added square euclidean at the dismay of many theoretical mathematicians (it's inadmissible) (but it's really fast)

astar.go

@@ -0,0 +1,266 @@
+package main
+
+import (
+	"container/heap"
+	"fmt"
+	"math"
+	"time"
+)
+
+type Item struct {
+	index    int     // index of the cell in the grid (y * width + x)
+	priority float32 // f = g + h
+	gScore   float32 // used to break f ties toward straighter paths
+}
+
+type PriorityQueue []*Item
+
+func (pq PriorityQueue) Len() int {
+	return len(pq)
+}
+
+func (pq PriorityQueue) Less(i, j int) bool {
+	if pq[i].priority != pq[j].priority {
+		return pq[i].priority < pq[j].priority
+	}
+	// Same f: prefer larger g (smaller h → closer to goal) for cleaner grid paths.
+	return pq[i].gScore > pq[j].gScore
+}
+
+func (pq PriorityQueue) Swap(i, j int) {
+	pq[i], pq[j] = pq[j], pq[i]
+}
+
+func (pq *PriorityQueue) Push(x interface{}) {
+	*pq = append(*pq, x.(*Item))
+}
+
+func (pq *PriorityQueue) Pop() interface{} {
+	old := *pq
+	n := len(old)
+	item := old[n-1]
+	old[n-1] = nil
+	*pq = old[0 : n-1]
+	return item
+}
+
+type AStar struct {
+	gridTypes []byte
+	gScores   []float32
+	parents   []byte
+	openSet   PriorityQueue
+	closedSet []bool
+	width     int
+	height    int
+	heuristic func(x int, y int, endX int, endY int) float32
+	timeTaken time.Duration
+}
+
+func (a *AStar) Init(width int, height int) {
+	a.gridTypes = make([]byte, width*height)
+	a.gScores = make([]float32, width*height)
+	a.parents = make([]byte, width*height)
+	a.openSet = make(PriorityQueue, 0, 2000000) // pre-allocate space for 2 million cells to avoid reallocations
+	a.closedSet = make([]bool, width*height)
+	a.heuristic = func(x int, y int, endX int, endY int) float32 {
+		return float32(math.Abs(float64(x-endX)) + math.Abs(float64(y-endY))) // Manhattan distance default
+	}
+	a.width = width
+	a.height = height
+
+	for i := range a.gScores {
+		a.gScores[i] = math.MaxFloat32
+	}
+}
+
+func (a *AStar) ResetGrid(withTypes bool) {
+	for i := range a.gScores {
+		if withTypes {
+			a.gridTypes[i] = 0
+		}
+		a.gScores[i] = math.MaxFloat32
+		a.parents[i] = 0
+		a.closedSet[i] = false
+	}
+	a.openSet = a.openSet[:0]
+}
+
+func (a *AStar) RebuildGrid(width int, height int) {
+	a.gridTypes = make([]byte, width*height)
+	a.gScores = make([]float32, width*height)
+	a.parents = make([]byte, width*height)
+	a.openSet = make(PriorityQueue, 0, 2000000)
+	a.closedSet = make([]bool, width*height)
+	a.width = width
+	a.height = height
+}
+
+func (a *AStar) SetHeuristic(heuristic int32) {
+	switch heuristic {
+	case 0:
+		a.heuristic = func(x int, y int, endX int, endY int) float32 {
+			return float32(math.Abs(float64(x-endX)) + math.Abs(float64(y-endY))) // Manhattan distance
+		}
+	case 1:
+		a.heuristic = func(x int, y int, endX int, endY int) float32 {
+			return float32(math.Sqrt(float64(x-endX)*float64(x-endX) + float64(y-endY)*float64(y-endY))) // Euclidean distance
+		}
+	case 2:
+		a.heuristic = func(x int, y int, endX int, endY int) float32 {
+			return float32(math.Max(float64(x-endX), float64(y-endY))) // Chebyshev distance
+		}
+	case 3:
+		a.heuristic = func(x int, y int, endX int, endY int) float32 {
+			return float32(math.Pow(float64(x-endX), 2) + math.Pow(float64(y-endY), 2)) // Squared Euclidean (extremely fast but not optimal/inadmissible)
+		}
+	}
+}
+
+func (a *AStar) SetGridType(x int, y int, gridType byte) {
+	/*
+		0 = empty
+		1 = wall
+		2 = start
+		3 = end
+	*/
+	a.gridTypes[y*a.width+x] = gridType
+}
+
+func (a *AStar) GetGridType(x int, y int) byte {
+	return a.gridTypes[y*a.width+x]
+}
+
+func (a *AStar) GetGridTypes() []byte {
+	return a.gridTypes
+}
+
+func (a *AStar) GetClosedSet() []bool {
+	return a.closedSet
+}
+
+func (a *AStar) SetGScores(x int, y int, gScore float32) {
