While the PingPong buffers were always texture-backed, currentScene
and transBuffer used to be backed by renderbuffers, which might have
been more optimized as render targets on older hardware; but since
all buffers in Graphics got switched to being texture backed to allow
blitting via rendering (when hardware blitting isn't available or broken,
eg. on mobile platforms), their reason to exist vanished.
For transBuffer, we can reuse the backbuffer of the PingPong structure,
while currentScene might have been useless from the start.
The default value is an empty string, which triggers the simple
transition. Passing null is not legal (and wasn't possible in
mkxp from Ruby side anyway).
Fixes#108.
Assuming that there is enough memory for mkxp to stay in the
background and that the OS doesn't kill the process, this should
allow smooth resuming after moving back into the foreground.
For now, EGL context loss is not handled.
Using the kitchen sink plane shader for viewport effects, even
if only a small part of them are active, incurs great performance
loss on mobile, so split the rendering into multiple optional
passes which additionally use the blending hardware for faster
mixing (lerping).
Also, don't mirror the PingPong textures if the viewport effect
covers the entire screen area anyway.
Setup active RGSS version at runtime. Desired version can be
specified via config, or as default, auto detected from the game
files. This removes the need to build specifically for each
version, which should help packaging a lot.
This also greatly reduces the danger of introducing code that
wouldn't compile on all RGSS version paths (as certain code paths
were completely ifdef'd out).
This can be optimized more, eg. not compiling shaders that aren't
needed in the active version.
Performance can still be crudely measured by turning off
the framelimit and observing the FPS count. For everything
else, there's always callgrind / apitrace.
GL entrypoint resolution is now done manually. This has a couple
immediate benefits, such as not having to retrieve hundreds of
functions pointers that we'll never use. It's also nice to have
an exact overview of all the entrypoints used by mkxp.
This change allows mkxp to run fine with core contexts, not sure
how relevant that is going to be in the future.
What's noteworthy is that _all_ entrypoints, even the ones core
in 1.1 and guaranteed to be in every libGL, are resolved
dynamically.
This has the added benefit of not having to link directly against
libGL anymore, which also cleans up the output of `ldd` quite
a bit (SDL2 loads most system deps dynamically at runtime).
GL headers are still required at build time.
