/*
------------------------------------------------------------
Fixed Rate Pig - a fixed logic frame rate demo
------------------------------------------------------------
* Copyright (C) 2004 David Olofson <david@olofson.net>
*
* This software is released under the terms of the GPL.
*
* Contact author for permission if you want to use this
* software, or work derived from it, under other terms.
*/
#ifndef PIG_ENGINE_H
#define PIG_ENGINE_H
#include "SDL.h"
#include <math.h>
#ifndef M_PI
# define M_PI 3.14159265358979323846 /* pi */
#endif
#include "dirty.h"
/*----------------------------------------------------------
Game Engine
----------------------------------------------------------*/
typedef struct PIG_object PIG_object;
typedef struct PIG_engine PIG_engine;
/* Interpolated point */
typedef struct PIG_ipoint
{
/* From the last logic frame: */
float ox, oy; /* Position */
/* From the last/current rendered frame: */
int gimage; /* Sprite frame index */
float gx, gy; /* Interpolated position */
} PIG_ipoint;
/*
* Game logic events
*
* PREFRAME:
* Occurs once per logic frame, before collision and
* off-screen detection, and before timer handlers.
*
* TIMERx:
* Occurs whenever timer x expires. Timers are one-
* shot, but can be reloaded by the handler for
* periodic action. Timer events are handled before
* before collision and off-screen detection.
*
* HIT_TILE:
* Occurs when the hot-spot of an object hits a
* marked side of a tile, and the corresponding bit
* in 'tilemask' is set.
*
* HIT_OBJECT:
* Occurs when the collision circle of an object
* intersects the collision circle of another object,
* provided one or more bits in 'hitgroup' of the
* other object matches bits in 'hitmask'.
*
* OFFSCREEN:
* Occurs when an object is off-screen. This takes
* in account the hot-spot and bounding rectangle of
* the current sprite frame.
*
* POSTFRAME:
* Occurs once per logic frame, after collision
* detection, off-screen detection and all other
* events.
*
*/
#define PIG_TIMERS 3
typedef enum
{
PIG_PREFRAME,
PIG_TIMER0,
PIG_TIMER1,
PIG_TIMER2,
PIG_HIT_TILE,
PIG_HIT_OBJECT,
PIG_OFFSCREEN,
PIG_POSTFRAME
} PIG_events;
typedef enum
{
PIG_NONE = 0,
/* Bit positions */
PIG_TOP_B = 0,
PIG_BOTTOM_B = 1,
PIG_LEFT_B = 2,
PIG_RIGHT_B = 3,
/* Masks */
PIG_TOP = 1 << PIG_TOP_B,
PIG_BOTTOM = 1 << PIG_BOTTOM_B,
PIG_LEFT = 1 << PIG_LEFT_B,
PIG_RIGHT = 1 << PIG_RIGHT_B,
/* Combined masks */
PIG_TL = PIG_TOP | PIG_LEFT,
PIG_TR = PIG_TOP | PIG_RIGHT,
PIG_BL = PIG_BOTTOM | PIG_LEFT,
PIG_BR = PIG_BOTTOM | PIG_RIGHT,
PIG_ALL = 0xf,
} PIG_sides;
typedef enum
{
PIG_UNCHANGED = -10000000,
PIG_MIN = -10000001,
PIG_CENTER = -10000002,
PIG_MAX = -10000003
} PIG_values;
/* Collision info */
typedef struct
{
float ff; /* Fractional frame */
int x, y; /* Exact position */
PIG_sides sides; /* Side of tile hit */
} PIG_cinfo;
typedef struct PIG_event
{
PIG_events type;
/* For HIT_TILE, HIT_OBJECT and OFFSCREEN: */
PIG_cinfo cinfo; /* Detailed collision info */
/* For HIT_OBJECT: */
PIG_object *obj; /* Which object? */
} PIG_event;
/* Logic object */
struct PIG_object
{
PIG_engine *owner;
PIG_object *next, *prev;
int id; /* Unique ID. 0 means "free". */
int ibase; /* Sprite frame base index */
int image; /* Sprite frame offset */
float x, y; /* Position */
float vx, vy; /* Speed */
float ax, ay; /* Acceleration */
PIG_ipoint ip;
int tilemask; /* Sprite/tile mask [PIG_ALL] */
int hitmask; /* Sprite/sprite mask [0] */
int hitgroup; /* Sprite/sprite group [0] */
int timer[PIG_TIMERS]; /* Down-counting timers */
int age; /* Age timer (logic frames) */
int score;
int power;
int target;
int state;
void (*handler)(PIG_object *po, const PIG_event *ev);
void *userdata;
};
/* Level map */
typedef struct PIG_map
{
PIG_engine *owner;
int w, h; /* Size of map (tiles) */
unsigned char *map; /* 2D aray of tile indices */
unsigned char *hit; /* 2D aray of collision flags */
int tw, th; /* Size of one tile (pixels) */
SDL_Surface *tiles; /* Tile palette image */
unsigned char hitinfo[256]; /* Collision info for the tiles */
} PIG_map;
/* Sprite frame */
typedef struct PIG_sprite
{
int w, h; /* Size of sprite (pixels) */
int hotx, hoty; /* Hot-spot offset (pixels) */
int radius; /* Collision zone radius (pixels) */
SDL_Surface *surface;
} PIG_sprite;
/* Engine */
struct PIG_engine
{
/* Video stuff */
SDL_Surface *screen;
SDL_Surface *buffer; /* For h/w surface displays */
SDL_Surface *surface; /* Where to render to */
int pages; /* # of display VRAM buffers */
SDL_Rect view; /* Viewport pos & size (pixels) */
int page; /* Current page (double buffer) */
PIG_dirtytable *pagedirty[2]; /* One table for each page */
PIG_dirtytable *workdirty; /* The work dirtytable */
/* "Live" switches */
int interpolation;
int direct; /* 1 ==> render directly to screen */
int show_dirtyrects;
/* Time */
double time; /* Logic time (frames) */
int frame; /* Logic time; integer part */
/* Background graphics */
PIG_map *map;
/* Sprites and stuff */
PIG_object *objects;
PIG_object *object_pool;
int object_id_counter;
int nsprites;
PIG_sprite **sprites;
/* Logic frame global handlers */
void (*before_objects)(PIG_engine *pe);
void (*after_objects)(PIG_engine *pe);
/* Space for user data */
void *userdata;
};
/*
* Engine
*/
PIG_engine *pig_open(SDL_Surface *screen);
void pig_close(PIG_engine *pe);
/* Set viewport size and position */
void pig_viewport(PIG_engine *pe, int x, int y, int w, int h);
/* Start engine at logic time 'frame' */
void pig_start(PIG_engine *pe, int frame);
/*
* Load a sprite palette image. The image is chopped up into
* sprites, based on 'sw' and 'sh', and added as new frames
* in the sprite bank. Default values:
* Hot-spot: (sw/2, sh/2)
* Collision radius: 0.2 * (sw + sh)
*
* Passing 0 for 'sw' and/or 'sh' makes pig_sprites() take
* the respective value from the image width and/or height.