+	a.gScores[y*a.width+x] = gScore
+}
+
+func (a *AStar) GetGScores(x int, y int) float32 {
+	return a.gScores[y*a.width+x]
+}
+
+func (a *AStar) SetParent(x int, y int, parentx int, parenty int) {
+	if parentx < x {
+		a.parents[y*a.width+x] = byte(0) // left of the node
+	} else if parentx > x {
+		a.parents[y*a.width+x] = byte(2) // right of the node
+	} else if parenty < y {
+		a.parents[y*a.width+x] = byte(1) // above the node
+	} else if parenty > y {
+		a.parents[y*a.width+x] = byte(3) // below the node
+	}
+}
+
+func (a *AStar) GetParent(x int, y int) byte {
+	return a.parents[y*a.width+x]
+}
+
+func (a *AStar) ParentIndexToXY(childx int, childy int, parent byte) (int, int) {
+	if parent == 0 {
+		return childx - 1, childy // parent left
+	} else if parent == 1 {
+		return childx, childy - 1 // parent above
+	} else if parent == 2 {
+		return childx + 1, childy // parent right
+	} else if parent == 3 {
+		return childx, childy + 1 // parent below
+	}
+	return childx, childy
+}
+
+func (a *AStar) ParentIndexToXYIndex(childx int, childy int, parent byte) int {
+	x, y := a.ParentIndexToXY(childx, childy, parent)
+	return y*a.width + x
+}
+
+func (a *AStar) GetNeighbors(x int, y int) []int {
+	neighbors := make([]int, 0)
+	if x > 0 {
+		neighbors = append(neighbors, y*a.width+x-1)
+	}
+	if x < a.width-1 {
+		neighbors = append(neighbors, y*a.width+x+1)
+	}
+	if y > 0 {
+		neighbors = append(neighbors, y*a.width+x-a.width)
+	}
+	if y < a.height-1 {
+		neighbors = append(neighbors, y*a.width+x+a.width)
+	}
+	return neighbors
+}
+
+func (a *AStar) GetTerrainCost(x int, y int) float32 {
+	return 1.0
+}
+
+func (a *AStar) GetEvaluatedCells() int {
+	cellsEvaluated := 0
+	for _, closed := range a.closedSet {
+		if closed {
+			cellsEvaluated++
+		}
+	}
+	return cellsEvaluated
+}
+
+func (a *AStar) GetTimeTaken() time.Duration {
+	return a.timeTaken
+}
+
+func (a *AStar) CalculatePath(startX int, startY int, endX int, endY int) [][]int {
+	timer := time.Now()
+	defer func() {
+		a.timeTaken = time.Since(timer)
+	}()
+	startIndex := startY*a.width + startX
+	endIndex := endY*a.width + endX
+	a.gScores[startIndex] = 0
+	startF := a.heuristic(startX, startY, endX, endY)
+	heap.Push(&a.openSet, &Item{index: startIndex, priority: startF, gScore: 0})
+
+	for a.openSet.Len() > 0 {
+		current := heap.Pop(&a.openSet).(*Item)
+		if a.closedSet[current.index] {
+			continue
+		}
+		if current.index == endIndex {
+			// We've found the goal!
+			fmt.Println("Found the goal!")
+			path := make([][]int, 0)
+			for currentIndex := current.index; currentIndex != startIndex; currentIndex = a.ParentIndexToXYIndex(currentIndex%a.width, currentIndex/a.width, a.parents[currentIndex]) {
+				x, y := a.ParentIndexToXY(currentIndex%a.width, currentIndex/a.width, a.parents[currentIndex])
+				path = append(path, []int{x, y})
+			}
+			return path
+		}
+
+		a.closedSet[current.index] = true
+
+		for _, neighborIndex := range a.GetNeighbors(current.index%a.width, current.index/a.width) {
+			if a.closedSet[neighborIndex] {
+				continue
+			}
+			if a.gridTypes[neighborIndex] == 1 {
+				a.gScores[neighborIndex] = math.MaxFloat32
+				continue
+			}
+			terrainCost := a.GetTerrainCost(neighborIndex%a.width, neighborIndex/a.width)
+			tentativeGScore := a.gScores[current.index] + terrainCost
+			if tentativeGScore < a.gScores[neighborIndex] {
+				a.SetParent(neighborIndex%a.width, neighborIndex/a.width, current.index%a.width, current.index/a.width)
+				a.gScores[neighborIndex] = tentativeGScore
+				priority := tentativeGScore + a.heuristic(neighborIndex%a.width, neighborIndex/a.width, endX, endY)
+				heap.Push(&a.openSet, &Item{index: neighborIndex, priority: priority, gScore: tentativeGScore})
+			}
+		}
+	}
+	return make([][]int, 0)
+}

