render: texture: Use texture regions in texture atlas.
[chickadee.git] / chickadee / render / texture.scm
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1;;; Chickadee Game Toolkit
2;;; Copyright © 2016 David Thompson <davet@gnu.org>
3;;;
4;;; Chickadee is free software: you can redistribute it and/or modify
5;;; it under the terms of the GNU General Public License as published
6;;; by the Free Software Foundation, either version 3 of the License,
7;;; or (at your option) any later version.
8;;;
9;;; Chickadee is distributed in the hope that it will be useful, but
10;;; WITHOUT ANY WARRANTY; without even the implied warranty of
11;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12;;; General Public License for more details.
13;;;
14;;; You should have received a copy of the GNU General Public License
15;;; along with this program. If not, see
16;;; <http://www.gnu.org/licenses/>.
17
18(define-module (chickadee render texture)
19 #:use-module (ice-9 format)
20 #:use-module (ice-9 match)
21 #:use-module (rnrs bytevectors)
22 #:use-module (srfi srfi-9)
23 #:use-module (srfi srfi-9 gnu)
51d3c475 24 #:use-module (system foreign)
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25 #:use-module (gl)
26 #:use-module ((gl enums)
27 #:select (texture-min-filter texture-mag-filter)
28 #:prefix gl:)
29 #:use-module ((sdl2 image) #:prefix sdl-image:)
30 #:use-module (sdl2 surface)
31 #:use-module (oop goops)
2f4eab3c 32 #:use-module (chickadee math rect)
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33 #:use-module (chickadee render gl)
34 #:use-module (chickadee render gpu)
35 #:export (make-texture
36 load-image
37 texture?
38 texture-null?
39 texture-id
40 texture-parent
41 texture-width
42 texture-height
43 texture-min-filter
44 texture-mag-filter
45 texture-wrap-s
46 texture-wrap-t
47 null-texture
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48 texture-set!
49 texture-ref
98dc87a0 50
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51 make-texture-region
52 texture-region?
53 texture-region-texture
54 texture-region-x
55 texture-region-y
56 texture-region-width
57 texture-region-height
58
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59 texture-atlas
60 list->texture-atlas
61 split-texture
62 texture-atlas?
69d61338 63 texture-atlas-texture
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64 texture-atlas-ref))
65
66\f
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67;;;
68;;; Textures
69;;;
70
71;; The <texture> object is a simple wrapper around an OpenGL texture
72;; id.
73(define-record-type <texture>
c7d382fd 74 (%make-texture id width height min-filter mag-filter wrap-s wrap-t gl-size)
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75 texture?
76 (id texture-id)
77 (width texture-width)
78 (height texture-height)
79 (min-filter texture-min-filter)
80 (mag-filter texture-mag-filter)
81 (wrap-s texture-wrap-s)
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82 (wrap-t texture-wrap-t)
83 (gl-size texture-gl-size))
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84
85(set-record-type-printer! <texture>
86 (lambda (texture port)
87 (format port
88 "#<texture width: ~d height: ~d min-filter: ~a mag-filter: ~a wrap-s: ~a wrap-t: ~a>"
89 (texture-width texture)
90 (texture-height texture)
91 (texture-min-filter texture)
92 (texture-mag-filter texture)
93 (texture-wrap-s texture)
94 (texture-wrap-t texture))))
95
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96(define null-texture
97 (%make-texture 0 0 0 'linear 'linear 'repeat 'repeat (f32vector 0.0 0.0)))
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98
99(define <<texture>> (class-of null-texture))
100
101(define (texture-null? texture)
102 "Return #t if TEXTURE is the null texture."
