaults to matrix identity.

XMMATRIX matrix = ...;
spriteBatch->Begin(SpriteSortMode_Deferred, nullptr,
    nullptr, nullptr, nullptr, nullptr, matrix );

This transformation parameter only works if you are using the standard sprite batch vertex shader.

The full transformation depends on the orientation setting and/or the viewport setting for the device. The viewport is obtained from the SpriteBatch::SetViewport method or by calling RSGetViewports on the current context, and then used to construct a view matrix based on the setting provided by theSpriteBatch::SetRotation method.

// DXGI_MODE_ROTATION_ROTATE90
finalMatrix =
    matrix * XMMATRIX(0, -yScale, 0, 0, -xScale, 0, 0, 0, 0, 0, 1, 0, 1, 1, 0, 1);

// DXGI_MODE_ROTATION_ROTATE270
finalMatrix =
    matrix * XMMATRIX(0, yScale, 0, 0, xScale, 0, 0, 0, 0, 0, 1, 0, -1, -1, 0, 1);

//DXGI_MODE_ROTATION_ROTATE180
finalMatrix =
    matrix * XMMATRIX(-xScale, 0, 0, 0, 0, yScale, 0, 0, 0, 0, 1, 0, 1, -1, 0, 1);

// DXGI_MODE_ROTATION_IDENTITY (the default)
finalMatrix =
    matrix * XMMATRIX(xScale, 0, 0, 0, 0, -yScale, 0, 0, 0, 0, 1, 0, -1, 1, 0, 1);

// DXGI_MODE_ROTATION_UNSPECIFIED
finalMatrix = matrix;

Custom clipping

If custom clipping of the sprites is desired (such as clipping font strings), you can achieve this by first creating a custom raster state with scissor rectangle culling enabled:

ID3D11RasterizerState* scissorState = nullptr;
CD3D11_RASTERIZER_DESC rsDesc(D3D11_FILL_SOLID, D3D11_CULL_BACK, FALSE,
    0, 0.f, 0.f, TRUE, TRUE, TRUE, FALSE);
if (FAILED(device->CreateRasterizerState(&rsDesc, &scissorState)))
    // error

Then when you call Begin provide a custom callback to set the scissor rectangle:

spriteBatch->Begin(SpriteSortMode_Deferred,
    nullptr, nullptr, nullptr, scissorState,
    [&]()
    {
        CD3D11_RECT r( /* pixel rectangle coordinates here */);
        context->RSSetScissorRects(1, &r);
    });

Applications

The same set of techniques that were used with XNA Game Studio's SpriteBatch can be adapted to the DirectXTK implementation.

Animated sprites

The AnimatedTexture class demonstrates drawing an animated sprite.

Scrolling background

The ScrollingBackground class demonstrates drawing a scrolling background.

Sprite Sheet

The SpriteSheet class demonstrates drawing sprites from a sprite sheet (aka "texture atlas") to more efficiently use texture memory.

Post processing effects

The techniques described for XNA Game Studio will work with the C++ SpriteBatch.

Bloom on Windows Phone
Postprocessing effects on WP7, Part I
Postprocessing effects on WP7, Part II
Postprocessing effects on WP7, Part III

For Direct3D Feature Level 10.0 or better hardware, these are better done using PostProcess

Normal-mapped sprites

The techniques described in the SpriteEffects sample for XNA Game Studio also work with the C++ SpriteBatch.

Feature Level Notes

The implementation in SpriteBatch uses dynamic vertex buffers with 4 vertices per sprite, which works on all feature levels. The submission maximum batch size (2048) is within the limits of Feature Level 9.1's requirement to use 16-bit indices (DXGI_FORMAT_R16_UINT) and the maximum primitives per batch limit of 65535. This is robust and works well for the typical scale of usage for sprite batch.

For more extreme usage scenarios (large particle systems, star fields, etc.), writing a custom sprite implementation is likely the better solution over using SpriteBatch. With Feature Level 9.3, you can make use of instancing, and on Feature Level 10.0+ you can make use of the geometry shader to implement point-sprites

Threading model

Creation is fully asynchronous, so you can instantiate multiple SpriteBatch instances at the same time on different threads. Each SpriteBatch instance only supports drawing from one thread at a time, but you can simultaneously submit sprites on multiple threads if you create a separate SpriteBatch instance per Direct3D 11 deferred context.

Immediate and Deferred Rendering

Orientation

For phones, laptops, and tablets the orientation of the display can be changed by the user. For Windows Store apps, DirectX applications are encouraged to handle the rotation internally rather than relying on DXGI's auto-rotation handling.

In older versions of DirectXTK, you had to handle orientation changes via the custom transform matrix on Begin(). In the latest version of DirectXTK, you can handle it via a rotation setting (which is applied after any custom transformation).

Using the DirectX starting template for Universal Windows Platform (UWP) apps, you will want to add to your CreateWindowSizeDependentResources method:

spriteBatch->SetRotation( m_deviceResources->ComputeDisplayRotation() );

In Common\DeviceResources.h, you need to make ComputeDisplayRotation a public function instead of being private.

When using the directx-vs-templates DeviceResources for UWP, use:

spriteBatch->SetRotation( m_deviceResources->GetRotation() );

State management

Unlike ID3DXSprite, SpriteBatch does not save and restore existing state. For efficiency, it simply sets the state it requires to render and assumes that any subsequent rendering after spriteBatch->End() will overwrite state that it needs.

SpriteBatch makes use of the following states:

BlendState
Constant buffer (Vertex Shader stage, slot 0)
DepthStencilState
Index buffer
Input layout
Pixel shader
Primitive topology
RasterizerState
SamplerState (Pixel Shader stage, slot 0)
Shader resources (Pixel Shader stage, slot 0)
Vertex buffer (slot 0)
Vertex shader

The SpriteBatch class assumes you've already set the Render Target view, Depth Stencil view, and Viewport. It will also read the first viewport set on the device unless you've explicitly called SetViewport.

Be sure that if you set any of the following shaders prior to using SpriteBatch that you clear them: Geometry Shader, Hull Shader, Domain Shader, Compute Shader.

Xbox One

When using Direct3D 11.x fast semantics, you must make use of SetViewport which is otherwise optional as RSGetViewports is not supported in this mode.