main.go

@@ -1,7 +1,11 @@
 package main
 
 import (
+	"image/color"
+	"math"
 	"strconv"
+	"strings"
+	"unsafe"
 
 	rg "github.com/gen2brain/raylib-go/raygui"
 	rl "github.com/gen2brain/raylib-go/raylib"
@@ -11,6 +15,219 @@ func canvasMouse() rl.Vector2 {
 	return rl.GetMousePosition()
 }
 
+// Keeps GPU texture uploads in sync with mapImage edits. Full uploads are used after
+// path rebuilds; edits use bounding boxes via UpdateTextureRec.
+type texSync struct {
+	needUpload bool
+	uploadFull bool
+	partialOk  bool
+	x0, y0     int
+	x1, y1     int
+	rectBuf    []color.RGBA
+}
+
+func absInt(v int) int {
+	if v < 0 {
+		return -v
+	}
+	return v
+}
+
+func (t *texSync) markFull() {
+	t.needUpload = true
+	t.uploadFull = true
+}
+
+func (t *texSync) markRegion(minX, minY, maxX, maxY, gridW, gridH int) {
+	if minX > maxX {
+		minX, maxX = maxX, minX
+	}
+	if minY > maxY {
+		minY, maxY = maxY, minY
+	}
+	if minX < 0 {
+		minX = 0
+	}
+	if minY < 0 {
+		minY = 0
+	}
+	if maxX >= gridW {
+		maxX = gridW - 1
+	}
+	if maxY >= gridH {
+		maxY = gridH - 1
+	}
+	if minX > maxX || minY > maxY {
+		return
+	}
+	t.needUpload = true
+	if t.uploadFull {
+		return
+	}
+	if !t.partialOk {
+		t.partialOk = true
+		t.x0, t.y0 = minX, minY
+		t.x1, t.y1 = maxX, maxY
+		return
+	}
+	if minX < t.x0 {
+		t.x0 = minX
+	}
+	if minY < t.y0 {
+		t.y0 = minY
+	}
+	if maxX > t.x1 {
+		t.x1 = maxX
+	}
+	if maxY > t.y1 {
+		t.y1 = maxY
+	}
+}
+
+func (t *texSync) flush(img *rl.Image, tex *rl.Texture2D, gridW, gridH int) {
+	if !t.needUpload {
+		return
+	}
+	if t.uploadFull {
+		ptr := (*color.RGBA)(unsafe.Pointer(img.Data))
+		pixels := unsafe.Slice(ptr, gridW*gridH)
+		rl.UpdateTexture(*tex, pixels)
+		t.uploadFull = false
+		t.partialOk = false
+	} else if t.partialOk {
+		w := t.x1 - t.x0 + 1
+		h := t.y1 - t.y0 + 1
+		n := w * h
+		if cap(t.rectBuf) < n {
+			t.rectBuf = make([]color.RGBA, n)
+		} else {
+			t.rectBuf = t.rectBuf[:n]
+		}
+		ptr := (*color.RGBA)(unsafe.Pointer(img.Data))
+		full := unsafe.Slice(ptr, gridW*gridH)
+		for row := 0; row < h; row++ {
+			src := (t.y0+row)*gridW + t.x0
+			copy(t.rectBuf[row*w:], full[src:src+w])
+		}
+		rec := rl.NewRectangle(float32(t.x0), float32(t.y0), float32(w), float32(h))
+		rl.UpdateTextureRec(*tex, rec, t.rectBuf)
+		t.partialOk = false
+	}
+	t.needUpload = false
+}
+
