The more detailed the cubemap, the more detailed the reflection. The more detailed the reflection, the more shiny the surface appears. A matte surface is just one which scatters light more.
So you need to either blur your cubemaps, or if you can't afford to do that, use a low res one, which you have done. The low res one will not be as good of quality as a blurred one though, because you're only sampling four pixels on the screen, so you're gonna miss a lot.
I have a function in the code archives which will do a hardware accelerated blur. If you use that with a lower res texture to boot, it might work. But it would probably be costly to blur a larger texture enough.
Hm... a thought just occured to me how one might do a real box blur using a setup similar to the one I used, but different. It would be a little slower because it would require you to copy the texture twice, but it would allow greater blur radiuses to be done in realtime.
It would involve drawing several copies of the texture offset horizontally on top of one another using the darken+add method I have in my blur function, and then copying the result, and then using the result to do the same thing vertically, and then copying that result to use it as the final texture. I think that would result in a proper box blur. The method I used leaves little circle cutout looking things at the corners of things in your texture. So a blurred square has little circles on the corners that are missing kinda. Also since it has to use so many copies of the image to render the texture large blur radiuses, there's a lot of overdraw.
So you need to either blur your cubemaps, or if you can't afford to do that, use a low res one, which you have done. The low res one will not be as good of quality as a blurred one though, because you're only sampling four pixels on the screen, so you're gonna miss a lot.
I have a function in the code archives which will do a hardware accelerated blur. If you use that with a lower res texture to boot, it might work. But it would probably be costly to blur a larger texture enough.
Hm... a thought just occured to me how one might do a real box blur using a setup similar to the one I used, but different. It would be a little slower because it would require you to copy the texture twice, but it would allow greater blur radiuses to be done in realtime.
It would involve drawing several copies of the texture offset horizontally on top of one another using the darken+add method I have in my blur function, and then copying the result, and then using the result to do the same thing vertically, and then copying that result to use it as the final texture. I think that would result in a proper box blur. The method I used leaves little circle cutout looking things at the corners of things in your texture. So a blurred square has little circles on the corners that are missing kinda. Also since it has to use so many copies of the image to render the texture large blur radiuses, there's a lot of overdraw.