103 (eq? texture null-texture))
104
105(define (free-texture texture)
106 (gl-delete-texture (texture-id texture)))
107
108(define-method (gpu-finalize (texture <<texture>>))
109 (free-texture texture))
110
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111(define (make-apply-texture n)
112 (let ((texture-unit (+ (version-1-3 texture0) n)))
113 (lambda (texture)
114 (set-gl-active-texture texture-unit)
115 (gl-bind-texture (texture-target texture-2d)
116 (texture-id texture)))))
98dc87a0 117
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118(define *texture-states*
119 (let ((states (make-vector 32)))
120 (let loop ((i 0))
121 (if (< i 32)
122 (begin
123 (vector-set! states i (make-gpu-state (make-apply-texture i)
124 null-texture))
125 (loop (1+ i)))
126 states))))
127
128(define (texture-ref! n)
129 (gpu-state-ref (vector-ref *texture-states* n)))
130
131(define (texture-set! n texture)
132 (gpu-state-set! (vector-ref *texture-states* n) texture))
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133
134(define* (make-texture pixels width height #:key
135 (min-filter 'linear)
136 (mag-filter 'linear)
137 (wrap-s 'repeat)
138 (wrap-t 'repeat)
139 (format 'rgba))
140 "Translate the bytevector PIXELS into an OpenGL texture with
141dimensions WIDTHxHEIGHT where each pixel is in 32-bit RGBA format.
142The generated texture uses MIN-FILTER for downscaling and MAG-FILTER
143for upscaling. WRAP-S and WRAP-T are symbols that control how texture
144access is handled for texture coordinates outside the [0, 1] range.
145Allowed symbols are: repeat (the default), clamp, clamp-to-border,
146clamp-to-edge. FORMAT specifies the pixel format. Currently only
14732-bit RGBA format is supported."
148 (define (gl-wrap mode)
149 (match mode
150 ('repeat (texture-wrap-mode repeat))
151 ('clamp (texture-wrap-mode clamp))
152 ('clamp-to-border (texture-wrap-mode clamp-to-border-sgis))
153 ('clamp-to-edge (texture-wrap-mode clamp-to-edge-sgis))))
154
155 (let ((texture (gpu-guard
156 (%make-texture (gl-generate-texture) width height
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157 min-filter mag-filter wrap-s wrap-t
158 (f32vector width height)))))
8152ddc9 159 (texture-set! 0 texture)
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160 (gl-texture-parameter (texture-target texture-2d)
161 (texture-parameter-name texture-min-filter)
162 (match min-filter
163 ('nearest (gl:texture-min-filter nearest))
164 ('linear (gl:texture-min-filter linear))))
165 (gl-texture-parameter (texture-target texture-2d)
166 (texture-parameter-name texture-mag-filter)
167 (match mag-filter
168 ('nearest (gl:texture-mag-filter nearest))
169 ('linear (gl:texture-mag-filter linear))))
170 (gl-texture-parameter (texture-target texture-2d)
171 (texture-parameter-name texture-wrap-s)
172 (gl-wrap wrap-s))
173 (gl-texture-parameter (texture-target texture-2d)
174 (texture-parameter-name texture-wrap-t)
175 (gl-wrap wrap-t))
176 (gl-texture-image-2d (texture-target texture-2d)
177 0 (pixel-format rgba) width height 0
178 (match format
179 ('rgba (pixel-format rgba)))
180 (color-pointer-type unsigned-byte)
51d3c475 181 (or pixels %null-pointer))
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182 texture))
183
184(define (flip-pixels-vertically pixels width height)
185 "Create a new bytevector that reverses the rows in PIXELS, a WIDTH x
186HEIGHT, 32 bit color bytevector."
187 (let ((buffer (make-u8vector (bytevector-length pixels)))
188 (row-width (* width 4))) ; assuming 32 bit color
189 (let loop ((y 0))
190 (when (< y height)
191 (let* ((y* (- height y 1))
192 (source-start (* y row-width))
193 (target-start (* y* row-width)))
194 (bytevector-copy! pixels source-start buffer target-start row-width)
195 (loop (1+ y)))))
196 buffer))
197
198(define (surface->texture surface min-filter mag-filter wrap-s wrap-t)
199 "Convert SURFACE, an SDL2 surface object, into a texture that uses
200the given MIN-FILTER and MAG-FILTER."
201 ;; Convert to 32 bit RGBA color.
202 (call-with-surface (convert-surface-format surface 'abgr8888)
203 (lambda (surface)
204 (let* ((width (surface-width surface))
205 (height (surface-height surface))
206 ;; OpenGL textures use the bottom-left corner as the
207 ;; origin, whereas SDL uses the top-left, so the rows
208 ;; of pixels must be reversed before creating a
209 ;; texture from them.
