1. download the dj hero 2 PS3 texture pack v1.2.1, and make sure your dolphin is updated to the newest version.
2. copy it to C:\Users\YourUserHere\Documents\Dolphin Emulator\ResourcePacks (don't do this if you set a custom ResourcePacks folder)
and make sure to delete the old one if you had it before this.
3. do not extract it.
4. open dolphin, and go to tools, then Resource Pack Manager
5. It should show up, click on it then click install
6. make sure you have upscaling atleast at 720p
7. go to the graphics menu, then advanced. Click on "Load Custom Textures" Then click on "Prefetch Custom Textures" (you can turn this option off if you have performance issues)
8. click close on the graphics screen, then go play your game. Enjoy!