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view libs/libimago/src/imago_gl.c @ 10:819c7ebb1bec

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added libimago to avoid the external dependency
author John Tsiombikas <nuclear@member.fsf.org>
date Fri, 18 Jul 2014 05:07:40 +0300
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1 #include "imago2.h"
2
3
4 /* to avoid dependency to OpenGL, I'll define all the relevant GL macros manually */
5 #define GL_UNSIGNED_BYTE 0x1401
6 #define GL_FLOAT 0x1406
7
8 #define GL_LUMINANCE 0x1909
9 #define GL_RGB 0x1907
10 #define GL_RGBA 0x1908
11
12 #define GL_RGBA32F 0x8814
13 #define GL_RGB32F 0x8815
14 #define GL_LUMINANCE32F 0x8818
15
16 #define GL_TEXTURE_2D 0x0de1
17 #define GL_TEXTURE_WRAP_S 0x2802
18 #define GL_TEXTURE_WRAP_T 0x2803
19 #define GL_TEXTURE_MAG_FILTER 0x2800
20 #define GL_TEXTURE_MIN_FILTER 0x2801
21 #define GL_LINEAR 0x2601
22 #define GL_REPEAT 0x2901
23
24
25 typedef unsigned int GLenum;
26 typedef unsigned int GLuint;
27 typedef int GLint;
28 typedef int GLsizei;
29 typedef void GLvoid;
30
31 /* for the same reason I'll load GL functions dynamically */
32 typedef void (*gl_gen_textures_func)(GLsizei, GLuint*);
33 typedef void (*gl_bind_texture_func)(GLenum, GLuint);
34 typedef void (*gl_tex_parameteri_func)(GLenum, GLenum, GLint);
35 typedef void (*gl_tex_image2d_func)(GLenum, GLint, GLint, GLsizei, GLsizei, GLint, GLenum, GLenum, const GLvoid*);
36
37 static gl_gen_textures_func gl_gen_textures;
38 static gl_bind_texture_func gl_bind_texture;
39 static gl_tex_parameteri_func gl_tex_parameteri;
40 static gl_tex_image2d_func gl_tex_image2d;
41
42 static int load_glfunc(void);
43
44 unsigned int img_fmt_glfmt(enum img_fmt fmt)
45 {
46 switch(fmt) {
47 case IMG_FMT_GREY8:
48 case IMG_FMT_GREYF:
49 return GL_LUMINANCE;
50
51 case IMG_FMT_RGB24:
52 case IMG_FMT_RGBF:
53 return GL_RGB;
54
55 case IMG_FMT_RGBA32:
56 case IMG_FMT_RGBAF:
57 return GL_RGBA;
58
59 default:
60 break;
61 }
62 return 0;
63 }
64
65 unsigned int img_fmt_gltype(enum img_fmt fmt)
66 {
67 switch(fmt) {
68 case IMG_FMT_GREY8:
69 case IMG_FMT_RGB24:
70 case IMG_FMT_RGBA32:
71 return GL_UNSIGNED_BYTE;
72
73 case IMG_FMT_GREYF:
74 case IMG_FMT_RGBF:
75 case IMG_FMT_RGBAF:
76 return GL_FLOAT;
77
78 default:
79 break;
80 }
81 return 0;
82 }
83
84 unsigned int img_fmt_glintfmt(enum img_fmt fmt)
85 {
86 switch(fmt) {
87 case IMG_FMT_GREY8:
88 return GL_LUMINANCE;
89 case IMG_FMT_RGB24:
90 return GL_RGB;
91 case IMG_FMT_RGBA32:
92 return GL_RGBA;
93 case IMG_FMT_GREYF:
94 return GL_LUMINANCE32F;
95 case IMG_FMT_RGBF:
96 return GL_RGB32F;
97 case IMG_FMT_RGBAF:
98 return GL_RGBA32F;
99 default:
100 break;
101 }
102 return 0;
103 }
104
105 unsigned int img_glfmt(struct img_pixmap *img)
106 {
107 return img_fmt_glfmt(img->fmt);
108 }
109
110 unsigned int img_gltype(struct img_pixmap *img)
111 {
112 return img_fmt_gltype(img->fmt);
113 }
114
115 unsigned int img_glintfmt(struct img_pixmap *img)
