refactor: use Body object

- Body defines an object's size and shape
- Body provides a universal function to detect collision

1 files changed, 49 insertions, 0 deletions

diff --git a/objects/Body.lua b/objects/Body.lua
new file mode 100644
index 0000000..72dbbe5
--- /dev/null
+++ b/objects/Body.lua
@@ -0,0 +1,49 @@
+Body = {}
+Body.__index = Body
+
+function Body:new(shape, sizeA, sizeB, sizeC)
+    local obj = {
+        shape = shape,
+        r = (shape == "circle" and sizeA or nil),
+        w = (shape == "rectangle" and sizeA or nil),
+        h = (shape == "rectangle" and sizeB or nil)
+    }
+
+    setmetatable(obj, Body)
+
+    return obj
+end
+
+function Body:collide(other, x1, y1, x2, y2)
+    if self.shape == "circle" and other.shape == "circle" then
+        -- circle to circle
+        local dx = x2 - x1
+        local dy = y2 - y1
+        local distance = math.sqrt(dx * dx + dy * dy)
+        return distance < (self.r + other.r)
+    elseif self.shape == "rectangle" and other.shape == "rectangle" then
+        -- rect to rect
+        return x1 < x2 + other.w and x1 + self.w > x2 and y1 < y2 + other.h and y1 + self.h > y2
+    elseif self.shape == "circle" and other.shape == "rectangle" then
+        -- circle to rect
+        local closestX = math.max(x2, math.min(x1, x2 + other.w))
+        local closestY = math.max(y2, math.min(y1, y2 + other.h))
+        local dx = x1 - closestX
+        local dy = y1 - closestY
+        return (dx * dx + dy * dy) < (self.r * self.r)
+    elseif self.shape == "rectangle" and other.shape == "circle" then
+        return other:collide(self, x2, y2, x1, y1)
+    end
+
+    return false
+end
+
+function Body:draw(x, y)
+    if self.shape == "circle" then
+        -- 绘制圆形
+        love.graphics.circle("fill", x, y, self.r)
+    elseif self.shape == "rectangle" then
+        -- 绘制矩形
+        love.graphics.rectangle("fill", x - self.w / 2, y - self.h / 2, self.w, self.h)
+    end
+end