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annotate libs/drawtext/drawgl.c @ 0:b2f14e535253

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author John Tsiombikas <nuclear@member.fsf.org>
date Sat, 01 Feb 2014 19:58:19 +0200
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nuclear@0 1 /*
nuclear@0 2 libdrawtext - a simple library for fast text rendering in OpenGL
nuclear@0 3 Copyright (C) 2011-2012 John Tsiombikas <nuclear@member.fsf.org>
nuclear@0 4
nuclear@0 5 This program is free software: you can redistribute it and/or modify
nuclear@0 6 it under the terms of the GNU Lesser General Public License as published by
nuclear@0 7 the Free Software Foundation, either version 3 of the License, or
nuclear@0 8 (at your option) any later version.
nuclear@0 9
nuclear@0 10 This program is distributed in the hope that it will be useful,
nuclear@0 11 but WITHOUT ANY WARRANTY; without even the implied warranty of
nuclear@0 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
nuclear@0 13 GNU Lesser General Public License for more details.
nuclear@0 14
nuclear@0 15 You should have received a copy of the GNU Lesser General Public License
nuclear@0 16 along with this program. If not, see <http://www.gnu.org/licenses/>.
nuclear@0 17 */
nuclear@0 18 #ifndef NO_OPENGL
nuclear@0 19 #include <stdarg.h>
nuclear@0 20 #include <math.h>
nuclear@0 21 #include <ctype.h>
nuclear@0 22
nuclear@0 23 #include <stdlib.h>
nuclear@0 24
nuclear@0 25 #ifdef _MSC_VER
nuclear@0 26 #include <malloc.h>
nuclear@0 27 #else
nuclear@0 28 #include <alloca.h>
nuclear@0 29 #endif
nuclear@0 30
nuclear@0 31 #ifdef TARGET_IPHONE
nuclear@0 32 #include <OpenGLES/ES2/gl.h>
nuclear@0 33
nuclear@0 34 #define GL_CLAMP GL_CLAMP_TO_EDGE
nuclear@0 35
nuclear@0 36 #else
nuclear@0 37 #include <GL/glew.h>
nuclear@0 38 #endif
nuclear@0 39
nuclear@0 40 #include "drawtext.h"
nuclear@0 41 #include "drawtext_impl.h"
nuclear@0 42
nuclear@0 43 struct vertex {
nuclear@0 44 float x, y;
nuclear@0 45 float s, t;
nuclear@0 46 };
nuclear@0 47
nuclear@0 48 struct quad {
nuclear@0 49 struct vertex v[6];
nuclear@0 50 };
nuclear@0 51
nuclear@0 52 static void cleanup(void);
nuclear@0 53 static void add_glyph(struct glyph *g, float x, float y);
nuclear@0 54
nuclear@0 55 #define QBUF_SZ 512
nuclear@0 56 static struct quad *qbuf;
nuclear@0 57 static int num_quads;
nuclear@0 58 static int vattr = -1;
nuclear@0 59 static int tattr = -1;
nuclear@0 60 static unsigned int font_tex;
nuclear@0 61 static int buf_mode = DTX_NBF;
nuclear@0 62
nuclear@0 63
nuclear@0 64 int dtx_gl_init(void)
nuclear@0 65 {
nuclear@0 66 if(qbuf) {
nuclear@0 67 return 0; /* already initialized */
nuclear@0 68 }
nuclear@0 69
nuclear@0 70 /*glewInit();*/
nuclear@0 71
nuclear@0 72 if(!(qbuf = malloc(QBUF_SZ * sizeof *qbuf))) {
nuclear@0 73 return -1;
nuclear@0 74 }
nuclear@0 75 num_quads = 0;
nuclear@0 76
nuclear@0 77 atexit(cleanup);
nuclear@0 78 return 0;
nuclear@0 79 }
nuclear@0 80
nuclear@0 81 static void cleanup(void)
nuclear@0 82 {
nuclear@0 83 free(qbuf);
nuclear@0 84 }
nuclear@0 85
nuclear@0 86
nuclear@0 87 void dtx_vertex_attribs(int vert_attr, int tex_attr)
nuclear@0 88 {
nuclear@0 89 vattr = vert_attr;
nuclear@0 90 tattr = tex_attr;
nuclear@0 91 }
nuclear@0 92
nuclear@0 93 static void set_glyphmap_texture(struct dtx_glyphmap *gmap)
nuclear@0 94 {
nuclear@0 95 if(!gmap->tex) {
nuclear@0 96 glGenTextures(1, &gmap->tex);
nuclear@0 97 glBindTexture(GL_TEXTURE_2D, gmap->tex);
nuclear@0 98 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
