racket/collects/plot/plot3d/matrix.rkt

56 lines
1.4 KiB
Racket

#lang racket/base
;; A small rotation matrix library, used to transform plot coordinates into view coordinates.
(require racket/match
"../common/vector.rkt"
"../common/math.rkt")
(provide (all-defined-out))
(define (m3-apply m v)
(match-define (vector v1 v2 v3) m)
(vector (vdot v1 v) (vdot v2 v) (vdot v3 v)))
(define (m3-transpose m)
(match-define (vector (vector m11 m12 m13)
(vector m21 m22 m23)
(vector m31 m32 m33)) m)
(vector (vector m11 m21 m31)
(vector m12 m22 m32)
(vector m13 m23 m33)))
(define (m3* m1 m2)
(match-define (vector v1 v2 v3) m1)
(define m (m3-transpose m2))
(vector (m3-apply m v1) (m3-apply m v2) (m3-apply m v3)))
#|
(m3* #(#(1 2 3)
#(4 5 6)
#(7 8 9))
#(#(10 20 30)
#(40 50 60)
#(70 80 90)))
#(#(300 360 420) #(660 810 960) #(1020 1260 1500))
|#
(define (m3-rotate-z theta)
(define cos-theta (cos theta))
(define sin-theta (sin theta))
(vector (vector cos-theta (- sin-theta) 0.0)
(vector sin-theta cos-theta 0.0)
(vector 0.0 0.0 1.0)))
(define (m3-rotate-x rho)
(define cos-rho (cos rho))
(define sin-rho (sin rho))
(vector (vector 1.0 0.0 0.0)
(vector 0.0 cos-rho (- sin-rho))
(vector 0.0 sin-rho cos-rho)))
(define (m3-scale x-scale y-scale z-scale)
(vector (vector x-scale 0.0 0.0)
(vector 0.0 y-scale 0.0)
(vector 0.0 0.0 z-scale)))