basic water render and physics

1 files changed, 98 insertions, 0 deletions

diff --git a/liquid.lua b/liquid.lua
new file mode 100644
index 0000000..cdddb02
--- /dev/null
+++ b/liquid.lua
@@ -0,0 +1,98 @@
+local Liquid = {}
+Liquid.__index = Liquid
+
+local function buildWorldPolygonPoints(entity)
+    local points = {}
+
+    if not entity.polygon then
+        return points
+    end
+
+    for i, point in ipairs(entity.polygon) do
+        points[#points+1] = {
+            x = entity.x + point.x,
+            y = entity.y + point.y
+        }
+    end
+
+    return points
+end
+
+function Liquid:new(source)
+    local self = setmetatable({}, Liquid)
+    self.entity = source
+    self.x = source.x or 0
+    self.y = source.y or 0
+    self.width = source.width or 0
+    self.height = source.height or 0
+    self.shape = source.shape
+    self.polygon = source.polygon or {}
+    self.worldPolygon = buildWorldPolygonPoints(source)
+    self.properties = source.properties or {}
+    self.type = "liquid"
+    self.triangles = {}
+
+    local flat = {}
+    for _, p in ipairs(self.worldPolygon) do
+        table.insert(flat, p.x)
+        table.insert(flat, p.y)
+    end
+
+    if #flat >= 6 then
+        self.triangles = love.math.triangulate(flat)
+    end
+    return self
+end
+
+function Liquid:getWorldPolygon()
+    return self.worldPolygon
+end
+
+function Liquid:containsEntityFully(entity)
+    local corners = getEntityCorners(entity)
+
+    for _, c in ipairs(corners) do
+        if not self:containsPoint(c.x, c.y) then
+            return false
+        end
+    end
+
+    return true
+end
+
+function Liquid:containsPoint(px, py)
+    local points = self.worldPolygon
+    local count = #points
+    if count < 3 then return false end
+
+    local inside = false
+    local j = count
+    for i = 1, count do
+        local xi, yi = points[i].x, points[i].y
+        local xj, yj = points[j].x, points[j].y
+        local intersects = ((yi > py) ~= (yj > py))
+            and (px < (xj - xi) * (py - yi) / ((yj - yi) + 1e-9) + xi)
+        if intersects then
+            inside = not inside
+        end
+        j = i
+    end
+    return inside
+end
+
+function Liquid:containsEntity(entity)
+    if not entity then return false end
+    local ex = entity.x or 0
+    local ey = entity.y or 0
+    local ew = entity.width or 0
+    local eh = entity.height or 0
+
+    local sampleX = ex + ew * 0.5
+    local sampleY = ey + eh
+    return self:containsPoint(sampleX, sampleY)
+end
+
+function Liquid:update(dt)
+end
+
+return Liquid
\ No newline at end of file