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#ifndef SPRITE_H

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#define SPRITE_H

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/* The following describes bunch of sprites to be drawn together in a single 3D

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 * bounding box. Used especially for various multi-sprite buildings (like

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 * depots or stations): */

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typedef struct DrawTileSeqStruct {

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	int8 delta_x; // 0x80 is sequence terminator

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	int8 delta_y;

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	int8 delta_z;

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	byte width,height;

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	byte unk; // 'depth', just z-size; TODO: rename

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	uint32 image;

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} DrawTileSeqStruct;

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typedef struct DrawTileSprites {

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	SpriteID ground_sprite;

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	DrawTileSeqStruct const *seq;

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} DrawTileSprites;

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// Iterate through all DrawTileSeqStructs in DrawTileSprites.

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#define foreach_draw_tile_seq(idx, list) for (idx = list; ((byte) idx->delta_x) != 0x80; idx++)

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/* This is for custom sprites: */

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struct SpriteGroup;

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struct RealSpriteGroup {

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	// XXX: Would anyone ever need more than 16 spritesets? Maybe we should

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	// use even less, now we take whole 8kb for custom sprites table, oh my!

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	byte sprites_per_set; // means number of directions - 4 or 8

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	// Loaded = in motion, loading = not moving

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	// Each group contains several spritesets, for various loading stages

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	// XXX: For stations the meaning is different - loaded is for stations

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	// with small amount of cargo whilst loading is for stations with a lot

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	// of da stuff.

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	byte loaded_count;

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	uint16 loaded[16]; // sprite ids

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	byte loading_count;

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	uint16 loading[16]; // sprite ids

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};

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/* Shared by deterministic and random groups. */

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enum VarSpriteGroupScope {

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	VSG_SCOPE_SELF,

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	// Engine of consists for vehicles, city for stations.

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	VSG_SCOPE_PARENT,

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};

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struct DeterministicSpriteGroupRanges;

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struct DeterministicSpriteGroup {

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	// Take this variable:

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	enum VarSpriteGroupScope var_scope;

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	byte variable;

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	// Do this with it:

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	byte shift_num;

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	byte and_mask;

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	// Then do this with it:

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	enum DeterministicSpriteGroupOperation {

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		DSG_OP_NONE,

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		DSG_OP_DIV,

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		DSG_OP_MOD,

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	} operation;

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	byte add_val;

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	byte divmod_val;

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	// And apply it to this:

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	byte num_ranges;

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	struct DeterministicSpriteGroupRange *ranges; // Dynamically allocated

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	// Dynamically allocated, this is the sole owner

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	struct SpriteGroup *default_group;

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};

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struct SpriteGroup {

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	enum SpriteGroupType {

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		SGT_REAL,

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		SGT_DETERMINISTIC,

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		SGT_RANDOM, /* TODO */

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	} type;

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	union {

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		struct RealSpriteGroup real;

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		struct DeterministicSpriteGroup determ;

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	} g;

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};

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struct DeterministicSpriteGroupRange {

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	struct SpriteGroup group;

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	byte low;

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	byte high;

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};

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/* This is a temporary helper for SpriteGroup users not supporting variational

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 * sprite groups yet - it just traverses those cowardly, always taking the

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 * default choice until it hits a real sprite group, returning it. */

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static struct RealSpriteGroup *TriviallyGetRSG(struct SpriteGroup *sg);

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/* This takes value (probably of the variable specified in the group) and

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 * chooses corresponding SpriteGroup accordingly to the given

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 * DeterministicSpriteGroup. */

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struct SpriteGroup *EvalDeterministicSpriteGroup(struct DeterministicSpriteGroup *dsg, int value);

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/* Get value of a common deterministic SpriteGroup variable. */

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int GetDeterministicSpriteValue(byte var);

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/**** Inline functions ****/

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static INLINE struct RealSpriteGroup *TriviallyGetRSG(struct SpriteGroup *sg)

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{

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	if (sg->type == SGT_REAL)

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		return &sg->g.real;

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	return TriviallyGetRSG(sg->g.determ.default_group);

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}

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#endif