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darnit_tilemap.h

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Steven Arnow edited this page Jun 8, 2013 · 9 revisions

DARNIT_TILEMAP

Tilemaps have a few properties with tile ID worth knowing about. Before a tile ID from the map is used to draw a tile, it is first logically AND'ed with a bitmask to mask out upper bits. LDMZ puts collision data in bit 16 and up. After masking these bits out, the ID is divided with a number specified at tilemap creation. If the division yields no reminder, the tile is not drawn, otherwise it is.

A tilemaps tile ID's can be modified directly. However, coordinates are cached, so after such modifications, the cache has to be flushed for changes to take effect. This can be done manually by calling d_tilemap_recalc. It also happens automatically every time a map is moved so that a tile previously visible is no longer visible, as only the visible tiles are cached.

See the article on isometric tilemaps for information on isometric tilemaps.

typedef struct {
        int             w;
        int             h;
        unsigned int    *data;
        void            *render;
} DARNIT_TILEMAP;
  • w - The width in tiles of the tilemap
  • h - Yjr height in tiles of the tilemap
  • data - The tile IDs. To calculate the position in the array for a tile, use i = (x + w * y)
  • render - Internal, don't use

Functions

d_tilemap_new

DARNIT_TILEMAP *d_tilemap_new(unsigned int invisibility_divider, DARNIT_TILESHEET *tilesheet, unsigned int mask, int w, int h);

Creates a new, blank, orthogonal tilemap.

Arguments

  • invisibility_divider - The tile ID is divided with this number. If the tile ID is evenly divisable with this number, the tile will be invisible. If set to 0, all tiles will be visible.
  • tilesheet - The tilesheet to use with the tilemap. A tilemap can only have one tilesheet
  • mask - The tile ID is AND'ed with this value before it's divided and used. Default is 0xFFF. Not using all the bits for tile ID means other information can be put in the upper bit. LDMZ puts collision data in bit 16 and up.
  • w - The width of the tilemap in tiles
  • h - The height of the tilemap in tiles

Return value

Returns NULL on failure, everything else is a valid DARNIT_TILEMAP.

d_tilemap_isom_new

DARNIT_TILEMAP *d_tilemap_isom_new(unsigned int invisibility_divider, DARNIT_TILESHEET *tilesheet, unsigned int mask, int w, int h, int tile_h);

Creates a new, blank, isometric tilemap.

Arguments

  • invisibility_divider - The tile ID is divided with this number. If the tile ID is evenly divisable with this number, the tile will be invisible. If set to 0, all tiles will be visible.
  • tilesheet - The tilesheet to use with the tilemap. A tilemap can only have one tilesheet
  • mask - The tile ID is AND'ed with this value before it's divided and used. Default is 0xFFF. Not using all the bits for tile ID means other information can be put in the upper bit. LDMZ puts collision data in bit 16 and up.
  • w - The width of the tilemap in tiles
  • h - The height of the tilemap in tiles
  • tile_h - The height of the tiles on the map. This height is usually lower than the tile height on the tilesheet for isometric maps.

Return value

Returns NULL on failure, everything else is a valid DARNIT_TILEMAP.

d_tilemap_load

DARNIT_TILEMAP *d_tilemap_load(const char *fname, unsigned int invisibility_divider, DARNIT_TILESHEET *tilesheet, unsigned int mask);

Creates an othogonal tilemap with the dimensions from a supplied image file (eg. PNG,) setting the tile ID for the tiles from the corresponding color value for the pixel at that coordinate in the image file.

Arguments

  • fname - File name of the image file to load
  • invisibility_divider - The tile ID is divided with this number. If the tile ID is evenly divisable with this number, the tile will be invisible. If set to 0, all tiles will be visible.
  • tilesheet - The tilesheet to use with the tilemap. A tilemap can only have one tilesheet
  • mask - The tile ID is AND'ed with this value before it's divided and used. Default is 0xFFF. Not using all the bits for tile ID means other information can be put in the upper bit. LDMZ puts collision data in bit 16 and up.

