/ld27

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bzr branch http://9ix.org/bzr/ld27
25 by Josh C
overhaul collision and physics to fix an annoying collision resolution
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-- monkey patches for zoetrope Sprite
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-- displace on a specific axis
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function Sprite:displaceDir(other, dir)
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   if not self.solid or self == other or not other.solid then return end
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   if STRICT then assert(other:instanceOf(Sprite), 'asked to displace a non-sprite') end
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   if other.sprites then
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      -- handle groups
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      for _, spr in pairs(other.sprites) do
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         self:displace(spr, dir)
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      end
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   else
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      -- handle sprites
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      local dim = util.dim(dir)
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      local negMove = (other[dir] - self[dir]) + other[dim]
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      local posMove = (self[dir] + self[dim]) - other[dir]
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      -- TODO: re-add hinting?
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      if negMove < posMove then
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         chg = - negMove
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      else
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         chg = posMove
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      end
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   end
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   other[dir] = other[dir] + chg
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end
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-- don't use zoetrope physics
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function Sprite:update(elapsed)
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   self:doPhysics('x', elapsed)
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   self:doPhysics('y', elapsed)
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   self:doPhysics('rotation', elapsed)
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   if self.onUpdate then self:onUpdate(elapsed) end
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end
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-- directional physics
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function Sprite:doPhysics(dir, elapsed)
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   local vel = self.velocity
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   local acc = self.acceleration
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   local drag = self.drag
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   local minVel = self.minVelocity
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   local maxVel = self.maxVelocity
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   -- check existence of properties
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   if STRICT then
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      assert(vel, 'active sprite has no velocity property')
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      assert(acc, 'active sprite has no acceleration property')
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      assert(drag, 'active sprite has no drag property')
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      assert(minVel, 'active sprite has no minVelocity property')
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      assert(maxVel, 'active sprite has no maxVelocity property')
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      assert(dir=='x' or dir=='y' or dir=='rotation', 'direction should be x, y, or rotation')
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   end
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   vel.x = vel.x or 0
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   vel.y = vel.y or 0
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   vel.rotation = vel.rotation or 0
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   -- physics
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   if acc[dir] and acc[dir] ~= 0 then
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      vel[dir] = vel[dir] + acc[dir] * elapsed
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   else
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      if drag[dir] then
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         if vel[dir] > 0 then
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            vel[dir] = vel[dir] - drag[dir] * elapsed
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            if vel[dir] < 0 then vel[dir] = 0 end
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         elseif vel[dir] < 0 then
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            vel[dir] = vel[dir] + drag[dir] * elapsed
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            if vel[dir] > 0 then vel[dir] = 0 end
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         end
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      end
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   end
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   if minVel[dir] and vel[dir] < minVel[dir] then vel[dir] = minVel[dir] end
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   if maxVel[dir] and vel[dir] > maxVel[dir] then vel[dir] = maxVel[dir] end
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   -- ugly hack for falling through floor on really slow frames
26 by Josh C
correct tile size for slow frame hack
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   if math.abs(vel[dir] * elapsed) > 16 then
25 by Josh C
overhaul collision and physics to fix an annoying collision resolution
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      print('skip')
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      return
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   end
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   if vel[dir] ~= 0 then self[dir] = self[dir] + vel[dir] * elapsed end
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27 by Josh C
title screen
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   if the.activeMaze and (dir == 'x' or dir == 'y') then -- doesn't make sense for rotation
25 by Josh C
overhaul collision and physics to fix an annoying collision resolution
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      if self[dir] < 0 then self[dir] = 0 end
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      local edge = the.activeMaze[util.dim(dir)] - the.player[util.dim(dir)]
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      -- TODO: take map position into account
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      if self[dir] > edge then self[dir] = edge end
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   end
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end