How to: Export a Texture for Use with Direct2D or Javascipt Apps
This document demonstrates these activities:
Configuring the source image to be processed by the Image Content Pipeline.
Generate a block-compressed .dds file.
Generate premultiplied alpha.
Disable mipmap generation.
Rendering conventions in Direct2D
Textures that are used in the context of Direct2D must conform to these Direct2D internal rendering conventions:
Direct2D implements transparency and translucency by using premultiplied alpha. Textures used with Direct2D must contain premultiplied alpha, even if the texture doesn't use transparency or translucency. For more information about premultiplied alpha, see How to: Export a Texture that has Premultiplied Alpha.
The texture must be supplied in .dds format, by using one of these block-compression formats:
Mipmaps are not supported.
To create a texture that's compatible with Direct2D rendering conventions
Begin with a basic texture. Load an existing image, or create a new one as described in How to: Create a Basic Texture. To support block-compression in .dds format, specify a texture that has a width and height that are multiples of four in size, for example, 100x100, 128x128, or 256x192. Because mipmapping is not supported, the texture does not have to be square and does not have to be a power of two in size.
Configure the texture file so that it's processed by the Image Content Pipeline. In Solution Explorer, open the shortcut menu for the texture file you just created and then choose Properties. On the Configuration Properties, General page, set the Item Type property to Image Content Pipeline. Make sure that the Content property is set to Yes and Exclude From Build is set to No, and then choose the Apply button. The Image Content Pipeline configuration property page appears.
Set the output format to one of the block-compressed formats. On the Configuration Properties, Image Content Pipeline, General page, set the Compress property to BC3_UNORM compression (/compress:BC3_UNORM). You could choose any of the other BC1, BC2, or BC3 formats, depending on your requirements. Direct2D doesn't currently support BC4, BC5, BC6, or BC7 textures. For more information about the different BC formats, see Block Compression (Direct3D 10).
The compression format that's specified determines the format of the file that's produced by the Image Content Pipeline. This is different than the Format property of the source image in the Image Editor, which determines the format of the source image file as stored on disk—that is, the working format. Typically, you don’t want a working format that's compressed.
Configure the Image Content Pipeline to produce output that uses premultiplied alpha. On the Configuration Properties, Image Content Pipeline, General page, set the Convert to pre-multiplied alpha format property to Yes (/generatepremultipliedalpha).
Configure the image content pipeline so that it doesn't generate mipmaps. On the Configuration Properties, Image Content Pipeline, General page, set the Generate Mips property to No.
Choose the OK button.
When you build the project, the Image Content Pipeline converts the source image from the working format to the output format that you specified—conversion includes generation of premultiplied alpha—and the result is copied to the project’s output directory.