nuclear@0 99 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
nuclear@0 100 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
nuclear@0 101 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
nuclear@0 102
nuclear@0 103 #ifdef GL_ES_VERSION_2_0
nuclear@0 104 glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA, gmap->xsz, gmap->ysz, 0, GL_ALPHA, GL_UNSIGNED_BYTE, gmap->pixels);
nuclear@0 105 glGenerateMipmap(GL_TEXTURE_2D);
nuclear@0 106 #else
nuclear@0 107 gluBuild2DMipmaps(GL_TEXTURE_2D, GL_ALPHA, gmap->xsz, gmap->ysz, GL_ALPHA, GL_UNSIGNED_BYTE, gmap->pixels);
nuclear@0 108 #endif
nuclear@0 109 }
nuclear@0 110
nuclear@0 111 if(font_tex != gmap->tex) {
nuclear@0 112 dtx_flush();
nuclear@0 113 }
nuclear@0 114 font_tex = gmap->tex;
nuclear@0 115 }
nuclear@0 116
nuclear@0 117 void dtx_glyph(int code)
nuclear@0 118 {
nuclear@0 119 struct dtx_glyphmap *gmap;
nuclear@0 120
nuclear@0 121 if(!dtx_font || !(gmap = dtx_get_font_glyphmap(dtx_font, dtx_font_sz, code))) {
nuclear@0 122 return;
nuclear@0 123 }
nuclear@0 124 set_glyphmap_texture(gmap);
nuclear@0 125
nuclear@0 126 add_glyph(gmap->glyphs + code - gmap->cstart, 0, 0);
nuclear@0 127 dtx_flush();
nuclear@0 128 }
nuclear@0 129
nuclear@0 130 static const char *put_char(const char *str, float *pos_x, float *pos_y, int *should_flush)
nuclear@0 131 {
nuclear@0 132 struct dtx_glyphmap *gmap;
nuclear@0 133 float px, py;
nuclear@0 134 int code = dtx_utf8_char_code(str);
nuclear@0 135 str = dtx_utf8_next_char((char*)str);
nuclear@0 136
nuclear@0 137 if(buf_mode == DTX_LBF && code == '\n') {
nuclear@0 138 *should_flush = 1;
nuclear@0 139 }
nuclear@0 140
nuclear@0 141 px = *pos_x;
nuclear@0 142 py = *pos_y;
nuclear@0 143
nuclear@0 144 if((gmap = dtx_proc_char(code, pos_x, pos_y))) {
nuclear@0 145 int idx = code - gmap->cstart;
nuclear@0 146
nuclear@0 147 set_glyphmap_texture(gmap);
nuclear@0 148 add_glyph(gmap->glyphs + idx, px, py);
nuclear@0 149 }
nuclear@0 150 return str;
nuclear@0 151 }
nuclear@0 152
nuclear@0 153 void dtx_string(const char *str)
nuclear@0 154 {
nuclear@0 155 int should_flush = buf_mode == DTX_NBF;
nuclear@0 156 float pos_x = 0.0f;
nuclear@0 157 float pos_y = 0.0f;
nuclear@0 158
nuclear@0 159 if(!dtx_font) {
nuclear@0 160 return;
nuclear@0 161 }
nuclear@0 162
nuclear@0 163 while(*str) {
nuclear@0 164 str = put_char(str, &pos_x, &pos_y, &should_flush);
nuclear@0 165 }
nuclear@0 166
nuclear@0 167 if(should_flush) {
nuclear@0 168 dtx_flush();
nuclear@0 169 }
nuclear@0 170 }
nuclear@0 171
nuclear@0 172 void dtx_printf(const char *fmt, ...)
nuclear@0 173 {
nuclear@0 174 va_list ap;
nuclear@0 175 int buf_size;
nuclear@0 176 char *buf, tmp;
nuclear@0 177
nuclear@0 178 if(!dtx_font) {
nuclear@0 179 return;
nuclear@0 180 }
nuclear@0 181
nuclear@0 182 va_start(ap, fmt);
nuclear@0 183 buf_size = vsnprintf(&tmp, 0, fmt, ap);
nuclear@0 184 va_end(ap);
nuclear@0 185
nuclear@0 186 if(buf_size == -1) {
nuclear@0 187 buf_size = 512;
nuclear@0 188 }
nuclear@0 189
nuclear@0 190 buf = alloca(buf_size + 1);
nuclear@0 191 va_start(ap, fmt);
nuclear@0 192 vsnprintf(buf, buf_size + 1, fmt, ap);
nuclear@0 193 va_end(ap);
nuclear@0 194
nuclear@0 195 dtx_string(buf);
nuclear@0 196 }
nuclear@0 197
nuclear@0 198 static void qvertex(struct vertex *v, float x, float y, float s, float t)
nuclear@0 199 {
nuclear@0 200 v->x = x;
nuclear@0 201 v->y = y;
nuclear@0 202 v->s = s;
nuclear@0 203 v->t = t;
nuclear@0 204 }
nuclear@0 205
nuclear@0 206 static void add_glyph(struct glyph *g, float x, float y)
nuclear@0 207 {
nuclear@0 208 struct quad *qptr = qbuf + num_quads;
