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annotate libs/drawtext/drawgl.c @ 22:d7fe157c402d

fonts
author John Tsiombikas <nuclear@member.fsf.org>
date Sat, 13 Jun 2015 05:32:07 +0300
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rev   line source
nuclear@10 1 /*
nuclear@10 2 libdrawtext - a simple library for fast text rendering in OpenGL
nuclear@10 3 Copyright (C) 2011-2012 John Tsiombikas <nuclear@member.fsf.org>
nuclear@10 4
nuclear@10 5 This program is free software: you can redistribute it and/or modify
nuclear@10 6 it under the terms of the GNU Lesser General Public License as published by
nuclear@10 7 the Free Software Foundation, either version 3 of the License, or
nuclear@10 8 (at your option) any later version.
nuclear@10 9
nuclear@10 10 This program is distributed in the hope that it will be useful,
nuclear@10 11 but WITHOUT ANY WARRANTY; without even the implied warranty of
nuclear@10 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
nuclear@10 13 GNU Lesser General Public License for more details.
nuclear@10 14
nuclear@10 15 You should have received a copy of the GNU Lesser General Public License
nuclear@10 16 along with this program. If not, see <http://www.gnu.org/licenses/>.
nuclear@10 17 */
nuclear@10 18 #ifndef NO_OPENGL
nuclear@10 19 #include <stdarg.h>
nuclear@10 20 #include <math.h>
nuclear@10 21 #include <ctype.h>
nuclear@10 22
nuclear@10 23 #include <stdlib.h>
nuclear@10 24
nuclear@10 25 #ifndef _MSC_VER
nuclear@10 26 #include <alloca.h>
nuclear@10 27 #else
nuclear@10 28 #include <malloc.h>
nuclear@10 29 #endif
nuclear@10 30
nuclear@10 31 #ifdef TARGET_IPHONE
nuclear@10 32 #include <OpenGLES/ES2/gl.h>
nuclear@10 33 #define GL_ES
nuclear@10 34 #elif defined(ANDROID)
nuclear@10 35 #include <GLES2/gl2.h>
nuclear@10 36 #define GL_ES
nuclear@10 37 #else
nuclear@10 38 #include <GL/glew.h>
nuclear@10 39 #endif
nuclear@10 40
nuclear@10 41 #include "drawtext.h"
nuclear@10 42 #include "drawtext_impl.h"
nuclear@10 43
nuclear@10 44 struct vertex {
nuclear@10 45 float x, y;
nuclear@10 46 float s, t;
nuclear@10 47 };
nuclear@10 48
nuclear@10 49 struct quad {
nuclear@10 50 struct vertex v[6];
nuclear@10 51 };
nuclear@10 52
nuclear@10 53 static void cleanup(void);
nuclear@10 54 static void add_glyph(struct glyph *g, float x, float y);
nuclear@10 55
nuclear@10 56 #define QBUF_SZ 512
nuclear@10 57 static struct quad *qbuf;
nuclear@10 58 static int num_quads;
nuclear@10 59 static int vattr = -1;
nuclear@10 60 static int tattr = -1;
nuclear@10 61 static unsigned int font_tex;
nuclear@10 62 static int buf_mode = DTX_NBF;
nuclear@10 63
nuclear@10 64
nuclear@10 65 int dtx_gl_init(void)
nuclear@10 66 {
nuclear@10 67 if(qbuf) {
nuclear@10 68 return 0; /* already initialized */
nuclear@10 69 }
nuclear@10 70
nuclear@10 71 #ifdef __glew_h__
nuclear@10 72 glewInit();
nuclear@10 73 #endif
nuclear@10 74
nuclear@10 75 if(!(qbuf = malloc(QBUF_SZ * sizeof *qbuf))) {
nuclear@10 76 return -1;
nuclear@10 77 }
nuclear@10 78 num_quads = 0;
nuclear@10 79
nuclear@10 80 atexit(cleanup);
nuclear@10 81 return 0;
nuclear@10 82 }
nuclear@10 83
nuclear@10 84 static void cleanup(void)
nuclear@10 85 {
