automated snapshot

sierpinski.go

@@ -0,0 +1,35 @@
+package main
+
+import (
+	rl "github.com/gen2brain/raylib-go/raylib"
+)
+
+type SierpinskiArrow struct{}
+
+func (s *SierpinskiArrow) Draw(ctx *RenderCtx) {
+	sierpinskiArrow(ctx, int(ctx.Ports["sierpinskiArrowDepth"]), ctx.Ports["sierpinskiArrowLength"])
+}
+
+func sierpinskiArrow(ctx *RenderCtx, order int, length float64) {
+	if order == 0 {
+		curve(ctx, order, length, ctx.Ports["sierpinskiArrowAngle"])
+	} else {
+		rl.Rotatef(float32(ctx.Ports["sierpinskiArrowAngle"]), 0, 0, 1)
+		curve(ctx, order, length, -ctx.Ports["sierpinskiArrowAngle"])
+	}
+}
+
+func curve(ctx *RenderCtx, order int, length float64, angle float64) {
+	if order == 0 {
+		len := int32(length)
+		rl.DrawLine(0, 0, len, 0, rl.Black)
+		rl.Translatef(float32(length), 0, 0)
+	} else {
+		curve(ctx, order-1, length/2, -angle)
+		rl.Rotatef(float32(angle), 0, 0, 1)
+		curve(ctx, order-1, length/2, angle)
+		rl.Rotatef(float32(angle), 0, 0, 1)
+		curve(ctx, order-1, length/2, -angle)
+	}
+}
+