210 (pixels (flip-pixels-vertically (surface-pixels surface)
211 width height)))
212 (make-texture pixels width height
213 #:min-filter min-filter
214 #:mag-filter mag-filter
215 #:wrap-s wrap-s
216 #:wrap-t wrap-t)))))
217
7015cd49 218(define* (load-image file #:key
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219 (min-filter 'nearest)
220 (mag-filter 'nearest)
221 (wrap-s 'repeat)
222 (wrap-t 'repeat))
223 "Load a texture from an image in FILE. MIN-FILTER and MAG-FILTER
224describe the method that should be used for minification and
225magnification. Valid values are 'nearest and 'linear. By default,
226'nearest is used."
227 (call-with-surface (sdl-image:load-image file)
228 (lambda (surface)
229 (surface->texture surface min-filter mag-filter wrap-s wrap-t))))
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230
231\f
232;;;
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233;;; Texture Regions
234;;;
235
236(define-record-type <texture-region>
237 (%make-texture-region texture x y width height gl-rect gl-size)
238 texture-region?
239 (texture texture-region-texture)
240 (x texture-region-x)
241 (y texture-region-y)
242 (width texture-region-width)
243 (height texture-region-height)
244 (gl-rect texture-region-gl-rect)
245 (gl-size texture-region-gl-size))
246
247(define (make-texture-region texture x y width height)
248 "Create a new texture region covering a section of TEXTURE defined
249by the bounding box X, Y, WIDTH, and HEIGHT. All coordinates are
250measured in pixels and must be integers."
251 (let* ((tw (texture-width texture))
252 (th (texture-height texture))
253 (gl-rect (make-rect (/ x tw) (/ y th)
254 (/ (+ x width) tw) (/ (+ y height) th))))
255 (%make-texture-region texture x y width height gl-rect
256 (f32vector width height))))
257
258\f
259;;;
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260;;; Texture Atlas
261;;;
262
263(define-record-type <texture-atlas>
264 (%make-texture-atlas texture vector)
265 texture-atlas?
266 (texture texture-atlas-texture)
267 (vector texture-atlas-vector))
268
269(define (list->texture-atlas texture rects)
270 "Return a new atlas for TEXTURE containing RECTS, a list of texture
271coordinate rects denoting the various tiles within."
272 (let ((v (make-vector (length rects))))
273 (let loop ((i 0)
274 (rects rects))
275 (match rects
276 (() (%make-texture-atlas texture v))
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277 (((x y width height) . rest)
278 (vector-set! v i (make-texture-region texture x y width height))
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279 (loop (1+ i) rest))))))
280
281(define (texture-atlas texture . rects)
282 "Return a new atlas for TEXTURE containing RECTS, a series of
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2834-tuples in the form (x y width height) describing the various tiles
284within."
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285 (list->texture-atlas texture rects))
286
287(define (texture-atlas-ref atlas index)
31b6f11b 288 "Return the texture region associated with INDEX in
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289ATLAS."
290 (vector-ref (texture-atlas-vector atlas) index))
291
292(define* (split-texture texture tile-width tile-height #:key
293 (margin 0) (spacing 0))
294 "Return a new texture atlas that splits TEXTURE into a grid of
295TILE-WIDTH by TILE-HEIGHT rectangles. Optionally, each tile may have
296SPACING pixels of horizontal and vertical space between surrounding
297tiles and the entire image may have MARGIN pixels of empty space
298around its border.
299
300This type of texture atlas layout is very common for tile map
301terrain."
302 (let* ((w (texture-width texture))
303 (h (texture-height texture))
304 (sw (/ tile-width w))
305 (th (/ tile-height h))
306 (rows (/ (- h margin) (+ tile-height spacing)))
307 (columns (/ (- w margin) (+ tile-width spacing)))
308 (v (make-vector (* rows columns))))
309 (define (make-tile tx ty)
310 (let* ((x (+ (* tx (+ tile-width spacing)) margin))
311 (y (+ (* ty (+ tile-height spacing)) margin)))
31b6f11b 312 (make-texture-region texture x y tile-width tile-height)))
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313 (let y-loop ((y 0))
314 (when (< y rows)
315 (let x-loop ((x 0))
316 (when (< x columns)
317 (vector-set! v (+ x (* y columns)) (make-tile x y))
318 (x-loop (1+ x))))
319 (y-loop (1+ y))))
320 (%make-texture-atlas texture v)))