TITANIC: Bad mouse cursor transparency

[csnover]

Build: 6fac0ace2c844aa68c2482362021981ed1db931b + PR 975, macOS 10.11, SDL 2.0.5, ASan on

Cursors currently are getting reduced to 1-bit alpha instead of the full alpha used by the original game, which does not look very good and does not match the original engine. I feel like CursorMan should be supporting this without too much difficulty already, but just rendering the cursor to the game surface itself would be fine too.

[dafioram]

Pointer Comparison

[dreammaster]

I have a branch with the cursor alpha dithering removed at ​https://github.com/dreammaster/scummvm/tree/titanic_cursors

I'd really prefer this to be resolved by adding support for alphas to the CursorMan backend, rather than trying to implement a bunch of cursor drawing code redundantly to the engine.

[dreammaster]

Finally fixed. Though note that with scalers turned on it requires SDL 2.0.6 for the cursors to show.