FreeTypeGL-0.0.1: src/demo/demo-glyph.c
/* =========================================================================
* Freetype GL - A C OpenGL Freetype engine
* Platform: Any
* WWW: http://code.google.com/p/freetype-gl/
* -------------------------------------------------------------------------
* Copyright 2011,2012 Nicolas P. Rougier. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY NICOLAS P. ROUGIER ''AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
* EVENT SHALL NICOLAS P. ROUGIER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* The views and conclusions contained in the software and documentation are
* those of the authors and should not be interpreted as representing official
* policies, either expressed or implied, of Nicolas P. Rougier.
* ========================================================================= */
#include "freetype-gl.h"
#include "font-manager.h"
#include "vertex-buffer.h"
#include "text-buffer.h"
#include "markup.h"
#include "shader.h"
// ------------------------------------------------------- typedef & struct ---
typedef struct {
float x, y, z; // position
float s, t; // texture
float r, g, b, a; // color
} vertex_t;
typedef struct {
float x, y;
vec4 color;
} point_t;
// ------------------------------------------------------- global variables ---
vertex_buffer_t * text_buffer;
vertex_buffer_t * line_buffer;
vertex_buffer_t * point_buffer;
// ---------------------------------------------------------------- display ---
void display( void )
{
int viewport[4];
glGetIntegerv( GL_VIEWPORT, viewport );
glClearColor(1,1,1,1);
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
glEnable( GL_BLEND );
glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
glEnable( GL_POINT_SMOOTH );
glColor4f(1,1,1,1);
glEnable( GL_TEXTURE_2D );
vertex_buffer_render( text_buffer, GL_TRIANGLES, "vtc" );
glDisable( GL_TEXTURE_2D );
vertex_buffer_render( line_buffer, GL_LINES, "vc" );
glPointSize( 10.0f );
vertex_buffer_render( point_buffer, GL_POINTS, "vc" );
glutSwapBuffers( );
}
// ---------------------------------------------------------------- reshape ---
void reshape(int width, int height)
{
glViewport(0, 0, width, height);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0, width, 0, height, -1, 1);
glMatrixMode(GL_MODELVIEW);
glutPostRedisplay();
}
// --------------------------------------------------------------- keyboard ---
void keyboard( unsigned char key, int x, int y )
{
if ( key == 27 )
{
exit( EXIT_SUCCESS );
}
}
// --------------------------------------------------------------- add_text ---
void add_text( vertex_buffer_t * buffer, texture_font_t * font,
wchar_t * text, vec4 * color, vec2 * pen )
{
size_t i;
float r = color->red, g = color->green, b = color->blue, a = color->alpha;
for( i=0; i<wcslen(text); ++i )
{
texture_glyph_t *glyph = texture_font_get_glyph( font, text[i] );
if( glyph != NULL )
{
int kerning = 0;
if( i > 0)
{
kerning = texture_font_glyph_get_kerning( font, glyph, text[i-1] );
}
pen->x += kerning;
int x0 = (int)( pen->x + glyph->offset_x );
int y0 = (int)( pen->y + glyph->offset_y );
int x1 = (int)( x0 + glyph->width );
int y1 = (int)( y0 - glyph->height );
float s0 = glyph->s0;
float t0 = glyph->t0;
float s1 = glyph->s1;
float t1 = glyph->t1;
GLuint indices[] = {0,1,2,0,2,3};
vertex_t vertices[] = { { x0,y0,0, s0,t0, r,g,b,a },
{ x0,y1,0, s0,t1, r,g,b,a },
{ x1,y1,0, s1,t1, r,g,b,a },
{ x1,y0,0, s1,t0, r,g,b,a } };
vertex_buffer_push_back( buffer, vertices, 4, indices, 6 );
pen->x += glyph->advance_x;
}
}
}
// ------------------------------------------------------------------- main ---
int main( int argc, char **argv )
{
int width = 600;
int height = 600;
glutInit( &argc, argv );
glutInitWindowSize( width, height );
glutInitDisplayMode( GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH );
