nuclear@24: /*
nuclear@24: libdrawtext - a simple library for fast text rendering in OpenGL
nuclear@29: Copyright (C) 2011-2012  John Tsiombikas <nuclear@member.fsf.org>
nuclear@24: 
nuclear@24: This program is free software: you can redistribute it and/or modify
nuclear@24: it under the terms of the GNU Lesser General Public License as published by
nuclear@24: the Free Software Foundation, either version 3 of the License, or
nuclear@24: (at your option) any later version.
nuclear@24: 
nuclear@24: This program is distributed in the hope that it will be useful,
nuclear@24: but WITHOUT ANY WARRANTY; without even the implied warranty of
nuclear@24: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
nuclear@24: GNU Lesser General Public License for more details.
nuclear@24: 
nuclear@24: You should have received a copy of the GNU Lesser General Public License
nuclear@24: along with this program.  If not, see <http://www.gnu.org/licenses/>.
nuclear@24: */
nuclear@24: #ifndef NO_OPENGL
nuclear@24: #include <math.h>
nuclear@24: #include <ctype.h>
nuclear@24: 
nuclear@24: #include <stdlib.h>
nuclear@24: 
nuclear@24: #ifdef TARGET_IPHONE
nuclear@24: #include <OpenGLES/ES2/gl.h>
nuclear@24: #else
nuclear@24: #include <GL/glew.h>
nuclear@24: #endif
nuclear@24: 
nuclear@24: #include "drawtext.h"
nuclear@24: #include "drawtext_impl.h"
nuclear@24: 
nuclear@24: struct vertex {
nuclear@24: 	float x, y;
nuclear@24: 	float s, t;
nuclear@24: };
nuclear@24: 
nuclear@24: struct quad {
nuclear@24: 	struct vertex v[6];
nuclear@24: };
nuclear@24: 
nuclear@24: static void cleanup(void);
nuclear@24: static void add_glyph(struct glyph *g, float x, float y);
nuclear@24: 
nuclear@24: #define QBUF_SZ		512
nuclear@24: static struct quad *qbuf;
nuclear@24: static int num_quads;
nuclear@24: static int vattr = -1;
nuclear@24: static int tattr = -1;
nuclear@24: static unsigned int font_tex;
nuclear@24: static int buf_mode = DTX_NBF;
nuclear@24: 
nuclear@24: 
nuclear@24: int dtx_gl_init(void)
nuclear@24: {
nuclear@24: 	if(qbuf) {
nuclear@24: 		return 0;	/* already initialized */
nuclear@24: 	}
nuclear@24: 
nuclear@24: 	glewInit();
nuclear@24: 
nuclear@24: 	if(!(qbuf = malloc(QBUF_SZ * sizeof *qbuf))) {
nuclear@24: 		return -1;
nuclear@24: 	}
nuclear@24: 	num_quads = 0;
nuclear@24: 
nuclear@24: 	atexit(cleanup);
nuclear@24: 	return 0;
nuclear@24: }
nuclear@24: 
nuclear@24: static void cleanup(void)
nuclear@24: {
nuclear@24: 	free(qbuf);
nuclear@24: }
nuclear@24: 
nuclear@24: 
nuclear@24: void dtx_vertex_attribs(int vert_attr, int tex_attr)
nuclear@24: {
nuclear@24: 	vattr = vert_attr;
nuclear@24: 	tattr = tex_attr;
nuclear@24: }
nuclear@24: 
nuclear@24: static void set_glyphmap_texture(struct dtx_glyphmap *gmap)
nuclear@24: {
nuclear@24: 	if(!gmap->tex) {
nuclear@24: 		glGenTextures(1, &gmap->tex);
nuclear@24: 		glBindTexture(GL_TEXTURE_2D, gmap->tex);
