init: tool for graphing functions and slope fields in love2d

2026-10-11 23:03:35 -04:00
parent 0bae59383e
commit db61937809
4 changed files with 243 additions and 0 deletions
@@ -0,0 +1,56 @@
+local function getPixelPosition(point, minPoint, maxPoint, drawBounds)
+    if
+        point[1] < minPoint[1]
+        or point[1] > maxPoint[1]
+        or point[2] < minPoint[2]
+        or point[2] > maxPoint[2]
+    then
+        error("Point ("..point[1]..", "..point[2]..") outside the bounds ("
+            ..minPoint[1]..", "..minPoint[2]..") to ("..maxPoint[1]..", "..maxPoint[2]..")")
+    end
+    local pointBound = {maxPoint[1] - minPoint[1], maxPoint[2] - minPoint[2]}
+    local pointOffset = {point[1] - minPoint[1], -point[2] - minPoint[2]}
+    local position = {
+        (pointOffset[1] / pointBound[1]) * drawBounds.width + drawBounds.x,
+        (pointOffset[2] / pointBound[2]) * drawBounds.height + drawBounds.y
+    }
+    return position[1], position[2]
+end
+
+function GraphFunction(x, y, width, height, func)
+    local points = {}
+    local origin = {x = (width + x) / 2, y = (height + y) / 2}
+    local neg_x, neg_y = -math.floor(origin.x), -math.floor(origin.y)
+    local pos_x, pos_y = math.floor(origin.x), math.floor(origin.y)
+    for i = neg_x, pos_x, 1 do
+        local j = math.floor(func(i))
+        if j > neg_y and j < pos_y then
+            local k, l = getPixelPosition({i,j}, {neg_x,neg_y}, {pos_x,pos_y},
+                {x=x,y=x,width=width,height=height})
+            table.insert(points, k)
+            table.insert(points, l)
+        end
+    end
+    return points
+end
+
+function GetLineFromSlope(midpoint, slope, length, color)
+    color = color or {1, 1, 1}
+    local delta_x, delta_y
+    if slope == nil then
+        delta_x, delta_y = 0, length
+    else
+        delta_x = math.sqrt((length ^ 2) / (1 + slope ^ 2))
+        delta_y = -(slope * delta_x)
+    end
+    local x1 = midpoint.x - delta_x / 2
+    local y1 = midpoint.y - delta_y / 2
+    local x2 = x1 + delta_x
+    local y2 = y1 + delta_y
+    return {
+        p1 = {x = x1, y = y1},
+        p2 = {x = x2, y = y2},
+        midpoint = midpoint,
+        color = color
+    }
+end