projects/geeknamensschilder_c/hardware/libraries/Sprite/Sprite.cpp

   1 /*
   2   Sprite.cpp - 2D sprite buffer library for Arduino & Wiring
   3   Copyright (c) 2006 David A. Mellis.  All right reserved.
   4
   5   This library is free software; you can redistribute it and/or
   6   modify it under the terms of the GNU Lesser General Public
   7   License as published by the Free Software Foundation; either
   8   version 2.1 of the License, or (at your option) any later version.
   9
  10   This library is distributed in the hope that it will be useful,
  11   but WITHOUT ANY WARRANTY; without even the implied warranty of
  12   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13   Lesser General Public License for more details.
  14
  15   You should have received a copy of the GNU Lesser General Public
  16   License along with this library; if not, write to the Free Software
  17   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  18 */
  19
  20 #include <stdlib.h>
  21 #include <stdarg.h>
  22 //#include <stdio.h>
  23
  24 #include "Sprite.h"
  25
  26 void Sprite::init(uint8_t width, uint8_t height)
  27 {
  28   _width = width >= 8 ? 8 : width;
  29   _height = height >= 8 ? 8 : height;
  30
  31   // for now, do nothing if this allocation fails.  methods that require it
  32   // should silently fail if _buffer is null.
  33   _buffer = (uint8_t *) calloc(_height, 1);
  34 }
  35
  36 Sprite::Sprite(uint8_t width, uint8_t height)
  37 {
  38   init(width, height);
  39 }
  40
  41 Sprite::Sprite(uint8_t width, uint8_t height, uint8_t row, ...)
  42 {
  43   init(width, height);
  44
  45   if (!_buffer) return;
  46
  47   va_list ap;
  48   va_start(ap, row);
  49
  50   int y = 0;
  51
  52   for (y = 0; ; y++) {
  53     for (int x = 0; x < width && x < 8; x++)
  54       write(x, y, (row >> (width - x - 1)) & 0x01);
  55
  56     if (y == height - 1)
  57       break;
  58
  59     row = va_arg(ap, int); // using '...' promotes uint8_t to int
  60   }
  61
  62   va_end(ap);
  63 }
  64
  65 uint8_t Sprite::width() const
  66 {
  67   return _width;
  68 }
  69
  70 uint8_t Sprite::height() const
  71 {
  72   return _height;
  73 }
  74
  75 void Sprite::write(uint8_t x, uint8_t y, uint8_t value)
  76 {
  77   if (!_buffer) return;
  78
  79   // uint8_t's can't be negative, so don't test for negative x and y.
  80   if (x >= _width || y >= _height) return;
  81
  82   // we need to bitwise-or the value of the other pixels in the byte with
  83   // the new value, masked and shifted into the proper bits.
  84   _buffer[y] = (_buffer[y] & ~(0x01 << x)) | ((value & 0x01) << x);
  85 }
  86
  87 uint8_t Sprite::read(uint8_t x, uint8_t y) const
  88 {
  89   if (!_buffer) return 0;
  90
  91   // uint8_t's can't be negative, so don't test for negative x and y.
  92   if (x >= _width || y >= _height) return 0;
  93
  94   return (_buffer[y] >> x) & 0x01;
  95 }