Adding preliminary Sprite library.

targets/arduino/Sprite.cpp

@@ -0,0 +1,121 @@
+/*
+  Sprite.cpp - 2D sprite buffer library for Arduino & Wiring
+  Copyright (c) 2006 David A. Mellis.  All right reserved.
+
+  This library is free software; you can redistribute it and/or
+  modify it under the terms of the GNU Lesser General Public
+  License as published by the Free Software Foundation; either
+  version 2.1 of the License, or (at your option) any later version.
+
+  This library is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public
+  License along with this library; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+
+#include <stdlib.h>
+#include <stdarg.h>
+//#include <stdio.h>
+
+#include "Sprite.h"
+
+void Sprite::init(uint8_t width, uint8_t height, uint8_t depth)
+{
+  _width = width;
+  _height = height;
+  _ppb = 8 / depth; // pixels per byte = 8 / bit depth
+  _depth = 8 / _ppb; // round bit depth up to nearest divisor of 8
+  _bpr = (_width + _ppb - 1) / _ppb; // bytes per row (rounding up)
+  _mask = (1 << _depth) - 1; // mask = a byte with 1's in the _depth LSBs
+
+  // _buffer packs _ppb pixels into each byte.  
+  // for example, Sprite(3, 2, 3) yields:
+  // _buffer[0] = LSN: pixel (0, 0); MSN: pixel (1, 0)
+  // _buffer[1] = LSN: pixel (2, 0); MSN: empty
+  // _buffer[2] = LSN: pixel (0, 1); MSN: pixel (1, 1)
+  // _buffer[3] = LSN: pixel (2, 1); MSN: empty
+  // LSN = least-significant nibble (bits 0 to 3),
+  // MSN = most-significant nibble (bits 4 to 7)
+
+  // for now, do nothing if this allocation fails.  methods that require it
+  // should silently fail if _buffer is null.
+  _buffer = (uint8_t *) calloc(_height * _bpr, 1);
+}
+  
+Sprite::Sprite(uint8_t width, uint8_t height, uint8_t depth)
+{
+  init(width, height, depth);
+}
+
+Sprite::Sprite(uint8_t width, uint8_t height, uint8_t depth, uint8_t row, ...)
+{
+  init(width, height, depth);
+  
+  if (!_buffer) return;
+  
+  va_list ap;
+  va_start(ap, row);
+
+  int y = 0;
+  
+  for  (y = 0; ; y++) {
+    for (int x = 0; x < width && x < 8; x++)
+      write(x, y, (row >> (width - x - 1)) & 0x01);
+    
+    if (y == height - 1)
+      break;
+      
+    row = va_arg(ap, int); // using '...' promotes uint8_t to int
+  }
+  
+  va_end(ap);
+}
+
+uint8_t Sprite::width() const
+{
+  return _width;
+}
+
+uint8_t Sprite::height() const
+{
+  return _height;
+}
+
+void Sprite::write(uint8_t x, uint8_t y, uint8_t value)
+{
+  if (!_buffer) return;
+  
+  // XXX: this should mask according to bit depth specified in constructor,
+  // not the rounded bit depth stored in _depth
+  
+  // (x, y) is in the x / _ppb byte of the y'th row (the y'th row starts at
+  // byte y * _bpr of _buffer).  this byte may contain more than one pixel.
+  uint8_t *p = _buffer + y * _bpr + x / _ppb;
+  
+  // pixel (x, y) is in position x % _ppb of the byte, and each position is
+  // _depth bits.
+  uint8_t offset = _depth * (x % _ppb);
+  
+  // we need to bitwise-or the value of the other pixels in the byte with
+  // the new value, masked and shifted into the proper bits.
+  *p = (*p & ~(_mask << offset)) | ((value & _mask) << offset);
+}
+
+uint8_t Sprite::read(uint8_t x, uint8_t y) const
+{
+  if (!_buffer) return 0;
+  
+  // (x, y) is in the x / _ppb byte of the y'th row (the y'th row starts at
+  // byte y * _bpr of _buffer).  this byte may contain more than one pixel.
+  uint8_t *p = _buffer + y * _bpr + x / _ppb;
+  
+  // pixel (x, y) is in position x % _ppb of the byte, and each position is
+  // _depth bits.
+  uint8_t offset = _depth * (x % _ppb);
+  
+  return (*p >> offset) & _mask;
+}

targets/arduino/Sprite.h

@@ -0,0 +1,50 @@
+/*
+  Sprite.cpp - 2D sprite buffers library for Arduino & Wiring
+  Copyright (c) 2006 David A. Mellis.  All right reserved.
+
+  This library is free software; you can redistribute it and/or
+  modify it under the terms of the GNU Lesser General Public
+  License as published by the Free Software Foundation; either
+  version 2.1 of the License, or (at your option) any later version.
+
+  This library is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public
+  License along with this library; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+
+#ifndef Sprite_h
+#define Sprite_h
+
+#include <inttypes.h>
+
+class Matrix;
+
+class Sprite
+{
+  private:
+    uint8_t _width;
+    uint8_t _height;
+    uint8_t _depth;
+    uint8_t _ppb;
+    uint8_t _bpr;
+    uint8_t _mask;
+    uint8_t *_buffer;
+    
+    void init(uint8_t width, uint8_t height, uint8_t depth);
+  public: 
+    Sprite(uint8_t width, uint8_t height, uint8_t depth);
+    Sprite(uint8_t width, uint8_t height, uint8_t depth, uint8_t row, ...);
+    uint8_t width() const;
+    uint8_t height() const;
+    void write(uint8_t x, uint8_t y, uint8_t value);
+    uint8_t read(uint8_t x, uint8_t y) const;
+    
+  friend class Matrix;
+};
+
+#endif

targets/arduino/WProgram.h

@@ -1,6 +1,8 @@
 #include <avr/io.h>
 
 #include "wiring.h"
+#include "Matrix.h"
+#include "Sprite.h"
 
-#include <avr/interrupt.h>
+#include <avr/interrupt.h>
 #include <avr/signal.h>