nuclear@24: 		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
nuclear@24: 		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
nuclear@24: 		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
nuclear@24: 		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
nuclear@24: 
nuclear@24: #ifdef GL_ES
nuclear@24: 		glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA, gmap->xsz, gmap->ysz, 0, GL_ALPHA, GL_UNSIGNED_BYTE, gmap->pixels);
nuclear@24: 		glGenerateMipmap(GL_TEXTURE_2D);
nuclear@24: #else
nuclear@24: 		gluBuild2DMipmaps(GL_TEXTURE_2D, GL_ALPHA, gmap->xsz, gmap->ysz, GL_ALPHA, GL_UNSIGNED_BYTE, gmap->pixels);
nuclear@24: #endif
nuclear@24: 	}
nuclear@24: 
nuclear@24: 	if(font_tex != gmap->tex) {
nuclear@24: 		dtx_flush();
nuclear@24: 	}
nuclear@24: 	font_tex = gmap->tex;
nuclear@24: }
nuclear@24: 
nuclear@24: void dtx_glyph(int code)
nuclear@24: {
nuclear@24: 	struct dtx_glyphmap *gmap;
nuclear@24: 
nuclear@24: 	if(!dtx_font || !(gmap = dtx_get_font_glyphmap(dtx_font, dtx_font_sz, code))) {
nuclear@24: 		return;
nuclear@24: 	}
nuclear@24: 	set_glyphmap_texture(gmap);
nuclear@24: 
nuclear@24: 	add_glyph(gmap->glyphs + code - gmap->cstart, 0, 0);
nuclear@24: 	dtx_flush();
nuclear@24: }
nuclear@24: 
nuclear@24: void dtx_string(const char *str)
nuclear@24: {
nuclear@24: 	struct dtx_glyphmap *gmap;
nuclear@24: 	int should_flush = buf_mode == DTX_NBF;
nuclear@24: 	float pos_x = 0.0f;
nuclear@24: 	float pos_y = 0.0f;
nuclear@24: 
nuclear@24: 	if(!dtx_font) {
nuclear@24: 		return;
nuclear@24: 	}
nuclear@24: 
nuclear@24: 	while(*str) {
nuclear@24: 		float px, py;
nuclear@24: 		int code = dtx_utf8_char_code(str);
nuclear@24: 		str = dtx_utf8_next_char((char*)str);
nuclear@24: 
nuclear@24: 		if(buf_mode == DTX_LBF && code == '\n') {
nuclear@24: 			should_flush = 1;
nuclear@24: 		}
nuclear@24: 
nuclear@24: 		px = pos_x;
nuclear@24: 		py = pos_y;
nuclear@24: 
nuclear@24: 		if((gmap = dtx_proc_char(code, &pos_x, &pos_y))) {
nuclear@24: 			int idx = code - gmap->cstart;
nuclear@24: 
nuclear@24: 			set_glyphmap_texture(gmap);
nuclear@24: 			add_glyph(gmap->glyphs + idx, px, py);
nuclear@24: 		}
nuclear@24: 	}
nuclear@24: 
nuclear@24: 	if(should_flush) {
nuclear@24: 		dtx_flush();
nuclear@24: 	}
nuclear@24: }
nuclear@24: 
nuclear@24: static void qvertex(struct vertex *v, float x, float y, float s, float t)
nuclear@24: {
nuclear@24: 	v->x = x;
nuclear@24: 	v->y = y;
nuclear@24: 	v->s = s;
nuclear@24: 	v->t = t;
nuclear@24: }
nuclear@24: 
nuclear@24: static void add_glyph(struct glyph *g, float x, float y)
nuclear@24: {
nuclear@24: 	struct quad *qptr = qbuf + num_quads;
nuclear@24: 
nuclear@24: 	x -= g->orig_x;
nuclear@24: 	y -= g->orig_y;
nuclear@24: 
nuclear@24: 	qvertex(qptr->v + 0, x, y, g->nx, g->ny + g->nheight);
nuclear@24: 	qvertex(qptr->v + 1, x + g->width, y, g->nx + g->nwidth, g->ny + g->nheight);
nuclear@24: 	qvertex(qptr->v + 2, x + g->width, y + g->height, g->nx + g->nwidth, g->ny);