+// paintWallLine updates both mapImage and the A* grid for every grid cell crossed by the segment.
+func paintWallLine(a *AStar, mapImage *rl.Image, x0, y0, x1, y1, gridW, gridH int, col color.RGBA, tex *texSync) {
+	minX := x0
+	if x1 < minX {
+		minX = x1
+	}
+	maxX := x0
+	if x1 > maxX {
+		maxX = x1
+	}
+	minY := y0
+	if y1 < minY {
+		minY = y1
+	}
+	maxY := y0
+	if y1 > maxY {
+		maxY = y1
+	}
+	tex.markRegion(minX, minY, maxX, maxY, gridW, gridH)
+
+	dx := absInt(x1 - x0)
+	dy := -absInt(y1 - y0)
+	sx := 1
+	sy := 1
+	if x0 > x1 {
+		sx = -1
+	}
+	if y0 > y1 {
+		sy = -1
+	}
+	err := dx + dy
+
+	for {
+		if x0 >= 0 && x0 < gridW && y0 >= 0 && y0 < gridH {
+			switch a.GetGridType(x0, y0) {
+			case 2, 3: // start / end
+			default:
+				rl.ImageDrawPixel(mapImage, int32(x0), int32(y0), col)
+				a.SetGridType(x0, y0, 1)
+			}
+		}
+		if x0 == x1 && y0 == y1 {
+			break
+		}
+		e2 := 2 * err
+		if e2 >= dy {
+			err += dy
+			x0 += sx
+		}
+		if e2 <= dx {
+			err += dx
+			y0 += sy
+		}
+	}
+}
+
+// paintEraseLine clears wall cells along the segment (same grid traversal as paintWallLine).
+func paintEraseLine(a *AStar, mapImage *rl.Image, x0, y0, x1, y1, gridW, gridH int, empty color.RGBA, tex *texSync) {
+	minX := x0
+	if x1 < minX {
+		minX = x1
+	}
+	maxX := x0
+	if x1 > maxX {
+		maxX = x1
+	}
+	minY := y0
+	if y1 < minY {
+		minY = y1
+	}
+	maxY := y0
+	if y1 > maxY {
+		maxY = y1
+	}
+	tex.markRegion(minX, minY, maxX, maxY, gridW, gridH)
+
+	dx := absInt(x1 - x0)
+	dy := -absInt(y1 - y0)
+	sx := 1
+	sy := 1
+	if x0 > x1 {
+		sx = -1
+	}
+	if y0 > y1 {
+		sy = -1
+	}
+	err := dx + dy
+
+	for {
+		if x0 >= 0 && x0 < gridW && y0 >= 0 && y0 < gridH {
+			switch a.GetGridType(x0, y0) {
+			case 2, 3: // start / end
+			default:
+				rl.ImageDrawPixel(mapImage, int32(x0), int32(y0), empty)
+				a.SetGridType(x0, y0, 0)
+			}
+		}
+		if x0 == x1 && y0 == y1 {
+			break
+		}
+		e2 := 2 * err
+		if e2 >= dy {
+			err += dy
+			x0 += sx
+		}
+		if e2 <= dx {
+			err += dx
+			y0 += sy
+		}
+	}
+}
+
 func drawInfiniteGridLines(camera rl.Camera2D, canvasW float32, canvasH float32, cellSize float32, width int, height int) {
 	// 1. Level of Detail (LOD) Check
 	// If we are zoomed out too far, don't draw the gridlines at all
@@ -48,10 +265,10 @@ func drawInfiniteGridLines(camera rl.Camera2D, canvasW float32, canvasH float32,
 
