The implementation was removed with the migration to ANGLE. This
reimplements it. This is required by Stimulation Clicker on neal.fun,
which does not clear the framebuffer itself, instead relying on the
browser doing it.
This is used to put together the list of supported WebGL extensions
based on the available extensions, per-extension required extensions
and WebGL version.
Namely:
- Perform case-insensitive matching
- Return the same extension objects every time
- Only enable the extension if it's supported by the current context
This causes it to enforce the sections "Differences Between WebGL and
OpenGL ES 2.0" from the WebGL 1 specification and "Differences Between
WebGL and OpenGL ES 3.0" from the WebGL 2 specification. It also
disables a bunch of extensions by default, which we must now request
with glRequestExtensionANGLE.
This is required to return original references to the shaders attached
to a program from getAttachedShaders. This is required for Figma (and
likely all other Emscripten compiled applications that use WebGL) to
get it's own generated shader IDs from the shaders returned from
getAttachedShaders.
We added these methods to propagate OOM errors at process startup, but
we longer fret about these tiny OOM failures. Requiring that these init
methods be called prohibits using these strings in processes that have
not set up a MainThreadVM. So let's just remove them and initialize the
strings in a sane manner.
In doing so, this also standardizes how we initialize strings whose C++
variable name differs from their string value. Instead of special-casing
these strings, we just include their string value in the x-macro list.
Previously the enforcement was only done on creation. Not enforcing it
on change would cause a crash if the canvas width/height was set to
zero or less.
Required by https://qwasm2.m-h.org.uk, which adds a custom `name`
attribute to objects it generates. It then gets some of these objects
out with getParameter, and expects the `name` attribute to be there.
By doing that we eliminate the need for the vertical flip flag.
As a side effect it fixes the bug when doing:
`canvasContext2d.drawImage(canvasWithWebGLContext, 0, 0);`
produced a flipped image because we didn't account for different origin
while serializing PaintingSurface into Gfx::Bitmap.
Visual progress on https://ciechanow.ski/curves-and-surfaces/
This way we could be sure that context object won't be deallocated
before any of the objects that belong to it.
Having a context pointer is also going to be used in upcoming changes
to generate an INVALID_OPERATION error if an object does not belong to
the context it's being used in.