glutCreateWindow( "Freetype OpenGL" );
glutReshapeFunc( reshape );
glutDisplayFunc( display );
glutKeyboardFunc( keyboard );
vec4 blue = {{0,0,1,1}};
vec4 black = {{0,0,0,1}};
texture_atlas_t * atlas = texture_atlas_new( 512, 512, 1);
texture_font_t * big = texture_font_new( atlas, "fonts/Vera.ttf", 400);
texture_font_t * small = texture_font_new( atlas, "fonts/Vera.ttf", 18);
texture_font_t * title = texture_font_new( atlas, "fonts/Vera.ttf", 32);
text_buffer = vertex_buffer_new( "v3f:t2f:c4f" );
line_buffer = vertex_buffer_new( "v2f:c4f" );
point_buffer = vertex_buffer_new( "v2f:c4f" );
vec2 pen, origin;
texture_glyph_t *glyph = texture_font_get_glyph( big, L'g' );
origin.x = width/2 - glyph->offset_x - glyph->width/2;
origin.y = height/2 - glyph->offset_y + glyph->height/2;
add_text( text_buffer, big, L"g", &black, &origin );
// title
pen.x = 50;
pen.y = 560;
add_text( text_buffer, title, L"Glyph metrics", &black, &pen );
point_t vertices[] =
{ // Baseline
{0.1*width, origin.y, black},
{0.9*width, origin.y, black},
// Top line
{0.1*width, origin.y + glyph->offset_y, black},
{0.9*width, origin.y + glyph->offset_y, black},
// Bottom line
{0.1*width, origin.y + glyph->offset_y - glyph->height, black},
{0.9*width, origin.y + glyph->offset_y - glyph->height, black},
// Left line at origin
{width/2-glyph->offset_x-glyph->width/2, 0.1*height, black},
{width/2-glyph->offset_x-glyph->width/2, 0.9*height, black},
// Left line
{width/2 - glyph->width/2, .3*height, black},
{width/2 - glyph->width/2, .9*height, black},
// Right line
{width/2 + glyph->width/2, .3*height, black},
{width/2 + glyph->width/2, .9*height, black},
// Right line at origin
{width/2-glyph->offset_x-glyph->width/2+glyph->advance_x, 0.1*height, black},
{width/2-glyph->offset_x-glyph->width/2+glyph->advance_x, 0.7*height, black},
// Width
{width/2 - glyph->width/2, 0.8*height, blue},
{width/2 + glyph->width/2, 0.8*height, blue},
// Advance_x
{width/2-glyph->width/2-glyph->offset_x, 0.2*height, blue},
{width/2-glyph->width/2-glyph->offset_x+glyph->advance_x, 0.2*height, blue},
// Offset_x
{width/2-glyph->width/2-glyph->offset_x, 0.85*height, blue},
{width/2-glyph->width/2, 0.85*height, blue},
// Height
{0.3*width/2, origin.y + glyph->offset_y - glyph->height,blue},
{0.3*width/2, origin.y + glyph->offset_y, blue},
// Offset y
{0.8*width, origin.y + glyph->offset_y, blue},
{0.8*width, origin.y , blue},
};
GLuint indices [] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,
13,14,15,16,17,18,19,20,21,22,23,24,25};
vertex_buffer_push_back( line_buffer, vertices, 26, indices, 26 );
pen.x = width/2 - 48;
pen.y = .2*height - 18;
add_text( text_buffer, small, L"advance_x", &blue, &pen );
pen.x = width/2 - 20;
pen.y = .8*height + 3;
add_text( text_buffer, small, L"width", &blue, &pen );
pen.x = width/2 - glyph->width/2 + 5;
pen.y = .85*height-8;
add_text( text_buffer, small, L"offset_x", &blue, &pen );
pen.x = 0.2*width/2-30;
pen.y = origin.y + glyph->offset_y - glyph->height/2;
add_text( text_buffer, small, L"height", &blue, &pen );
pen.x = 0.8*width+3;
pen.y = origin.y + glyph->offset_y/2 -6;
add_text( text_buffer, small, L"offset_y", &blue, &pen );
pen.x = width/2 - glyph->offset_x - glyph->width/2 - 58;
pen.y = height/2 - glyph->offset_y + glyph->height/2 - 20;
add_text( text_buffer, small, L"Origin", &black, &pen );
GLuint i = 0;
point_t p;
p.color = black;
// Origin point
p.x = width/2 - glyph->offset_x - glyph->width/2;
p.y = height/2 - glyph->offset_y + glyph->height/2;
vertex_buffer_push_back( point_buffer, &p, 1, &i, 1 );
// Advance point
p.x = width/2 - glyph->offset_x - glyph->width/2 + glyph->advance_x;
p.y = height/2 - glyph->offset_y + glyph->height/2;
vertex_buffer_push_back( point_buffer, &p, 1, &i, 1 );
glutMainLoop( );
return 0;
}