libdrawtext

diff src/drawgl.c @ 0:bfe431dd1d80

initial commit
author John Tsiombikas <nuclear@mutantstargoat.com>
date Thu, 15 Sep 2011 10:47:38 +0300
parents
children fe0c54e574ae
line diff
     1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/src/drawgl.c	Thu Sep 15 10:47:38 2011 +0300
     1.3 @@ -0,0 +1,255 @@
     1.4 +#ifndef NO_OPENGL
     1.5 +#include <math.h>
     1.6 +#include <ctype.h>
     1.7 +
     1.8 +#include <stdlib.h>
     1.9 +
    1.10 +#if defined(__IPHONE_3_0) || defined(__IPHONE_3_2) || defined(__IPHONE_4_0)
    1.11 +#include <OpenGLES/ES2/gl.h>
    1.12 +#else
    1.13 +#include <GL/glew.h>
    1.14 +#endif
    1.15 +
    1.16 +#include "drawtext.h"
    1.17 +#include "drawtext_impl.h"
    1.18 +
    1.19 +struct vertex {
    1.20 +	float x, y;
    1.21 +	float s, t;
    1.22 +};
    1.23 +
    1.24 +struct quad {
    1.25 +	struct vertex v[6];
    1.26 +};
    1.27 +
    1.28 +static int init(void);
    1.29 +static void cleanup(void);
    1.30 +static void add_glyph(struct glyph *g, float x, float y);
    1.31 +
    1.32 +#define QBUF_SZ		512
    1.33 +static struct quad *qbuf;
    1.34 +static int num_quads;
    1.35 +static int vattr = -1;
    1.36 +static int tattr = -1;
    1.37 +static unsigned int font_tex;
    1.38 +static int buf_mode = DTX_LBF;
    1.39 +
    1.40 +static struct dtx_font *font;
    1.41 +static int font_sz;
    1.42 +
    1.43 +
    1.44 +static int init(void)
    1.45 +{
    1.46 +	if(qbuf) {
    1.47 +		return 0;	/* already initialized */
    1.48 +	}
    1.49 +
    1.50 +	glewInit();
    1.51 +
    1.52 +	if(!(qbuf = malloc(QBUF_SZ * sizeof *qbuf))) {
    1.53 +		return -1;
    1.54 +	}
    1.55 +	num_quads = 0;
    1.56 +
    1.57 +	atexit(cleanup);
    1.58 +	return 0;
    1.59 +}
    1.60 +
    1.61 +static void cleanup(void)
    1.62 +{
    1.63 +	free(qbuf);
    1.64 +}
    1.65 +
    1.66 +
    1.67 +void dtx_use_font(struct dtx_font *fnt, int sz)
    1.68 +{
    1.69 +	init();
    1.70 +
    1.71 +	font = fnt;
    1.72 +	font_sz = sz;
    1.73 +}
    1.74 +
    1.75 +void dtx_vertex_attribs(int vert_attr, int tex_attr)
    1.76 +{
    1.77 +	vattr = vert_attr;
    1.78 +	tattr = tex_attr;
    1.79 +}
    1.80 +
    1.81 +static void set_glyphmap_texture(struct dtx_glyphmap *gmap)
    1.82 +{
    1.83 +	if(!gmap->tex) {
    1.84 +		glGenTextures(1, &gmap->tex);
    1.85 +		glBindTexture(GL_TEXTURE_2D, gmap->tex);
    1.86 +		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
    1.87 +		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    1.88 +		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
    1.89 +		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
    1.90 +
    1.91 +#ifdef GL_ES
    1.92 +		glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA, gmap->xsz, gmap->ysz, 0, GL_ALPHA, GL_UNSIGNED_BYTE, gmap->pixels);
    1.93 +		glGenerateMipmap(GL_TEXTURE_2D);
    1.94 +#else
    1.95 +		gluBuild2DMipmaps(GL_TEXTURE_2D, GL_ALPHA, gmap->xsz, gmap->ysz, GL_ALPHA, GL_UNSIGNED_BYTE, gmap->pixels);
    1.96 +#endif
    1.97 +	}
    1.98 +
    1.99 +	if(font_tex != gmap->tex) {
   1.100 +		dtx_flush();
   1.101 +	}
   1.102 +	font_tex = gmap->tex;
   1.103 +}
   1.104 +
   1.105 +void dtx_glyph(int code)
   1.106 +{
   1.107 +	struct dtx_glyphmap *gmap;
   1.108 +
   1.109 +	if(!font || !(gmap = dtx_get_font_glyphmap(font, font_sz, code))) {
   1.110 +		return;
   1.111 +	}
   1.112 +	set_glyphmap_texture(gmap);
   1.113 +
   1.114 +	add_glyph(gmap->glyphs + code - gmap->cstart, 0, 0);
   1.115 +	dtx_flush();
   1.116 +}
   1.117 +
   1.118 +void dtx_string(const char *str)
   1.119 +{
   1.120 +	struct dtx_glyphmap *gmap;
   1.121 +	int should_flush = buf_mode == DTX_NBF;
   1.122 +	float pos_x = 0.0f;
   1.123 +	float pos_y = 0.0f;
   1.124 +
   1.125 +	if(!font) {
   1.126 +		return;
   1.127 +	}
   1.128 +
   1.129 +	while(*str) {
   1.130 +		int code = dtx_utf8_char_code(str);
