libdrawtext

annotate src/drawgl.c @ 6:7e0c702f1223

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implemented the metrics functions
author John Tsiombikas <nuclear@mutantstargoat.com>
date Sat, 17 Sep 2011 10:09:58 +0300
parents 095ff7ca4e74
children 9d44f6b0591f
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 void cleanup(void);
nuclear@0 43 static void add_glyph(struct glyph *g, float x, float y);
nuclear@0 44
nuclear@0 45 #define QBUF_SZ 512
nuclear@0 46 static struct quad *qbuf;
nuclear@0 47 static int num_quads;
nuclear@0 48 static int vattr = -1;
nuclear@0 49 static int tattr = -1;
nuclear@0 50 static unsigned int font_tex;
nuclear@3 51 static int buf_mode = DTX_NBF;
nuclear@0 52
nuclear@0 53
nuclear@6 54 int dtx_gl_init(void)
nuclear@0 55 {
nuclear@0 56 if(qbuf) {
nuclear@0 57 return 0; /* already initialized */
nuclear@0 58 }
nuclear@0 59
nuclear@0 60 glewInit();
nuclear@0 61
nuclear@0 62 if(!(qbuf = malloc(QBUF_SZ * sizeof *qbuf))) {
nuclear@0 63 return -1;
nuclear@0 64 }
nuclear@0 65 num_quads = 0;
nuclear@0 66
nuclear@0 67 atexit(cleanup);
nuclear@0 68 return 0;
nuclear@0 69 }
nuclear@0 70
nuclear@0 71 static void cleanup(void)
nuclear@0 72 {
nuclear@0 73 free(qbuf);
nuclear@0 74 }
nuclear@0 75
nuclear@0 76
nuclear@0 77 void dtx_vertex_attribs(int vert_attr, int tex_attr)
nuclear@0 78 {
nuclear@0 79 vattr = vert_attr;
nuclear@0 80 tattr = tex_attr;
nuclear@0 81 }
nuclear@0 82
nuclear@0 83 static void set_glyphmap_texture(struct dtx_glyphmap *gmap)
nuclear@0 84 {
nuclear@0 85 if(!gmap->tex) {
nuclear@0 86 glGenTextures(1, &gmap->tex);
nuclear@0 87 glBindTexture(GL_TEXTURE_2D, gmap->tex);
nuclear@0 88 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
nuclear@0 89 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
nuclear@0 90 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
nuclear@0 91 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
nuclear@0 92
nuclear@0 93 #ifdef GL_ES
nuclear@0 94 glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA, gmap->xsz, gmap->ysz, 0, GL_ALPHA, GL_UNSIGNED_BYTE, gmap->pixels);
nuclear@0 95 glGenerateMipmap(GL_TEXTURE_2D);
nuclear@0 96 #else
nuclear@0 97 gluBuild2DMipmaps(GL_TEXTURE_2D, GL_ALPHA, gmap->xsz, gmap->ysz, GL_ALPHA, GL_UNSIGNED_BYTE, gmap->pixels);
nuclear@0 98 #endif
nuclear@0 99 }
nuclear@0 100
nuclear@0 101 if(font_tex != gmap->tex) {
nuclear@0 102 dtx_flush();
nuclear@0 103 }
nuclear@0 104 font_tex = gmap->tex;
nuclear@0 105 }
nuclear@0 106
nuclear@0 107 void dtx_glyph(int code)
nuclear@0 108 {
nuclear@0 109 struct dtx_glyphmap *gmap;
nuclear@0 110
nuclear@6 111 if(!dtx_font || !(gmap = dtx_get_font_glyphmap(dtx_font, dtx_font_sz, code))) {
nuclear@0 112 return;
nuclear@0 113 }
nuclear@0 114 set_glyphmap_texture(gmap);
nuclear@0 115
nuclear@0 116 add_glyph(gmap->glyphs + code - gmap->cstart, 0, 0);
nuclear@0 117 dtx_flush();
nuclear@0 118 }
nuclear@0 119
nuclear@0 120 void dtx_string(const char *str)
nuclear@0 121 {
nuclear@0 122 struct dtx_glyphmap *gmap;
nuclear@0 123 int should_flush = buf_mode == DTX_NBF;
nuclear@0 124 float pos_x = 0.0f;
nuclear@0 125 float pos_y = 0.0f;
nuclear@0 126
nuclear@6 127 if(!dtx_font) {
nuclear@0 128 return;
nuclear@0 129 }
nuclear@0 130
nuclear@0 131 while(*str) {
nuclear@6 132 float px, py;
nuclear@0 133 int code = dtx_utf8_char_code(str);
nuclear@0 134 str = dtx_utf8_next_char((char*)str);
nuclear@0 135
nuclear@6 136 if(buf_mode == DTX_LBF && code == '\n') {
nuclear@6 137 should_flush = 1;
nuclear@6 138 }
nuclear@0 139
nuclear@6 140 px = pos_x;
nuclear@6 141 py = pos_y;
nuclear@0 142
nuclear@6 143 if((gmap = dtx_proc_char(code, &pos_x, &pos_y))) {