nuclear@0 209
nuclear@0 210 x -= g->orig_x;
nuclear@0 211 y -= g->orig_y;
nuclear@0 212
nuclear@0 213 qvertex(qptr->v + 0, x, y, g->nx, g->ny + g->nheight);
nuclear@0 214 qvertex(qptr->v + 1, x + g->width, y, g->nx + g->nwidth, g->ny + g->nheight);
nuclear@0 215 qvertex(qptr->v + 2, x + g->width, y + g->height, g->nx + g->nwidth, g->ny);
nuclear@0 216
nuclear@0 217 qvertex(qptr->v + 3, x, y, g->nx, g->ny + g->nheight);
nuclear@0 218 qvertex(qptr->v + 4, x + g->width, y + g->height, g->nx + g->nwidth, g->ny);
nuclear@0 219 qvertex(qptr->v + 5, x, y + g->height, g->nx, g->ny);
nuclear@0 220
nuclear@0 221 if(++num_quads >= QBUF_SZ) {
nuclear@0 222 dtx_flush();
nuclear@0 223 }
nuclear@0 224 }
nuclear@0 225
nuclear@0 226 void dtx_draw_buffering(int mode)
nuclear@0 227 {
nuclear@0 228 dtx_flush();
nuclear@0 229 buf_mode = mode;
nuclear@0 230 }
nuclear@0 231
nuclear@0 232 void dtx_flush(void)
nuclear@0 233 {
nuclear@0 234 int vbo;
nuclear@0 235
nuclear@0 236 if(!num_quads) {
nuclear@0 237 return;
nuclear@0 238 }
nuclear@0 239
nuclear@0 240 if(glBindBuffer) {
nuclear@0 241 glGetIntegerv(GL_ARRAY_BUFFER_BINDING, &vbo);
nuclear@0 242 glBindBuffer(GL_ARRAY_BUFFER, 0);
nuclear@0 243 }
nuclear@0 244
nuclear@0 245 #ifndef GL_ES_VERSION_2_0
nuclear@0 246 glPushAttrib(GL_ENABLE_BIT);
nuclear@0 247 glEnable(GL_TEXTURE_2D);
nuclear@0 248 #endif
nuclear@0 249 glBindTexture(GL_TEXTURE_2D, font_tex);
nuclear@0 250
nuclear@0 251 if(vattr != -1 && glEnableVertexAttribArray) {
nuclear@0 252 glEnableVertexAttribArray(vattr);
nuclear@0 253 glVertexAttribPointer(vattr, 2, GL_FLOAT, 0, sizeof(struct vertex), qbuf);
nuclear@0 254 #ifndef GL_ES_VERSION_2_0
nuclear@0 255 } else {
nuclear@0 256 glEnableClientState(GL_VERTEX_ARRAY);
nuclear@0 257 glVertexPointer(2, GL_FLOAT, sizeof(struct vertex), qbuf);
nuclear@0 258 #endif
nuclear@0 259 }
nuclear@0 260 if(tattr != -1 && glEnableVertexAttribArray) {
nuclear@0 261 glEnableVertexAttribArray(tattr);
nuclear@0 262 glVertexAttribPointer(tattr, 2, GL_FLOAT, 0, sizeof(struct vertex), &qbuf->v[0].s);
nuclear@0 263 #ifndef GL_ES_VERSION_2_0
nuclear@0 264 } else {
nuclear@0 265 glEnableClientState(GL_TEXTURE_COORD_ARRAY);
nuclear@0 266 glTexCoordPointer(2, GL_FLOAT, sizeof(struct vertex), &qbuf->v[0].s);
nuclear@0 267 #endif
nuclear@0 268 }
nuclear@0 269
nuclear@0 270 glEnable(GL_BLEND);
nuclear@0 271 glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
nuclear@0 272
nuclear@0 273 glDepthMask(0);
nuclear@0 274
nuclear@0 275 glDrawArrays(GL_TRIANGLES, 0, num_quads * 6);
nuclear@0 276
nuclear@0 277 glDepthMask(1);
nuclear@0 278
nuclear@0 279 if(vattr != -1 && glDisableVertexAttribArray) {
nuclear@0 280 glDisableVertexAttribArray(vattr);
nuclear@0 281 #ifndef GL_ES_VERSION_2_0
nuclear@0 282 } else {
nuclear@0 283 glDisableClientState(GL_VERTEX_ARRAY);
nuclear@0 284 #endif
nuclear@0 285 }
nuclear@0 286 if(tattr != -1 && glDisableVertexAttribArray) {
nuclear@0 287 glDisableVertexAttribArray(tattr);
nuclear@0 288 #ifndef GL_ES_VERSION_2_0
nuclear@0 289 } else {
nuclear@0 290 glDisableClientState(GL_TEXTURE_COORD_ARRAY);
nuclear@0 291 #endif
nuclear@0 292 }
nuclear@0 293
nuclear@0 294 #ifndef GL_ES_VERSION_2_0
nuclear@0 295 glPopAttrib();
nuclear@0 296 #else
nuclear@0 297 glDisable(GL_BLEND);
nuclear@0 298 #endif
nuclear@0 299
nuclear@0 300 if(glBindBuffer && vbo) {
nuclear@0 301 glBindBuffer(GL_ARRAY_BUFFER, vbo);
nuclear@0 302 }
nuclear@0 303
nuclear@0 304 num_quads = 0;
nuclear@0 305 }
nuclear@0 306
nuclear@0 307 #endif /* !def NO_OPENGL */