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