nuclear@6 144 int idx = code - gmap->cstart;
nuclear@0 145
nuclear@6 146 set_glyphmap_texture(gmap);
nuclear@6 147 add_glyph(gmap->glyphs + idx, px, py);
nuclear@0 148 }
nuclear@0 149 }
nuclear@0 150
nuclear@0 151 if(should_flush) {
nuclear@0 152 dtx_flush();
nuclear@0 153 }
nuclear@0 154 }
nuclear@0 155
nuclear@0 156 static void qvertex(struct vertex *v, float x, float y, float s, float t)
nuclear@0 157 {
nuclear@0 158 v->x = x;
nuclear@0 159 v->y = y;
nuclear@0 160 v->s = s;
nuclear@0 161 v->t = t;
nuclear@0 162 }
nuclear@0 163
nuclear@0 164 static void add_glyph(struct glyph *g, float x, float y)
nuclear@0 165 {
nuclear@0 166 struct quad *qptr = qbuf + num_quads;
nuclear@0 167
nuclear@0 168 x -= g->orig_x;
nuclear@0 169 y -= g->orig_y;
nuclear@0 170
nuclear@0 171 qvertex(qptr->v + 0, x, y, g->nx, g->ny + g->nheight);
nuclear@0 172 qvertex(qptr->v + 1, x + g->width, y, g->nx + g->nwidth, g->ny + g->nheight);
nuclear@0 173 qvertex(qptr->v + 2, x + g->width, y + g->height, g->nx + g->nwidth, g->ny);
nuclear@0 174
nuclear@0 175 qvertex(qptr->v + 3, x, y, g->nx, g->ny + g->nheight);
nuclear@0 176 qvertex(qptr->v + 4, x + g->width, y + g->height, g->nx + g->nwidth, g->ny);
nuclear@0 177 qvertex(qptr->v + 5, x, y + g->height, g->nx, g->ny);
nuclear@0 178
nuclear@0 179 if(++num_quads >= QBUF_SZ) {
nuclear@0 180 dtx_flush();
nuclear@0 181 }
nuclear@0 182 }
nuclear@0 183
nuclear@0 184 void dtx_flush(void)
nuclear@0 185 {
nuclear@0 186 if(!num_quads) {
nuclear@0 187 return;
nuclear@0 188 }
nuclear@0 189
nuclear@0 190 #ifndef GL_ES
nuclear@0 191 glPushAttrib(GL_ENABLE_BIT);
nuclear@0 192 glEnable(GL_TEXTURE_2D);
nuclear@0 193 #endif
nuclear@0 194 glBindTexture(GL_TEXTURE_2D, font_tex);
nuclear@0 195
nuclear@0 196 if(vattr != -1 && glEnableVertexAttribArray) {
nuclear@0 197 glEnableVertexAttribArray(vattr);
nuclear@0 198 glVertexAttribPointer(vattr, 2, GL_FLOAT, 0, sizeof(struct vertex), qbuf);
nuclear@0 199 #ifndef GL_ES
nuclear@0 200 } else {
nuclear@0 201 glEnableClientState(GL_VERTEX_ARRAY);
nuclear@0 202 glVertexPointer(2, GL_FLOAT, sizeof(struct vertex), qbuf);
nuclear@0 203 #endif
nuclear@0 204 }
nuclear@0 205 if(tattr != -1 && glEnableVertexAttribArray) {
nuclear@0 206 glEnableVertexAttribArray(tattr);
nuclear@0 207 glVertexAttribPointer(tattr, 2, GL_FLOAT, 0, sizeof(struct vertex), &qbuf->v[0].s);
nuclear@0 208 #ifndef GL_ES
nuclear@0 209 } else {
nuclear@0 210 glEnableClientState(GL_TEXTURE_COORD_ARRAY);
nuclear@0 211 glTexCoordPointer(2, GL_FLOAT, sizeof(struct vertex), &qbuf->v[0].s);
nuclear@0 212 #endif
nuclear@0 213 }
nuclear@0 214
nuclear@0 215 glEnable(GL_BLEND);
nuclear@0 216 glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
nuclear@0 217
nuclear@0 218 glDepthMask(0);
nuclear@0 219
nuclear@0 220 glDrawArrays(GL_TRIANGLES, 0, num_quads * 6);
nuclear@0 221
nuclear@0 222 glDepthMask(1);
nuclear@0 223
nuclear@0 224 if(vattr != -1 && glDisableVertexAttribArray) {
nuclear@0 225 glDisableVertexAttribArray(vattr);
nuclear@0 226 #ifndef GL_ES
nuclear@0 227 } else {
nuclear@0 228 glDisableClientState(GL_VERTEX_ARRAY);
nuclear@0 229 #endif
nuclear@0 230 }
nuclear@0 231 if(tattr != -1 && glDisableVertexAttribArray) {
nuclear@0 232 glDisableVertexAttribArray(tattr);
nuclear@0 233 #ifndef GL_ES
nuclear@0 234 } else {
nuclear@0 235 glDisableClientState(GL_TEXTURE_COORD_ARRAY);
nuclear@0 236 #endif
nuclear@0 237 }
nuclear@0 238
nuclear@0 239 #ifndef GL_ES
nuclear@0 240 glPopAttrib();
nuclear@0 241 #else
nuclear@0 242 glDisable(GL_BLEND);
nuclear@0 243 #endif
nuclear@0 244
nuclear@0 245 num_quads = 0;
nuclear@0 246 }
nuclear@0 247
nuclear@0 248 #endif /* !def NO_OPENGL */