Click here to Skip to main content
15,891,375 members
Articles / Multimedia / OpenGL

OAG Library (OpenGL) Part 2.3 - Drawing 2D Textures Using the Mouse and Programatically

Rate me:
Please Sign up or sign in to vote.
4.29/5 (6 votes)
22 Oct 2010CPOL3 min read 34.1K   1.3K   17  
This tutorial shows library code for 2D Textures and how to draw them programatically using the mouse in an MFC application.
/***************************************************************************/
/*                                                                         */
/*  ftsystem.c                                                             */
/*                                                                         */
/*    Unix-specific FreeType low-level system interface (body).            */
/*                                                                         */
/*  Copyright 1996-2001, 2002, 2004, 2005, 2006, 2007, 2008 by             */
/*  David Turner, Robert Wilhelm, and Werner Lemberg.                      */
/*                                                                         */
/*  This file is part of the FreeType project, and may only be used,       */
/*  modified, and distributed under the terms of the FreeType project      */
/*  license, LICENSE.TXT.  By continuing to use, modify, or distribute     */
/*  this file you indicate that you have read the license and              */
/*  understand and accept it fully.                                        */
/*                                                                         */
/***************************************************************************/


#include <ft2build.h>
  /* we use our special ftconfig.h file, not the standard one */
#include <ftconfig.h>
#include FT_INTERNAL_DEBUG_H
#include FT_SYSTEM_H
#include FT_ERRORS_H
#include FT_TYPES_H
#include FT_INTERNAL_STREAM_H

  /* memory-mapping includes and definitions */
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#include <sys/mman.h>
#ifndef MAP_FILE
#define MAP_FILE  0x00
#endif

#ifdef MUNMAP_USES_VOIDP
#define MUNMAP_ARG_CAST  void *
#else
#define MUNMAP_ARG_CAST  char *
#endif

#ifdef NEED_MUNMAP_DECL

#ifdef __cplusplus
  extern "C"
#else
  extern
#endif
  int
  munmap( char*  addr,
          int    len );

#define MUNMAP_ARG_CAST  char *

#endif /* NEED_DECLARATION_MUNMAP */


#include <sys/types.h>
#include <sys/stat.h>

#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>


  /*************************************************************************/
  /*                                                                       */
  /*                       MEMORY MANAGEMENT INTERFACE                     */
  /*                                                                       */
  /*************************************************************************/


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    ft_alloc                                                           */
  /*                                                                       */
  /* <Description>                                                         */
  /*    The memory allocation function.                                    */
  /*                                                                       */
  /* <Input>                                                               */
  /*    memory :: A pointer to the memory object.                          */
  /*                                                                       */
  /*    size   :: The requested size in bytes.                             */
  /*                                                                       */
  /* <Return>                                                              */
  /*    The address of newly allocated block.                              */
  /*                                                                       */
  FT_CALLBACK_DEF( void* )
  ft_alloc( FT_Memory  memory,
            long       size )
  {
    FT_UNUSED( memory );

    return malloc( size );
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    ft_realloc                                                         */
  /*                                                                       */
  /* <Description>                                                         */
  /*    The memory reallocation function.                                  */
  /*                                                                       */
  /* <Input>                                                               */
  /*    memory   :: A pointer to the memory object.                        */
  /*                                                                       */
  /*    cur_size :: The current size of the allocated memory block.        */
  /*                                                                       */
  /*    new_size :: The newly requested size in bytes.                     */
  /*                                                                       */
  /*    block    :: The current address of the block in memory.            */
  /*                                                                       */
  /* <Return>                                                              */
  /*    The address of the reallocated memory block.                       */
  /*                                                                       */
  FT_CALLBACK_DEF( void* )
  ft_realloc( FT_Memory  memory,
              long       cur_size,
              long       new_size,
              void*      block )
  {
    FT_UNUSED( memory );
    FT_UNUSED( cur_size );

    return realloc( block, new_size );
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    ft_free                                                            */
  /*                                                                       */
  /* <Description>                                                         */
  /*    The memory release function.                                       */
  /*                                                                       */
  /* <Input>                                                               */
  /*    memory :: A pointer to the memory object.                          */
  /*                                                                       */
  /*    block  :: The address of block in memory to be freed.              */
  /*                                                                       */
  FT_CALLBACK_DEF( void )
  ft_free( FT_Memory  memory,
           void*      block )
  {
    FT_UNUSED( memory );

    free( block );
  }


  /*************************************************************************/
  /*                                                                       */
  /*                     RESOURCE MANAGEMENT INTERFACE                     */
  /*                                                                       */
  /*************************************************************************/


