This Windows XNA application implements Gaussian blurring on a source texture image. The Gaussian blur is implemented as an HLSL effect. This demo performs the Gaussian blur on a pre rendered texture bitmap image. However the Gaussian blur can be performed as a post process on a scene rendered to a render target texture. Gaussian blurs are commonly used in conjunction with more advanced post processing shader effects such as full screen specular bloom shaders.

A 2D Gaussian distribution is said to be circularly symmetric. This means that the Gaussian blur operation is linearly separable. Instead of applying the 2D filter kernel matrix to the image we can instead perform the Gaussian blur operation in two passes using a 1D filter kernel matrix. We perform a horizontal Gaussian blur pass on the image followed by a vertical Gaussian blur pass. This produces the same result as performing a single Gaussian blur pass on the image using the 2D filter kernel matrix. However performing the blur in two passes using 1D filter kernel matrices is much faster.

To learn more about Gaussian blurring see here.

Note:
1. This demo requires shader model 2.0 or higher support.
2. This demo is provided in source form only. No pre built binaries are supplied.

Download source, assets, and XNA Game Studio 4.0 solution files.

Change History:

15 January 2011.
Initial release of demo for XNA Game Studio 4.0. The previous XNA Game Studio 3.0 version of the demo is no longer supported and is now only available upon request.

16 November 2008.
Initial release of demo for XNA Game Studio 3.0. The previous XNA Game Studio 2.0 version of the demo is no longer supported and is now only available upon request.