v0.5.0

HDR is now on by default. On a display that reports extended dynamic range, present routes through the BT.2446-A inverse tone mapper (operated in ICtCp, so saturated content stays saturated as it is lifted) and the layer runs as a float surface tagged for extended linear output, with the shader's peak following the display's live headroom frame by frame. Previously this was opt-in behind color.hdr.enable in mtld3d.conf.

The display decides, not the setting. HDR only engages when the attached screen actually reports EDR headroom, so a monitor without it renders exactly the same frames it did before; nothing about the game's rendering changes, only what the final present does with the brightness the panel has available. To go back to the SDR path on a display that does have headroom, set color.hdr.enable = false in mtld3d.conf, or launch with MTLD3D_CONFIG="color.hdr.enable=false".

The reason it was opt-in was that the HDR path shipped young, and it showed: the ICtCp matrix pair went out in two different scalings, which quietly halved every chromatic difference; the drawable was pinned to the game's back-buffer size, so the compositor resampled the whole frame on the way to the screen; and a fresh float drawable could reach the display with nothing written into it, which is what the reported pink flash was. Those are fixed and have been in the last three releases, and what is left is a better picture than the SDR path can give on a panel with headroom, since that path throws away every nit above paper white.

Also in this release: the log line that reports HDR being disabled now names the actual config key. It printed hdr.enable=false, which is not a key anyone can type, and it is exactly the line someone turning HDR off would search for.

Installing is unchanged, and covered in INSTALL.md inside the bundle.

Full changelog: v0.4.2...v0.5.0