  /*************************************************************************/
  /*                                                                       */
  /* The macro FT_COMPONENT is used in trace mode.  It is an implicit      */
  /* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log  */
  /* messages during execution.                                            */
  /*                                                                       */
#undef  FT_COMPONENT
#define FT_COMPONENT  trace_io

  /* We use the macro STREAM_FILE for convenience to extract the       */
  /* system-specific stream handle from a given FreeType stream object */
#define STREAM_FILE( stream )  ( (FILE*)stream->descriptor.pointer )


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    ft_close_stream_by_munmap                                          */
  /*                                                                       */
  /* <Description>                                                         */
  /*    The function to close a stream which is opened by mmap.            */
  /*                                                                       */
  /* <Input>                                                               */
  /*    stream :: A pointer to the stream object.                          */
  /*                                                                       */
  FT_CALLBACK_DEF( void )
  ft_close_stream_by_munmap( FT_Stream  stream )
  {
    munmap( (MUNMAP_ARG_CAST)stream->descriptor.pointer, stream->size );

    stream->descriptor.pointer = NULL;
    stream->size               = 0;
    stream->base               = 0;
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    ft_close_stream_by_free                                            */
  /*                                                                       */
  /* <Description>                                                         */
  /*    The function to close a stream which is created by ft_alloc.       */
  /*                                                                       */
  /* <Input>                                                               */
  /*    stream :: A pointer to the stream object.                          */
  /*                                                                       */
  FT_CALLBACK_DEF( void )
  ft_close_stream_by_free( FT_Stream  stream )
  {
    ft_free( NULL, stream->descriptor.pointer );

    stream->descriptor.pointer = NULL;
    stream->size               = 0;
    stream->base               = 0;
  }


  /* documentation is in ftobjs.h */

  FT_BASE_DEF( FT_Error )
  FT_Stream_Open( FT_Stream    stream,
                  const char*  filepathname )
  {
    int          file;
    struct stat  stat_buf;


    if ( !stream )
      return FT_Err_Invalid_Stream_Handle;

    /* open the file */
    file = open( filepathname, O_RDONLY );
    if ( file < 0 )
    {
      FT_ERROR(( "FT_Stream_Open:" ));
      FT_ERROR(( " could not open `%s'\n", filepathname ));
      return FT_Err_Cannot_Open_Resource;
    }

    /* Here we ensure that a "fork" will _not_ duplicate   */
    /* our opened input streams on Unix.  This is critical */
    /* since it avoids some (possible) access control      */
    /* issues and cleans up the kernel file table a bit.   */
    /*                                                     */
#ifdef F_SETFD
#ifdef FD_CLOEXEC
    (void)fcntl( file, F_SETFD, FD_CLOEXEC );
#else
    (void)fcntl( file, F_SETFD, 1 );
#endif /* FD_CLOEXEC */
#endif /* F_SETFD */

    if ( fstat( file, &stat_buf ) < 0 )
    {
      FT_ERROR(( "FT_Stream_Open:" ));
      FT_ERROR(( " could not `fstat' file `%s'\n", filepathname ));
      goto Fail_Map;
    }

    /* XXX: TODO -- real 64bit platform support                        */
    /*                                                                 */
    /* `stream->size' is typedef'd to unsigned long (in                */
    /* freetype/ftsystem.h); `stat_buf.st_size', however, is usually   */
    /* typedef'd to off_t (in sys/stat.h).                             */
    /* On some platforms, the former is 32bit and the latter is 64bit. */
    /* To avoid overflow caused by fonts in huge files larger than     */
    /* 2GB, do a test.  Temporary fix proposed by Sean McBride.        */
    /*                                                                 */
    if ( stat_buf.st_size > LONG_MAX )
    {
      FT_ERROR(( "FT_Stream_Open: file is too big\n" ));
      goto Fail_Map;
    }
    else if ( stat_buf.st_size == 0 )
    {
      FT_ERROR(( "FT_Stream_Open: zero-length file\n" ));
      goto Fail_Map;
    }

