libdrawtext

annotate src/drawgl.c @ 5:095ff7ca4e74

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added copyright notices
author John Tsiombikas <nuclear@mutantstargoat.com>
date Fri, 16 Sep 2011 08:42:07 +0300
parents fe0c54e574ae
children 7e0c702f1223
rev   line source
nuclear@5 1 /*
nuclear@5 2 libdrawtext - a simple library for fast text rendering in OpenGL
nuclear@5 3 Copyright (C) 2011 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@0 19 #include <math.h>
nuclear@0 20 #include <ctype.h>
nuclear@0 21
nuclear@0 22 #include <stdlib.h>
nuclear@0 23
nuclear@0 24 #if defined(__IPHONE_3_0) || defined(__IPHONE_3_2) || defined(__IPHONE_4_0)
nuclear@0 25 #include <OpenGLES/ES2/gl.h>
nuclear@0 26 #else
nuclear@0 27 #include <GL/glew.h>
nuclear@0 28 #endif
nuclear@0 29
nuclear@0 30 #include "drawtext.h"
nuclear@0 31 #include "drawtext_impl.h"
nuclear@0 32
nuclear@0 33 struct vertex {
nuclear@0 34 float x, y;
nuclear@0 35 float s, t;
nuclear@0 36 };
nuclear@0 37
nuclear@0 38 struct quad {
nuclear@0 39 struct vertex v[6];
nuclear@0 40 };
nuclear@0 41
nuclear@0 42 static int init(void);
nuclear@0 43 static void cleanup(void);
nuclear@0 44 static void add_glyph(struct glyph *g, float x, float y);
nuclear@0 45
nuclear@0 46 #define QBUF_SZ 512
nuclear@0 47 static struct quad *qbuf;
nuclear@0 48 static int num_quads;
nuclear@0 49 static int vattr = -1;
nuclear@0 50 static int tattr = -1;
nuclear@0 51 static unsigned int font_tex;
nuclear@3 52 static int buf_mode = DTX_NBF;
nuclear@0 53
nuclear@0 54 static struct dtx_font *font;
nuclear@0 55 static int font_sz;
nuclear@0 56
nuclear@0 57
nuclear@0 58 static int init(void)
nuclear@0 59 {
nuclear@0 60 if(qbuf) {
nuclear@0 61 return 0; /* already initialized */
nuclear@0 62 }
nuclear@0 63
nuclear@0 64 glewInit();
nuclear@0 65
nuclear@0 66 if(!(qbuf = malloc(QBUF_SZ * sizeof *qbuf))) {
nuclear@0 67 return -1;
nuclear@0 68 }
nuclear@0 69 num_quads = 0;
nuclear@0 70
nuclear@0 71 atexit(cleanup);
nuclear@0 72 return 0;
nuclear@0 73 }
nuclear@0 74
nuclear@0 75 static void cleanup(void)
nuclear@0 76 {
nuclear@0 77 free(qbuf);
nuclear@0 78 }
nuclear@0 79
nuclear@0 80
nuclear@0 81 void dtx_use_font(struct dtx_font *fnt, int sz)
nuclear@0 82 {
nuclear@0 83 init();
nuclear@0 84
nuclear@0 85 font = fnt;
nuclear@0 86 font_sz = sz;
nuclear@0 87 }
nuclear@0 88
nuclear@0 89 void dtx_vertex_attribs(int vert_attr, int tex_attr)
nuclear@0 90 {
nuclear@0 91 vattr = vert_attr;
nuclear@0 92 tattr = tex_attr;
nuclear@0 93 }
nuclear@0 94
nuclear@0 95 static void set_glyphmap_texture(struct dtx_glyphmap *gmap)
nuclear@0 96 {
nuclear@0 97 if(!gmap->tex) {
nuclear@0 98 glGenTextures(1, &gmap->tex);
nuclear@0 99 glBindTexture(GL_TEXTURE_2D, gmap->tex);
nuclear@0 100 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
nuclear@0 101 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
nuclear@0 102 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
