A ShapeTile representation that stores the canonical (lexicographically minimal) orientation among all flipped variants. More...
#include <canonical_shape_tile.hpp>
Public Member Functions | |
| CanonicalShapeTile (const ShapeTile< PixelType > &tile) | |
| Constructs a CanonicalShapeTile by finding the canonical orientation of the input tile. | |
| auto | operator<=> (const CanonicalShapeTile &other) const =default |
| Three-way comparison operator that compares all fields. | |
| bool | h_flip () const |
| Returns the horizontal flip flag. | |
| bool | v_flip () const |
| Returns the vertical flip flag. | |
 Public Member Functions inherited from porytiles::ShapeTile< PixelType > | |
| virtual | ~ShapeTile ()=default |
| ShapeTile ()=default | |
| auto | operator<=> (const ShapeTile &other) const =default |
| bool | is_transparent () const |
| Checks if this entire ShapeTile is transparent. | |
| ShapeTile | flip (bool h, bool v) const |
| Creates a flipped version of this ShapeTile. | |
| const std::map< ShapeMask, PixelType > & | colors () const |
| Returns the internal map of shape masks to pixel values. | |
| void | set (const ShapeMask &mask, const PixelType &color) |
| Sets or updates the pixel value for a specific shape mask. | |
Additional Inherited Members | |
| Static Public Member Functions inherited from porytiles::ShapeTile< PixelType > | |
| static bool | compare_shape_only (const ShapeTile &lhs, const ShapeTile &rhs) |
| Compares two ShapeTiles based ONLY on shape masks, ignoring pixel values. | |
Detailed Description
class porytiles::CanonicalShapeTile< PixelType >
A ShapeTile representation that stores the canonical (lexicographically minimal) orientation among all flipped variants.
CanonicalShapeTile finds and stores the canonical orientation of a tile by evaluating all four possible flip combinations (no flip, horizontal only, vertical only, and both horizontal and vertical). The canonical orientation is defined as the lexicographically minimal tile shape among these four variants.
This representation enables:
- Shape-based tile deduplication: can detect when two tiles are isomorphic under flip or color transformations
- Canonical shape comparison: tiles can be compared in a normalized form regardless of their original orientation
- Orientation tracking: the flip flags record how to transform the canonical form back to the original orientation
The stored flip flags (h_flip_ and v_flip_) represent the transformation needed to convert the canonical tile back to the original input tile. For example, if the input tile's horizontal flip is its canonical form, h_flip() will return true, indicating that horizontally flipping the canonical tile reproduces the original.
Key difference from CanonicalPixelTile:
- Uses ShapeTile::compare_shape_only() which compares ONLY shape masks (geometry), not pixel values (colors)
- This means tiles with the same shape but different color assignments will canonicalize to the same shape structure
- This is critical for shape-based tile deduplication that is color-agnostic
This approach is particularly useful for:
- Tileset generation where tiles should be deduplicated based on shape regardless of colors
- Hardware targeting that supports tile flipping (e.g., GBA hardware attributes)
- Optimizing tileset size by identifying tiles that are rotations/flips of each other by shape
- Palette-independent tile analysis and optimization
- Template Parameters
-
PixelType The pixel type stored for each shape region
Definition at line 44 of file canonical_shape_tile.hpp.
Constructor & Destructor Documentation
◆ CanonicalShapeTile()
|
inlineexplicit |
Constructs a CanonicalShapeTile by finding the canonical orientation of the input tile.
This constructor evaluates all four possible flip combinations of the input tile:
- No flip (original orientation)
- Horizontal flip only
- Vertical flip only
- Both horizontal and vertical flip
The lexicographically minimal tile among these four variants is selected as the canonical form and stored as the base ShapeTile data. The flip flags that transform this canonical form back to the input tile are stored in h_flip_ and v_flip_.
The lexicographic comparison uses a two-phase approach: first, ShapeTile::compare_shape_only compares ONLY shape masks (geometry), ignoring pixel values. If the shape comparison produces a tie (which occurs with shapes that are symmetric under one or more flips), the full ShapeTile comparison (including pixel values) is used as a tiebreaker. This ensures that two tiles which are flips of each other with identical colors will select the same canonical form and produce identical color maps. This is critical for correct color version deduplication in shape group analysis.
- Parameters
-
tile The input ShapeTile to canonicalize
Definition at line 69 of file canonical_shape_tile.hpp.
Member Function Documentation
◆ h_flip()
|
inline |
Returns the horizontal flip flag.
Indicates whether the canonical tile must be horizontally flipped to reproduce the original input tile. If true, applying a horizontal flip to this CanonicalShapeTile's tile data will yield the original tile orientation.
- Returns
- True if horizontal flip is needed to reconstruct the original tile, false otherwise
Definition at line 141 of file canonical_shape_tile.hpp.
◆ operator<=>()
|
default |
Three-way comparison operator that compares all fields.
Performs member-wise comparison in declaration order:
- Base ShapeTile (shape masks AND pixel values via ShapeTile::operator<=>)
- h_flip_ flag
- v_flip_ flag
This operator is consistent with operator==, ensuring that:
- If (a <=> b) == 0, then (a == b) is true
- If (a == b) is true, then (a <=> b) == 0
- Parameters
-
other The CanonicalShapeTile to compare against
- Returns
- A std::strong_ordering indicating less than, equal to, or greater than relationship
◆ v_flip()
|
inline |
Returns the vertical flip flag.
Indicates whether the canonical tile must be vertically flipped to reproduce the original input tile. If true, applying a vertical flip to this CanonicalShapeTile's tile data will yield the original tile orientation.
- Returns
- True if vertical flip is needed to reconstruct the original tile, false otherwise
Definition at line 155 of file canonical_shape_tile.hpp.
The documentation for this class was generated from the following file:
- porytiles/include/porytiles/domain/models/canonical_shape_tile.hpp
