X-Git-Url: https://jasonwoof.com/gitweb/?p=vor.git;a=blobdiff_plain;f=sprite.c;h=19055106dfe28d7765d9ebce30cdaf0b5b9a7701;hp=38dae30fc504afa41b5346cd963734a5625eec13;hb=e9eaa65259d7c35d5a9b08aba9016145fa8f118d;hpb=5c8f059629c2127848ce4051296d2f5897bf5c0f

diff --git a/sprite.c b/sprite.c
index 38dae30..1905510 100644
--- a/sprite.c
+++ b/sprite.c
@@ -1,3 +1,4 @@
+#include <math.h>
 #include <stdlib.h>
 #include <string.h>
 #include "config.h"
@@ -32,6 +33,7 @@ get_shape(Sprite *s)
 	uint16_t *px, transp;
 	uint32_t bits = 0, bit, *p;
 
+	s->area = 0;
 	if(s->image->format->BytesPerPixel != 2) {
 		fprintf(stderr, "get_shape(): not a 16-bit image!\n");
 		exit(1);
@@ -54,7 +56,7 @@ get_shape(Sprite *s)
 		bit = 0;
 		for(x=0; x<s->image->w; x++) {
 			if(!bit) { bits = 0; bit = 0x80000000; }
-			if(*px++ != transp) { bits |= bit; }
+			if(*px++ != transp) { bits |= bit; s->area++; }
 			bit >>= 1;
 			if(!bit || x == s->image->w - 1) { *(p++) = bits; }
 		}
@@ -196,6 +198,8 @@ collide(Sprite *a, Sprite *b)
 {
 	int dx, dy, xov, yov;
 
+	if(a->type < 0 || b->type < 0) return false;
+
 	if(b->x < a->x) { Sprite *tmp = a; a = b; b = tmp; }
 
 	dx = b->x - a->x;
@@ -204,26 +208,37 @@ collide(Sprite *a, Sprite *b)
 	xov = max(min(a->w - dx, b->w), 0);
 
 	if(dy >= 0) yov = max(min(a->h - dy, b->h), 0);
-	else yov = -max(min(a->h - -dy, b->h), 0);
+	else yov = -max(min(b->h - -dy, a->h), 0);
 
 	if(xov == 0 || yov == 0) return false;
 	else return mask_collide(xov, yov, a, b);
 }
 
-int
+void
+collisions(void)
+{
+	int i;
+	Sprite *a, *b;
+	for(i=0; i<gw*gh; i++)
+		for(a=sprites[set][i]; a; a=a->next)
+			for(b=a->next; b; b=b->next)
+				if(collide(a, b)) do_collision(a, b);
+}
+
+Sprite *
 hit_in_square(Sprite *r, Sprite *s)
 {
-	for(; r; r=r->next) {
-		if(collide(r, s)) return true;
-	}
-	return false;
+	for(; r; r=r->next)
+		if(collide(r, s)) break;
+	return r;
 }
 
-int
+Sprite *
 collides(Sprite *s)
 {
 	int l, r, t, b;
 	Sprite **sq;
+	Sprite *c;
 
 	l = (s->x + grid_size) / grid_size;
 	r = (s->x + s->w + grid_size) / grid_size;
@@ -231,21 +246,21 @@ collides(Sprite *s)
 	b = (s->y + s->h + grid_size) / grid_size;
 	sq = &sprites[set][l + t*gw];
 
-	if(hit_in_square(*sq, s)) return true;
-	if(l > 0 && hit_in_square(*(sq-1), s)) return true;
-	if(t > 0 && hit_in_square(*(sq-gw), s)) return true;
-	if(l > 0 && t > 0 && hit_in_square(*(sq-1-gw), s)) return true;
+	if((c = hit_in_square(*sq, s))) return c;
+	if(l > 0 && (c = hit_in_square(*(sq-1), s))) return c;
+	if(t > 0 && (c = hit_in_square(*(sq-gw), s))) return c;
+	if(l > 0 && t > 0 && (c = hit_in_square(*(sq-1-gw), s))) return c;
 
 	if(r > l) {
-		if(hit_in_square(*(sq+1), s)) return true;
-		if(t > 0 && hit_in_square(*(sq+1-gw), s)) return true;
+		if((c = hit_in_square(*(sq+1), s))) return c;
+		if(t > 0 && hit_in_square(*(sq+1-gw), s)) return c;
 	}
 	if(b > t) {
-		if(hit_in_square(*(sq+gw), s)) return true;
-		if(l > 0 && hit_in_square(*(sq-1+gw), s)) return true;
+		if((c = hit_in_square(*(sq+gw), s))) return c;
+		if(l > 0 && (c = hit_in_square(*(sq-1+gw), s))) return c;
 	}
-	if(r > l && b > t && hit_in_square(*(sq+1+gw), s)) return true;
-	return false;
+	if(r > l && b > t && (c = hit_in_square(*(sq+1+gw), s))) return c;
+	return NULL;
 }
 
 int
@@ -283,3 +298,36 @@ pixel_collides(float x, float y)
 	if(l > 0 && t > 0 && pixel_hit_in_square(*(sq-1-gw), x, y)) return true;
 	return false;
 }
+
+
+static float
+sprite_mass(Sprite *s)
+{
+	if(s->type == SHIP) return s->area;
+	else if(s->type == ROCK) return 3*s->area;
+	else return 0;
+}
+
+void
+bounce(Sprite *a, Sprite *b)
+{
+	float x, y, n;
+	float va, vb;
+	float ma, mb, mr;
+
+	// (x, y) is unit vector pointing from A's center to B's center.
+	x = (b->x + b->w / 2) - (a->x + a->w / 2);
+	y = (b->y + b->h / 2) - (a->y + a->h / 2);
+	n = sqrt(x*x + y*y); x /= n; y /= n;
+
+	// velocities along (x, y), or 0 if already moving away.
+	va = max(x*a->dx + y*a->dy, 0);
+	vb = min(x*b->dx + y*b->dy, 0);
+
+	// mass ratio
+	ma = sprite_mass(a); mb = sprite_mass(b);
+	if(ma && mb) mr = mb/ma; else mr = 1;
+
+	a->dx += x*(mb*vb - ma*va)/ma; a->dy += y*(mb*vb - ma*va)/ma;
+	b->dx += x*(ma*va - mb*vb)/mb; b->dy += y*(ma*va - mb*vb)/mb;
+}