diff options
Diffstat (limited to 'collision.c')
| -rw-r--r-- | collision.c | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/collision.c b/collision.c index 3890f66..1fa083b 100644 --- a/collision.c +++ b/collision.c @@ -1,5 +1,9 @@ #include "balls.h" +static int clamp(int v, int lo, int hi); +static int min(int a, int b); +static int max(int a, int b); + int iscollision(Point p, Point q) { int dx, dy; @@ -8,3 +12,57 @@ iscollision(Point p, Point q) { dy = p.y - q.y; return (dx*dx + dy*dy) <= 4*RADIUS*RADIUS; } + +void +collideball(Ball *b1, const Ball *b2) { + Point midpoint; + Vec d, n; + double magnitude; + + if (!iscollision(b1->p, b2->p)) + return; + midpoint = divpt(addpt(b1->p, b2->p), 2); + d = Vpt(b2->p, b1->p); + b1->p = ptaddv(midpoint, vmuls(unitnorm(d), RADIUS)); + + printf("collision (%d,%d), (%d,%d)\n", b1->p.x, b1->p.y, b2->p.x, b2->p.y); + + printf("oldv: (%2.2f,%2.2f\n", b1->v.x, b1->v.y); + + n = unitnorm(Vpt(b2->p, b1->p)); + magnitude = 2*(vdot(b1->v, n) - vdot(b2->v, n)) / (b1->m + b2->m); + + printf("n: (%2.2f,%2.2f), magnitude: %2.2f\n", n.x, n.y, magnitude); + + b1->v = vsub(b1->v, vmuls(n, magnitude * b1->m)); + + printf("newv: (%2.2f,%2.2f)\n", b1->v.x, b1->v.y); +} + +void +collidewall(Ball *b, Rectangle wall) { + if (b->p.x < wall.min.x+RADIUS || b->p.x > wall.max.x-RADIUS) { + b->p.x = clamp(b->p.x, wall.min.x+RADIUS, wall.max.x-RADIUS); + printf("clamped to %d\n", b->p.x); + b->v.x = -b->v.x; + } + if (b->p.y < wall.min.y+RADIUS || b->p.y > wall.max.y-RADIUS) { + b->p.y = clamp(b->p.y, wall.min.y+RADIUS, wall.max.y-RADIUS); + b->v.y = -b->v.y; + } +} + +static int +clamp(int v, int lo, int hi) { + return min(hi, max(v, lo)); +} + +static int +min(int a, int b) { + return (a < b) ? a : b; +} + +static int +max(int a, int b) { + return (a > b) ? a : b; +}
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