summaryrefslogtreecommitdiff
path: root/2d/sprite.scm
blob: f47a38ebd16938e710afcc6f1a0a3b36daea515a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
;;; guile-2d
;;; Copyright (C) 2013 David Thompson <dthompson2@worcester.edu>
;;;
;;; Guile-2d is free software: you can redistribute it and/or modify it
;;; under the terms of the GNU Lesser General Public License as
;;; published by the Free Software Foundation, either version 3 of the
;;; License, or (at your option) any later version.
;;;
;;; Guile-2d is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
;;; Lesser General Public License for more details.
;;;
;;; You should have received a copy of the GNU Lesser General Public
;;; License along with this program.  If not, see
;;; <http://www.gnu.org/licenses/>.

;;; Commentary:
;;
;; Sprites are typically the most important part of a 2D game. This
;; module provides sprites as an abstraction around OpenGL textures.
;;
;;; Code:

(define-module (2d sprite)
  #:use-module (srfi srfi-9)
  #:use-module (srfi srfi-42)
  #:use-module (figl gl)
  #:use-module (figl contrib packed-struct)
  #:use-module ((sdl sdl) #:prefix SDL:)
  #:use-module (2d vector)
  #:export (make-texture
            texture?
            texture-id
            texture-width
            texture-height
            surface->texture
            load-texture
            texture-quad
            make-texture-region
            texture-region?
            texture-region-texture
            texture-region-width
            texture-region-height
            texture-region-u
            texture-region-v
            texture-region-u2
            texture-region-v2
            split-texture
            make-sprite
            sprite?
            sprite-texture
            sprite-position
            set-sprite-position!
            sprite-scale
            set-sprite-scale!
            sprite-rotation
            set-sprite-rotation!
            sprite-color
            set-sprite-color!
            sprite-anchor
            set-sprite-anchor!
            sprite-vertices
            set-sprite-vertices!
            load-sprite
            draw-sprite
            make-sprite-batch
            sprite-batch?
            sprite-batch-max-size
            sprite-batch-size
            set-sprite-batch-size!
            sprite-batch-texture
            set-sprite-batch-texture!
            sprite-batch-vertices
            sprite-batch-draw
            with-sprite-batch))

;;;
;;; Textures
;;;

;; The <texture> object is a simple wrapper around an OpenGL texture
;; id.
(define-record-type <texture>
  (make-texture id width height)
  texture?
  (id texture-id)
  (width texture-width)
  (height texture-height))

;; Use a guardian and an after GC hook that ensures that OpenGL
;; textures are deleted when texture objects are GC'd.
(define texture-guardian (make-guardian))

(define (reap-textures)
  (let loop ((texture (texture-guardian)))
    (when texture
      ;; When attempting to reap structures upon guile exit, the
      ;; dynamic pointer to gl-delete-textures becomes invalid. So, we
      ;; ignore the error and move on.
      (catch 'misc-error
        (lambda () (gl-delete-textures (list (texture-id texture))))
        (lambda (key . args) #f))
      (loop (texture-guardian)))))

(add-hook! after-gc-hook reap-textures)

(define (surface-pixel-format surface)
  "Returns the OpenGL pixel format for a surface. RGB and RGBA formats
are supported."
  (case (SDL:surface:depth surface)
    ((24) (pixel-format rgb))
    ((32) (pixel-format rgba))
    (else (throw 'unsupported-pixel-format))))

(define (surface->texture surface)
  "Translates an SDL surface into an OpenGL texture.
Currently only works with RGBA format surfaces."
  (let ((texture-id (gl-generate-texture))
        (pixel-format (surface-pixel-format surface)))
    (with-gl-bind-texture (texture-target texture-2d) texture-id
      (gl-texture-parameter (texture-target texture-2d)
                            (texture-parameter-name texture-min-filter)
                            (texture-min-filter linear))
      (gl-texture-parameter (texture-target texture-2d)
                            (texture-parameter-name texture-mag-filter)
                            (texture-mag-filter linear))
      (gl-texture-image-2d (texture-target texture-2d)
                           0
                           pixel-format
                           (SDL:surface:w surface)
                           (SDL:surface:h surface)
                           0
                           pixel-format
                           (color-pointer-type unsigned-byte)
                           (SDL:surface-pixels surface)))
    (let ((texture (make-texture texture-id
                                 (SDL:surface:w surface)
                                 (SDL:surface:h surface))))
      (texture-guardian texture)
      texture)))

(define (load-texture filename)
  "Loads a texture from a file."
  (surface->texture (SDL:load-image filename)))

(define* (texture-quad texture x y w h #:optional (color '(1 1 1))
                       (u 0) (v 0) (u2 1) (v2 1))
  "Renders a textured quad."
  (let ((x2 (+ x w))
        (y2 (+ y h)))
    (with-gl-bind-texture (texture-target texture-2d) (texture-id texture)
      (gl-begin (begin-mode quads)
        (apply gl-color color)
        (gl-texture-coordinates u v)
        (gl-vertex x y)
        (gl-texture-coordinates u2 v)
        (gl-vertex x2 y)
        (gl-texture-coordinates u2 v2)
        (gl-vertex x2 y2)
        (gl-texture-coordinates u v2)
        (gl-vertex x y2)))))

;;;
;;; Texture Regions
;;;

;; Texture regions represent a segment of a texture.