   1.131 +		str = dtx_utf8_next_char((char*)str);
   1.132 +
   1.133 +		switch(code) {
   1.134 +		case '\n':
   1.135 +			if(buf_mode == DTX_LBF) {
   1.136 +				should_flush = 1;
   1.137 +			}
   1.138 +			pos_x = 0.0;
   1.139 +			pos_y -= gmap->line_advance;
   1.140 +			break;
   1.141 +
   1.142 +		case '\t':
   1.143 +			pos_x = fmod(pos_x, 4.0) + 4.0;
   1.144 +			break;
   1.145 +
   1.146 +		case '\r':
   1.147 +			pos_x = 0.0;
   1.148 +			break;
   1.149 +
   1.150 +		default:
   1.151 +			if((gmap = dtx_get_font_glyphmap(font, font_sz, code))) {
   1.152 +				int idx = code - gmap->cstart;
   1.153 +
   1.154 +				set_glyphmap_texture(gmap);
   1.155 +				add_glyph(gmap->glyphs + idx, pos_x, pos_y);
   1.156 +				pos_x += gmap->glyphs[idx].advance;
   1.157 +			}
   1.158 +		}
   1.159 +	}
   1.160 +
   1.161 +	if(should_flush) {
   1.162 +		dtx_flush();
   1.163 +	}
   1.164 +}
   1.165 +
   1.166 +static void qvertex(struct vertex *v, float x, float y, float s, float t)
   1.167 +{
   1.168 +	v->x = x;
   1.169 +	v->y = y;
   1.170 +	v->s = s;
   1.171 +	v->t = t;
   1.172 +}
   1.173 +
   1.174 +static void add_glyph(struct glyph *g, float x, float y)
   1.175 +{
   1.176 +	struct quad *qptr = qbuf + num_quads;
   1.177 +
   1.178 +	x -= g->orig_x;
   1.179 +	y -= g->orig_y;
   1.180 +
   1.181 +	qvertex(qptr->v + 0, x, y, g->nx, g->ny + g->nheight);
   1.182 +	qvertex(qptr->v + 1, x + g->width, y, g->nx + g->nwidth, g->ny + g->nheight);
   1.183 +	qvertex(qptr->v + 2, x + g->width, y + g->height, g->nx + g->nwidth, g->ny);
   1.184 +
   1.185 +	qvertex(qptr->v + 3, x, y, g->nx, g->ny + g->nheight);
   1.186 +	qvertex(qptr->v + 4, x + g->width, y + g->height, g->nx + g->nwidth, g->ny);
   1.187 +	qvertex(qptr->v + 5, x, y + g->height, g->nx, g->ny);
   1.188 +
   1.189 +	if(++num_quads >= QBUF_SZ) {
   1.190 +		dtx_flush();
   1.191 +	}
   1.192 +}
   1.193 +
   1.194 +void dtx_flush(void)
   1.195 +{
   1.196 +	if(!num_quads) {
   1.197 +		return;
   1.198 +	}
   1.199 +
   1.200 +#ifndef GL_ES
   1.201 +	glPushAttrib(GL_ENABLE_BIT);
   1.202 +	glEnable(GL_TEXTURE_2D);
   1.203 +#endif
   1.204 +	glBindTexture(GL_TEXTURE_2D, font_tex);
   1.205 +
   1.206 +	if(vattr != -1 && glEnableVertexAttribArray) {
   1.207 +		glEnableVertexAttribArray(vattr);
   1.208 +		glVertexAttribPointer(vattr, 2, GL_FLOAT, 0, sizeof(struct vertex), qbuf);
   1.209 +#ifndef GL_ES
   1.210 +	} else {
   1.211 +		glEnableClientState(GL_VERTEX_ARRAY);
   1.212 +		glVertexPointer(2, GL_FLOAT, sizeof(struct vertex), qbuf);
   1.213 +#endif
   1.214 +	}
   1.215 +	if(tattr != -1 && glEnableVertexAttribArray) {
   1.216 +		glEnableVertexAttribArray(tattr);
   1.217 +		glVertexAttribPointer(tattr, 2, GL_FLOAT, 0, sizeof(struct vertex), &qbuf->v[0].s);
   1.218 +#ifndef GL_ES
   1.219 +	} else {
   1.220 +		glEnableClientState(GL_TEXTURE_COORD_ARRAY);
   1.221 +		glTexCoordPointer(2, GL_FLOAT, sizeof(struct vertex), &qbuf->v[0].s);
   1.222 +#endif
   1.223 +	}
   1.224 +
   1.225 +	glEnable(GL_BLEND);
   1.226 +	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
   1.227 +
   1.228 +	glDepthMask(0);
   1.229 +
   1.230 +	glDrawArrays(GL_TRIANGLES, 0, num_quads * 6);
   1.231 +
   1.232 +	glDepthMask(1);
   1.233 +
   1.234 +	if(vattr != -1 && glDisableVertexAttribArray) {
   1.235 +		glDisableVertexAttribArray(vattr);
   1.236 +#ifndef GL_ES
   1.237 +	} else {
   1.238 +		glDisableClientState(GL_VERTEX_ARRAY);
   1.239 +#endif
   1.240 +	}
   1.241 +	if(tattr != -1 && glDisableVertexAttribArray) {
   1.242 +		glDisableVertexAttribArray(tattr);
   1.243 +#ifndef GL_ES
   1.244 +	} else {
   1.245 +		glDisableClientState(GL_TEXTURE_COORD_ARRAY);
   1.246 +#endif
   1.247 +	}
   1.248 +
   1.249 +#ifndef GL_ES
   1.250 +	glPopAttrib();
   1.251 +#else
   1.252 +	glDisable(GL_BLEND);
   1.253 +#endif
   1.254 +
   1.255 +	num_quads = 0;
   1.256 +}
   1.257 +
   1.258 +#endif	/* !def NO_OPENGL */