scripts/isCollisionTop.gml
From spelunky.gmk, Spelunky Classic 1.1's source, © 2008, 2009 Derek Yu and Mossmouth, LLC, shown whole under the Spelunky User License v1.1b. Extracted by spelunky.ai's tools, an unofficial fan project, one file per script or event; the // ==== lines are the extractor's, naming each action of the event. Some scripts are others' work that Derek Yu credits in the source's readme.txt: Martin Piecyk's platform engine, ChevyRay's view scaling scripts and tsg1zzn's Super Sound System.
The script isCollisionTop, 9 lines of GML.
/*An object can only use this script after calling "setCollisionBounds."0: Number of pixels above the collision rectangle to check for a collisionwith a solid object.*/calculateCollisionBounds()if collision_line(round(lb),round(tb-argument0),round(rb-1),round(tb-argument0),oSolid,1,1)>0 return 1return 0