summaryrefslogtreecommitdiff
path: root/2d/sprite.scm
blob: ac57adbf297686aacab7e1015bd0c138406d984b (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
;;; 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-1)
  #:use-module (srfi srfi-9)
  #:use-module (figl gl)
  #:use-module (figl contrib packed-struct)
  #:use-module ((sdl sdl) #:prefix SDL:)
  #:use-module (2d animation)
  #:use-module (2d color)
  #:use-module (2d helpers)
  #:use-module (2d math)
  #:use-module (2d texture)
  #:use-module (2d vector2)
  #:use-module (2d wrappers gl))

;;;
;;; Sprite Vertices
;;;

;; Used to build OpenGL vertex array for a sprite.
(define-packed-struct sprite-vertex
  ;; Position
  (x float)
  (y float)
  ;; Color
  (r float)
  (g float)
  (b float)
  (a float)
  ;; Texture Coordinates
  (s float)
  (t float))

(define sprite-vertex-size (packed-struct-size sprite-vertex))
(define x-offset (packed-struct-offset sprite-vertex x))
(define r-offset (packed-struct-offset sprite-vertex r))
(define s-offset (packed-struct-offset sprite-vertex s))

(define (pack-sprite-vertices vertices offset x y width height origin-x origin-y
                              scale-x scale-y rotation s1 t1 s2 t2 color)
  (define (pack-sprite x1 y1 x2 y2 x3 y3 x4 y4)
    (let ((r (color-r color))
          (g (color-g color))
          (b (color-b color))
          (a (color-a color)))
      ;; Vertices go counter clockwise, starting from the top-left
      ;; corner.
      (pack vertices offset sprite-vertex
            x1 y1
            r g b a
            s1 t1)
      (pack vertices (+ offset 1) sprite-vertex
            x2 y2
            r g b a
            s1 t2)
      (pack vertices (+ offset 2) sprite-vertex
            x3 y3
            r g b a
            s2 t2)
      (pack vertices (+ offset 3) sprite-vertex
            x4 y4
            r g b a
            s2 t1)))

  (let ((local-x1 (* (- origin-x) scale-x))
        (local-y1 (* (- origin-y) scale-y))
        (local-x2 (* (- width origin-x) scale-x))
        (local-y2 (* (- height origin-y) scale-y)))
    (if (= rotation 0)
        (begin
          (let ((x1 (+ x local-x1))
                (y1 (+ y local-y1))
                (x2 (+ x local-x2))
                (y2 (+ y local-y2)))
            (pack-sprite x1 y1 x1 y2 x2 y2 x2 y1)))
        (begin
          (let* ((sin (sin-degrees rotation))
                 (cos (cos-degrees rotation))
                 (x1 (+ x (- (* cos local-x1) (* sin local-y1))))
                 (y1 (+ y (* sin local-x1) (* cos local-y1)))
                 (x2 (+ x (- (* cos local-x1) (* sin local-y2))))
                 (y2 (+ y (* sin local-x1) (* cos local-y2)))
                 (x3 (+ x (- (* cos local-x2) (* sin local-y2))))
                 (y3 (+ y (* sin local-x2) (* cos local-y2)))
                 (x4 (+ x1 (- x3 x2)))
                 (y4 (- y3 (- y2 y1))))
            (pack-sprite x1 y1 x2 y2 x3 y3 x4 y4))))))

(define (draw-sprite-vertices texture vertices size)
  (let ((pointer-type (tex-coord-pointer-type float)))
    (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 pointer-type
                           vertices
                           2
                           #:stride sprite-vertex-size
                           #:offset x-offset)
      (set-gl-color-array pointer-type
                          vertices
                          4
                          #:stride sprite-vertex-size
                          #:offset r-offset)
      (set-gl-texture-coordinates-array pointer-type
                                        vertices
                                        #:stride sprite-vertex-size
                                        #:offset s-offset)
      (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))))

;;;
;;; Sprites
;;;

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

(define* (make-sprite drawable #:optional #:key
                      (position (vector2 0 0)) (scale (vector2 1 1))
                      (rotation 0) (color white) (anchor 'center))
  "Makes a new sprite object."
  (let ((vertices (make-packed-array sprite-vertex 4))
        (animation-state (if (animation? drawable)
                             (make-animation-state drawable)
                             #f)))
    (%make-sprite drawable position scale rotation color anchor vertices #t animation-state)))

(define-syntax-rule (dirty-sprite-setter setter private-setter)
  "Defines a setter that calls the private version of the given
procedure name (prefix with %) and marks the sprite as dirty. Any
operation that requires a refresh of the vertex array should use this macro."
  (define (setter sprite value)
    (private-setter sprite value)
    (set-sprite-dirty! sprite #t)))

(dirty-sprite-setter set-sprite-position! %set-sprite-position!)
(dirty-sprite-setter set-sprite-scale! %set-sprite-scale!)
(dirty-sprite-setter set-sprite-rotation! %set-sprite-rotation!)
(dirty-sprite-setter set-sprite-color! %set-sprite-color!)
(dirty-sprite-setter set-sprite-anchor! %set-sprite-anchor!)

