Probably fixed probable I/O race condition when loading images.
Fixed Visual mode stuttering due to floating point precision degradation when running the editor for several days without restarting (internal timer is now reset when saving the map or creating a new one).
Fixed, Nodes Viewer, cosmetic: Nodes Viewer window position was reset after pressing the "Rebuild Nodes" button.
Added Eternity Game configurations by printz.
Updated ZDoom_ACS.cfg (CheckClass).
Updated ZDoom ACC (CheckClass).
Changed, Sectors mode: "Flip Linedefs" and "Align Linedefs" actions will no longer flip single-sided linedefs with only front side.
Fixed, Script Editor: fixed a crash when trying to update script navigator combo box when switching to a never saved ACS script.
Fixed, DECORATE support: the editor was unable to determine actor sprite when the actor itself had no sprites defined and the actor it inherited from was only defined in the game configuration.
Fixed, Drag geometry modes: linedefs without both sides were removed after dragging them when "Replace with Dragged Geometry" mode was active.
Updated ZDoom_DECORATE.cfg.
Fixed: voxel support logic was outdated, which in some cases resulted in voxels not being loaded and in some weird behaviour when trying to change pitch/roll of associated things.
Updated sprites lookup logic. Now it correctly handles sprites named like NNNNA0B0.
Fixed: in some cases DECORATE parser was unable to correctly detect sprite name & frame(s) block.
Updated ZDoom_ACS.cfg.
Updated ZDoom_DECORATE.cfg.
Changed, "Align Things to Nearest Linedef" action: the action can now also align things with FLATSPRITE and WALLSPRITE flags (previously only things with attached models were aligned).
Changed, "Align Things to Nearest Linedef" action: the action can now align things to the middle part of double-sided linedef, if it has a middle texture assigned.
Fixed: parts of UniFileds.UniValuesMatch() logic were inverted. In some cases this resulted in incorrect behavior of "Select Similar" action in UDMF map format.
Fixed, UDMF: alpha should be ignored when applying sector fade/light color gradients.
Ported eevee's fix for incorrect sector geometry occasionally created after dragging map elements (more info: https://github.com/sirjuddington/SLADE/issues/542).
Changed, Map Analysis mode: the view is now much more zoomed after clocking on a "Check very short linedefs" error check result.
Removed single testing engine launchable by the editor at once limitation (it worked properly only when using Test map actions anyway).
Fixed: re-did the fix for invalid geometry created when drawing very large grids from R2653, because it caused other issues.
Added "doomthingrotationangles" Game Configuration property. When enabled, editor actions related to changing thing angle will snap the resulting angle to 45 degree increments. This property is set to true for vanilla game configurations.
Fixed a crash when changing game configuration from one without Thing actions support to one with them while in Things mode.
Fixed, cosmetic, DB2 bug: current editing mode button was deselected after reloading resources.
Updated documentation ("Game Configuration - Basic Settings" page).
Changed: multi-part sectors are now better preserved after drawing new lines.
Changed, TEXTURES parser: patch loading errors are now ignored for textures with "NullTexture" option.
Changed, Game configurations: changed default door action arguments to better match vanilla ones.
Fixed, Actions: in some cases keyboard shortcuts involving Ctrl/Alt/Shift modifier keys were displayed incorrectly.
Fixed(?): probably fixed inability to save map wad in Slade 3.
Updated ZDoom_ACS.cfg.
Updated ZDoom_DECORATE.cfg.
Updated ZDoom ACC.
Updated model pitch handling to match current GZDoom implementation.
Fixed imprecise vertex coordinates generated by Draw Ellipse mode.
Fixed a resource loading exception when opened map file wad was located in the root of a Directory resource.
Internal: changed output of all InterpolationTools methods from int to float.
Fixed, Internal: InterpolationTools.InterpolateColor() delta usage was inverted.
Removed "Adjust heights to match relatively with surrounding sector" option from Preferences -> Pasting, because sector height adjustments are now handled by Edit Selection mode.
Fixed, Sector info panel: in some cases 0 deg. floor/ceiling texture rotation was triggering texture offset/scale/rotation UI parts to be shown.
