libdrawtext

annotate src/drawgl.c @ 87:1dce395c2a3f

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added github mirror info in the readme
author John Tsiombikas <nuclear@member.fsf.org>
date Thu, 17 Apr 2014 06:57:15 +0300
parents 462bcb69de15
children 00f98842608f
rev   line source
nuclear@5 1 /*
nuclear@5 2 libdrawtext - a simple library for fast text rendering in OpenGL
nuclear@12 3 Copyright (C) 2011-2012 John Tsiombikas <nuclear@member.fsf.org>
nuclear@5 4
nuclear@5 5 This program is free software: you can redistribute it and/or modify
nuclear@5 6 it under the terms of the GNU Lesser General Public License as published by
nuclear@5 7 the Free Software Foundation, either version 3 of the License, or
nuclear@5 8 (at your option) any later version.
nuclear@5 9
nuclear@5 10 This program is distributed in the hope that it will be useful,
nuclear@5 11 but WITHOUT ANY WARRANTY; without even the implied warranty of
nuclear@5 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
nuclear@5 13 GNU Lesser General Public License for more details.
nuclear@5 14
nuclear@5 15 You should have received a copy of the GNU Lesser General Public License
nuclear@5 16 along with this program. If not, see <http://www.gnu.org/licenses/>.
nuclear@5 17 */
nuclear@0 18 #ifndef NO_OPENGL
nuclear@15 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@16 25 #ifndef _MSC_VER
nuclear@16 26 #include <alloca.h>
nuclear@16 27 #else
nuclear@16 28 #include <malloc.h>
nuclear@16 29 #endif
nuclear@16 30
nuclear@9 31 #ifdef TARGET_IPHONE
nuclear@0 32 #include <OpenGLES/ES2/gl.h>
nuclear@0 33 #else
nuclear@0 34 #include <GL/glew.h>
nuclear@0 35 #endif
nuclear@0 36
nuclear@0 37 #include "drawtext.h"
nuclear@0 38 #include "drawtext_impl.h"
nuclear@0 39
nuclear@0 40 struct vertex {
nuclear@0 41 float x, y;
nuclear@0 42 float s, t;
nuclear@0 43 };
nuclear@0 44
nuclear@0 45 struct quad {
nuclear@0 46 struct vertex v[6];
nuclear@0 47 };
nuclear@0 48
nuclear@0 49 static void cleanup(void);
nuclear@0 50 static void add_glyph(struct glyph *g, float x, float y);
nuclear@0 51
nuclear@0 52 #define QBUF_SZ 512
nuclear@0 53 static struct quad *qbuf;
nuclear@0 54 static int num_quads;
nuclear@0 55 static int vattr = -1;
nuclear@0 56 static int tattr = -1;
nuclear@0 57 static unsigned int font_tex;
nuclear@3 58 static int buf_mode = DTX_NBF;
nuclear@0 59
nuclear@0 60
nuclear@6 61 int dtx_gl_init(void)
nuclear@0 62 {
nuclear@0 63 if(qbuf) {
nuclear@0 64 return 0; /* already initialized */
nuclear@0 65 }
nuclear@0 66
nuclear@0 67 glewInit();
nuclear@0 68
nuclear@0 69 if(!(qbuf = malloc(QBUF_SZ * sizeof *qbuf))) {
nuclear@0 70 return -1;
nuclear@0 71 }
nuclear@0 72 num_quads = 0;
nuclear@0 73
nuclear@0 74 atexit(cleanup);
nuclear@0 75 return 0;
nuclear@0 76 }
nuclear@0 77
nuclear@0 78 static void cleanup(void)
nuclear@0 79 {
nuclear@0 80 free(qbuf);
nuclear@0 81 }
nuclear@0 82
nuclear@0 83
nuclear@0 84 void dtx_vertex_attribs(int vert_attr, int tex_attr)
nuclear@0 85 {
nuclear@0 86 vattr = vert_attr;
nuclear@0 87 tattr = tex_attr;
nuclear@0 88 }
nuclear@0 89
nuclear@0 90 static void set_glyphmap_texture(struct dtx_glyphmap *gmap)
nuclear@0 91 {
nuclear@0 92 if(!gmap->tex) {
nuclear@0 93 glGenTextures(1, &gmap->tex);
nuclear@0 94 glBindTexture(GL_TEXTURE_2D, gmap->tex);
nuclear@0 95 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
nuclear@0 96 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
