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A quick hack to load binary STL files using ztellman's gloss and pjstadig's nio library.
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| (ns stl-reader | |
| (:require [nio.core :as nio]) | |
| (:use [gloss core io])) | |
| (defcodec stl-codec | |
| {:header (string :ascii :length 80) | |
| :shape (repeated (ordered-map :normal [:float32-le :float32-le :float32-le] | |
| :v1 [:float32-le :float32-le :float32-le] | |
| :v2 [:float32-le :float32-le :float32-le] | |
| :v3 [:float32-le :float32-le :float32-le] | |
| :attr-count :uint16) | |
| :prefix :uint32-le)}) | |
| (def stl-test (decode stl-codec (to-buf-seq (nio/mmap "some-file.stl")))) |
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| ;; OpenGL turned out to be painful in Java, so I also wrote a loader in Common Lisp | |
| ;; (a little longer because I didn't use a fancy DSL like gloss) | |
| (ql:quickload "ieee-floats") | |
| (use-package 'ieee-floats) | |
| (defun read-uint-32 (in) | |
| (let ((uint 0)) | |
| (dotimes (i 4) | |
| (setf (ldb (byte 8 (* i 8)) uint) (read-byte in))) | |
| uint)) | |
| (defun read-3d-vector (in) | |
| (loop repeat 3 collect (ieee-floats:decode-float32 (read-uint-32 in)))) | |
| (defun read-binary-stl (in) | |
| (file-position in 80) ;; useless header | |
| (loop repeat (read-uint-32 in) collect | |
| (let ((normal (read-3d-vector in)) | |
| (vertices (loop repeat 3 collect (read-3d-vector in)))) | |
| (file-position in (+ (file-position in) 2)) ;; skip! | |
| `((:normal . ,normal) (:vertices . ,vertices))))) | |
| (with-open-file (in #P"cube.stl" :element-type '(unsigned-byte 8)) | |
| (read-binary-stl in)) |
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| ;; ...and a Racket version | |
| ;; (it turned out racket had the best OpenGL support) | |
| (define (load-binary-stl in) | |
| (define (bytes->3d-vector in) | |
| (for/list [(v 3)] (floating-point-bytes->real (read-bytes 4 in)))) | |
| (read-bytes 80 in) ;; header junk | |
| (let [(triangle-count (integer-bytes->integer (read-bytes 4 in) #f))] | |
| (for/list [(t triangle-count)] | |
| (let [(normal (bytes->3d-vector in)) | |
| (vertices (for/list [(v 3)] (bytes->3d-vector in)))] | |
| (read-bytes 2 in) ;; eat the empty attrib mark | |
| `((:normal . ,normal) (:vertices . ,vertices)))))) | |
| (call-with-input-file "cube.stl" load-binary-stl) |
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