 func main() {
 	rl.SetConfigFlags(rl.FlagWindowResizable)
-	rl.InitWindow(int32(800), int32(450), "A* Visualizer")
+	rl.InitWindow(int32(800), int32(600), "A* Visualizer")
 	defer rl.CloseWindow()
 
-	scale := rl.GetWindowScaleDPI().X
+	scale := rl.GetWindowScaleDPI().X + 0.25
 	if scale == 0 {
 		scale = 2.0 // Fallback value
 	}
@@ -73,14 +290,36 @@ func main() {
 	heightInputValue := "10"
 	editModeWidth := false
 	editModeHeight := false
+	generateGridError := false
+	posError := false
+
+	toolOptions := []string{"Wall", "Start", "End", "Erase"}
+	toolOptionsText := strings.Join(toolOptions, ";")
+	activeTool := int32(0)
+	toolDropdownOpen := false
+	var tex texSync // GPU uploads: partial rects while painting; full after path resets
+
+	heuristicOptions := []string{"Manhattan", "Euclidean", "Chebyshev", "Squared Euclidean"}
+	heuristicOptionsText := strings.Join(heuristicOptions, ";")
+	activeHeuristic := int32(0)
+	heuristicDropdownOpen := false
 
 	cellSize := float32(25)
 
+	lastMousePos := rl.NewVector2(-1, -1)
+	startPos := rl.NewVector2(-1, -1)
+	endPos := rl.NewVector2(-1, -1)
+
 	mapImage := rl.GenImageColor(width, height, rl.NewColor(240, 240, 240, 255))
 	mapTexture := rl.LoadTextureFromImage(mapImage)
 	defer rl.UnloadTexture(mapTexture)
 	defer rl.UnloadImage(mapImage)
 
+	autoCompute := false
+
+	astar := AStar{}
+	astar.Init(width, height)
+
 	for !rl.WindowShouldClose() {
 		screenWidth := float32(rl.GetScreenWidth())
 		screenHeight := float32(rl.GetScreenHeight())
@@ -100,9 +339,9 @@ func main() {
 			// 1. Where is the mouse in the world BEFORE zooming?
 			worldPosBefore := rl.GetScreenToWorld2D(mousePos, camera)
 
-			// 2. Apply the zoom
+			// 2. Apply proportional zoom so wheel steps get smaller as the view zooms out.
-			camera.Zoom += float32(wheel) * 0.1
+			camera.Zoom *= float32(math.Pow(1.1, float64(wheel)))
-			if camera.Zoom < 0.01 {
+			if camera.Zoom < 0.01 && width > 2000 && height > 2000 {
 				camera.Zoom = 0.01
 			}
 
@@ -121,6 +360,106 @@ func main() {
 			camera.Target.Y -= delta.Y / camera.Zoom
 		}
 
