1 /* cairo - a vector graphics library with display and print output
2 *
3 * Copyright © 2010 Linaro Limited
4 *
5 * This library is free software; you can redistribute it and/or
6 * modify it either under the terms of the GNU Lesser General Public
7 * License version 2.1 as published by the Free Software Foundation
8 * (the "LGPL") or, at your option, under the terms of the Mozilla
9 * Public License Version 1.1 (the "MPL"). If you do not alter this
10 * notice, a recipient may use your version of this file under either
11 * the MPL or the LGPL.
12 *
13 * You should have received a copy of the LGPL along with this library
14 * in the file COPYING-LGPL-2.1; if not, write to the Free Software
15 * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA
16 * You should have received a copy of the MPL along with this library
17 * in the file COPYING-MPL-1.1
18 *
19 * The contents of this file are subject to the Mozilla Public License
20 * Version 1.1 (the "License"); you may not use this file except in
21 * compliance with the License. You may obtain a copy of the License at
22 * http://www.mozilla.org/MPL/
23 *
24 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
25 * OF ANY KIND, either express or implied. See the LGPL or the MPL for
26 * the specific language governing rights and limitations.
27 *
28 * Contributor(s):
29 * Alexandros Frantzis <alexandros.frantzis@linaro.org>
30 * Heiko Lewin <heiko.lewin@gmx.de>
31 */
32
33 #include "cairoint.h"
34 #include "cairo-gl-private.h"
35
36 #include <errno.h>
37
38 int
_cairo_gl_get_version(void)39 _cairo_gl_get_version (void)
40 {
41 int major, minor;
42 const char *version = (const char *) glGetString (GL_VERSION);
43 const char *dot = version == NULL ? NULL : strchr (version, '.');
44 const char *major_start = dot;
45
46 /* Sanity check */
47 if (dot == NULL || dot == version || *(dot + 1) == '\0') {
48 major = 0;
49 minor = 0;
50 } else {
51 /* Find the start of the major version in the string */
52 while (major_start > version && *major_start != ' ')
53 --major_start;
54 major = strtol (major_start, NULL, 10);
55 minor = strtol (dot + 1, NULL, 10);
56 }
57
58 return CAIRO_GL_VERSION_ENCODE (major, minor);
59 }
60
61
62 cairo_gl_flavor_t
_cairo_gl_degrade_flavor_by_build_features(cairo_gl_flavor_t flavor)63 _cairo_gl_degrade_flavor_by_build_features (cairo_gl_flavor_t flavor) {
64 switch(flavor) {
65 case CAIRO_GL_FLAVOR_DESKTOP:
66 #if CAIRO_HAS_GL_SURFACE
67 return CAIRO_GL_FLAVOR_DESKTOP;
68 #else
69 return CAIRO_GL_FLAVOR_NONE;
70 #endif
71
72 case CAIRO_GL_FLAVOR_ES3:
73 #if CAIRO_HAS_GLESV3_SURFACE
74 return CAIRO_GL_FLAVOR_ES3;
75 #else
76 /* intentional fall through: degrade to GLESv2 if GLESv3-surfaces are not available */
77 #endif
78
79 case CAIRO_GL_FLAVOR_ES2:
80 #if CAIRO_HAS_GLESV2_SURFACE
81 return CAIRO_GL_FLAVOR_ES2;
82 #else
83 /* intentional fall through: no OpenGL in first place or no surfaces for it's version */
84 #endif
85
86 default:
87 return CAIRO_GL_FLAVOR_NONE;
88 }
89 }
90
91 cairo_gl_flavor_t
_cairo_gl_get_flavor(void)92 _cairo_gl_get_flavor (void)
93 {
94 const char *version = (const char *) glGetString (GL_VERSION);
95 cairo_gl_flavor_t flavor;
96
97 if (version == NULL) {
98 flavor = CAIRO_GL_FLAVOR_NONE;
99 } else if (strstr (version, "OpenGL ES 3") != NULL) {
100 flavor = CAIRO_GL_FLAVOR_ES3;
101 } else if (strstr (version, "OpenGL ES 2") != NULL) {
102 flavor = CAIRO_GL_FLAVOR_ES2;
103 } else {
104 flavor = CAIRO_GL_FLAVOR_DESKTOP;
105 }
106
107 return _cairo_gl_degrade_flavor_by_build_features(flavor);
108 }
109
110 unsigned long
_cairo_gl_get_vbo_size(void)111 _cairo_gl_get_vbo_size (void)
112 {
113 unsigned long vbo_size;
114
115 const char *env = getenv ("CAIRO_GL_VBO_SIZE");
116 if (env == NULL) {
117 vbo_size = CAIRO_GL_VBO_SIZE_DEFAULT;
118 } else {
119 errno = 0;
120 vbo_size = strtol (env, NULL, 10);
121 assert (errno == 0);
122 assert (vbo_size > 0);
123 }
124
125 return vbo_size;
126 }
127
128 cairo_bool_t
_cairo_gl_has_extension(const char * ext)129 _cairo_gl_has_extension (const char *ext)
130 {
131 const char *extensions = (const char *) glGetString (GL_EXTENSIONS);
132 size_t len = strlen (ext);
133 const char *ext_ptr = extensions;
134
135 if (unlikely (ext_ptr == NULL))
136 return 0;
137
138 while ((ext_ptr = strstr (ext_ptr, ext)) != NULL) {
139 if (ext_ptr[len] == ' ' || ext_ptr[len] == '\0')
140 break;
141 ext_ptr += len;
142 }
143
144 return (ext_ptr != NULL);
145 }
146