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#include "asset.h"
#include "config.h"
#include "map.h"
#include "maths.h"
#include "physics.h"
#include "rect.h"
#include "render.h"
int test_bit(
unsigned* data,
int x,
int y,
int w
) {
int idx = x + y * w;
return data[idx >> 5] & (1 << (idx & 0x1f));
}
static int solve_mask(
unsigned char t,
int* y,
int* vy,
const Rect* col,
const Rect* r,
const Rect* tr,
int* od
) {
int n, d = 0;
const Bitmap* b = get_bitmap(asset_id_mask_img);
unsigned* mp;
int xoff = 0;
int mx = r->x + r->w / 2;
int my = (r->y + r->h) - f1;
mx -= tr->x;
my -= tr->y;
mx >>= fbits;
my >>= fbits;
if (mx < 0 || mx >= map_tile_size)
return 0;
if ((n = my - map_tile_size) >= 0 && n < 4)
my = map_tile_size - 1;
mp = (unsigned*)&b[1];
xoff = (t & 0xf) * map_tile_size;
if (my >= map_tile_size) return 0;
if (my < 0 || *vy < 0) goto up;
if (test_bit(mp, mx + xoff, my, b->w)) {
d = -1;
my = map_tile_size - 1;
} else {
up:
my = (r->y - tr->y) >> fbits;
if (my < 0) {
if (my >= -4) my = 0;
else return 0;
}
if (my >= map_tile_size) return 0;
if (test_bit(mp, mx + xoff, my, b->w)) d = 1;
my = 0;
}
if (!d) return 0;
if (d < 0 && *vy <= 0) return 0;
if (d > 0 && *vy >= 0) return 0;
for (
;
test_bit(mp, mx + xoff, my, b->w) &&
my >= 0 &&
my < map_tile_size;
my += d
);
if (d < 0) {
*y = (tr->y - (col->y + col->h));
*y += (my << fbits) + f1 * 2;
} else {
*y = (tr->y + tr->h) - col->y;
*y -= ((map_tile_size - my) << fbits);
}
*vy = 0;
*od = d;
return 1;
}
void update_body(
const struct Map* map,
int* x,
int* y,
int* vx,
int* vy,
int* grounded,
int* headbutted,
int* on_ramp,
const Rect* r
) {
Rect rect = { 0 };
int ramp = 0, d;
rect.w = r->w;
rect.h = r->h;
if (grounded[0] < 3) {
*vx = (*vx << fbits) / (f1 + player_friction);
}
grounded[0]++;
headbutted[0] = 0;
#define ittiles(expr) { \
int sx, sy, ex, ey, tx, ty; \
Rect tr; \
rect.x = *x + r->x; \
rect.y = *y + r->y; \
sx = (rect.x >> fbits) / map_tile_size; \
sy = (rect.y >> fbits) / map_tile_size; \
ex = ((rect.x + rect.w) >> fbits) / map_tile_size; \
ey = ((rect.y + rect.h) >> fbits) / map_tile_size; \
tr.w = map_tile_size << fbits; \
tr.h = map_tile_size << fbits; \
for (ty = sy; ty <= ey && ty < map_h; ty++) { \
for (tx = sx; tx <= ex && tx < map_w; tx++) { \
int tc = map->collision[tx + ty * map_w]; \
tr.x = (tx * map_tile_size) << fbits; \
tr.y = (ty * map_tile_size) << fbits; \
if (rects_overlap(&tr, &rect)) \
expr \
} \
}}
/* increase the gravity if i'm on a ramp, to
* smoothly slide down instead of skipping */
*vy += main_gravity + main_gravity_ramp * (*on_ramp && *grounded < 3);
if (*vy) {
*y += *vy;
ittiles({
if (tc > 1) {
int id = tc - 2;
if (solve_mask(
id,
y,
vy,
r,
&rect,
&tr,
&d
)) {
if (d < 0)
*grounded = 0;
else {
*headbutted = 1;
}
ramp = 1;
}
}
});
if (ramp) goto do_x;
ittiles({
if (tc == 1) {
if (*vy > 0) {
*y = tr.y - (r->y + r->h);
*vy = 0;
*grounded = 0;
} else if (*vy < 0) {
*y = (tr.y + tr.h) - r->y;
*vy = 0;
*headbutted = 1;
}
}
});
}
do_x:
*on_ramp = ramp;
if (*vx) {
*x += *vx;
if (ramp) {
/* Handle the case where the body is at the top
* of a ramp hitting into a block. */
ittiles({
if (tc == 1) {
int cy;
if (d < 0) cy = rect.y;
else cy = rect.y + rect.h;
if (*vx < 0 && point_rect_overlap(
&tr,
rect.x,
cy
)) *x = (tr.x + tr.w) - r->x;
if (*vx > 0 && point_rect_overlap(
&tr,
rect.x + rect.w,
cy
)) *x = tr.x - (r->x + r->w);
}
});
return;
}
ittiles({
if (tc == 1) {
if (*vx > 0) {
*x = tr.x - (r->x + r->w);
*vx = 0;
} else if (*vx < 0) {
*x = (tr.x + tr.w) - r->x;
*vx = 0;
}
}
});
}
}
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