nuclear@10 86 free(qbuf);
nuclear@10 87 }
nuclear@10 88
nuclear@10 89
nuclear@10 90 void dtx_vertex_attribs(int vert_attr, int tex_attr)
nuclear@10 91 {
nuclear@10 92 vattr = vert_attr;
nuclear@10 93 tattr = tex_attr;
nuclear@10 94 }
nuclear@10 95
nuclear@10 96 static void set_glyphmap_texture(struct dtx_glyphmap *gmap)
nuclear@10 97 {
nuclear@10 98 if(!gmap->tex) {
nuclear@10 99 glGenTextures(1, &gmap->tex);
nuclear@10 100 glBindTexture(GL_TEXTURE_2D, gmap->tex);
nuclear@10 101 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
nuclear@10 102 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
nuclear@10 103 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
nuclear@10 104 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
nuclear@10 105
nuclear@10 106 #ifdef GL_ES
nuclear@10 107 glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA, gmap->xsz, gmap->ysz, 0, GL_ALPHA, GL_UNSIGNED_BYTE, gmap->pixels);
nuclear@10 108 glGenerateMipmap(GL_TEXTURE_2D);
nuclear@10 109 #else
nuclear@10 110 gluBuild2DMipmaps(GL_TEXTURE_2D, GL_ALPHA, gmap->xsz, gmap->ysz, GL_ALPHA, GL_UNSIGNED_BYTE, gmap->pixels);
nuclear@10 111 #endif
nuclear@10 112 }
nuclear@10 113
nuclear@10 114 if(font_tex != gmap->tex) {
nuclear@10 115 dtx_flush();
nuclear@10 116 }
nuclear@10 117 font_tex = gmap->tex;
nuclear@10 118 }
nuclear@10 119
nuclear@10 120 void dtx_glyph(int code)
nuclear@10 121 {
nuclear@10 122 struct dtx_glyphmap *gmap;
nuclear@10 123
nuclear@10 124 if(!dtx_font || !(gmap = dtx_get_font_glyphmap(dtx_font, dtx_font_sz, code))) {
nuclear@10 125 return;
nuclear@10 126 }
nuclear@10 127 set_glyphmap_texture(gmap);
nuclear@10 128
nuclear@10 129 add_glyph(gmap->glyphs + code - gmap->cstart, 0, 0);
nuclear@10 130 dtx_flush();
nuclear@10 131 }
nuclear@10 132
nuclear@10 133 static const char *put_char(const char *str, float *pos_x, float *pos_y, int *should_flush)
nuclear@10 134 {
nuclear@10 135 struct dtx_glyphmap *gmap;
nuclear@10 136 float px, py;
nuclear@10 137 int code = dtx_utf8_char_code(str);
nuclear@10 138 str = dtx_utf8_next_char((char*)str);
nuclear@10 139
nuclear@10 140 if(buf_mode == DTX_LBF && code == '\n') {
nuclear@10 141 *should_flush = 1;
nuclear@10 142 }
nuclear@10 143
nuclear@10 144 px = *pos_x;
nuclear@10 145 py = *pos_y;
nuclear@10 146
nuclear@10 147 if((gmap = dtx_proc_char(code, pos_x, pos_y))) {
nuclear@10 148 int idx = code - gmap->cstart;
nuclear@10 149
nuclear@10 150 set_glyphmap_texture(gmap);
nuclear@10 151 add_glyph(gmap->glyphs + idx, px, py);
nuclear@10 152 }
nuclear@10 153 return str;
nuclear@10 154 }
nuclear@10 155
nuclear@10 156 void dtx_string(const char *str)
nuclear@10 157 {
nuclear@10 158 int should_flush = buf_mode == DTX_NBF;
nuclear@10 159 float pos_x = 0.0f;
nuclear@10 160 float pos_y = 0.0f;
nuclear@10 161
nuclear@10 162 if(!dtx_font) {
nuclear@10 163 return;
nuclear@10 164 }
nuclear@10 165
nuclear@10 166 while(*str) {
nuclear@10 167 str = put_char(str, &pos_x, &pos_y, &should_flush);
nuclear@10 168 }
nuclear@10 169
nuclear@10 170 if(should_flush) {
nuclear@10 171 dtx_flush();
nuclear@10 172 }
nuclear@10 173 }
nuclear@10 174
nuclear@10 175 void dtx_printf(const char *fmt, ...)
