PS2 uses a -0.5 offset before sampling so texels must be rounded to half-pixel boundary
If fixes glitches on Venus and taisho-mononoke
Note: I didn't fixed yet texture render in reverse because I don't have any test for it.
UserHacks_round_sprite_offset = 1 <= enable correction of flat sprites
UserHacks_round_sprite_offset = 2 <= enable correction of all sprites (better on a couple of dump but not sure of the consequence)
I completely redo the algorithm. This time I do the projection and
interpolation of the 2 extrem vertex. This way I can compute the min/max
valid texture coordinate.
It gives stronger guarantee that texture sampling will be done inside the texture.
However it might have a performance impact, likely reasonable because it
is limited to sprite vertex.
A big thanks you to all people that provide me GS dump and test reports.
It is replacement of the previous hack (UserHacks_stretch_sprite). Don't enable both in the same time!
The idea of the hack is to move the sprite to the pixel boundary. It
avoids most of rounding issue. It also rescales verticaly the sprite (avoid horizontal line on ace combat).
I don't like this rescaling maybe we can limit it to only 1 pixels.
On my limited testcase, results are much better with any upscaling factor.
I still have a bad line in Kingdom heart. If you have issue with others
game please provide us a GS dump.
2x upscaling is pixel perfects. Bigger upscaling is better but not yet perfect
Feedbacks are welcomes (note it doesn't solve all upscaling issue, only wrong texture sampling)
For the history:
If you have a texture of [0;16[ texels and draws a primitive [0;16[
The formulae to sample last pixels of texture is
0.5 + (16*s-1)/(16*s) * 16
Native (s==1): 15.5 (good)
2x (s==2): 16 (bad, outside of the texture)
4x (s==4): 16.25 (bad, really outside of the texure))
+ This is not yet perfect. Really, this standard seems like a load of crap to me in fact...
At least it works now. Should test again when gcc 5 & new c++ libs gets out.. Until then, it will do.
On Linux, CPUs with AVX2 instruction sets that have TSX disabled (by
microcode update or otherwise) fail to build GSdx. The __RTM__ macro is
undefined, with leads to the TSX RTM instruction set (_xbegin, _xend,
_xabort, etc.) being unavailable.
Modify the preprocessor check so that the RTM instructions are only used
if available.
It conflicts with the global definition
I don't remember why this option was set on GSdx. Potentially it could be dropped (or fixed correctly)
Anyway, it will help to enable Address Sanitizer on Linux Build
Gregory Hainaut