The plain present path copied the VRAM image into the swapchain with
vkCmdBlitImage, alpha included. VRAM alpha is the PSX mask/STP bit, 0 on
most pixels, and AMD's compositor honours it even with an OPAQUE
compositeAlpha: parts of the window went see-through (8x8 black/white
blocks of whatever sat behind it). Reported in #411.
vk_renderer_present_vram/_wide now draw the displayed rect with a
fullscreen triangle whose fragment shader writes alpha = 1 (new
present.vert/.frag). The pass is self-contained and created lazily; if
any of it fails to build, presents fall back to the old blit. Its render
pass ends in TRANSFER_DST_OPTIMAL so finish_present (OSD + present
barrier) is unchanged. Wide surfaces gain SAMPLED usage for it.
Checked on an RX 7900 XT: intro/logo screens render correctly, no new
validation-layer messages.
Most of this was written by Claude Opus 5.5; I reviewed and tested it.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Martin Penkava