8.10
10 RRLL: Helpers
Racket Rogue-Like Library: Miscellaneous Helpers
These are miscellaneous modules containing commonly used algorithms and/or (optionally enabled) unsafe ops for some data structures.
10.1 Clipping Helpers
| (require rrll/helper/clipping) | package: rrll-helpers |
This module contains clipping helpers used by other RRLL packages.
Makes sure the range from x (inclusive) to (+ x w)
(exclusive) fits within the range bx (inclusive) to
(+ bx bw) (exclusive).
Returns clipped x and w. If returned w is not positive?, it should be treated as empty range.
procedure
(clip-rect x y w h bx by bw bh) →
fixnum? fixnum? fixnum? fixnum? x : fixnum? y : fixnum? w : fixnum? h : fixnum? bx : fixnum? by : fixnum? bw : fixnum? bh : fixnum?
Uses clip-range to clip both horizontal and vertical range
of a rectangle against another rectangle.
procedure
(double-clip-range sx sw dx dw) →
fixnum? fixnum? fixnum? fixnum? sx : fixnum? sw : fixnum? dx : fixnum? dw : fixnum?
Like clip-range but if dx is negative, makes sure
it is 0 and adjusts sx accordingly before clipping it further.
Returns all four values clipped - although dw is never changed.
Uses double-clip-range to clip a rectangle against another.
The dw and dh arguments are returned unchanged.
procedure
(clip-range/scale x w bx bw us ue) →
fixnum? fixnum? flonum? flonum? x : fixnum? w : fixnum? bx : fixnum? bw : fixnum? us : flonum? ue : flonum?
Like clip-range but also clips associated flonum?
coordinates proportionally.
10.2 Sorting Helpers
| (require rrll/helper/ordering) | package: rrll-helpers |
This module contains helpers for sorting vertices of triangles on screen.
procedure
(order-pairs x1 y1 x2 y2 x3 y3) →
fixnum? fixnum? fixnum? fixnum? fixnum? fixnum? x1 : fixnum? y1 : fixnum? x2 : fixnum? y2 : fixnum? x3 : fixnum? y3 : fixnum?
Returns the three pairs sorted by the Y-coordinate.
10.3 Generic Syntax Variant Helpers
| (require rrll/helper/syntax) | package: rrll-helpers |
This module reprovides all of racket/base for syntax stage and the make-variant-id for syntax stage as well.
Returns a new syntax identifier in the same scope as stx
using fmt format string and format argument list
sids.