Dogcows Code - chaz/yoink/blob - src/tilemap.hh

   1
   2 /*******************************************************************************
   3
   4  Copyright (c) 2009, Charles McGarvey
   5  All rights reserved.
   6
   7  Redistribution   and   use  in  source  and  binary  forms,  with  or  without
   8  modification, are permitted provided that the following conditions are met:
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  10    * Redistributions  of  source  code  must retain the above copyright notice,
  11      this list of conditions and the following disclaimer.
  12    * Redistributions  in binary form must reproduce the above copyright notice,
  13      this  list of conditions and the following disclaimer in the documentation
  14      and/or other materials provided with the distribution.
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  16  THIS  SOFTWARE  IS  PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  17  AND  ANY  EXPRESS  OR  IMPLIED  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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  27 *******************************************************************************/
  28
  29 #ifndef _TILEMAP_HH_
  30 #define _TILEMAP_HH_
  31
  32 /**
  33  * @file tilemap.hh
  34  * Small subclass to give some basic tile-mapping functionality to textures.
  35  */
  36
  37 #include <cassert>
  38
  39 #include <boost/shared_ptr.hpp>
  40
  41 #include "opengl.hh"
  42 #include "texture.hh"
  43
  44
  45 namespace dc {
  46
  47
  48 namespace tile {
  49
  50 /**
  51  * Possible orientations for texture coordinates.
  52  */
  53
  54 typedef enum
  55 {
  56         normal =                        0,                      ///< Normal orientation.
  57         flip =                          1,                      ///< Flip over a horizontal axis.
  58         reverse =                       2,                      ///< Flip over a vertical axis.
  59         flip_and_reverse =      3                       ///< Flip over both.
  60 } orientation;
  61
  62 } // namespace tile
  63
  64
  65 /**
  66  * A tilemap is a texture which is meant to be divided into smaller sprites.
  67  * This class provides all the functionality of a texture and adds some methods
  68  * to get texture coordinates to individual tiles within the tilemap.  For
  69  * simplicity, this class assumes square tiles.
  70  */
  71
  72 class tilemap : public texture
  73 {
  74 public:
  75         tilemap(const std::string& filePath, bool keepInMemory = false,
  76                         unsigned tilesU = 1, unsigned tilesV = 1)
  77                 : texture(filePath, keepInMemory), tilesU_(tilesU), tilesV_(tilesV) {}
  78
  79
  80         /**
  81          * Set the number of rows and columns of square tiles.
  82          * @param tilesU Columns of tiles.
  83          * @param tilesV Rows of tiles.
  84          */
  85
  86         void setTileDimensions(unsigned tilesU, unsigned tilesV)
  87         {
  88                 tilesU_ = tilesU;
  89                 tilesV_ = tilesV;
  90         }
  91
  92
  93         /**
  94          * Calculate texture coordinates for a tile at a certain index.  Tiles are
  95          * indexed start with zero as the to-left tile and moving across, then down.
  96          * @param index The tile index.
  97          * @param coords An array of floats where the texture coordinates will be
  98          * stored after this call.  The first coordinate (u,v) will be in the first
  99          * two places and so on until all four coordinates are stored, therefore
 100          * requiring enough room for an array of eight floats.  The winding of the
 101          * coordinates is always counter-clockwise (the GL default).
 102          */
 103
 104         void getTileCoords(unsigned index, float coords[8])
 105         {
 106                 assert(index < tilesU_ * tilesV_);
 107
 108                 float w = 1.0 / float(tilesU_);
 109                 float h = 1.0 / float(tilesV_);
 110
 111                 coords[0] = float(index % tilesU_) * w;
 112                 coords[1] = (float(tilesV_ - 1) - float(index / tilesU_)) * h;
 113                 coords[2] = coords[0] + w;
 114                 coords[3] = coords[1];
 115                 coords[4] = coords[2];
 116                 coords[5] = coords[1] + h;
 117                 coords[6] = coords[0];
 118                 coords[7] = coords[5];
 119         }
 120
 121         /**
 122          * This version let's you specify an orientation that will be reflected in
 123          * the texture coordinates.  This allows you to easily map a texture
 124          * backwards or upside-down.
 125          * @param what The orientation; can be flip, reverse, or flip_and_reverse.
 126          */
 127
 128         void getTileCoords(unsigned index, float coords[8], tile::orientation what)
 129         {
 130                 getTileCoords(index, coords);
 131
 132                 if (what & tile::flip)
 133                 {
 134                         coords[1] = coords[5];
 135                         coords[5] = coords[3];
 136                         coords[3] = coords[7];
 137                         coords[7] = coords[5];
 138                 }
 139                 if (what & tile::reverse)
 140                 {
 141                         coords[0] = coords[2];
 142                         coords[2] = coords[6];
 143                         coords[4] = coords[6];
 144                         coords[6] = coords[0];
 145                 }
 146         }
 147
 148 private:
 149         unsigned tilesU_;
 150         unsigned tilesV_;
 151 };
 152
 153
 154 } // namespace dc
 155
 156 #endif // _TILEMAP_HH_
 157