sharpemu/docs/rendering-resolution.md

Rendering resolution

Options → Rendering exposes two independent sizes, globally and per game:

• Resolution sets the host window size or exclusive fullscreen mode.
• Game display mode reports a 1080p display to the game by default. Select 3840×2160 to request a 4K display. A registered presentation buffer cannot change this setting.

The CLI equivalents are --resolution=1280x720 and --guest-resolution=1920x1080 (or 3840x2160). For example, a 1080p game display can be presented in a 720p window; changing the window alone does not reduce the work the game renders.

The game chooses its internal render targets. Some games adapt those targets to the reported display mode; others render at a fixed resolution and may still register 4K buffers with a 1080p display. Silent Hill: The Short Message does so in current testing. The size of that presentation buffer alone also does not establish the sizes of its intermediate scene targets.

Arbitrary internal resolution scaling is not implemented. The previous RenderResolutionScale setting and its SHARPEMU_RENDER_SCALE export had no renderer consumer; they have been removed. They did not change rendering work. A correct implementation must preserve guest memory layouts while scaling host attachments, viewports, scissors, image fetches, compute accesses, aliases and readbacks consistently. Reducing only the output image or window is not an internal-resolution implementation.