BasicPostProcess

DirectXTK	PostProcess

Performs basic post-processing with a built-in set of shaders which operate using one input texture.

Header

#include "PostProcess.h"

Initialization

Construction requires a Direct3D 12 device, a shader selection parameter, and state description:

std::unique_ptr<BasicPostProcess> postProcess;

RenderTargetState rtState(m_deviceResources->GetBackBufferFormat(),
    m_deviceResources->GetDepthBufferFormat());

postProcess = std::make_unique<BasicPostProcess>(device, rtState, BasicPostProcess::Sepia);

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

Shader selection

BasicPostProcess can be configured to use various pixel shaders when creating the instance:

• Copy: Performs a simple read of the input texture, outputting the same color.
• Monochrome: Converts the input texture pixels to a luminance value.
• Sepia: Implements a sepia-tone effect.
• DownScale_2x2: Downscales each 2x2 block of pixels to an average. This is intended to write to a render target that is half the size of the source texture in each dimension.
• DownScale_4x4: Downscales each 4x4 block of pixels to an average. This is intended to write to a render target that is a quarter the size of the source texture in each dimension.
• GaussianBlur_5x5: Performs a Gaussian blur with a 5x5 kernel
• BloomExtract: Performs a bloom extract, which is the first pass in implementing a bloom effect
• BloomBlur: Performs a horizontal or vertical blur which is typically the second and third passes of implementing a bloom effect.

Properties

• SetSourceTexture is used to set the input texture as a Shader Resource View Descriptor. Because some internal parameters are based on the resource size, a the resource should be provided as well.

• SetGaussianParameter sets the multiplier for the GaussianBlur_5x5 shader.

• SetBloomExtractParameter sets the extract parameter for the BloomExtract shader.

• SetBloomBlurParameters sets the horizontal vs. vertical mode as well as the size and brightness factors for the BloomBlur shader.

Example

If drawing a single texture which fills the render viewport, then using the Copy effect above is faster than using SpriteBatch.

std::unique_ptr<BasicPostProcess> postProcess;
postProcess = std::make_unique<BasicPostProcess>(device, rtState, BasicPostProcess::Copy);

...
postProcess->SetSourceTexture(
    m_resourceDescriptors->GetGpuHandle(Descriptors::Background),
    m_texture.Get());

// Set RSSetViewports to the rectangle you want to fill with the texture.

// If the viewport is not the full render target, be sure to call RSSetScissors as well.

postProcess->Process(commandList);

Remarks

This class in Copy mode can be used for GPU-based format conversion by using a render-to-texture render-target of the desired target format. This can also be used to achieve GPU-based texture resizing as well. The main limitations are that the source format must be supported as a 2D texture for your Direct3D Hardware Feature Level, and the target format must be supported as a render-target. See Microsoft Docs for details on supported formats.