porytiles2::ShapeMask Class Reference

Represents which pixels in an 8x8 tile are non-transparent. More...

#include <shape_mask.hpp>

Public Member Functions
	ShapeMask ()=default
	ShapeMask (const std::array< uint8_t, tile::side_length_pix > &rows)
	Constructs a ShapeMask from an array of row data.
auto	operator<=> (const ShapeMask &) const =default
ShapeMask	flip (bool h, bool v) const
	Returns a flipped version of this mask.
void	set (int row, int col)
	Sets the bit at the specified row and column to 1.
void	unset (int row, int col)
	Sets the bit at the specified row and column to 0.
bool	get (int row, int col) const
	Gets the bit value at the specified row and column.
bool	is_transparent () const
	Checks if this entire ShapeMask is transparent.
const std::array< uint8_t, 8 > &	rows () const
	Returns the raw row data.

Detailed Description

Represents which pixels in an 8x8 tile are non-transparent.

ShapeMask uses 1 bit per pixel to track the "shape" of 8x8 tile. Each of the 8 rows is stored as a uint8_t, where the most significant bit represents the leftmost pixel (column 0) and the least significant bit represents the rightmost pixel (column 7).

The class provides flipping operations and bitwise manipulation to set or unset individual pixels. Comparison operators are lexicographic on the rows array.

In the tile canonicalization system, ShapeMask serves as a shape-based tile representation that separates tile geometry from color assignments. It is the fundamental building block for representing tile shapes. Multiple ShapeMask instances can be combined to define different color regions within a single tile, with each mask mapping to a specific color index. The flipping operations and lexicographic comparison enable the compiler to find canonical (minimal) orientations for tiles in a color-agnostic way, allowing deduplication of tiles that are identical under flips or color transformations.

Invariant

Default-constructed ShapeMask is transparent (satisfies SupportsTransparency design invariant). That is, ShapeMask{} produces a fully transparent mask with all bits unset (all rows are 0).

Definition at line 31 of file shape_mask.hpp.

Constructor & Destructor Documentation

ShapeMask() [1/2]

porytiles2::ShapeMask::ShapeMask ( )

default

ShapeMask() [2/2]

porytiles2::ShapeMask::ShapeMask ( const std::array< uint8_t, tile::side_length_pix > &  rows )

inlineexplicit

Constructs a ShapeMask from an array of row data.

Each element in the array represents one row of the 8x8 tile, where bit 7 is the leftmost pixel and bit 0 is the rightmost pixel.

Parameters

rows	An array of 8 bytes representing the tile rows

Definition at line 44 of file shape_mask.hpp.

Member Function Documentation

flip()

ShapeMask porytiles2::ShapeMask::flip	(	bool	h,
		bool	v
	)		const

Returns a flipped version of this mask.

Creates a new ShapeMask that is horizontally and/or vertically flipped. Horizontal flipping reverses the bits in each row. Vertical flipping reverses the order of the rows. If neither h nor v is true, returns a copy of the original mask.

Parameters

h	True to flip horizontally
v	True to flip vertically

Returns

The flipped mask

Definition at line 10 of file shape_mask.cpp.

get()

bool porytiles2::ShapeMask::get	(	int	row,
		int	col
	)		const

Gets the bit value at the specified row and column.

Returns true if the pixel at the given position is marked as non-transparent (bit is 1), false otherwise. Column 0 is the leftmost pixel (bit 7) and column 7 is the rightmost pixel (bit 0).

Parameters

row	The row index (0-7)
col	The column index (0-7)

Returns

True if the bit is set, false otherwise

Definition at line 37 of file shape_mask.cpp.

is_transparent()

bool porytiles2::ShapeMask::is_transparent

(

)

const

Checks if this entire ShapeMask is transparent.

A ShapeMask is transparent if every bit in every mask integer is unset.

Returns

True if all bits in the mask are unset, false otherwise

Definition at line 42 of file shape_mask.cpp.

operator<=>()

auto porytiles2::ShapeMask::operator<=> ( const ShapeMask &  ) const

default

rows()

const std::array< uint8_t, 8 > & porytiles2::ShapeMask::rows ( ) const

inline

Returns the raw row data.

Returns a const reference to the internal array of 8 bytes representing the tile rows.

Returns

A const reference to the rows array

Definition at line 118 of file shape_mask.hpp.

set()

void porytiles2::ShapeMask::set	(	int	row,
		int	col
	)

Sets the bit at the specified row and column to 1.

Marks the pixel at the given position as non-transparent. Column 0 is the leftmost pixel (bit 7) and column 7 is the rightmost pixel (bit 0).

Parameters

row	The row index (0-7)
col	The column index (0-7)

Definition at line 27 of file shape_mask.cpp.

unset()

void porytiles2::ShapeMask::unset	(	int	row,
		int	col
	)

Sets the bit at the specified row and column to 0.

Marks the pixel at the given position as transparent. Column 0 is the leftmost pixel (bit 7) and column 7 is the rightmost pixel (bit 0).

Parameters

row	The row index (0-7)
col	The column index (0-7)

Definition at line 32 of file shape_mask.cpp.

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The documentation for this class was generated from the following files:

• Porytiles2/include/porytiles2/domain/models/shape_mask.hpp
• Porytiles2/lib/domain/models/shape_mask.cpp