With BL_VKBRIDGE_CEF_ANGLE=vulkan the CEF GPU process stopped crashing but
Chromium still composited in software (gpu_compositing: disabled_software,
Steam "Disabling GPU acceleration: Disabled/RuntimeDetect", VizCompositorThread
at a full core). The GPU report shows why: "eglCreateWindowSurface failed with
error EGL_BAD_CONFIG". ANGLE's Vulkan backend on X11 gives every EGL config the
root window's visual; Chromium's X11 surface asks for a config whose
EGL_NATIVE_VISUAL_ID is the ARGB visual whenever a compositing manager owns
_NET_WM_CM_S0 (gamescope does), finds none and passes a null config.
bl_webhelper_layout() now adds +Vulkan +VulkanFromANGLE +DefaultANGLEVulkan
for ANGLE on Vulkan, so Skia composites through an xcb swapchain on ANGLE's
Vulkan device and no EGL window surface is needed. BL_VKBRIDGE_CEF_VULKAN=0
leaves it off; unset BL_VKBRIDGE_CEF_ANGLE still means Steam's stock layout.
Steam drops -cef-use-angle: on the bridge the CEF GPU process reports
ANGLE_OPENGL (ANGLE on Zink) with -cef-use-angle=vulkan on the command line.
An explicit BL_VKBRIDGE_CEF_ANGLE now also becomes --use-gl=angle
--use-angle=<backend> on steamwebhelper's own argv (stock process layout kept);
unset, nothing changes.
Ahmad Sayed Alsayed Ebrahim