gistfile1.txt

Vec2 = class(function(vec,x,y)
  vec.x = x
  vec.y = y
end)
function Vec2:set(v)
  self.x = v.x
  self.y = v.y
  return self
end
function Vec2:add(v)
  self.x = self.x + v.x;
  self.y = self.y + v.y;
  return self
end
function Vec2:add(v)
  self.x = self.x + v.x;
  self.y = self.y + v.y;
  return self
end
function Vec2.det(x1,y1, x2,y2)
  return x1*y2 - y1*x2
end
function Vec2:mult(s) -- by scalar
  self.x = self.x * s;
  self.y = self.y * s;
  return self
end
function Vec2:sub(v)
  self.x = self.x - v.x;
  self.y = self.y - v.y;
  return self
end
function Vec2:length()
  return math.sqrt(self.x*self.x + self.y * self.y)
end
function Vec2:normalize()
  length = math.sqrt(self.x*self.x + self.y*self.y)
  if length > 0 then
    self.x = self.x/length
    self.y = self.y/length
  else
    self.x = 0
    self.y = 0
  end
  return self
end
function Vec2:rotate(a)
  local px = self.x*math.cos(a) - self.y*math.sin(a)
  local py = self.x*math.sin(a) + self.y*math.cos(a)
  self.x, self.y = px, py
  return self
end
function Vec2:copy()
  return Vec2(self.x, self.y)
end
function Vec2:angle()
  return math.atan2(self.x, self.y)
end
function Vec2:distance(v)
  if not v then
    print(debug.traceback())
  end
  return math.sqrt((self.x-v.x)^2 + (self.y-v.y)^2)
end
function Vec2:distanceSq(v)
  if not v then
    print(debug.traceback())
  end
  return (self.x-v.x)^2 + (self.y-v.y)^2
end
function Vec2:distanceSq(v)
  if not v then
    print(debug.traceback())
  end
  return (self.x-v.x)^2 + (self.y-v.y)^2
end
function Vec2:__eq(b)
  return self.x == b.x and self.y == b.y
end

function Vec2:__tostring()
  return "Vector: " .. self.x .. ", " .. self.y
end

Line2d = class(function(line,x1,y1,x2,y2)
  line.v1 = Vec2(x1,y1)
  line.v2 = Vec2(x2,y2)
end)

-- http://www.angelfire.com/fl/houseofbartlett/solutions/lineinter2d.html
function Line2d:check_tri_clock_dir(v1,v2,v3)
  test = (((v2.x - v1.x)*(v3.y - v1.y)) - ((v3.x - v1.x)*(v2.y - v1.y)));
  if (test > 0) then return 0 -- counter clockwise
  elseif(test < 0) then return 1 -- clockwise
  else return 3 end -- line
end

function Line2d:check_intersection(l2)
  test1_a = self:check_tri_clock_dir(self.v1,self.v2,l2.v1)
  test1_b = self:check_tri_clock_dir(self.v1,self.v2,l2.v2)
  if(test1_a ~= test1_b) then  
    test2_a = self:check_tri_clock_dir(l2.v1,l2.v2,self.v1)
    test2_b = self:check_tri_clock_dir(l2.v1,l2.v2,self.v2)
    if(test2_a ~= test2_b) then
      return true
    end
  end
  return false
end

-- Rectangle Class
Rectangle = class(function(rect, x, y, w, h)
  rect.w = w
  rect.h = h
  rect.pos = Vec2(0,0)
  rect.x1 = 0
  rect.y1 = 0  
  rect.x2 = 0
  rect.y2 = 0  
  rect.red = 0;
  rect.green = 0;
  rect.blue = 0;
  rect.tint = {r=255, g=255, b=255, a=255}
  Rectangle.setPosition(rect, x, y)
  rect.layer = 0
end)

function Rectangle:setPosition(x,y)
-- added some type coersion
  self.pos.x = x+0
  self.pos.y = y+0
  self.x1 = x+0
  self.y1 = y+0
  self.x2 = x+self.w
  self.y2 = y+self.h
end

function Rectangle:setColor(r,g,b)
	self.red = r;
	self.green = g;
	self.blue = b;
  Object.setColor(self, r,g,b)
end
function Rectangle:sync()
end

function Rectangle:draw()
  -- draw the box
  local c = {self.pos.x, self.pos.y, self.w, self.h}
  local tl = {c[1], c[2]}
  local tr = {c[1]+c[3], c[2]}
  local bl = {c[1], c[2]+c[4]}
  local br = {c[1]+c[3], c[2]+c[4]}
  sheets["ui"]:addCornerTile(sprites["ui"]["white.png"], tl[1],tl[2], tr[1],tr[2], br[1],br[2], bl[1],bl[2], self.layer, self.tint.r, self.tint.g, self.tint.b, self.tint.a)
end
function Rectangle:drawDrop(s, color)
  -- draw the dropshadow
  local c = {self.pos.x, self.pos.y, self.w, self.h}
  local tl = {c[1], c[2]}
  local tr = {c[1]+c[3], c[2]}
  local bl = {c[1], c[2]+c[4]}
  local br = {c[1]+c[3], c[2]+c[4]}
  local h = s
  if not retina then h=h/2 end
  tl = {bl[1], bl[2]}
  tr = {br[1], br[2]}
  bl = {bl[1]+h/2, bl[2]+h}
  br = {br[1]-h/2, br[2]+h}
  sheets["ui"]:addCornerTile(sprites["ui"]["white.png"], tl[1],tl[2], tr[1],tr[2], br[1],br[2], bl[1],bl[2], self.layer, color.r,color.g,color.b,255)
  self:draw()
end
function Rectangle:drawTopDrop(h)
  local c = {self.pos.x, self.pos.y, self.w, self.h}
  local tl = {c[1], c[2]}
  local tr = {c[1]+c[3], c[2]}
  local bl = {c[1], c[2]+c[4]}
  local br = {c[1]+c[3], c[2]+c[4]}
  if not retina then h=h/2 end
  tl = {tl[1], tl[2]}
  tr = {tr[1], tr[2]}
  bl = {tl[1], tl[2]-h}
  br = {tr[1], tr[2]-h}
  sheet:addCornerTile(sprites["white.png"], tl[1],tl[2], tr[1],tr[2], br[1],br[2], bl[1],bl[2], self.layer, 159,155,140,255)
  self:draw()  
end