+		// Paint logic
+		if rl.IsMouseButtonDown(rl.MouseLeftButton) {
+			mousePos := rl.GetMousePosition()
+			if int(mousePos.X) < int(canvasWidth) {
+				worldPos := rl.GetScreenToWorld2D(rl.GetMousePosition(), camera)
+				x := int(worldPos.X / cellSize)
+				y := int(worldPos.Y / cellSize)
+				if x >= 0 && x < width && y >= 0 && y < height {
+					// mapImage is one pixel per cell; drawing uses cell indices, not raw world coords.
+					switch activeTool {
+					case 0: // Wall — Bresenham line into image + simulator grid (skips start/end cells)
+						wallCol := color.RGBA{A: 255}
+						if lastMousePos.X != -1 && lastMousePos.Y != -1 {
+							prevX := int(lastMousePos.X / cellSize)
+							prevY := int(lastMousePos.Y / cellSize)
+							paintWallLine(&astar, mapImage, prevX, prevY, x, y, width, height, wallCol, &tex)
+						} else {
+							paintWallLine(&astar, mapImage, x, y, x, y, width, height, wallCol, &tex)
+						}
+					case 1: // Start — must run on first paint frame (lastMousePos may be -1 after release)
+						if int(startPos.X) != x || int(startPos.Y) != y {
+							if startPos.X >= 0 && startPos.Y >= 0 {
+								ox, oy := int(startPos.X), int(startPos.Y)
+								rl.ImageDrawPixel(mapImage, int32(startPos.X), int32(startPos.Y), rl.NewColor(240, 240, 240, 255))
+								astar.SetGridType(ox, oy, 0)
+								tex.markRegion(ox, oy, ox, oy, width, height)
+							}
+							rl.ImageDrawPixel(mapImage, int32(x), int32(y), rl.NewColor(0, 255, 0, 255))
+							tex.markRegion(x, y, x, y, width, height)
+							startPos = rl.NewVector2(float32(x), float32(y))
+							astar.SetGridType(x, y, 2)
+						}
+					case 2: // End
+						if int(endPos.X) != x || int(endPos.Y) != y {
+							if endPos.X >= 0 && endPos.Y >= 0 {
+								ox, oy := int(endPos.X), int(endPos.Y)
+								rl.ImageDrawPixel(mapImage, int32(endPos.X), int32(endPos.Y), rl.NewColor(240, 240, 240, 255))
+								astar.SetGridType(ox, oy, 0)
+								tex.markRegion(ox, oy, ox, oy, width, height)
+							}
+							rl.ImageDrawPixel(mapImage, int32(x), int32(y), rl.NewColor(255, 0, 0, 255))
+							tex.markRegion(x, y, x, y, width, height)
+							endPos = rl.NewVector2(float32(x), float32(y))
+							astar.SetGridType(x, y, 3)
+						}
+					case 3: // Erase — same cell indices as walls; ImageDrawLine used world coords before (wrong space).
+						emptyCol := color.RGBA{R: 240, G: 240, B: 240, A: 255}
+						if lastMousePos.X != -1 && lastMousePos.Y != -1 {
+							prevX := int(lastMousePos.X / cellSize)
+							prevY := int(lastMousePos.Y / cellSize)
+							paintEraseLine(&astar, mapImage, prevX, prevY, x, y, width, height, emptyCol, &tex)
+						} else {
+							paintEraseLine(&astar, mapImage, x, y, x, y, width, height, emptyCol, &tex)
+						}
+					}
+					lastMousePos = worldPos
+				}
+			}
+		}
+
+		if rl.IsMouseButtonReleased(rl.MouseLeftButton) {
+			if autoCompute && lastMousePos.X != -1 && lastMousePos.Y != -1 && int(startPos.X) >= 0 && int(startPos.X) < width && int(startPos.Y) >= 0 && int(startPos.Y) < height && int(endPos.X) >= 0 && int(endPos.X) < width && int(endPos.Y) >= 0 && int(endPos.Y) < height {
+				astar.ResetGrid(false) // keep grid types, otherwise it will delete the board before simulating
+				gridTypes := astar.GetGridTypes()
+				for i, gridType := range gridTypes {
+					// reset the map image
+					switch gridType {
+					case 0:
+						rl.ImageDrawPixel(mapImage, int32(i%width), int32(i/width), rl.NewColor(240, 240, 240, 255))
+					case 1:
+						rl.ImageDrawPixel(mapImage, int32(i%width), int32(i/width), rl.NewColor(0, 0, 0, 255))
+					case 2:
+						rl.ImageDrawPixel(mapImage, int32(i%width), int32(i/width), rl.NewColor(0, 255, 0, 255))
+					case 3:
+						rl.ImageDrawPixel(mapImage, int32(i%width), int32(i/width), rl.NewColor(255, 0, 0, 255))
+					}
+				}
+				tex.markFull()
+				astar.SetHeuristic(activeHeuristic)
+				path := astar.CalculatePath(int(startPos.X), int(startPos.Y), int(endPos.X), int(endPos.Y))
+				closedSet := astar.GetClosedSet()
+				for i, closed := range closedSet {
+					if closed {
+						x := i % width
+						y := i / width
+						if x != int(startPos.X) || y != int(startPos.Y) {
+							rl.ImageDrawPixel(mapImage, int32(x), int32(y), rl.NewColor(0, 0, 255, 255))
+						}
+					}
+				}
+				for _, p := range path {
+					if p[0] != int(startPos.X) || p[1] != int(startPos.Y) { // we want to keep the start position green
+						rl.ImageDrawPixel(mapImage, int32(p[0]), int32(p[1]), rl.NewColor(255, 255, 0, 255))
+					}
+				}
+				tex.markFull()
+			}
+			lastMousePos = rl.NewVector2(-1, -1)
+		}
+
 		// --- DRAWING ---
 		rl.BeginDrawing()
 		rl.ClearBackground(rl.White)
@@ -128,6 +467,7 @@ func main() {
 		// 1. Draw Canvas
 		rl.BeginScissorMode(0, 0, int32(canvasWidth), int32(screenHeight))
 		rl.BeginMode2D(camera)
+		tex.flush(mapImage, &mapTexture, width, height)
 		rl.DrawTextureEx(
 			mapTexture,
 			rl.NewVector2(0, 0), // Position
@@ -143,6 +483,7 @@ func main() {
 		sidebarX := canvasWidth
 		rl.DrawRectangleRec(rl.NewRectangle(sidebarX, 0, sidebarWidth, screenHeight), rl.RayWhite)
 