*
* Returns the index of the first frame loaded.
*/
int pig_sprites(PIG_engine *pe, const char *filename, int sw, int sh);
/* Set hot-spot of sprite 'frame' to (hotx, hoty) */
int pig_hotspot(PIG_engine *pe, int frame, int hotx, int hoty);
/* Set sprite/sprite collision zone radius of 'frame' */
int pig_radius(PIG_engine *pe, int frame, int radius);
/* Advance logic time by 'frames' logic frames */
void pig_animate(PIG_engine *pe, float frames);
/*
* Manually add a dirtyrect for pig_refresh().
* 'dr' can be outside the engine viewport.
*/
void pig_dirty(PIG_engine *pe, SDL_Rect *dr);
/*
* Do what's needed to deal with the dirtyrects
* and then make the new frame visible.
*/
void pig_flip(PIG_engine *pe);
/*
* Refresh the viewport and any additional dirtyrects.
*
* Note that this does not refresh the entire viewport;
* only the areas that have actually changed!
*/
void pig_refresh(PIG_engine *pe);
/*
* Refresh the whole viewport, including sprites.
*/
void pig_refresh_all(PIG_engine *pe);
/* Render a sprite "manually", bypassing the engine */
void pig_draw_sprite(PIG_engine *pe, int frame, int x, int y);
/*
* Get the collision flags for the tile at (x, y),
* where the unit of x and y is pixels. The return
* is the PIG_sides flags for the tile, or PIG_NONE
* if (x, y) is outside the map.
*/
int pig_test_map(PIG_engine *pe, int x, int y);
/*
* Find the first "collidable" tile side when going from
* (x1, y1) to (x2, y2). 'mask' determines which tile sides
* are considered for collisions.
*
* Returns the side(s) hit, if any tile was hit. If the return
* is non-zero, the PIG_cinfo struct at 'ci' contains detailed
* information about the collision.
*/
int pig_test_map_vector(PIG_engine *pe, int x1, int y1, int x2, int y2,
int mask, PIG_cinfo *ci);
/*
* Map
*/
PIG_map *pig_map_open(PIG_engine *pe, int w, int h);
void pig_map_close(PIG_map *pm);
/* Load a tile palette image */
int pig_map_tiles(PIG_map *pm, const char *filename, int tw, int th);
/*
* Set tile collision info for 'count' tiles, starting at
* 'first'. Each tile in the tile palette has a set of
* PIG_sides flags that determine which sides the tile are
* considered for sprite/map collisions.
*/
void pig_map_collisions(PIG_map *pm, unsigned first, unsigned count,
PIG_sides sides);
/*
* Load a map from a string (one byte/tile). 'trans'
* is a string used for translating 'data' into integer
* tile indices. Each position in 'trans' corresponds
* to one tile in the tile palette.
*/
int pig_map_from_string(PIG_map *pm, const char *trans, const char *data);
/*
* Object
*/
/*
* Create an object with the initial position (x, y). If
* 'last' is 1, the object will end up last in the
* processing and rendering order, otherwise, first.
*
* Note that relative processing order is very important
* to objects that chase each other and stuff like that!
* If they're placed in the "wrong" order, the tracking
* objects get an extra frame of reaction time, which is
* annoying if it's not what you intend.
*/
PIG_object *pig_object_open(PIG_engine *pe, int x, int y, int last);
/*
* Delete an object.
*
* Note that objects are never actually deleted. Instead,
* they are placed in a free pool, where pig_object_open()
* looks for objects to recycle.
*
* In fact, they are not even freed when you ask for it,
* but rather kept around until the next rendered frame,
* so they can be removed from the screen correctly.
*/
void pig_object_close(PIG_object *po);
/*
* Close all objects.
*/
void pig_object_close_all(PIG_engine *pe);
/*
* Find object by 'id', starting at object 'start'.
*
* The search starts at 'start' and is done in both
* directions in parallel, assuming that the matching
* object is near 'start' in the list. (It usually is
* when dealing with linked objects.)
*
* Returns NULL if the object was not found.
*/
PIG_object *pig_object_find(PIG_object *start, int id);
#endif /* PIG_ENGINE_H */