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
|
;;; 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:
;;
;; Textures and texture regions are high level wrappers over OpenGL
;; textures.
;;
;;; Code:
(define-module (2d texture)
#:use-module (srfi srfi-9)
#:use-module (figl gl)
#:use-module (2d color)
#:use-module (2d helpers)
#:use-module (2d wrappers gl)
#:use-module (2d wrappers freeimage)
#:export (make-texture
make-texture-region
load-texture
texture?
texture-region?
texture-id
texture-width
texture-height
texture-s1
texture-t1
texture-s2
texture-t2
surface->texture
draw-texture))
;;;
;;; Textures
;;;
;; The <texture> object is a simple wrapper around an OpenGL texture
;; id.
(define-record-type <texture>
(%make-texture id parent width height s1 t1 s2 t2)
texture?
(id texture-id)
(parent texture-parent)
(width texture-width)
(height texture-height)
(s1 texture-s1)
(t1 texture-t1)
(s2 texture-s2)
(t2 texture-t2))
(define (texture-region? texture)
"Return #t if TEXTURE has a parent texture."
(texture? (texture-parent texture)))
(define (make-texture id parent width height s1 t1 s2 t2)
"Create a new texture object. ID is the OpenGL texture id. PARENT is
a texture object (if this texture only represents a region of another
texture) or #f. WIDTH and HEIGHT are the texture dimensions in
pixels. S1, T1, S2, and T2 are the OpenGL texture coordinates
representing the area of the texture that will be rendered."
(let ((texture (%make-texture id parent width height s1 t1 s2 t2)))
(texture-guardian texture)
texture))
(define (make-texture-region texture x y width height)
"Creates new texture region object. TEXTURE is the region's parent
texture. X, Y, WIDTH, and HEIGHT represent the region of the texture
that will be rendered, in pixels."
(let* ((w (texture-width texture))
(h (texture-height texture)))
(make-texture (texture-id texture)
texture
width
height
(/ x w)
(/ y h)
(/ (+ x width) w)
(/ (+ y height) h))))
;; Use a guardian and an after GC hook that ensures that OpenGL
;; textures are deleted when texture objects are GC'd.
(define-guardian texture-guardian
(lambda (texture)
;; Do not reap texture regions
(unless (texture-region? 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.
(false-if-exception (gl-delete-texture (texture-id texture))))))
(define (bitmap->texture bitmap)
"Translates a freeimage bitmap into an OpenGL texture."
(let ((texture-id (gl-generate-texture))
(pixels (freeimage-get-bits bitmap)))
(with-gl-bind-texture (texture-target texture-2d) texture-id
;; Use "nearest" scaling method so that pixel art doesn't become
;; blurry when scaled.
(gl-texture-parameter (texture-target texture-2d)
(texture-parameter-name texture-min-filter)
(texture-min-filter nearest))
(gl-texture-parameter (texture-target texture-2d)
(texture-parameter-name texture-mag-filter)
(texture-mag-filter nearest))
(gl-texture-image-2d (texture-target texture-2d)
0
(pixel-format rgba)
(freeimage-get-width bitmap)
(freeimage-get-height bitmap)
0
(version-1-2 bgra)
(color-pointer-type unsigned-byte)
pixels))
(make-texture texture-id
#f
(freeimage-get-width bitmap)
(freeimage-get-height bitmap)
0 0 1 1)))
(define (load-bitmap filename)
;; Throw an error if image file does not exist or else we will
;; segfault later.
(unless (file-exists? filename)
(throw 'image-not-found filename))
;; Load image and convert it to 32 bit color.
(let* ((image-type (freeimage-get-file-type filename))
(bitmap (freeimage-load image-type filename))
(32bit-bitmap (freeimage-convert-to-32-bits bitmap)))
(freeimage-unload bitmap)
;; Need to flip because y-axis is reversed.
(freeimage-flip-vertical 32bit-bitmap)
32bit-bitmap))
(define (load-texture filename)
"Load a texture from an image file at FILENAME."
(let* ((bitmap (load-bitmap filename))
(texture (bitmap->texture bitmap)))
(freeimage-unload bitmap)
texture))
|
