In order to avoid DLL preloading attacks, we should be careful about where we
load DLLs from. These packages load graphics DLLs, which may be provided by the
OS, by a graphics vendor, or even by individual applications. As such, we can't
restrict loading them to just system32-provided paths. Instead, we invoke
LoadLibraryEx [0] with the LOAD_LIBRARY_SEARCH_DEFAULT_DIRS path, which will search
system32, application-defined paths, and the path of the primary application
executable. This mode ignores the system %PATH% variable, which dramatically
reduces the attack surface of malicious or unintended DLLs.
Applications may add custom paths to the search list by calling the standard
windows AddDllDirectory function [1] prior to attempting to initialize GL.
Thanks to Mohsen Mirzakhani and Utkarsh Satya Prakash for bringing this to
our attention.
[0] https://learn.microsoft.com/en-us/windows/win32/api/libloaderapi/nf-libloaderapi-loadlibraryexa
[1] https://learn.microsoft.com/en-us/windows/win32/api/libloaderapi/nf-libloaderapi-adddlldirectory
Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
All GPU APIs except OpenGL ES 2 can generate mipmaps for textures.
This trades 33% more GPU memory use for improved rendering quality
and speed for downscaled images.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Before that change, Gio could crash when the WebGL context was lost
unexpectedly. Now, Gio will properly handle such situation and
recreate the buffers/resources when context is restored and will
wait until context is recovered.
Signed-off-by: Inkeliz <inkeliz@inkeliz.com>
As suggested by Egon Elbre, passing a large struct of function pointers
forces Cgo checks on all of the pointer on every Cgo call. This
change instead passes only the relevant function pointer.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Before that patch, the Call function was used to call each
JS function related to WebGL. The Call function contains
strings, which is slow on most browsers. Now, it uses
Bind on the initialization and re-use the same function,
avoiding the usage of strings.
Signed-off-by: Inkeliz <inkeliz@inkeliz.com>
On my Fedora Intel GPU, issuing a glBufferSubData immediately after a
glBufferData with no data may leave the buffer cleared.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
OpenGL ES 2.0 doesn't support glBlitFramebuffer, but does support
glCopyTexSubImage2D. Fortunately, we don't need the extra features of
glBlitFramebuffer anyway.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Modern API such as Metal and Vulkan want clients to compile expensive
state changes into pipeline objects. Change our GPU driver abstraction
to match, thereby paving the way for future drivers.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
To ease the integration with foreign OpenGL contexts, carefully save the
context state before rendering a frame and restore it afterwards. Gio
rendering can then be mixed with OpenGL code that expects exclusive
control over context state.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
This changes moves the macOS specific setup for desktop OpenGL to the
portable opengl package. The opengl package already takes care of the
desktop OpenGL setup for sRGB framebuffers, and by moving the code we
avoid calling the wrong OpenGL functions in case both OpenGL.framework
and ANGLE libGLESv2.dylib is linked into the program.
Remove the interface casting expressions for gl.Functions; it wasn't
worth the trouble to keep updated.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Desktop OpenGL implements a GL_FRAMEBUFFER_SRGB setting; query that instead
of the frambuffer color encoding.
With this change it is no longer necessary to enable FRAMEBUFFER_SRGB
in the macOS setup; remove it.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
macOS is the only platform where desktop OpenGL is used. To support
foreign ANGLE contexts add a setting to override Gio's selection of
OpenGL implementation.
The bulk of this change is making all function pointers per-context
instead of global, and loading the OpenGL library dynamically. As a side
effect we're closer to Gio tolerating a platform without any OpenGL
implementation. For example, Apple has deprecated OpenGL and OpenGL ES
on its platforms and may remove them in the future.
Note that as a side-effect of this change, Gio needs Go 1.16 or newer to
run on iOS.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
There was a special case for optional symbols for macOS/iOS. It turns out
dlsym(3) works as expected, so this change deletes the special case.
The change is required to make Gio work with ANGLE, which emulates
OpenGL ES on top of Metal.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Egon Elbre