If a game is doing a screen shake (for example, DOTT when the
stereo is on), and the user does an RTL, the screen shake offset
may get stuck if the engine does not reset it on shutdown. To
avoid this in all cases, just always reset the screen shake
whenever the graphics manager is told to switch to a new graphics
mode.
The SDL graphics manager was just ignoring calls from CursorMan to
set the cursor to a blank cursor, which meant engines that did not
immediately send a cursor to CursorMan at startup would still show
the launcher's cursor (usually with a broken palette).
The OpenGL graphics manager would try to generate and draw an
invalid cursor surface when receiving an empty cursor.
The only reason we show the system cursor outside the game area is
to show users where their mouse is when the window is resized and
the mouse is outside the game area. If the game cannot be
interacted with, then the mouse also does not need to be shown in
the black areas.
This patch refactors the OpenGL and SDL graphics backends,
primarily to unify window scaling and mouse handling, and to
fix coordinate mapping between the ScummVM window and the
virtual game screen when they have different aspect ratios.
Unified code for these two backends has been moved to a new
header-only WindowedGraphicsManager class, so named because it
contains code for managing graphics managers that interact with
a windowing system and render virtual screens within a larger
physical content window.
The biggest behavioral change here is with the coordinate
system mapping:
Previously, mouse offsets were converted by mapping the whole
space within the window as input to the virtual game screen
without maintaining aspect ratio. This was done to prevent
'stickiness' when the mouse cursor was within the window but
outside of the virtual game screen, but it caused noticeable
distortion of mouse movement speed on the axis with blank
space.
Instead of introducing mouse speed distortion to prevent
stickiness, this patch changes coordinate transformation to
show the system cursor when the mouse moves outside of the virtual
game screen when mouse grab is off, or by holding the mouse inside
the virtual game screen (instead of the entire window) when mouse
grab is on.
This patch also improves some other properties of the
GraphicsManager/PaletteManager interfaces:
* Nullipotent operations (getWidth, getHeight, etc.) of the
PaletteManager/GraphicsManager interfaces are now const
* Methods marked `virtual` but not inherited by any subclass have
been de-virtualized
* Extra unnecessary calculations of hardware height in
SurfaceSdlGraphicsManager have been removed
* Methods have been renamed where appropriate for clarity
(setWindowSize -> handleResize, etc.)
* C++11 support improved with `override` specifier added on
overridden virtual methods in subclasses (primarily to avoid
myself accidentally creating new methods in the subclasses
by changing types/names during refactoring)
Additional refactoring can and should be done at some point to
continue to deduplicate code between the OpenGL and SDL backends.
Since the primary goal here was to improve the coordinate mapping,
full refactoring of these backends was not completed here.
Previously we were clearing the whole backbuffer for 3 frames after a
window size change, and then only clearing the game area. This assumes
the OpenGL driver uses at most 3 render buffer and uses them in
sequential order. This does not seem to be the case on Linux when using
an Intel integrated GPU.
Instead we now clear the whole backbuffer on each frame to make sure
there are no leftovers remaining on the screen. All semi-recent GPUs
should have hardware clear anyway so this should not impact negatively
performance.
Possibly fixes#10025.
Updating the cursor's texture is not necessary if it is not going to be drawn.
Fixes glDrawArrays sometimes failing due to using a framebuffer with an
incomplete color attachment. In SCI32 games, the framebuffer is incomplete
because the engine does not define pixel data for the cursor.
This replaces the two graphics modes "OpenGL (No filtering)" and
"OpenGL". Now there is a single "OpenGL" mode and filtering is
controlled by the kFeatureFilteringMode.
This allows us to use various framebuffer settings easily. Now the GPU
accelerated CLUT8 surface implementation does not need to query former
framebuffer state anymore.
GLES2 requires precision qualifiers to be set and allows use of precision
qualifiers. For GLES2 we define a default precision now. Since precision
qualifiers are not supported in the GLSL version we use for GL, we
introduce compatibility #defines.
This is basically an interface extracted from Texture without any knowledge
about any actual implementation, except for copyRectToTexture, fill, and
dirty rect handling. These are convenient helpers.