(define* (load-sprite filename #:optional #:key
                      (position (vector2 0 0)) (scale (vector2 1 1))
                      (rotation 0) (color white) (anchor 'center))
  "Loads a sprite from file."
  (make-sprite (load-texture filename) #:position position #:scale scale
               #:rotation rotation #:color color #:anchor anchor))

(define (sprite-animation-frame sprite)
  (animation-state-frame (sprite-animation-state sprite)))

(define (sprite-texture sprite)
  "Returns the texture for the sprite's drawable object."
    (let ((drawable (sprite-drawable sprite)))
      (cond ((texture? drawable)
             drawable)
            ((animation? drawable)
             (sprite-animation-frame sprite)))))

(define (sprite-anchor-vector sprite)
  "Returns a vector of the coordinates for the center point of a
sprite."
  (let ((anchor (sprite-anchor sprite))
        (texture (sprite-texture sprite)))
    (cond
     ((eq? anchor 'center)
        (vector2 (/ (texture-width texture) 2)
                 (/ (texture-height texture) 2)))
     (else anchor))))

(define (update-sprite-vertices! sprite)
  "Rebuilds the internal vertex array."
  (let ((pos (sprite-position sprite))
        (scale (sprite-scale sprite))
        (anchor (sprite-anchor-vector sprite))
        (texture (sprite-texture sprite)))
    (pack-sprite-vertices (sprite-vertices sprite)
                          0
                          (vx pos)
                          (vy pos)
                          (texture-width texture)
                          (texture-height texture)
                          (vx anchor)
                          (vy anchor)
                          (vx scale)
                          (vy scale)
                          (sprite-rotation sprite)
                          (texture-s1 texture)
                          (texture-t1 texture)
                          (texture-s2 texture)
                          (texture-t2 texture)
                          (sprite-color sprite))))

(define (update-sprite-animation-state! sprite)
  (set-sprite-animation-state!
   sprite
   (tick-animation-state (sprite-animation-state sprite))))

(define (draw-sprite sprite)
  "Renders a sprite. A sprite batch will be used if one is currently
bound."
  (when (sprite-dirty? sprite)
    (update-sprite-vertices! sprite))
  (when (animation? (sprite-drawable sprite))
    (update-sprite-animation-state! sprite))
  (if *sprite-batch*
      (draw-sprite-batched sprite)
      (draw-sprite-vertices (sprite-texture sprite)
                            (sprite-vertices sprite)
                            1)))

(define (draw-sprite-batched sprite)
  "Adds a sprite to the batch."
  (let ((texture (sprite-texture sprite))
        (pos (sprite-position sprite))
        (scale (sprite-scale sprite))
        (anchor (sprite-anchor-vector sprite)))
    (%sprite-batch-draw *sprite-batch*
                        texture
                        (vx pos)
                        (vy pos)
                        (texture-width texture)
                        (texture-height texture)
                        (vx anchor)
                        (vy anchor)
                        (vx scale)
                        (vy scale)
                        (sprite-rotation sprite)
                        (texture-s1 texture)
                        (texture-t1 texture)
                        (texture-s2 texture)
                        (texture-t2 texture)
                        (sprite-color sprite))))

(export make-sprite
        sprite?
        sprite-drawable
        set-sprite-drawable!
        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)

;;;
;;; 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))

;; Dynamic state for the current sprite batch.
(define *sprite-batch* #f)

(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))))

(define (sprite-batch-draw . args)
  "Adds a textured quad to the current sprite batch."
  (apply %sprite-batch-draw *sprite-batch* args))

(define* (%sprite-batch-draw batch texture x y width height origin-x origin-y
                             scale-x scale-y rotation u v u2 v2 color)
  "Adds a textured quad to the sprite batch."
  ;; 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, taking into account scaling and rotation.
  (pack-sprite-vertices (sprite-batch-vertices batch)
                        (* 4 (sprite-batch-size batch))
                        x y width height origin-x origin-y
                        scale-x scale-y rotation u v u2 v2 color)

  ;; 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-sprite-vertices (sprite-batch-texture batch)
                          (sprite-batch-vertices batch)
                          (sprite-batch-size batch))
    ;; 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* batch)
    (set-sprite-batch-size! batch 0)
    (set-sprite-batch-texture! batch #f)
    body
    ...
    (sprite-batch-render batch)
    (set! *sprite-batch* #f)))

(export 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)