    /* This cast potentially truncates a 64bit to 32bit! */
    stream->size = (unsigned long)stat_buf.st_size;
    stream->pos  = 0;
    stream->base = (unsigned char *)mmap( NULL,
                                          stream->size,
                                          PROT_READ,
                                          MAP_FILE | MAP_PRIVATE,
                                          file,
                                          0 );

    /* on some RTOS, mmap might return 0 */
    if ( (long)stream->base != -1 && stream->base != NULL )
      stream->close = ft_close_stream_by_munmap;
    else
    {
      ssize_t  total_read_count;


      FT_ERROR(( "FT_Stream_Open:" ));
      FT_ERROR(( " could not `mmap' file `%s'\n", filepathname ));

      stream->base = (unsigned char*)ft_alloc( NULL, stream->size );

      if ( !stream->base )
      {
        FT_ERROR(( "FT_Stream_Open:" ));
        FT_ERROR(( " could not `alloc' memory\n" ));
        goto Fail_Map;
      }

      total_read_count = 0;
      do {
        ssize_t  read_count;


        read_count = read( file,
                           stream->base + total_read_count,
                           stream->size - total_read_count );

        if ( read_count <= 0 )
        {
          if ( read_count == -1 && errno == EINTR )
            continue;

          FT_ERROR(( "FT_Stream_Open:" ));
          FT_ERROR(( " error while `read'ing file `%s'\n", filepathname ));
          goto Fail_Read;
        }

        total_read_count += read_count;

      } while ( (unsigned long)total_read_count != stream->size );

      stream->close = ft_close_stream_by_free;
    }

    close( file );

    stream->descriptor.pointer = stream->base;
    stream->pathname.pointer   = (char*)filepathname;

    stream->read = 0;

    FT_TRACE1(( "FT_Stream_Open:" ));
    FT_TRACE1(( " opened `%s' (%d bytes) successfully\n",
                filepathname, stream->size ));

    return FT_Err_Ok;

  Fail_Read:
    ft_free( NULL, stream->base );

  Fail_Map:
    close( file );

    stream->base = NULL;
    stream->size = 0;
    stream->pos  = 0;

    return FT_Err_Cannot_Open_Stream;
  }


#ifdef FT_DEBUG_MEMORY

  extern FT_Int
  ft_mem_debug_init( FT_Memory  memory );

  extern void
  ft_mem_debug_done( FT_Memory  memory );

#endif


  /* documentation is in ftobjs.h */

  FT_BASE_DEF( FT_Memory )
  FT_New_Memory( void )
  {
    FT_Memory  memory;


    memory = (FT_Memory)malloc( sizeof ( *memory ) );
    if ( memory )
    {
      memory->user    = 0;
      memory->alloc   = ft_alloc;
      memory->realloc = ft_realloc;
      memory->free    = ft_free;
#ifdef FT_DEBUG_MEMORY
      ft_mem_debug_init( memory );
#endif
    }

    return memory;
  }


  /* documentation is in ftobjs.h */

  FT_BASE_DEF( void )
  FT_Done_Memory( FT_Memory  memory )
  {
#ifdef FT_DEBUG_MEMORY
    ft_mem_debug_done( memory );
#endif
    memory->free( memory, memory );
  }


/* END */

By viewing downloads associated with this article you agree to the Terms of Service and the article's licence.

If a file you wish to view isn't highlighted, and is a text file (not binary), please let us know and we'll add colourisation support for it.

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)


Written By
Software Developer
Brazil Brazil
I live in Matão, a small city in Brazil. I studied as Programmer in a College for Software Development in Database.
After finishing the College I have been working with java, c# and Computer Graphics with searches for OpenGL.

Comments and Discussions