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;; Copyright 2016 Eduardo Cavazos
;;
;; Licensed under the Apache License, Version 2.0 (the "License");
;; you may not use this file except in compliance with the License.
;; You may obtain a copy of the License at
;;
;; http://www.apache.org/licenses/LICENSE-2.0
;;
;; Unless required by applicable law or agreed to in writing, software
;; distributed under the License is distributed on an "AS IS" BASIS,
;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
;; See the License for the specific language governing permissions and
;; limitations under the License.
(library (box2d-lite edges)
(export make-edges
edges-in-edge-1 edges-in-edge-1-set!
edges-out-edge-1 edges-out-edge-1-set!
edges-in-edge-2 edges-in-edge-2-set!
edges-out-edge-2 edges-out-edge-2-set!
is-edges
import-edges
create-edges
edges-equal?
flip)
(import (rnrs)
(box2d-lite util define-record-type)
(box2d-lite edge-numbers))
;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(define-record-type++ edges
is-edges
import-edges
(fields (mutable in-edge-1)
(mutable out-edge-1)
(mutable in-edge-2)
(mutable out-edge-2))
(methods))
(define (create-edges)
(make-edges NO-EDGE NO-EDGE NO-EDGE NO-EDGE))
;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(define (edges-equal? a b)
(is-edges a)
(is-edges b)
(and (equal? a.in-edge-1 b.in-edge-1)
(equal? a.out-edge-1 b.out-edge-1)
(equal? a.in-edge-2 b.in-edge-2)
(equal? a.out-edge-2 b.out-edge-2)))
;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(define (flip e)
(is-edges e)
(let ((tmp e.in-edge-1))
(e.in-edge-1! e.in-edge-2)
(e.in-edge-2! tmp))
(let ((tmp e.out-edge-1))
(e.out-edge-1! e.out-edge-2)
(e.out-edge-2! tmp)))
;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
)