Converted VectorTest into project

prototypes/phystest.p8

@@ -0,0 +1,154 @@
+pico-8 cartridge // http://www.pico-8.com
+version 34
+__lua__
+pi=3.14159
+balls = 8
+ball_rad = 4
+
+function _init()
+	bullets = {}
+	collisions = {}
+	for i=1,balls do
+		bullets[i] = {id=i,coll=false,pos={x=rnd(127),y=rnd(127)},vel=normalize{x=rnd()-0.5,y=rnd()-0.5}}
+	end
+end
+
+function _update60()
+	for b in all(bullets) do
+		//grav(b,5)
+		move(b)
+		edgebounce(b)
+		handle_collisions(b)
+	end
+end
+
+function magnitude(v)
+	return sqrt(v.x^2 + v.y^2)
+end
+
+function normalize(v)
+	length = magnitude(v)
+	return {x=v.x/length,y=v.y/length}
+end
+
+function dot(v1,v2)
+ return v1.x*v2.x + v1.y*v2.y
+end
+
+function reflect(v,n)
+	n = normalize(n)
+	return vsub(scale(scale(n,dot(v,n)),2),v)
+end
+
+function bounce(v,n)
+	n = normalize(n)
+	return vadd(vmul(vmul(n,dot(v,n)),-2),v)
+end
+
+function vadd(v1,v2)
+	return {x=v1.x+v2.x,y=v1.y+v2.y}
+end
+
+function vsub(v1,v2)
+	return {x=v1.x-v2.x,y=v1.y-v2.y}
+end
+	
+function vmul(v,s)
+	return {x=v.x*s, y=v.y*s}
+end
+
+function vdiv(v,s)
+	return {x=v.x/s, y=v.y/s}
+end
+
+function vinv(v)
+ return {x=-v.x,y=-v.y}
+end
+
+function handle_collisions(b)
+	for t in all(bullets) do
+		if t.id != b.id then
+			diff = vsub(b.pos,t.pos)
+			if (magnitude(diff) < ball_rad*2) then
+ 			body_bounce(b,t)
+			end
+		end
+	end
+end
+
+function body_bounce(b1,b2)
+		diff = vsub(b1.pos,b2.pos)
+	 ndif = normalize(diff)
+		midp = vmul(vadd(b1.pos,b2.pos),0.5)		
+		
+		add_collision(midp)
+		
+		b1.pos = vadd(midp,vmul(ndif,ball_rad+0.5))
+ 	b2.pos = vsub(midp,vmul(ndif,ball_rad+0.5))
+
+		b1.vel = vsub(b1.vel,vmul(vsub(b1.pos,b2.pos),dot(vsub(b1.vel,b2.vel),vsub(b1.pos,b2.pos)),magnitude(vsub(b1.pos,b2.pos))^2))
+		b2.vel = vsub(b2.vel,vmul(vsub(b2.pos,b1.pos),dot(vsub(b2.vel,b1.vel),vsub(b2.pos,b1.pos)),magnitude(vsub(b2.pos,b1.pos))^2))
+end
+
+function add_collision(v)
+	add(collisions,v)
+	if(#collisions > 10) then
+		del(collisions, collisions[1])
+	end
+end
+
+function move(b)
+	b.pos.x += b.vel.x
+	b.pos.y += b.vel.y
+end
+
+function chaos(b, rate)
+	b.vel.x += rnd(rate) - rate/2
+	b.vel.y += rnd(rate) - rate/2
+end
+
+function edgebounce(b)
+	pos = b.pos
+	n = {x=0,y=0}
+	if (pos.x < 0) then
+	 b.pos.x = -pos.x
+	 n.x = 1
+	elseif (pos.x > 127) then
+		b.pos.x = 127 - (pos.x - 127)
+		n.x = -1
+	end
+	if (pos.y < 0) then
+		b.pos.y = -pos.y
+		n.y = 1
+	elseif (pos.y > 127) then
+		b.pos.y = 127 - (pos.y - 127)
+		n.y = -1
+	end
+	if (n.x != 0 or n.y != 0) then
+		n = normalize(n)
+		b.vel = bounce(b.vel, n)
+	end  
+end
+
+function grav(b, speed)
+	b.vel.y += speed/60
+end
+
+function _draw()
+	cls()
+	for c in all(collisions) do
+		circfill(c.x, c.y, 1, 10)
+	end
+	for b in all(bullets) do
+		circfill(b.pos.x, b.pos.y, ball_rad, 7)
+	end
+	//print(bullets[1].vel.x)
+	//print(bullets[1].vel.y)
+end
+__gfx__
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