nuclear@0 97 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
nuclear@0 98 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
nuclear@0 99
nuclear@0 100 #ifdef GL_ES
nuclear@0 101 glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA, gmap->xsz, gmap->ysz, 0, GL_ALPHA, GL_UNSIGNED_BYTE, gmap->pixels);
nuclear@0 102 glGenerateMipmap(GL_TEXTURE_2D);
nuclear@0 103 #else
nuclear@0 104 gluBuild2DMipmaps(GL_TEXTURE_2D, GL_ALPHA, gmap->xsz, gmap->ysz, GL_ALPHA, GL_UNSIGNED_BYTE, gmap->pixels);
nuclear@0 105 #endif
nuclear@0 106 }
nuclear@0 107
nuclear@0 108 if(font_tex != gmap->tex) {
nuclear@0 109 dtx_flush();
nuclear@0 110 }
nuclear@0 111 font_tex = gmap->tex;
nuclear@0 112 }
nuclear@0 113
nuclear@0 114 void dtx_glyph(int code)
nuclear@0 115 {
nuclear@0 116 struct dtx_glyphmap *gmap;
nuclear@0 117
nuclear@6 118 if(!dtx_font || !(gmap = dtx_get_font_glyphmap(dtx_font, dtx_font_sz, code))) {
nuclear@0 119 return;
nuclear@0 120 }
nuclear@0 121 set_glyphmap_texture(gmap);
nuclear@0 122
nuclear@0 123 add_glyph(gmap->glyphs + code - gmap->cstart, 0, 0);
nuclear@0 124 dtx_flush();
nuclear@0 125 }
nuclear@0 126
nuclear@15 127 static const char *put_char(const char *str, float *pos_x, float *pos_y, int *should_flush)
nuclear@15 128 {
nuclear@15 129 struct dtx_glyphmap *gmap;
nuclear@15 130 float px, py;
nuclear@15 131 int code = dtx_utf8_char_code(str);
nuclear@15 132 str = dtx_utf8_next_char((char*)str);
nuclear@15 133
nuclear@15 134 if(buf_mode == DTX_LBF && code == '\n') {
nuclear@15 135 *should_flush = 1;
nuclear@15 136 }
nuclear@15 137
nuclear@15 138 px = *pos_x;
nuclear@15 139 py = *pos_y;
nuclear@15 140
nuclear@15 141 if((gmap = dtx_proc_char(code, pos_x, pos_y))) {
nuclear@15 142 int idx = code - gmap->cstart;
nuclear@15 143
nuclear@15 144 set_glyphmap_texture(gmap);
nuclear@15 145 add_glyph(gmap->glyphs + idx, px, py);
nuclear@15 146 }
nuclear@15 147 return str;
nuclear@15 148 }
nuclear@15 149
nuclear@0 150 void dtx_string(const char *str)
nuclear@0 151 {
nuclear@0 152 int should_flush = buf_mode == DTX_NBF;
nuclear@0 153 float pos_x = 0.0f;
nuclear@0 154 float pos_y = 0.0f;
nuclear@0 155
nuclear@6 156 if(!dtx_font) {
nuclear@0 157 return;
nuclear@0 158 }
nuclear@0 159
nuclear@0 160 while(*str) {
nuclear@15 161 str = put_char(str, &pos_x, &pos_y, &should_flush);
nuclear@0 162 }
nuclear@0 163
nuclear@0 164 if(should_flush) {
nuclear@0 165 dtx_flush();
nuclear@0 166 }
nuclear@0 167 }
nuclear@0 168
nuclear@15 169 void dtx_printf(const char *fmt, ...)
nuclear@15 170 {
nuclear@15 171 va_list ap;
nuclear@15 172 int buf_size;
nuclear@15 173 char *buf, tmp;
nuclear@15 174
nuclear@15 175 if(!dtx_font) {
nuclear@15 176 return;
nuclear@15 177 }
nuclear@15 178
nuclear@15 179 va_start(ap, fmt);
nuclear@15 180 buf_size = vsnprintf(&tmp, 0, fmt, ap);
nuclear@15 181 va_end(ap);
nuclear@15 182
nuclear@15 183 if(buf_size == -1) {
nuclear@15 184 buf_size = 512;
nuclear@15 185 }
nuclear@15 186
nuclear@15 187 buf = alloca(buf_size + 1);
nuclear@15 188 va_start(ap, fmt);
nuclear@15 189 vsnprintf(buf, buf_size + 1, fmt, ap);
nuclear@15 190 va_end(ap);
nuclear@15 191
nuclear@15 192 dtx_string(buf);
nuclear@15 193 }
nuclear@15 194
nuclear@0 195 static void qvertex(struct vertex *v, float x, float y, float s, float t)
nuclear@0 196 {
nuclear@0 197 v->x = x;
nuclear@0 198 v->y = y;
nuclear@0 199 v->s = s;
nuclear@0 200 v->t = t;
nuclear@0 201 }
nuclear@0 202