function Rectangle:drawOutline()
  -- tl to tr
  lb:addLine(self.pos.x, self.pos.y, self.pos.x+self.w, self.pos.y)
  -- tr to br
  lb:addLine(self.pos.x+self.w, self.pos.y, self.pos.x+self.w, self.pos.y+self.h)
  -- br to bl
  lb:addLine(self.pos.x+self.w, self.pos.y+self.h, self.pos.x, self.pos.y+self.h)
  -- bl to tl
  lb:addLine(self.pos.x, self.pos.y+self.h, self.pos.x, self.pos.y)
end
function Rectangle:doesPointTouch(v)
  if (v.x >= self.pos.x and v.x < self.pos.x+self.w) then
    if (v.y >= self.pos.y and v.y < self.pos.y+self.h) then
      return true
    end
  end
  return false
end
function Rectangle:doesRectangleTouch(r)
  return
    (r.pos.x + r.w > self.pos.x) and
    (r.pos.x < self.pos.x+self.w) and
    (r.pos.y + r.h > self.pos.y) and
    (r.pos.y < self.pos.y + self.h)
end
function Rectangle:whatSideDoesLineTouch(line, velocity)
  -- check the top and bottom intersections
  if velocity.y > 0 then
    side = Line2d(self.x1,self.y1,self.x2,self.y1)
    if(line:check_intersection(side)) then
      return 1
    end
  elseif velocity.y < 0 then
    side = Line2d(self.x1,self.y2,self.x2,self.y2)
    if(line:check_intersection(side)) then
      return 3
    end
  end 
  -- check the left and right intersections
  if velocity.x > 0 then
    side = Line2d(self.x1,self.y1,self.x1,self.y2)
    if(line:check_intersection(side)) then
      return 4
    end
  elseif velocity.x < 0 then
    side = Line2d(self.x2,self.y1,self.x2,self.y2)
    if(line:check_intersection(side)) then 
      return 2
    end
  end 
  return 0
end

-- returns if there is an intersection and the distance to the intersection
function Rectangle:raycast(o, d)
  local ox, oy = o.x, o.y
  local dx, dy = d.x, d.y
  local tx_min, ty_min, tx_max, ty_max
  local a = 1/dx
  local mMin = self.pos
  local mMax = Vec2(self.pos.x+self.w, self.pos.y+self.h)
  -- x intersection
  if a >= 0 then
    tx_min = (mMin.x-ox)*a;
    tx_max = (mMax.x-ox)*a;
  else
    tx_min = (mMax.x-ox)*a;
    tx_max = (mMin.x-ox)*a;
  end
  local b = 1/dy
  if b >= 0 then
    ty_min = (mMin.y-oy)*b;
    ty_max = (mMax.y-oy)*b;
  else
    ty_min = (mMax.y-oy)*b;
    ty_max = (mMin.y-oy)*b;
  end
  local t0 = math.max(tx_min, ty_min)
  local t1 = math.min(tx_max, ty_max)
  if t0 < t1 and t1 > 0 then
    return true, t0
  end
  return false
end

local a, b = {max={}, min={}}, {max={}, min={}}
local va, vb = Vec2(0,0), Vec2(0,0)
local u_0 = Vec2(0,0)
local u_1, displacement = Vec2(1, 1), Vec2(0,0)

-- tests if two moving rectangles intersect with each other, and if so at what point
function Rectangle:sweepTest(r2, r1Movement, r2Movement)
  a.max.x, a.min.x, a.max.y, a.min.y = self.pos.x+self.w, self.pos.x, self.pos.y+self.h, self.pos.y
  b.max.x, b.min.x, b.max.y, b.min.y = r2.pos.x+r2.w, r2.pos.x, r2.pos.y+r2.h, r2.pos.y
  va.x, vb.x = r1Movement.x, r1Movement.y
  vb.x, vb.y = r2Movement.x, r2Movement.y
  -- get the displacement from the perspective of the first box
  displacement.x, displacement.y = vb.x-va.x, vb.y-va.y
  u_0.x, u_0.y = 0,0
  u_1.x, u_1.y = 1, 1
  -- if the objects were overlapping at the start of the frame
  if (Object.overlap(self, r2)) then
    return true, 0, 0
  end
  -- check on each axis
  for i,v in ipairs({"x", "y"}) do
    if a.max[v]<b.min[v] and displacement[v]<0 then
      u_0[v] = (a.max[v] - b.min[v]) / displacement[v];
    elseif b.max[v]<a.min[v] and displacement[v]>0 then
      u_0[v] = (a.min[v] - b.max[v]) / displacement[v];
    end
    if b.max[v]>a.min[v] and displacement[v]<0 then
      u_1[v] = (a.min[v] - b.max[v]) / displacement[v];
    elseif a.max[v]>b.min[v] and displacement[v]>0 then
      u_1[v] = (a.max[v] - b.min[v]) / displacement[v];
    end
  end
  local u0 = math.max(u_0.x, u_0.y)
  local u1 = math.min(u_1.x, u_1.y)
  return u0<=u1, u0, u1
end