FreeTypeGL-0.0.1: src/demo/demo-distance-field.c
/* =========================================================================
* Freetype GL - A C OpenGL Freetype engine
* Platform: Any
* WWW: http://code.google.com/p/freetype-gl/
* -------------------------------------------------------------------------
* Copyright 2011 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 "edtaa3func.h"
#include "font-manager.h"
#include "vertex-buffer.h"
#include "text-buffer.h"
#include "markup.h"
#include "shader.h"
#define max(a,b) ((a) > (b) ? (a) : (b))
#define min(a,b) ((a) < (b) ? (a) : (b))
// ------------------------------------------------------- typedef & struct ---
typedef struct {
float x, y, zoom;
} viewport_t;
// ------------------------------------------------------- global variables ---
texture_atlas_t * atlas = 0;
viewport_t viewport = {0,0,1};
GLuint program = 0;
// ---------------------------------------------------------------- display ---
void
display( void )
{
int v[4];
glGetIntegerv( GL_VIEWPORT, v );
GLuint width = v[2];
GLuint height = v[3];
glClearColor(0.5,0.5,0.5,1.00);
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, atlas->id);
glEnable( GL_TEXTURE_2D );
glEnable( GL_BLEND );
glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
GLuint handle;
handle = glGetUniformLocation( program, "texture" );
glUniform1i( handle, 0);
int x = viewport.x;
int y = viewport.y;
width *= viewport.zoom;
height *= viewport.zoom;
glColor4f( 1.0, 1.0, 1.0, 1.0 );
glPushMatrix();
glBegin(GL_QUADS);
glTexCoord2f( 0, 1 ); glVertex2i( x, y );
glTexCoord2f( 0, 0 ); glVertex2i( x, y+height );
glTexCoord2f( 1, 0 ); glVertex2i( x+width, y+height );
glTexCoord2f( 1, 1 ); glVertex2i( x+width, y );
glEnd();
glPopMatrix();
glutSwapBuffers( );
}
// ----------------------------------------------------------- mouse_motion ---
void
mouse_motion( int x, int y )
{
int v[4];
glGetIntegerv( GL_VIEWPORT, v );
GLfloat width = v[2], height = v[3];
float nx = min( max( x/width, 0.0), 1.0 );
float ny = 1-min( max( y/height, 0.0), 1.0 );
viewport.x = nx*width*(1-viewport.zoom);
viewport.y = ny*height*(1-viewport.zoom);
glutPostRedisplay();
}
// ------------------------------------------------------------- mouse_drag ---
void
mouse_drag( int x, int y )
{
static int _x=-1, _y=-1;
if( (_x == -1) && (_y == -1) )
{
_x = x; _y = y;
return;
}
int dy = y - _y;
if (dy < 0)
{
viewport.zoom *= 1.05;
}
else
{
viewport.zoom /= 1.05;
}
_x = x; _y = y;
mouse_motion(x,y);
}
// ---------------------------------------------------------------- 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_distance_map ---
unsigned char *
make_distance_map( unsigned char *img,
unsigned int width, unsigned int height )
{
short * xdist = (short *) malloc( width * height * sizeof(short) );
short * ydist = (short *) malloc( width * height * sizeof(short) );
double * gx = (double *) calloc( width * height, sizeof(double) );
double * gy = (double *) calloc( width * height, sizeof(double) );
double * data = (double *) calloc( width * height, sizeof(double) );
double * outside = (double *) calloc( width * height, sizeof(double) );
double * inside = (double *) calloc( width * height, sizeof(double) );
int i;
// Convert img into double (data)
double img_min = 255, img_max = -255;
for( i=0; i<width*height; ++i)
{
double v = img[i];
data[i] = v;
if (v > img_max) img_max = v;
if (v < img_min) img_min = v;
}
// Rescale image levels between 0 and 1
for( i=0; i<width*height; ++i)
{
data[i] = (img[i]-img_min)/img_max;
}
// Compute outside = edtaa3(bitmap); % Transform background (0's)
computegradient( data, width, height, gx, gy);
edtaa3(data, gx, gy, height, width, xdist, ydist, outside);
for( i=0; i<width*height; ++i)
if( outside[i] < 0 )
outside[i] = 0.0;
// Compute inside = edtaa3(1-bitmap); % Transform foreground (1's)
memset(gx, 0, sizeof(double)*width*height );
memset(gy, 0, sizeof(double)*width*height );
for( i=0; i<width*height; ++i)
data[i] = 1 - data[i];
computegradient( data, width, height, gx, gy);
edtaa3(data, gx, gy, height, width, xdist, ydist, inside);
for( i=0; i<width*height; ++i)
if( inside[i] < 0 )
inside[i] = 0.0;
// distmap = outside - inside; % Bipolar distance field
unsigned char *out = (unsigned char *) malloc( width * height * sizeof(unsigned char) );
for( i=0; i<width*height; ++i)
{
outside[i] -= inside[i];
outside[i] = 128+outside[i]*16;
if( outside[i] < 0 ) outside[i] = 0;
if( outside[i] > 255 ) outside[i] = 255;
out[i] = 255 - (unsigned char) outside[i];
//out[i] = (unsigned char) outside[i];
}
free( xdist );
free( ydist );
free( gx );
free( gy );
free( data );
free( outside );
free( inside );
return out;
}
// ------------------------------------------------------------------- main ---
int
main( int argc, char **argv )
{
glutInit( &argc, argv );
glutInitWindowSize( 512, 512 );
glutInitDisplayMode( GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH );
glutCreateWindow( "Freetype OpenGL width shaders" );
glutReshapeFunc( reshape );
glutDisplayFunc( display );
glutMotionFunc( mouse_drag );
glutPassiveMotionFunc( mouse_motion );
glutKeyboardFunc( keyboard );
unsigned char *map;
texture_font_t * font;
const char *filename = "fonts/Vera.ttf";
const wchar_t *cache = L" !\"#$%&'()*+,-./0123456789:;<=>?"
L"@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_"
L"`abcdefghijklmnopqrstuvwxyz{|}~";
atlas = texture_atlas_new( 512, 512, 1 );
font = texture_font_new( atlas, filename, 72 );
texture_font_load_glyphs( font, cache );
texture_font_delete( font );
fprintf( stderr, "Generating distance map...\n" );
map = make_distance_map(atlas->data, atlas->width, atlas->height);
fprintf( stderr, "done !\n");
memcpy( atlas->data, map, atlas->width*atlas->height*sizeof(unsigned char) );
free(map);
texture_atlas_upload( atlas );
// Create the GLSL program
program = shader_load( "shaders/distance-field.vert",
"shaders/distance-field.frag" );
glUseProgram( program );
glutMainLoop( );
return 0;
}