nuclear@0 203 static void add_glyph(struct glyph *g, float x, float y)
nuclear@0 204 {
nuclear@0 205 struct quad *qptr = qbuf + num_quads;
nuclear@0 206
nuclear@0 207 x -= g->orig_x;
nuclear@0 208 y -= g->orig_y;
nuclear@0 209
nuclear@0 210 qvertex(qptr->v + 0, x, y, g->nx, g->ny + g->nheight);
nuclear@0 211 qvertex(qptr->v + 1, x + g->width, y, g->nx + g->nwidth, g->ny + g->nheight);
nuclear@0 212 qvertex(qptr->v + 2, x + g->width, y + g->height, g->nx + g->nwidth, g->ny);
nuclear@0 213
nuclear@0 214 qvertex(qptr->v + 3, x, y, g->nx, g->ny + g->nheight);
nuclear@0 215 qvertex(qptr->v + 4, x + g->width, y + g->height, g->nx + g->nwidth, g->ny);
nuclear@0 216 qvertex(qptr->v + 5, x, y + g->height, g->nx, g->ny);
nuclear@0 217
nuclear@0 218 if(++num_quads >= QBUF_SZ) {
nuclear@0 219 dtx_flush();
nuclear@0 220 }
nuclear@0 221 }
nuclear@0 222
nuclear@0 223 void dtx_flush(void)
nuclear@0 224 {
nuclear@12 225 int vbo;
nuclear@12 226
nuclear@0 227 if(!num_quads) {
nuclear@0 228 return;
nuclear@0 229 }
nuclear@0 230
nuclear@12 231 if(glBindBuffer) {
nuclear@12 232 glGetIntegerv(GL_ARRAY_BUFFER_BINDING, &vbo);
nuclear@12 233 glBindBuffer(GL_ARRAY_BUFFER, 0);
nuclear@12 234 }
nuclear@12 235
nuclear@0 236 #ifndef GL_ES
nuclear@0 237 glPushAttrib(GL_ENABLE_BIT);
nuclear@0 238 glEnable(GL_TEXTURE_2D);
nuclear@0 239 #endif
nuclear@0 240 glBindTexture(GL_TEXTURE_2D, font_tex);
nuclear@0 241
nuclear@0 242 if(vattr != -1 && glEnableVertexAttribArray) {
nuclear@0 243 glEnableVertexAttribArray(vattr);
nuclear@0 244 glVertexAttribPointer(vattr, 2, GL_FLOAT, 0, sizeof(struct vertex), qbuf);
nuclear@0 245 #ifndef GL_ES
nuclear@0 246 } else {
nuclear@0 247 glEnableClientState(GL_VERTEX_ARRAY);
nuclear@0 248 glVertexPointer(2, GL_FLOAT, sizeof(struct vertex), qbuf);
nuclear@0 249 #endif
nuclear@0 250 }
nuclear@0 251 if(tattr != -1 && glEnableVertexAttribArray) {
nuclear@0 252 glEnableVertexAttribArray(tattr);
nuclear@0 253 glVertexAttribPointer(tattr, 2, GL_FLOAT, 0, sizeof(struct vertex), &qbuf->v[0].s);
nuclear@0 254 #ifndef GL_ES
nuclear@0 255 } else {
nuclear@0 256 glEnableClientState(GL_TEXTURE_COORD_ARRAY);
nuclear@0 257 glTexCoordPointer(2, GL_FLOAT, sizeof(struct vertex), &qbuf->v[0].s);
nuclear@0 258 #endif
nuclear@0 259 }
nuclear@0 260
nuclear@0 261 glEnable(GL_BLEND);
nuclear@0 262 glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
nuclear@0 263
nuclear@0 264 glDepthMask(0);
nuclear@0 265
nuclear@0 266 glDrawArrays(GL_TRIANGLES, 0, num_quads * 6);
nuclear@0 267
nuclear@0 268 glDepthMask(1);
nuclear@0 269
nuclear@0 270 if(vattr != -1 && glDisableVertexAttribArray) {
nuclear@0 271 glDisableVertexAttribArray(vattr);
nuclear@0 272 #ifndef GL_ES
nuclear@0 273 } else {
nuclear@0 274 glDisableClientState(GL_VERTEX_ARRAY);
nuclear@0 275 #endif
nuclear@0 276 }
nuclear@0 277 if(tattr != -1 && glDisableVertexAttribArray) {
nuclear@0 278 glDisableVertexAttribArray(tattr);
nuclear@0 279 #ifndef GL_ES
nuclear@0 280 } else {
nuclear@0 281 glDisableClientState(GL_TEXTURE_COORD_ARRAY);
nuclear@0 282 #endif
nuclear@0 283 }
nuclear@0 284
nuclear@0 285 #ifndef GL_ES
nuclear@0 286 glPopAttrib();
nuclear@0 287 #else
nuclear@0 288 glDisable(GL_BLEND);
nuclear@0 289 #endif
nuclear@0 290
nuclear@12 291 if(glBindBuffer && vbo) {
nuclear@12 292 glBindBuffer(GL_ARRAY_BUFFER, vbo);
nuclear@12 293 }
nuclear@12 294
nuclear@0 295 num_quads = 0;
nuclear@0 296 }
nuclear@0 297
nuclear@0 298 #endif /* !def NO_OPENGL */