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(ql:quickload :lispbuilder-sdl) (ql:quickload :lispbuilder-sdl-gfx) (defun inner-cycloid (rc rm theta) (let ((x (+ (* (- rc rm) (cos theta)) (* rm (cos (* (/ (- rc rm) rm) theta))))) (y (- (* (- rc rm) (sin theta)) (* rm (sin (* (/ (- rc rm) rm) theta)))))) (values x y))) (defun inner-cycloid-viewer (rc rm) (let ((win-size (* rc 2.5)) (points '()) (rad 0)) (sdl:with-init () (sdl:window (round (* rc 2.5)) (round (* rc 2.5)) :title-caption "inner-cycloid") (sdl:with-events () (:quit-event () t) (:idle () (sdl:clear-display sdl:*black*) (multiple-value-bind (x y) (inner-cycloid rc rm rad) (pushnew (cons x y) points) (loop for point in points for px = (car point) for py = (cdr point) do (sdl:draw-pixel-* (round (+ px (/ win-size 2))) (round (+ py (/ win-size 2))) :color sdl:*cyan*)) (sdl:draw-circle-* (round (+ x (/ win-size 2))) (round (+ y (/ win-size 2))) 5 :color sdl:*cyan*) (incf rad 0.1) (sdl:update-display))))))) (defun hypotrochoid (rc rm rd theta) (let ((x (+ (* (- rc rm) (cos theta)) (* rd (cos (* (/ (- rc rm) rm) theta))))) (y (- (* (- rc rm) (sin theta)) (* rd (sin (* (/ (- rc rm) rm) theta)))))) (values x y))) (defun hypotrochoid-viewer (rc rm rd) (let ((win-size (* (max rc rm rd) 2.5)) (points '()) (rad 0)) (sdl:with-init () (sdl:window win-size win-size :title-caption "inner-cycloid") (sdl:with-events () (:quit-event () t) (:idle () (sdl:clear-display sdl:*black*) (multiple-value-bind (x y) (hypotrochoid rc rm rd rad) (pushnew (cons x y) points) (loop for point in points for px = (car point) for py = (cdr point) do (sdl:draw-pixel-* (round (+ px (/ win-size 2))) (round (+ py (/ win-size 2))) :color sdl:*cyan*)) (sdl:draw-circle-* (round (+ x (/ win-size 2))) (round (+ y (/ win-size 2))) 5 :color sdl:*cyan*) (incf rad 0.1) (sdl:update-display)))))))