In this tutorial, I explain how to use batch processing in Photoshop to convert the format of multiple images to DDS.
1. Download and install NVIDIA Texture Tools for Adobe Photoshop from here. This will install NVIDIA DDS plug-in. The NVIDIA DDS plug-in supports the DXTC texture compression format and allows you to open and save .dds files in RGB format.
2. Open Adobe Photoshop.
3. Open the “Actions” palette (Window | Actions).
4. Create a new action and name it File Format DXT1.
5. Choose File | New from the main menu and press OK.
6. In the Action palette, select the red circle. This is the “Record” icon.
7. Now, you are recording the macro. Select File | Save As. Then select D3D/DDS type, and click Save. In new dialog that appears, select DXT1 RGB 4 bpp | no alpha (Known as DXT1c) and click Save button. After the image is saved, hit the stop button (black square).
8. Select File | Automate | Batch.
9. In the Batch dialog box, after selecting Action | File Format, select the Source. The Source folder is the folder that contains the files to be processed.
10. In the Batch dialog box, select the Destination folder. All the files in source folder are saved as DDS in destination folder.
11. Select “Override Action ‘Save As’ Command”
12. Make sure “Document Name” and “extension” are selected in the two consecutive File Naming fields.
13. Select ‘OK’. The files will now open and close one at a time. Once the operation is complete, converted images will be in destination folder.
14. Vanda Engine 1 assumes that DXT1 format has no alpha channel. The reason is that Nvidia plugin does not set the alpha bit when writing out DXT1 ARGB 4 bpp | 1 bit alpha (Known as DXT1a). Due to that, Vanda Engine 1 does not know how to distinguish between DXT1a and DXT1c formats. In this case, Vanda Engine 1 does not read the alpha channel and does not apply it to geometries. If your original textures have an alpha channel and you want that Vanda Engine 1 applies the alpha channel to appropriate geometries, you should save the textures as DXT3 or DXT5. To do this, repeat the above procedure for DXT3 ARGB 8 bpp | explicit alpha or DXT5 ARGB 8 bpp | interpolated alpha.