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/* ============================================================================
* 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.
* ============================================================================
*
* Example showing regular font usage
*
* ============================================================================
*/
#include <stdio.h>
#include <wchar.h>

#include "freetype-gl.h"
#include "mat4.h"
#include "shader.h"
#include "vertex-buffer.h"
#if defined(__APPLE__)
#include <Glut/glut.h>
#elif defined(_WIN32) || defined(_WIN64)
#include <GLUT/glut.h>
#else
#include <GL/glut.h>
#endif


// ------------------------------------------------------- typedef & struct ---
typedef struct {
float x, y, z; // position
float s, t; // texture
float r, g, b, a; // color
} vertex_t;


// ------------------------------------------------------- global variables ---
GLuint shader;
vertex_buffer_t *buffer;
mat4 model, view, projection;


// ---------------------------------------------------------------- display ---
void display( void )
{
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 );

glUseProgram( shader );
{
glUniform1i( glGetUniformLocation( shader, "texture" ),
0 );
glUniformMatrix4fv( glGetUniformLocation( shader, "model" ),
1, 0, model.data);
glUniformMatrix4fv( glGetUniformLocation( shader, "view" ),
1, 0, view.data);
glUniformMatrix4fv( glGetUniformLocation( shader, "projection" ),
1, 0, projection.data);
vertex_buffer_render( buffer, GL_TRIANGLES );
}
glutSwapBuffers( );
}


// ---------------------------------------------------------------- reshape ---
void reshape(int width, int height)
{
glViewport(0, 0, width, height);
mat4_set_orthographic( &projection, 0, width, 0, height, -1, 1);
}


// --------------------------------------------------------------- keyboard ---
void keyboard( unsigned char key, int x, int y )
{
if ( key == 27 )
{
exit( 1 );
}
}


// --------------------------------------------------------------- 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_glyph_get_kerning( 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[6] = {0,1,2, 0,2,3};
vertex_t vertices[4] = { { 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 )
{
glutInit( &argc, argv );
glutInitWindowSize( 800, 400 );
glutInitDisplayMode( GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH );
glutCreateWindow( argv[0] );
glutReshapeFunc( reshape );
glutDisplayFunc( display );
glutKeyboardFunc( keyboard );

GLenum err = glewInit();
if (GLEW_OK != err)
{
/* Problem: glewInit failed, something is seriously wrong. */
fprintf( stderr, "Error: %s\n", glewGetErrorString(err) );
exit( EXIT_FAILURE );
}
fprintf( stderr, "Using GLEW %s\n", glewGetString(GLEW_VERSION) );

size_t i;
texture_font_t *font = 0;
texture_atlas_t *atlas = texture_atlas_new( 512, 512, 1 );
const char * filename = "fonts/Vera.ttf";
wchar_t *text = L"A Quick Brown Fox Jumps Over The Lazy Dog 0123456789";
buffer = vertex_buffer_new( "vertex:3f,tex_coord:2f,color:4f" );
vec2 pen = {{5,400}};
vec4 black = {{0,0,0,1}};
for( i=7; i < 27; ++i)
{
font = texture_font_new( atlas, filename, i );
pen.x = 5;
pen.y -= font->height;
texture_font_load_glyphs( font, text );
add_text( buffer, font, text, &black, &pen );
texture_font_delete( font );
}
glBindTexture( GL_TEXTURE_2D, atlas->id );

shader = shader_load("shaders/v3f-t2f-c4f.vert",
"shaders/v3f-t2f-c4f.frag");
mat4_set_identity( &projection );
mat4_set_identity( &model );
mat4_set_identity( &view );

glutMainLoop( );
return 0;
}

Change log

r219 by Nicolas.Rougier on May 2, 2013   Diff
Applied patch from  issue #56 
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Older revisions

r193 by Nicolas.Rougier on Mar 7, 2013   Diff
Merge changes from the gl-3.0 branch
r139 by Nicolas.Rougier on May 17, 2012   Diff
Fix a lot of issue reported by Andrei
Petrovici
r134 by Nicolas.Rougier on May 7, 2012   Diff
Big code cleanup and added
documentation
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