stuburns said:
Also because I now I don't see why PS1 BC on PS2 and PS2 BC on PS3 don't allow for higher native resolutions. It's stupid not to allow it if can be done. Also my lack of emulator experience no doubt didn't help.
In the PS2's case, the BC PS3s have the PS2 graphics chip processing the PS2 graphics with the RSX just copying the final image and upscaling it for display. Only the CPU, IO and storage are emulated. So there's no way to change the resolution there.
On the PS1 case... well, I need to explain the difference between full software emulation and HLE first:
Before UltraHLE, all emulators emulated all of the hardware entirely in software, by writing code that reproduced the low-level logic performed by the original hardware as accurately as possible. This means emulating the graphics hardware functions down to what it does to draw every single pixel. A system emulated like that can only run at it's native resolution, because it replicates the hardware accurately. It was fine for 16-bit and 2D arcade emulators.
When 3D consoles came into market, emulator authors hit a wall: it was simply impossible to emulate the specialized 3D hardware in those consoles at playable speed with the PCs available. It was just too slow, and they couldn't apply software-rendering tricks like Quake1's because that wasn't how the emulated hardware worked. This was specially bad with the N64, which had graphic features which were beyond anything software renderers could do in real time (mainly bilinear filtering and z-buffering).
In order to emulate those consoles at playable speeds, emulator authors took advantage of the fact that the 3D hardware in them were black boxes: the games simply send commands for drawing polygons, setting textures and turning effects on/off and the hardware took care of outputting the image to the TV. It was just a matter of translating these drawing commands into something a PC videocard can work with and have it do the rendering instead. This was called
High
Level
Emulation: the emulator doesn't emulates the graphics chip down to every transistor anymore, it simply emulates the interface used by the system to talk to the graphics.
Now, back to the PS3... the PSX emulator on the PS3 seems to be entirely software based, for three reasons: 1) It's
far easier to code it this way, 2) They have plenty of power for full speed software emulator and 3) HLE introduces a plethora of glitches and bugs which requires years of testing and tweaking and game-specific hacks to get rid of.
(There's actually a 4th reason: Sony bought Connectix' PSX emulator years ago, which was 100% software-based and had a massively high compatibility.)
That's why there's no texture smoothing option on the PS3. On the PS2 the graphics was emulated via HLE using the PS2 GPU, which was designed to make it easier to run PSX games and could enable bilinear filtering. But even that introduced glitches in some games.
