LittleJS 1.27.1 - Faster Post Processing in Firefox and Physics Helpers

1.27.1 - 2026-10-14

New Changes

• debugLineWidth and setDebugLineWidth(width): the width in pixels of the outlines debug shapes are drawn with, the physics boxes and the tile collision view among them, 2 as before, larger to make them easier to see
• render3D.fogDepth measures fog by depth along the view instead of distance from the camera, and render3D.fogFadeStart / fogFadeEnd fade see through draws to transparent with distance, so a scene can melt into its sky instead of a fog color
• getVelocityAtPoint(pos) on an object: the velocity of a point on it, its velocity and its spin together, so the tip of a spinning blade moves faster than its middle; a Box2dObject asks Box2D, about its center of mass
• collideWithTile gets a third argument, isHit: true when the object overlaps the tile where its move put it, or a bullet's ray goes into it, and false for the places the physics only tries to find which side it hit, so a game can act on a hit once and ignore the rest
• The Object Collect short: balls drifting through a square and a circle, colored by engineObjectsCallback while inside and counted by engineObjectsCollect, and a click pushes away the balls near the mouse
• A debug build warns once when a game sets a child object's pos or angle, which its parent puts back every frame, naming localPos or localAngle to set instead
• The example browser's Share button copies a link to the code as it is in the editor, crushed into the link with JSONCrush so nothing is stored anywhere; the link opens the example it was made from and runs the shared code
• PostProcessPlugin and setShaderCode take a built in effect on its own, new PostProcessPlugin(postProcessVignette()), joining it with postProcessEffects as they would have needed; before, that failed to compile with an error about uv
• emitter.finishCallback on ParticleEmitter and ParticleEmitter3D: called once with the emitter when it finishes, done emitting and its last particle gone, so a game can play a sound or start the next effect when an explosion is over; not when it is destroyed immediately, as a scene clear does
• Box2D beginContact gets a fourth argument, impactSpeed: how fast the two bodies were closing along the contact normal as they touched, spin included, so a game can tell a hard hit from a graze; the Box2D Pool short's click goes by it

Fixes

• PostProcessPlugin copies the frame into its texture on the GPU with copyTexImage2D instead of uploading the canvas, which Firefox read back to the CPU every frame; a game with a post process there ran several times slower, AstroBlast's glow at 7 fps where it now runs at 31
• particleEffect's assert for an option it does not have lists the options it does, and names the one meant when only its case is off, emitrate for emitRate
• The build scripts, the engine's and the starter, module and TypeScript examples', run their tools with node and no shell, so a file name can not run as a command; a data file with a space in its name no longer breaks the examples' zip, and a tool that is not installed fails with a message to run npm install instead of being downloaded by npx