nuclear@0 103 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
nuclear@0 104
nuclear@0 105 #ifdef GL_ES
nuclear@0 106 glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA, gmap->xsz, gmap->ysz, 0, GL_ALPHA, GL_UNSIGNED_BYTE, gmap->pixels);
nuclear@0 107 glGenerateMipmap(GL_TEXTURE_2D);
nuclear@0 108 #else
nuclear@0 109 gluBuild2DMipmaps(GL_TEXTURE_2D, GL_ALPHA, gmap->xsz, gmap->ysz, GL_ALPHA, GL_UNSIGNED_BYTE, gmap->pixels);
nuclear@0 110 #endif
nuclear@0 111 }
nuclear@0 112
nuclear@0 113 if(font_tex != gmap->tex) {
nuclear@0 114 dtx_flush();
nuclear@0 115 }
nuclear@0 116 font_tex = gmap->tex;
nuclear@0 117 }
nuclear@0 118
nuclear@0 119 void dtx_glyph(int code)
nuclear@0 120 {
nuclear@0 121 struct dtx_glyphmap *gmap;
nuclear@0 122
nuclear@0 123 if(!font || !(gmap = dtx_get_font_glyphmap(font, font_sz, code))) {
nuclear@0 124 return;
nuclear@0 125 }
nuclear@0 126 set_glyphmap_texture(gmap);
nuclear@0 127
nuclear@0 128 add_glyph(gmap->glyphs + code - gmap->cstart, 0, 0);
nuclear@0 129 dtx_flush();
nuclear@0 130 }
nuclear@0 131
nuclear@0 132 void dtx_string(const char *str)
nuclear@0 133 {
nuclear@0 134 struct dtx_glyphmap *gmap;
nuclear@0 135 int should_flush = buf_mode == DTX_NBF;
nuclear@0 136 float pos_x = 0.0f;
nuclear@0 137 float pos_y = 0.0f;
nuclear@0 138
nuclear@0 139 if(!font) {
nuclear@0 140 return;
nuclear@0 141 }
nuclear@0 142
nuclear@0 143 while(*str) {
nuclear@0 144 int code = dtx_utf8_char_code(str);
nuclear@0 145 str = dtx_utf8_next_char((char*)str);
nuclear@0 146
nuclear@0 147 switch(code) {
nuclear@0 148 case '\n':
nuclear@0 149 if(buf_mode == DTX_LBF) {
nuclear@0 150 should_flush = 1;
nuclear@0 151 }
nuclear@0 152 pos_x = 0.0;
nuclear@0 153 pos_y -= gmap->line_advance;
nuclear@0 154 break;
nuclear@0 155
nuclear@0 156 case '\t':
nuclear@0 157 pos_x = fmod(pos_x, 4.0) + 4.0;
nuclear@0 158 break;
nuclear@0 159
nuclear@0 160 case '\r':
nuclear@0 161 pos_x = 0.0;
nuclear@0 162 break;
nuclear@0 163
nuclear@0 164 default:
nuclear@0 165 if((gmap = dtx_get_font_glyphmap(font, font_sz, code))) {
nuclear@0 166 int idx = code - gmap->cstart;
nuclear@0 167
nuclear@0 168 set_glyphmap_texture(gmap);
nuclear@0 169 add_glyph(gmap->glyphs + idx, pos_x, pos_y);
nuclear@0 170 pos_x += gmap->glyphs[idx].advance;
nuclear@0 171 }
nuclear@0 172 }
nuclear@0 173 }
nuclear@0 174
nuclear@0 175 if(should_flush) {
nuclear@0 176 dtx_flush();
nuclear@0 177 }
nuclear@0 178 }
nuclear@0 179
nuclear@0 180 static void qvertex(struct vertex *v, float x, float y, float s, float t)
nuclear@0 181 {
nuclear@0 182 v->x = x;
nuclear@0 183 v->y = y;
nuclear@0 184 v->s = s;
nuclear@0 185 v->t = t;
nuclear@0 186 }
nuclear@0 187
nuclear@0 188 static void add_glyph(struct glyph *g, float x, float y)
nuclear@0 189 {
nuclear@0 190 struct quad *qptr = qbuf + num_quads;
nuclear@0 191
nuclear@0 192 x -= g->orig_x;
nuclear@0 193 y -= g->orig_y;
