demo-texture.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 showing texture atlas packing
 *
 * ============================================================================
 */
#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

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


// ---------------------------------------------------------------- display ---
void display( void )
{
    glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
    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 );
    }
}

// ------------------------------------------------------------------- main ---
int main( int argc, char **argv )
{
    glutInit( &argc, argv );
    glutInitWindowSize( 512, 512 );
    glutInitDisplayMode( GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH );
    glutCreateWindow( argv[0] );
    glutReshapeFunc( reshape );
    glutDisplayFunc( display );
    glutKeyboardFunc( keyboard );

    glewExperimental = GL_TRUE;
    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) );

    texture_atlas_t * atlas = texture_atlas_new( 512, 512, 1 );
    const char *filename = "fonts/Vera.ttf";
    const wchar_t *cache = L" !\"#$%&'()*+,-./0123456789:;<=>?"
                           L"@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_"
                           L"`abcdefghijklmnopqrstuvwxyz{|}~";
    size_t minsize = 8, maxsize = 27;
    size_t count = maxsize - minsize;
    size_t i, missed = 0;

    for( i=minsize; i < maxsize; ++i )
    {
        texture_font_t * font = texture_font_new_from_file( atlas, i, filename );
        missed += texture_font_load_glyphs( font, cache );
        texture_font_delete( font );
    }

    printf( "Matched font               : %s\n", filename );
    printf( "Number of fonts            : %ld\n", count );
    printf( "Number of glyphs per font  : %ld\n", wcslen(cache) );
    printf( "Number of missed glyphs    : %ld\n", missed );
    printf( "Total number of glyphs     : %ld/%ld\n",
            wcslen(cache)*count - missed, wcslen(cache)*count );
    printf( "Texture size               : %ldx%ld\n", atlas->width, atlas->height );
    printf( "Texture occupancy          : %.2f%%\n", 
            100.0*atlas->used/(float)(atlas->width*atlas->height) );

    glClearColor(1,1,1,1);
    glEnable( GL_BLEND );
    glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
    glEnable( GL_TEXTURE_2D );
    glBindTexture( GL_TEXTURE_2D, atlas->id );

    typedef struct { float x,y,z, u,v, r,g,b,a; } vertex_t;
    vertex_t vertices[4] =  {
        {  0, 0, 0, 0,1, 0,0,0,1},
        {  0,512,0, 0,0, 0,0,0,1},
        {512,512,0, 1,0, 0,0,0,1},
        {512,  0,0, 1,1, 0,0,0,1} };
    GLuint indices[6] = { 0, 1, 2, 0,2,3 };
    buffer = vertex_buffer_new( "vertex:3f,tex_coord:2f,color:4f" );
    vertex_buffer_push_back( buffer, vertices, 4, indices, 6 );

    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;
}