nuclear@24: 
nuclear@24: 	qvertex(qptr->v + 3, x, y, g->nx, g->ny + g->nheight);
nuclear@24: 	qvertex(qptr->v + 4, x + g->width, y + g->height, g->nx + g->nwidth, g->ny);
nuclear@24: 	qvertex(qptr->v + 5, x, y + g->height, g->nx, g->ny);
nuclear@24: 
nuclear@24: 	if(++num_quads >= QBUF_SZ) {
nuclear@24: 		dtx_flush();
nuclear@24: 	}
nuclear@24: }
nuclear@24: 
nuclear@24: void dtx_flush(void)
nuclear@24: {
nuclear@29: 	int vbo;
nuclear@29: 
nuclear@24: 	if(!num_quads) {
nuclear@24: 		return;
nuclear@24: 	}
nuclear@24: 
nuclear@29: 	if(glBindBuffer) {
nuclear@29: 		glGetIntegerv(GL_ARRAY_BUFFER_BINDING, &vbo);
nuclear@29: 		glBindBuffer(GL_ARRAY_BUFFER, 0);
nuclear@29: 	}
nuclear@29: 
nuclear@24: #ifndef GL_ES
nuclear@24: 	glPushAttrib(GL_ENABLE_BIT);
nuclear@24: 	glEnable(GL_TEXTURE_2D);
nuclear@24: #endif
nuclear@24: 	glBindTexture(GL_TEXTURE_2D, font_tex);
nuclear@24: 
nuclear@24: 	if(vattr != -1 && glEnableVertexAttribArray) {
nuclear@24: 		glEnableVertexAttribArray(vattr);
nuclear@24: 		glVertexAttribPointer(vattr, 2, GL_FLOAT, 0, sizeof(struct vertex), qbuf);
nuclear@24: #ifndef GL_ES
nuclear@24: 	} else {
nuclear@24: 		glEnableClientState(GL_VERTEX_ARRAY);
nuclear@24: 		glVertexPointer(2, GL_FLOAT, sizeof(struct vertex), qbuf);
nuclear@24: #endif
nuclear@24: 	}
nuclear@24: 	if(tattr != -1 && glEnableVertexAttribArray) {
nuclear@24: 		glEnableVertexAttribArray(tattr);
nuclear@24: 		glVertexAttribPointer(tattr, 2, GL_FLOAT, 0, sizeof(struct vertex), &qbuf->v[0].s);
nuclear@24: #ifndef GL_ES
nuclear@24: 	} else {
nuclear@24: 		glEnableClientState(GL_TEXTURE_COORD_ARRAY);
nuclear@24: 		glTexCoordPointer(2, GL_FLOAT, sizeof(struct vertex), &qbuf->v[0].s);
nuclear@24: #endif
nuclear@24: 	}
nuclear@24: 
nuclear@24: 	glEnable(GL_BLEND);
nuclear@24: 	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
nuclear@24: 
nuclear@24: 	glDepthMask(0);
nuclear@24: 
nuclear@24: 	glDrawArrays(GL_TRIANGLES, 0, num_quads * 6);
nuclear@24: 
nuclear@24: 	glDepthMask(1);
nuclear@24: 
nuclear@24: 	if(vattr != -1 && glDisableVertexAttribArray) {
nuclear@24: 		glDisableVertexAttribArray(vattr);
nuclear@24: #ifndef GL_ES
nuclear@24: 	} else {
nuclear@24: 		glDisableClientState(GL_VERTEX_ARRAY);
nuclear@24: #endif
nuclear@24: 	}
nuclear@24: 	if(tattr != -1 && glDisableVertexAttribArray) {
nuclear@24: 		glDisableVertexAttribArray(tattr);
nuclear@24: #ifndef GL_ES
nuclear@24: 	} else {
nuclear@24: 		glDisableClientState(GL_TEXTURE_COORD_ARRAY);
nuclear@24: #endif
nuclear@24: 	}
nuclear@24: 
nuclear@24: #ifndef GL_ES
nuclear@24: 	glPopAttrib();
nuclear@24: #else
nuclear@24: 	glDisable(GL_BLEND);
nuclear@24: #endif
nuclear@24: 
nuclear@29: 	if(glBindBuffer && vbo) {
nuclear@29: 		glBindBuffer(GL_ARRAY_BUFFER, vbo);
nuclear@29: 	}
nuclear@29: 
nuclear@24: 	num_quads = 0;
nuclear@24: }
nuclear@24: 
nuclear@24: #endif	/* !def NO_OPENGL */