Add directional sticky and skewer box variants

generic_skewer.lua

@@ -0,0 +1,89 @@
+require "entity"
+
+GenericSkewer = class("GenericSkewer", Entity)
+
+local edgeDirections = {
+	{x = 1, y = 0}, {x = -1, y = 0},
+	{x = 0, y = 1}, {x = 0, y = -1},
+}
+
+local function shapeHasCell(shape, x, y)
+	for _, cell in ipairs(shape) do
+		if cell.x == x and cell.y == y then return true end
+	end
+	return false
+end
+
+-- Draw two teeth on every exposed cell edge. The art remains synthetic: the
+-- underlying box sprite and its collision shape are still the authored base.
+function drawSkewerSprite(sprite, cellShape, x, y, scale)
+	cellShape = cellShape or {{x = 1, y = 1}}
+	local cellSize = 16 * scale
+	local inset = scale
+	local reach = 3 * scale
+	local halfBase = 1.5 * scale
+
+	for _, cell in ipairs(cellShape) do
+		local left = x + (cell.x - 1) * cellSize
+		local top = y + (cell.y - 1) * cellSize
+		for _, direction in ipairs(edgeDirections) do
+			if not shapeHasCell(cellShape, cell.x + direction.x, cell.y + direction.y) then
+				for _, along in ipairs({5, 11}) do
+					if direction.x ~= 0 then
+						local edgeX = direction.x > 0 and left + cellSize - inset or left + inset
+						local centerY = top + along * scale
+						love.graphics.polygon("fill",
+							edgeX, centerY - halfBase,
+							edgeX + direction.x * reach, centerY,
+							edgeX, centerY + halfBase
+						)
+					else
+						local edgeY = direction.y > 0 and top + cellSize - inset or top + inset
+						local centerX = left + along * scale
+						love.graphics.polygon("fill",
+							centerX - halfBase, edgeY,
+							centerX, edgeY + direction.y * reach,
+							centerX + halfBase, edgeY
+						)
+					end
+				end
+			end
+		end
+	end
+
+	love.graphics.draw(sprite, x, y, 0, scale, scale)
+end
+
+function GenericSkewer:initialize(x, y, color, sprite, name, cellShape)
+	Entity.initialize(self, {
+		name = name,
+		x = x,
+		y = y,
+		color = color,
+		collision = "moveable",
+		skewer = true,
+		sprite = sprite,
+		cellShape = cellShape
+	})
+end
+
+function GenericSkewer:update()
+
+end
+
+function GenericSkewer:draw(channel)
+	local sprite = self.sprites[channel]
+	if not sprite then return end
+	love.graphics.setColor(gColor[channel]:set())
+	local p = self:getDrawPos()
+	drawSkewerSprite(
+		sprite, self:getCellShape(),
+		p.x + self.drawOffset.x * drawScale,
+		p.y + self.drawOffset.y * drawScale,
+		drawScale
+	)
+end
+
+function GenericSkewer:tick()
+
+end