Files
tetris_clone/src/io/input.c
2025-07-02 10:30:59 +02:00

83 lines
2.3 KiB
C

#include "input.h"
#include <SDL_events.h>
#include <SDL_scancode.h>
#include <time.h>
#include "../game/time.h"
#include "../util/types.h"
#include "window.h"
/* processes an incoming scancode, returns the associated movement data, or performs the close action directly
* NOTE: if the action is mapped to multiple keys, pressing both and then releasing one, disables the action. Minor issue, won't fix. */
__attribute__((const)) static int procscancode(SDL_Scancode code) {
switch (code) {
case SDL_SCANCODE_Q:
return MOVRL;
case SDL_SCANCODE_E:
return MOVRR;
case SDL_SCANCODE_LEFT:
case SDL_SCANCODE_A:
case SDL_SCANCODE_H:
return MOVL;
case SDL_SCANCODE_RIGHT:
case SDL_SCANCODE_D:
case SDL_SCANCODE_L:
return MOVR;
case SDL_SCANCODE_DOWN:
case SDL_SCANCODE_S:
case SDL_SCANCODE_J:
case SDL_SCANCODE_SPACE:
return MOVD;
case SDL_SCANCODE_ESCAPE:
window_close();
return 0;
default: return 0;
}
}
static int timeout_mask(time_t time) {
static time_t timeout = 0, timeout_roll = 0;
int msk = 0;
// only add to the mask if time_poll returns `1`, negating becomes `-1`; 0b1111...
// this is masked with the desired movement action.
msk |= ((MOVR | MOVL | MOVD) & -!!time_poll(time, 64, &timeout));
msk |= ((MOVRL | MOVRR) & -!!time_poll(time, 100, &timeout_roll));
return msk;
}
int input_getdat(time_t time) {
static u8 movdat = 0, nmovdat = 0, lmovdat = 0; // stores the static movement data
int mov = movdat, nmov = nmovdat, lmov = lmovdat; // stores the runtime movement data for easy register access
// process the events
SDL_Event e;
while (SDL_PollEvent(&e)) {
switch (e.type) {
case SDL_QUIT: window_close(); break;
case SDL_KEYDOWN: mov |= procscancode(e.key.keysym.scancode); break;
case SDL_KEYUP: nmov |= procscancode(e.key.keysym.scancode); break;
}
}
// compute the current movement
int mask = timeout_mask(time);
// handle releasing of keys
mov &= ~(nmov & lmov & mask); // only remove the keys that have been pressed since lmov
lmov = mov; // set the value of lmov to the new value mov
nmov &= mov; // set nmov to only those in mov
int cmov = mov & mask;
// write to static variables (shrinking the values, and memory usage)
movdat = mov;
lmovdat = lmov;
nmovdat = nmov;
return cmov;
}