diff options
| -rw-r--r-- | sly/transform.scm | 27 |
1 files changed, 10 insertions, 17 deletions
diff --git a/sly/transform.scm b/sly/transform.scm index 05ce32d..ece4b06 100644 --- a/sly/transform.scm +++ b/sly/transform.scm @@ -114,26 +114,19 @@ null-transform if called without any arguments." (define (transform* . transforms) "Return the product of all given transformation matrices. Return identity-transform if called without any arguments." - (cond - ((null? transforms) - identity-transform) - ((null? (cdr transforms)) - (car transforms)) - (else - (let ((result (make-4x4-matrix))) - (array-copy! (transform-matrix (car transforms)) result) - (for-each - (lambda (t) - (let ((m (transform-matrix t))) - (do-ec + (define (mul a b) + (let ((m1 (transform-matrix a)) + (m2 (transform-matrix b)) + (m3 (make-4x4-matrix))) + (do-ec (: r 4) (: c 4) (let ((x (sum-ec (: k 4) - (* (array-ref m r k) - (array-ref result k c))))) - (array-set! result x r c))))) - (cdr transforms)) - (%make-transform result))))) + (* (array-ref m1 r k) + (array-ref m2 k c))))) + (array-set! m3 x r c))) + (%make-transform m3))) + (reduce mul identity-transform transforms)) (define (translate v) "Return a new transform that translates by the 2D or 3D vector V." |