nuclear@0 194
nuclear@0 195 qvertex(qptr->v + 0, x, y, g->nx, g->ny + g->nheight);
nuclear@0 196 qvertex(qptr->v + 1, x + g->width, y, g->nx + g->nwidth, g->ny + g->nheight);
nuclear@0 197 qvertex(qptr->v + 2, x + g->width, y + g->height, g->nx + g->nwidth, g->ny);
nuclear@0 198
nuclear@0 199 qvertex(qptr->v + 3, x, y, g->nx, g->ny + g->nheight);
nuclear@0 200 qvertex(qptr->v + 4, x + g->width, y + g->height, g->nx + g->nwidth, g->ny);
nuclear@0 201 qvertex(qptr->v + 5, x, y + g->height, g->nx, g->ny);
nuclear@0 202
nuclear@0 203 if(++num_quads >= QBUF_SZ) {
nuclear@0 204 dtx_flush();
nuclear@0 205 }
nuclear@0 206 }
nuclear@0 207
nuclear@0 208 void dtx_flush(void)
nuclear@0 209 {
nuclear@0 210 if(!num_quads) {
nuclear@0 211 return;
nuclear@0 212 }
nuclear@0 213
nuclear@0 214 #ifndef GL_ES
nuclear@0 215 glPushAttrib(GL_ENABLE_BIT);
nuclear@0 216 glEnable(GL_TEXTURE_2D);
nuclear@0 217 #endif
nuclear@0 218 glBindTexture(GL_TEXTURE_2D, font_tex);
nuclear@0 219
nuclear@0 220 if(vattr != -1 && glEnableVertexAttribArray) {
nuclear@0 221 glEnableVertexAttribArray(vattr);
nuclear@0 222 glVertexAttribPointer(vattr, 2, GL_FLOAT, 0, sizeof(struct vertex), qbuf);
nuclear@0 223 #ifndef GL_ES
nuclear@0 224 } else {
nuclear@0 225 glEnableClientState(GL_VERTEX_ARRAY);
nuclear@0 226 glVertexPointer(2, GL_FLOAT, sizeof(struct vertex), qbuf);
nuclear@0 227 #endif
nuclear@0 228 }
nuclear@0 229 if(tattr != -1 && glEnableVertexAttribArray) {
nuclear@0 230 glEnableVertexAttribArray(tattr);
nuclear@0 231 glVertexAttribPointer(tattr, 2, GL_FLOAT, 0, sizeof(struct vertex), &qbuf->v[0].s);
nuclear@0 232 #ifndef GL_ES
nuclear@0 233 } else {
nuclear@0 234 glEnableClientState(GL_TEXTURE_COORD_ARRAY);
nuclear@0 235 glTexCoordPointer(2, GL_FLOAT, sizeof(struct vertex), &qbuf->v[0].s);
nuclear@0 236 #endif
nuclear@0 237 }
nuclear@0 238
nuclear@0 239 glEnable(GL_BLEND);
nuclear@0 240 glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
nuclear@0 241
nuclear@0 242 glDepthMask(0);
nuclear@0 243
nuclear@0 244 glDrawArrays(GL_TRIANGLES, 0, num_quads * 6);
nuclear@0 245
nuclear@0 246 glDepthMask(1);
nuclear@0 247
nuclear@0 248 if(vattr != -1 && glDisableVertexAttribArray) {
nuclear@0 249 glDisableVertexAttribArray(vattr);
nuclear@0 250 #ifndef GL_ES
nuclear@0 251 } else {
nuclear@0 252 glDisableClientState(GL_VERTEX_ARRAY);
nuclear@0 253 #endif
nuclear@0 254 }
nuclear@0 255 if(tattr != -1 && glDisableVertexAttribArray) {
nuclear@0 256 glDisableVertexAttribArray(tattr);
nuclear@0 257 #ifndef GL_ES
nuclear@0 258 } else {
nuclear@0 259 glDisableClientState(GL_TEXTURE_COORD_ARRAY);
nuclear@0 260 #endif
nuclear@0 261 }
nuclear@0 262
nuclear@0 263 #ifndef GL_ES
nuclear@0 264 glPopAttrib();
nuclear@0 265 #else
nuclear@0 266 glDisable(GL_BLEND);
nuclear@0 267 #endif
nuclear@0 268
nuclear@0 269 num_quads = 0;
nuclear@0 270 }
nuclear@0 271
nuclear@0 272 #endif /* !def NO_OPENGL */