Fixed even more cases when sidedefs belonging to linedefs, which were moved on top of existing linedefs, were incorrectly reassigned when applying Edit Selection and Drag Geometry modes.
Fixed, Bridge mode: in some cases calculated floor/ceiling heights were not applied to the sectors created by the mode.
Changed, internal: changed program's CurrentCulture to InvariantCulture.
Added, Sound Environments mode: current sound environment is now highlighted (can be toggled using "Toggle Highlight" action).
Added: Tag selectors now have up/down buttons.
Fixed, Sound Environments mode: sound environments were not updated after performing Undo/Redo actions.
Fixed, Sound Propagation mode: sound zones were not updated after performing Undo/Redo actions.
Internal: moved "Toggle Highlight" action to the core, also changed it's category to "View".
Internal: "Toggle Highlight" action state is now saved in the Program configuration.
Updated ZDoom_DECORATE.cfg (GetZAt).
Updated ZDoom_linedefs.cfg (Sector_SetPortal args).
Fixed, Visual mode: both "With same texture" and "With same height" Select modifiers are now checked when both of them are used at once (previously a sidedef part/floor/ceiling was selected when any of those matched).
Added/restored, Visual mode: restored "Move Texture Left/Right/Up/Down by 8" actions, added "Move Texture Left/Right/Up/Down by Grid Size" actions (default keys are Ctrl+arrow keys).
Fixed, Game configurations: Hexen's Bell actor was missing "hangs" flag.
Fixed severe lock-up after finishing dragging many vertices/linedefs/sectors in Classic modes.
Updated documentation ("Synchronizing camera position").
Fixed, Visual mode: in some cases not all sidedef geometry was updated when updating sectors with Plane Align (181) action. Also fixed some more unnecessary geometry updates.
Fixed, Linedefs mode, Things mode: in some cases deleting linedefs/things caused a crash when trying to update text labels.
Fixed, Draw Lines mode: in some cases the drawing was prematurely finished when "Auto-finish drawing" option was enabled.
Fixed: CVARINFO parser was unable to parse negative int/float values.
Fixed: in some cases TextLabel text size was checked before it was calculated.
Internal, Visual mode: reduced the number of unnecessary geometry updates when changing map geometry.
Updated ZDoom_DECORATE.cfg (atan2 and VectorAngle).
Fixed, Things mode: in some cases selection labels were not updated after editing a thing.
Fixed, Things mode: selection labels were positioned incorrectly on things with FixedSize setting.
Fixed, Sectors mode: fixed a crash when selecting self-referencing sector when selection labels were enabled.
Fixed, Visual mode: in some cases Auto-align texture actions were not working when "use long texture names" Map Options setting was enabled.
Fixed, MD2/MD3 loader: available animation frames upper bound check was performed incorrectly, which would cause a crash in some very special cases.
Fixed, Game configurations: most Hexen/ZDoom teleport actions use TeleportDests as teleport targets, not MapSpots.
Added, "Check polyobjects" error check: added a check for matching Polyobject and Mirror Polyobject numbers of Polyobj_StartLine action.
Changed, Visual mode: anisotropic filtering is now always applied (previously it was applied only when bilinear filtering was enabled).
Fixed, Visual mode: in some cases light values were incorrectly transferred between 3d floors and regular floors/ceilings.
Fixed, ACS parser: includes for each library must be stored separately (fixes inability to compile a script with an included library, which in turn includes files already included by the script).
Fixed, Visual mode: alpha-based texture picking didn't work correctly on HiRes images.
Fixed, Visual mode: fog density was calculated incorrectly for things lit by dynamic lights.
Fixed, Edit Sector window, UDMF: "Fade" and "Light" color pickers initial values were incorrect when displaying mixed values.
Fixed, Edit Thing window, UDMF: "Color" color picker initial value was incorrect when displaying mixed values.
Changed, Draw Lines and Draw Curve modes: "Auto-finish drawing" option now works regardless of "Continuous drawing" option (previously it worked only when the latter was enabled).
Changed: position and size of the "Errors and Warnings" window is now stored while the editor is running.