(define-record-type <texture-region>
  (%make-texture-region texture width height u v u2 v2)
  texture-region?
  (texture texture-region-texture)
  (width texture-region-width)
  (height texture-region-height)
  (u texture-region-u)
  (v texture-region-v)
  (u2 texture-region-u2)
  (v2 texture-region-v2))

(define (make-texture-region texture x y width height)
  "Creates a new texture region given a texture and a pixel region."
  (let* ((w (texture-width texture))
         (h (texture-height texture))
         (u (/ x w))
         (v (/ y h))
         (u2 (/ (+ x width) w))
         (v2 (/ (+ y height) h)))
    (%make-texture-region texture width height u v u2 v2)))

(define* (split-texture texture width height
                        #:optional #:key (margin 0) (spacing 0))
  "Splits a texture into a vector of texture regions of width x height
size."
  (define (build-tile tx ty)
    (let* ((x (+ (* tx (+ width spacing)) margin))
           (y (+ (* ty (+ height spacing)) margin)))
      (make-texture-region texture x y width height)))

  (let* ((tw (texture-width texture))
         (th (texture-height texture))
         (rows (/ (- tw margin) (+ width spacing)))
         (columns (/ (- tw margin) (+ height spacing))))
    (vector-ec (: y rows) (: x columns) (build-tile x y))))

;;;
;;; Sprites
;;;

;; Used to build OpenGL vertex array for a sprite.
(define-packed-struct sprite-vertex
  (x float)
  (y float)

  (r float)
  (g float)
  (b float)
  (a float)

  (s float)
  (t float))

;; The <sprite> object represents a texture with a given position, scale,
;; rotation, and color.
(define-record-type <sprite>
  (%make-sprite texture position scale rotation color anchor vertices)
  sprite?
  (texture sprite-texture)
  (position sprite-position set-sprite-position!)
  (scale sprite-scale set-sprite-scale!)
  (rotation sprite-rotation set-sprite-rotation!)
  (color sprite-color set-sprite-color!)
  (anchor sprite-anchor set-sprite-anchor!)
  (vertices sprite-vertices set-sprite-vertices!))

(define* (make-sprite texture #:optional #:key (position #(0 0)) (scale #(1 1))
                      (rotation 0) (color '(1 1 1)) (anchor 'center))
  "Makes a new sprite object."
  (let ((vertices (make-packed-array sprite-vertex 4)))
    (%make-sprite texture position scale rotation color anchor vertices)))

(define* (load-sprite filename #:optional #:key (position #(0 0)) (scale #(1 1))
                      (rotation 0) (color '(1 1 1)) (anchor 'center))
  "Loads a sprite from file."
  (make-sprite (load-texture filename) #:position position #:scale scale
               #:rotation rotation #:color color #:anchor anchor))

(define (sprite-anchor-vector sprite)
  (let ((anchor (sprite-anchor sprite)))
    (cond
     ((eq? anchor 'center)
      (let ((texture (sprite-texture sprite)))
        (vector (/ (texture-width texture) 2)
                (/ (texture-height texture) 2))))
     (else anchor))))

(define (update-sprite-vertices sprite)
  (let* ((vertices (sprite-vertices sprite))
         (texture (sprite-texture sprite))
         (anchor (sprite-anchor-vector sprite))
         (x (- (vx anchor)))
         (y (- (vy anchor)))
         (x2 (+ x (texture-width texture)))
         (y2 (+ y (texture-width texture))))
    (pack vertices 0 sprite-vertex
          x y
          1 1 1 1
          0 0)
    (pack vertices 1 sprite-vertex
          x2 y
          1 1 1 1
          1 0)
    (pack vertices 2 sprite-vertex
          x2 y2
          1 1 1 1
          1 1)
    (pack vertices 3 sprite-vertex
          x y2
          1 1 1 1
          0 1)))

(define (draw-sprite sprite)
  "Renders a sprite."
  (update-sprite-vertices sprite)
  (let* ((texture (sprite-texture sprite))
         (width (texture-width texture))
         (height (texture-height texture))
         (pos (sprite-position sprite))
         (scale (sprite-scale sprite))
         (vertices (sprite-vertices sprite)))
    (with-gl-push-matrix
      (gl-translate (vx pos) (vy pos) 0)
      (gl-rotate (sprite-rotation sprite) 0 0 1)
      (gl-scale (vx scale) (vy scale) 0)
      ;; Draw vertex array
      (gl-enable-client-state (enable-cap vertex-array))
      (gl-enable-client-state (enable-cap color-array))
      (gl-enable-client-state (enable-cap texture-coord-array))
      (with-gl-bind-texture (texture-target texture-2d) (texture-id texture)
        (set-gl-vertex-array (vertex-pointer-type float)
                             vertices
                             2
                             #:stride (packed-struct-size sprite-vertex)
                             #:offset (packed-struct-offset sprite-vertex x))
        (set-gl-color-array (color-pointer-type float)
                            vertices
                            4
                            #:stride (packed-struct-size sprite-vertex)
                            #:offset (packed-struct-offset sprite-vertex r))
        (set-gl-texture-coordinates-array (tex-coord-pointer-type float)
                                          vertices
                                          #:stride (packed-struct-size sprite-vertex)
                                          #:offset (packed-struct-offset sprite-vertex s))
        (gl-draw-arrays (begin-mode quads) 0 (packed-array-length vertices sprite-vertex)))
      (gl-disable-client-state (enable-cap texture-coord-array))
      (gl-disable-client-state (enable-cap color-array))
      (gl-disable-client-state (enable-cap vertex-array)))))