116 {
117 return img_fmt_glintfmt(img->fmt);
118 }
119
120 unsigned int img_gltexture(struct img_pixmap *img)
121 {
122 unsigned int tex;
123 unsigned int intfmt, fmt, type;
124
125 if(!gl_gen_textures) {
126 if(load_glfunc() == -1) {
127 fprintf(stderr, "imago: failed to initialize the OpenGL helpers\n");
128 return 0;
129 }
130 }
131
132 intfmt = img_glintfmt(img);
133 fmt = img_glfmt(img);
134 type = img_gltype(img);
135
136 gl_gen_textures(1, &tex);
137 gl_bind_texture(GL_TEXTURE_2D, tex);
138 gl_tex_parameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
139 gl_tex_parameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
140 gl_tex_parameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
141 gl_tex_parameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
142 gl_tex_image2d(GL_TEXTURE_2D, 0, intfmt, img->width, img->height, 0, fmt, type, img->pixels);
143 return tex;
144 }
145
146 unsigned int img_gltexture_load(const char *fname)
147 {
148 struct img_pixmap img;
149 unsigned int tex;
150
151 img_init(&img);
152 if(img_load(&img, fname) == -1) {
153 img_destroy(&img);
154 return 0;
155 }
156
157 tex = img_gltexture(&img);
158 img_destroy(&img);
159 return tex;
160 }
161
162 unsigned int img_gltexture_read_file(FILE *fp)
163 {
164 struct img_pixmap img;
165 unsigned int tex;
166
167 img_init(&img);
168 if(img_read_file(&img, fp) == -1) {
169 img_destroy(&img);
170 return 0;
171 }
172
173 tex = img_gltexture(&img);
174 img_destroy(&img);
175 return tex;
176 }
177
178 unsigned int img_gltexture_read(struct img_io *io)
179 {
180 struct img_pixmap img;
181 unsigned int tex;
182
183 img_init(&img);
184 if(img_read(&img, io) == -1) {
185 img_destroy(&img);
186 return 0;
187 }
188
189 tex = img_gltexture(&img);
190 img_destroy(&img);
191 return tex;
192 }
193
194 #if defined(__unix__) || defined(__APPLE__)
195 #ifndef __USE_GNU
196 #define __USE_GNU
197 #endif
198
199 #include <dlfcn.h>
200 #endif
201 #ifdef WIN32
202 #include <windows.h>
203 #endif
204
205 static int load_glfunc(void)
206 {
207 #if defined(__unix__) || defined(__APPLE__)
208 gl_gen_textures = (gl_gen_textures_func)dlsym(RTLD_DEFAULT, "glGenTextures");
209 gl_bind_texture = (gl_bind_texture_func)dlsym(RTLD_DEFAULT, "glBindTexture");
210 gl_tex_parameteri = (gl_tex_parameteri_func)dlsym(RTLD_DEFAULT, "glTexParameteri");
211 gl_tex_image2d = (gl_tex_image2d_func)dlsym(RTLD_DEFAULT, "glTexImage2D");
212 #endif
213
214 #ifdef WIN32
215 HMODULE handle = GetModuleHandle(0);
216 gl_gen_textures = (gl_gen_textures_func)GetProcAddress(handle, "glGenTextures");
217 gl_bind_texture = (gl_bind_texture_func)GetProcAddress(handle, "glBindTexture");
218 gl_tex_parameteri = (gl_tex_parameteri_func)GetProcAddress(handle, "glTexParameteri");
219 gl_tex_image2d = (gl_tex_image2d_func)GetProcAddress(handle, "glTexImage2D");
220 #endif
221
222 return (gl_gen_textures && gl_bind_texture && gl_tex_parameteri && gl_tex_image2d) ? 0 : -1;
223 }