diff options
| author | David Thompson <dthompson2@worcester.edu> | 2014-05-02 23:44:59 -0400 |
|---|---|---|
| committer | David Thompson <dthompson2@worcester.edu> | 2014-05-02 23:44:59 -0400 |
| commit | 84aa43d4606a99bc18d8d32d2506598f9452e970 (patch) | |
| tree | f881f0b2846de58e0fa79428c68cb29b5989a7ab | |
| parent | a160708eac84695e6d27adfcaed8a40ecb9208fc (diff) | |
Add transform-position procedure.
* 2d/transform.scm (transform-position): New procedure.
| -rw-r--r-- | 2d/transform.scm | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/2d/transform.scm b/2d/transform.scm index df2f943..e7b5c31 100644 --- a/2d/transform.scm +++ b/2d/transform.scm @@ -33,6 +33,7 @@ transform-matrix transpose transform-vector2 + transform-position transform+ transform* transform-translate @@ -103,6 +104,11 @@ column-major format." (* y (array-ref m 1 1)) (array-ref m 1 3))))) +(define (transform-position transform) + "Extract 2D vector from TRANSFORM." + (let ((m (transform-matrix transform))) + (vector2 (array-ref m 0 3) (array-ref m 1 3)))) + (define (transform+ . transforms) "Return the sum of all given transformation matrices. Return null-transform if called without any arguments." |