;;;
;;; Sprite batches
;;;

;; Sprite batches allow for efficient texture rendering. Sprites drawn
;; with the same texture are drawn in the same draw call using a
;; vertex array, rather than re-binding the texture for each
;; individual draw call.
(define-record-type <sprite-batch>
  (%make-sprite-batch max-size size texture vertices)
  sprite-batch?
  (max-size sprite-batch-max-size)
  (size sprite-batch-size set-sprite-batch-size!)
  (texture sprite-batch-texture set-sprite-batch-texture!)
  (vertices sprite-batch-vertices))

(define* (make-sprite-batch #:optional (max-size 1000))
  "Creates a new sprite batch. The default max-size is 1000."
  (%make-sprite-batch max-size 0 #f (make-packed-array sprite-vertex (* 4 max-size))))

;; TODO add transformation logic for scaling and rotating.
;; TODO add support for colors
;; TODO add support for different blending modes.
(define* (sprite-batch-draw batch texture x y center-x center-y
                            width height scale-x scale-y rotation
                            #:optional (u 0) (v 0) (u2 1) (v2 1))
  ;; Render the batch when it's full or the texture changes.
  (cond ((= (sprite-batch-size batch) (sprite-batch-max-size batch))
         (sprite-batch-render batch))
        ((not (equal? texture (sprite-batch-texture batch)))
         (sprite-batch-switch-texture batch texture)))
  ;; Add 4 new vertices.
  (let ((base (* 4 (sprite-batch-size batch)))
        (vertices (sprite-batch-vertices batch))
        (x (- x center-x))
        (y (- y center-y))
        (x2 (+ x width))
        (y2 (+ y height)))
    (pack vertices base sprite-vertex
          x y
          1 1 1 1
          u v)
    (pack vertices (+ base 1) sprite-vertex
          x2 y
          1 1 1 1
          u2 v)
    (pack vertices (+ base 2) sprite-vertex
          x2 y2
          1 1 1 1
          u2 v2)
    (pack vertices (+ base 3) sprite-vertex
          x y2
          1 1 1 1
          u v2))
  ;; Increment batch size
  (set-sprite-batch-size! batch (1+ (sprite-batch-size batch))))

(define (sprite-batch-switch-texture batch texture)
  "Change the currently bound texture. This requires flushing the
batched texture vertices first."
  (sprite-batch-render batch)
  (set-sprite-batch-texture! batch texture))

(define (sprite-batch-render batch)
  "Renders and flushes the currently batched texture vertices."
  (unless (= (sprite-batch-size batch) 0)
    ;; Draw vertex array.
    (gl-enable-client-state (enable-cap vertex-array))
    (gl-enable-client-state (enable-cap color-array))
    (gl-enable-client-state (enable-cap texture-coord-array))
    (let* ((texture (sprite-batch-texture batch))
           (size (sprite-batch-size batch))
           (struct-size (packed-struct-size sprite-vertex))
           (vertices (sprite-batch-vertices batch))
           (vertex-count (* 4 size)))
      (with-gl-bind-texture (texture-target texture-2d) (texture-id texture)
        (set-gl-vertex-array (vertex-pointer-type float)
                             vertices
                             2
                             #:stride struct-size
                             #:offset (packed-struct-offset sprite-vertex x))
        (set-gl-color-array (color-pointer-type float)
                            vertices
                            4
                            #:stride struct-size
                            #:offset (packed-struct-offset sprite-vertex r))
        (set-gl-texture-coordinates-array (tex-coord-pointer-type float)
                                          vertices
                                          #:stride struct-size
                                          #:offset (packed-struct-offset sprite-vertex s))
        (gl-draw-arrays (begin-mode quads) 0 vertex-count)))
    (gl-disable-client-state (enable-cap texture-coord-array))
    (gl-disable-client-state (enable-cap color-array))
    (gl-disable-client-state (enable-cap vertex-array))
    ;; Reset batch size to 0.
    (set-sprite-batch-size! batch 0)))

;; emacs: (put 'with-sprite-batch 'scheme-indent-function 1)
(define-syntax-rule (with-sprite-batch batch body ...)
  (begin
    (set-sprite-batch-size! batch 0)
    (set-sprite-batch-texture! batch #f)
    body
    ...
    (sprite-batch-render batch)))