Return value

Returns NULL on failure, everything else is a valid DARNIT_TILEMAP.

d_tilemap_isom_load

DARNIT_TILEMAP *d_tilemap_isom_load(const char *fname, unsigned int invisibility_divider, DARNIT_TILESHEET *tilesheet, unsigned int mask, int tile_h);

Creates an isometric tilemap with the dimensions from a supplied image file (eg. PNG,) setting the tile ID for the tiles from the corresponding color value for the pixel at that coordinate in the image file.

Arguments

  • fname - File name of the image file to load
  • invisibility_divider - The tile ID is divided with this number. If the tile ID is evenly divisable with this number, the tile will be invisible. If set to 0, all tiles will be visible.
  • tilesheet - The tilesheet to use with the tilemap. A tilemap can only have one tilesheet
  • mask - The tile ID is AND'ed with this value before it's divided and used. Default is 0xFFF. Not using all the bits for tile ID means other information can be put in the upper bit. LDMZ puts collision data in bit 16 and up.
  • tile_h - The height of the tiles on the map. This height is usually lower than the tile height on the tilesheet for isometric maps.

Return value

Returns NULL on failure, everything else is a valid DARNIT_TILEMAP.

d_tilemap_recalc

void d_tilemap_recalc(DARNIT_TILEMAP *tilemap);

Flushes the coordinate cache used for rendering a tilemap. This must be done for changes in the tile data to be visible.

Arguments

  • tilemap - The tilemap to flush the coordinate cache for

Return value None.

d_tilemap_sprite_add

int d_tilemap_sprite_add(DARNIT_TILEMAP *tilemap, DARNIT_SPRITE *sprite);

Adds a sprite to the tilemaps list of sprites to render as the tilemap is rendered. Using this feature only really makes sense for isometric maps, when a part of the map can cover a sprite.

Arguments

  • tilemap - The tilemap to add a sprite to
  • sprite - The sprite to add to the tilemap

Return value

Returns -1 on failure. 0 or greater indicates success.

d_tilemap_sprite_delete

int d_tilemap_sprite_delete(DARNIT_TILEMAP *tilemap, DARNIT_SPRITE *sprite);

Deletes a sprite from the tilemap.

Arguments

  • tilemap - The tilemap to delete a sprite from
  • sprite - The sprite to delete

Return value

Returns -1 if the sprite was not found in the tilemap. 0 or greater means that the sprite was found and removed.

d_tilemap_camera_move

void d_tilemap_camera_move(DARNIT_TILEMAP *tilemap, int cam_x, int cam_y);

Moves the camera for the tilemap to coordinates x, y, making that area of the tilemap visible.

Arguments

  • tilemap - The tilemap to move the camera for
  • cam_x - The X-coordinate for the camera in pixels
  • cam_y - The Y-coordinate for the camera in pixels

Return value None.

d_tilemap_draw

void d_tilemap_draw(DARNIT_TILEMAP *tilemap);

Draws the tilemap.

Arguments

  • tilemap - The tilemap to draw

Return value None.

d_tilemap_free

DARNIT_TILEMAP *d_tilemap_free(DARNIT_TILEMAP *tilemap);

Frees a tilemap and releases all of its resources. It does not free any sprites added to it., and does not free the tilesheet it was assigned.

Arguments

  • tilemap - The tilemap to free

Return value

Returns NULL for compact pointer clearing.

d_tilemap_screen_to_iso

void d_tilemap_screen_to_iso(DARNIT_TILEMAP *tm, int x, int y, int *tile_x, int *tile_y);

Translates an orthogonal pixel coordinate to the tile coordinate in the tilemap. This function only makes sense when using isometric maps.

Arguments

  • tm - The tilemap to translate a coordinate to
  • x - The orthogonal X-coordinate to translate
  • y - The orthogonal Y-coordinate to translate
  • tile_w - The isometric tile X-coordinate
  • tile_h - The isometric tile Y-coordinate

Return value None.

d_tilemap_iso_to_screen

void d_tilemap_iso_to_screen(DARNIT_TILEMAP *tm, int tile_x, int tile_y, int *x, int *y);

Translates an isometric tile coordinate to an orthogonal pixel coordinate

Arguments

  • tm - The tilemap to translate a coordinate from
  • tile_w - The tile X-coordinate to translate
  • tile_h - The tile Y-coordinate to translate
  • x - The orthogonal translated X coordinate
  • y - The orthogonal translated Y coordinate
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