8/16 bit display mode emulation is now implemented internally instead of
relying on the builtin Windows shims, as those are sometimes unreliable
(not triggering for some games on some systems when they should).
External DirectDraw hooks (such as the DWM8And16BitMitigation shim)
are disabled to avoid interference.
Fixes issues reported in #8, #9, #15.
AMD drivers reject system memory surfaces that are larger than the maximum
texture width/height supported by the driver (usually 4096x4096 for AMD).
This can cause issues in games that create larger system memory surfaces.
This workaround crops the driver resource dimensions to the allowed
maximum values and handles blitting outside this region by creating a
temporary resource that maps to the actual affected system memory region.
Fixes crashes with AMD drivers in Rainbow Six games and Desperados,
mentioned in issue #2 and #8.
On recent drivers, double buffered DirectDraw flips no longer wait for the
vertical sync before returning and instead just insert the flip into the
flip queue for later execution. This effectively results in triple buffered
behavior (in the render-ahead sense) and causes up to an extra frame of
latency even if the flip queue size is set to 1.
To restore the legacy double buffered behavior, each flip waits for the
presented frame to leave the flip queue before returning.
To restore the legacy triple buffered behavior, the flip queue size is
forced to 1. This causes the flip to wait if the previous flip is still
pending.
Video memory render target surfaces get an additional video memory off-screen
plain surface used for providing efficient direct memory access (locking).
All 2D operations starting with a lock are redirected to the off-screen plain
surface until the next rendering operation requires the render target surface.
The two surfaces are kept in sync via blits as needed.
Fixes performance issues in Rogue Spear menus, mentioned in issue #2.
Legacy DirectDraw interfaces specify the z-buffer format as a single bit depth
number instead of as a DDPIXELFORMAT struct. DirectDraw seems to convert a
legacy z-buffer bit depth of N into a DDPIXELFORMAT with dwFlags = DDPF_ZBUFFER,
dwZBufferBitDepth = N and dwZBitMask set to 1s in the lowest N bits.
Some drivers (so far noticed with AMD only) report the list of supported
z-buffer bit depths incorrectly, resulting in a game potentially selecting a
bit depth that can't actually be created via the legacy interfaces.
For example, the driver may report 16 and 32 bits as supported whereas all
32 bit z-buffer pixel formats use only 24 bits for z-buffer (with the
remaining bits unused or used as stencil buffer). Meanwhile the same driver
doesn't report 24 bits as supported when it's actually supported.
This fix overrides the set of supported z-buffer bit depths in D3DDEVICEDESC
structs for HAL devices to align with the actually supported pixel formats.
Fixes a startup issue in Rainbow Six mentioned in issue #2.
