PPSSPP/Dolphin output no video (Metal)

[2V3EvG4LMJFdRe]

Description

The macOS Metal build of RetroArch's PPSSPP/Dolphin core work in that I can load a game and hear sounds come out of it as I use my controller, but the screen remains pitch black the whole time.

Expected behavior

Any graphics whatsoever.

Steps to reproduce the bug

1. Download macOS Metal build
2. Load a game on PPSSPP/Dolphin using the metal driver

Bisect Results

PPSSPP and Dolphin output video if ran with the OpenGL build of RA under the OpenGL video driver.
Flycast core outptus video as well under Metal. I'm only mentioning this because it seems comparable.

Version/Commit

• RetroArch: 1.15.0

Environment information

• OS: macOS 10.13.6

[2V3EvG4LMJFdRe]

Related issues: #14822 #14424 #13172

Some kinda progress at least for my needs: the new builds of Metal RA now include the options metal vulkan gl and glcore, making it possible to run PPSSPP through OpenGL. The performance seems alright for my needs. Dolphin runs as well, but the performance is poor, as documented.