FreeTypeGL-0.0.1: src/demo/demo-display-list.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.
* =========================================================================
*
* Example usage with display lists
*
* ========================================================================= */
#include "freetype-gl.h"
// ------------------------------------------------------- global variables ---
vector_t * fonts;
texture_atlas_t *atlas;
char *filename = "fonts/Vera.ttf";
wchar_t *text = L"A Quick Brown Fox Jumps Over The Lazy Dog 0123456789";
// --------------------------------------------------------------- gl_print ---
void gl_print( texture_font_t * font,
wchar_t * text )
{
size_t i;
texture_glyph_t * glyph = 0;
texture_atlas_t * atlas = font->atlas;
glEnable( GL_TEXTURE_2D );
glBindTexture( GL_TEXTURE_2D, atlas->id );
glEnable( GL_BLEND );
// For ALPHA texture (atlas depth = 1)
if( atlas->depth == 1 )
{
glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
glColor4f( 0, 0, 0, 1 ); // Actual font color
}
// For RGB texture (atlas depth = 3)
else if( atlas->depth == 3 )
{
glEnable( GL_COLOR_MATERIAL );
glBlendFunc( GL_CONSTANT_COLOR_EXT, GL_ONE_MINUS_SRC_COLOR );
glColor4f( 1, 1, 1, 1 );
glBlendColor( 0, 0, 0, 1 );
}
glPushMatrix();
for( i=0; i<wcslen(text); ++i)
{
glyph = (texture_glyph_t *) texture_font_get_glyph( font, text[i] );
if( i > 0 )
{
glTranslatef(0, texture_font_glyph_get_kerning( font, glyph, text[i-1] ), 0);
}
glCallList( glyph->id );
glTranslatef( (int)glyph->advance_x, 0, 0 );
}
glPopMatrix();
}
// ------------------------------------------------------------ gl_print_at ---
void gl_print_at( texture_font_t * font,
int x, int y, wchar_t * text )
{
glPushMatrix();
glTranslatef(x, y-(int)font->height, 0);
gl_print( font, text );
glPopMatrix();
}
// ---------------------------------------------------------------- display ---
void display( void )
{
size_t i;
GLint viewport[4];
glGetIntegerv( GL_VIEWPORT, viewport );
glClearColor(1,1,1,1);
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
glPushMatrix();
glTranslatef(5, viewport[3], 0);
for( i=0; i<vector_size(fonts); ++i)
{
texture_font_t * font = (texture_font_t *) vector_get(fonts, i);
glTranslatef(0, -(int)font->height, 0);
gl_print( font, text );
}
glPopMatrix();
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( 1 );
}
}
// ----------------------------------------------------- make_display_lists ---
void
make_display_lists( texture_font_t * self )
{
size_t i;
texture_glyph_t * glyph;
for( i=0; i<vector_size(self->glyphs) ; ++i)
{
glyph = *(texture_glyph_t **) vector_get( self->glyphs, i);
int x = glyph->offset_x;
int y = glyph->offset_y;
int w = glyph->width;
int h = glyph->height;
float s0 = glyph->s0;
float t0 = glyph->t0;
float s1 = glyph->s1;
float t1 = glyph->t1;
if( glyph->id )
{
glDeleteLists( glyph->id, 1 );
}
glyph->id = glGenLists( 1 );
glNewList( glyph->id,GL_COMPILE );
glBegin( GL_TRIANGLES );
glTexCoord2f( s0, t0 ); glVertex2i( x, y );
glTexCoord2f( s0, t1 ); glVertex2i( x, y-h );
glTexCoord2f( s1, t1 ); glVertex2i( x+w, y-h );
glTexCoord2f( s0, t0 ); glVertex2i( x, y );
glTexCoord2f( s1, t1 ); glVertex2i( x+w, y-h );
glTexCoord2f( s1, t0 ); glVertex2i( x+w, y );
glEnd();
glEndList();
}
};
// ------------------------------------------------------------------- main ---
int main( int argc, char **argv )
{
size_t i;
glutInit( &argc, argv );
glutInitWindowSize( 800, 400 );
glutInitDisplayMode( GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH );
glutCreateWindow( "Freetype OpenGL / display lists" );
glutReshapeFunc( reshape );
glutDisplayFunc( display );
glutKeyboardFunc( keyboard );
// Build fonts and corresponding display lists
fonts = vector_new( sizeof(texture_font_t) );
atlas = texture_atlas_new( 512, 512, 1 );
for( i=7; i < 27; ++i)
{
texture_font_t * font = texture_font_new( atlas, filename, i );
texture_font_load_glyphs( font, text );
make_display_lists( font );
vector_push_back( fonts, font );
free( font ); // We're only freeing the local copy of the font
}
glutMainLoop( );
texture_atlas_delete( atlas );
return 0;
}