Internal: rewritten parts of long texture names support code. It now involves much less special handling.
Updated ZDoom_DECORATE.cfg (A_QuakeEx, A_CheckBlock).
Updated ZDoom_ACS.cfg (QuakeEx).
Updated ZDoom ACC (QuakeEx).
Added, Draw Line and Draw Curve modes: added "Auto-finish drawing" setting. When enabled, the modes will automatically finish drawing when currently drawn lines and already existing level geometry form a closed shape.
Changed: sector-wise linedef flipping is now done using the new "Align Linedefs" action. "Flip Linedefs" action works the same as in DB2 again.
Changed: when a map was already loaded, using "Open Map" action will use that map's directory as the starting directory.
Changed: official IWADs can no longer be saved.
Changed: disabled lump ranges/duplicate entries checks for official IWADs.
Changed: wad type is now preserved when saving a map (previously all wads were saved as PWADs).
Changed: moved Updater.exe launch much closer to the editor termination point to avoid any chance of it closing the editor before it properly closes itself.
Updated ZDoom_DECORATE.cfg (A_Blast).
Updated documentation.
Changed, cosmetic: elapsed time is now displayed after resources loading finishes.
Changed, internal: changed Clock.CurrentTime type to long.
Fixed, Tag Statistics window: in some cases the map view was not updated after selecting items in Sectors/Linedefs/Things columns.
Fixed, cosmetic: Draw Curve mode icon was missing a shadow.
Fixed, Visual mode: in some cases GLDEFS glow effect was not updated after changing floor/ceiling texture.
Fixed, Draw Rectangle and Draw Ellipse modes: in some cases pressing "Reset" button did not update the shape preview.
Fixed, DB2 bug: sector geometry was not updated after undoing "Flip Sidedefs" action.
Fixed, Map Analysis window: fixed an exception on copying warnings to clipboard when the clipboard was used by other application.
Fixed, TEXTURES parser: added special handling for "TNT1A0" sprite name so a texture with this sprite as a single patch is no longer treated as failed loading.
Fixed, Visual mode: in some cases (like line slopes used in several adjacent sectors) sector effect updates were triggered multiple times for the same sector, resulting in noticeable slowdowns and in some cases in infinite recursion.
Updated ZDoom ACC.
Added, Visual mode: highlight/selection based on texture alpha now works on 3d floors.
Changed, Game configurations, TranslucentLine:208 action: renamed the second argument from "Translucency Amount" to "Opacity".
Internal, documentation: updated udmf_zdoom.txt.
Fixed, Visual mode: UDMF sidedef brightness should be ignored when a wall section is affected by Transfer Brightness effect.
Fixed, Visual mode: any custom fog should be rendered regardless of sector brightness.
Fixed, Visual mode: "fogdensity" and "outsidefogdensity" MAPINFO values were processed incorrectly.
Fixed, Visual mode: in some cases Things were rendered twice during a render pass.
Fixed, Visual mode: floor glow effect should affect thing brightness only when applied to floor of the sector thing is in.
Fixed, TEXTURES parser: TEXTURES group was named incorrectly in the Textures Browser window when parsed from a WAD file.
Fixed, MAPINFO, GLDEFS, DECORATE parsers: "//$GZDB_SKIP" special comment was processed incorrectly.
Fixed, MAPINFO parser: "fogdensity" and "outsidefogdensity" properties are now initialized using GZDoom default value (255) instead of 0.
Updated skybox model to better match GZDoom's skybox. Also the sky texture was flipped horizontally.
Fixed, Visual mode: "Select with the same texture" action is now able to select sidedef parts only visible because of slopes.
Fixed, Visual mode: skybox texture was not updated after using "Open map in current wad" action.
Fixed, Visual mode: in some cases Visual camera was placed below sector's floor when "Sync camera position between 2D and 3D modes" setting was enabled.
Fixed: numeric thing flags with inverted UDMF flag defined in "thingflagstranslation" Game configuration block were lost when copy-pasting a thing.
Fixed, command line arguments: fixed a crash when loading a map from a wad with existing .dbs file.