nuclear@10 176 {
nuclear@10 177 va_list ap;
nuclear@10 178 int buf_size;
nuclear@10 179 char *buf, tmp;
nuclear@10 180
nuclear@10 181 if(!dtx_font) {
nuclear@10 182 return;
nuclear@10 183 }
nuclear@10 184
nuclear@10 185 va_start(ap, fmt);
nuclear@10 186 buf_size = vsnprintf(&tmp, 0, fmt, ap);
nuclear@10 187 va_end(ap);
nuclear@10 188
nuclear@10 189 if(buf_size == -1) {
nuclear@10 190 buf_size = 512;
nuclear@10 191 }
nuclear@10 192
nuclear@10 193 buf = alloca(buf_size + 1);
nuclear@10 194 va_start(ap, fmt);
nuclear@10 195 vsnprintf(buf, buf_size + 1, fmt, ap);
nuclear@10 196 va_end(ap);
nuclear@10 197
nuclear@10 198 dtx_string(buf);
nuclear@10 199 }
nuclear@10 200
nuclear@10 201 static void qvertex(struct vertex *v, float x, float y, float s, float t)
nuclear@10 202 {
nuclear@10 203 v->x = x;
nuclear@10 204 v->y = y;
nuclear@10 205 v->s = s;
nuclear@10 206 v->t = t;
nuclear@10 207 }
nuclear@10 208
nuclear@10 209 static void add_glyph(struct glyph *g, float x, float y)
nuclear@10 210 {
nuclear@10 211 struct quad *qptr = qbuf + num_quads;
nuclear@10 212
nuclear@10 213 x -= g->orig_x;
nuclear@10 214 y -= g->orig_y;
nuclear@10 215
nuclear@10 216 qvertex(qptr->v + 0, x, y, g->nx, g->ny + g->nheight);
nuclear@10 217 qvertex(qptr->v + 1, x + g->width, y, g->nx + g->nwidth, g->ny + g->nheight);
nuclear@10 218 qvertex(qptr->v + 2, x + g->width, y + g->height, g->nx + g->nwidth, g->ny);
nuclear@10 219
nuclear@10 220 qvertex(qptr->v + 3, x, y, g->nx, g->ny + g->nheight);
nuclear@10 221 qvertex(qptr->v + 4, x + g->width, y + g->height, g->nx + g->nwidth, g->ny);
nuclear@10 222 qvertex(qptr->v + 5, x, y + g->height, g->nx, g->ny);
nuclear@10 223
nuclear@10 224 if(++num_quads >= QBUF_SZ) {
nuclear@10 225 dtx_flush();
nuclear@10 226 }
nuclear@10 227 }
nuclear@10 228
nuclear@10 229 void dtx_flush(void)
nuclear@10 230 {
nuclear@10 231 int vbo;
nuclear@10 232
nuclear@10 233 if(!num_quads) {
nuclear@10 234 return;
nuclear@10 235 }
nuclear@10 236
nuclear@10 237 glGetIntegerv(GL_ARRAY_BUFFER_BINDING, &vbo);
nuclear@10 238 glBindBuffer(GL_ARRAY_BUFFER, 0);
nuclear@10 239
nuclear@10 240 #ifndef GL_ES
nuclear@10 241 glPushAttrib(GL_ENABLE_BIT);
nuclear@10 242 glEnable(GL_TEXTURE_2D);
nuclear@10 243 #endif
nuclear@10 244 glBindTexture(GL_TEXTURE_2D, font_tex);
nuclear@10 245
nuclear@10 246 if(vattr != -1) {
nuclear@10 247 glEnableVertexAttribArray(vattr);
nuclear@10 248 glVertexAttribPointer(vattr, 2, GL_FLOAT, 0, sizeof(struct vertex), qbuf);
nuclear@10 249 #ifndef GL_ES
nuclear@10 250 } else {
nuclear@10 251 glEnableClientState(GL_VERTEX_ARRAY);
nuclear@10 252 glVertexPointer(2, GL_FLOAT, sizeof(struct vertex), qbuf);
nuclear@10 253 #endif
nuclear@10 254 }
nuclear@10 255 if(tattr != -1) {
nuclear@10 256 glEnableVertexAttribArray(tattr);
nuclear@10 257 glVertexAttribPointer(tattr, 2, GL_FLOAT, 0, sizeof(struct vertex), &qbuf->v[0].s);
nuclear@10 258 #ifndef GL_ES
nuclear@10 259 } else {
nuclear@10 260 glEnableClientState(GL_TEXTURE_COORD_ARRAY);
nuclear@10 261 glTexCoordPointer(2, GL_FLOAT, sizeof(struct vertex), &qbuf->v[0].s);
nuclear@10 262 #endif
nuclear@10 263 }
nuclear@10 264
nuclear@10 265 glEnable(GL_BLEND);
nuclear@10 266 glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
nuclear@10 267
nuclear@10 268 glDepthMask(0);
nuclear@10 269
nuclear@10 270 glDrawArrays(GL_TRIANGLES, 0, num_quads * 6);
nuclear@10 271
nuclear@10 272 glDepthMask(1);
nuclear@10 273
nuclear@10 274 if(vattr != -1) {
nuclear@10 275 glDisableVertexAttribArray(vattr);
nuclear@10 276 #ifndef GL_ES
nuclear@10 277 } else {
nuclear@10 278 glDisableClientState(GL_VERTEX_ARRAY);
nuclear@10 279 #endif
nuclear@10 280 }
nuclear@10 281 if(tattr != -1) {
nuclear@10 282 glDisableVertexAttribArray(tattr);
nuclear@10 283 #ifndef GL_ES
nuclear@10 284 } else {
nuclear@10 285 glDisableClientState(GL_TEXTURE_COORD_ARRAY);
nuclear@10 286 #endif
nuclear@10 287 }
nuclear@10 288
nuclear@10 289 #ifndef GL_ES
nuclear@10 290 glPopAttrib();
nuclear@10 291 #else
nuclear@10 292 glDisable(GL_BLEND);
nuclear@10 293 #endif
nuclear@10 294
nuclear@10 295 if(vbo) {
nuclear@10 296 glBindBuffer(GL_ARRAY_BUFFER, vbo);
nuclear@10 297 }
nuclear@10 298
nuclear@10 299 num_quads = 0;
nuclear@10 300 }
nuclear@10 301
nuclear@10 302 #endif /* !def NO_OPENGL */