+		// Width Input
 		if rg.TextBox(rl.NewRectangle(sidebarX+(10*scale), (10*scale), (80*scale), (20*scale)), &widthInputValue, 20, editModeWidth) {
 			editModeWidth = !editModeWidth
 			if editModeWidth {
@@ -151,6 +492,7 @@ func main() {
 		}
 		rg.Label(rl.NewRectangle(sidebarX+(95*scale), (10*scale), (10*scale), (20*scale)), "x")
 
+		// Height Input
 		if rg.TextBox(rl.NewRectangle(sidebarX+(110*scale), (10*scale), (80*scale), (20*scale)), &heightInputValue, 20, editModeHeight) {
 			editModeHeight = !editModeHeight
 			if editModeHeight {
@@ -158,15 +500,121 @@ func main() {
 			}
 		}
 
+		if generateGridError {
+			result := rg.MessageBox(rl.NewRectangle(screenWidth/2-(100*scale), screenHeight/2-(40*scale), (200*scale), (120*scale)), "Error", "Width and/or height must be\nless than 16000", "OK")
+			if result >= 0 {
+				generateGridError = false
+			}
+		}
+
+		if posError {
+			result := rg.MessageBox(rl.NewRectangle(screenWidth/2-(100*scale), screenHeight/2-(40*scale), (200*scale), (120*scale)), "Error", "Start and end positions must be\nwithin the generated grid", "OK")
+			if result >= 0 {
+				posError = false
+			}
+		}
+
+		// Generate Grid Button
 		if rg.Button(rl.NewRectangle(sidebarX+(10*scale), (40*scale), (180*scale), (30*scale)), "Generate Grid") {
 			width, _ = strconv.Atoi(widthInputValue)
 			height, _ = strconv.Atoi(heightInputValue)
-			mapImage = rl.GenImageColor(width, height, rl.NewColor(240, 240, 240, 255))
+			if width > 16000 || height > 16000 {
-			mapTexture = rl.LoadTextureFromImage(mapImage)
+				generateGridError = true
-			defer rl.UnloadTexture(mapTexture)
+			} else {
-			defer rl.UnloadImage(mapImage)
+				rl.UnloadTexture(mapTexture)
+				rl.UnloadImage(mapImage)
+				mapImage = rl.GenImageColor(width, height, rl.NewColor(240, 240, 240, 255))
+				mapTexture = rl.LoadTextureFromImage(mapImage)
+				astar.RebuildGrid(width, height)
+				startPos = rl.NewVector2(-1, -1)
+				endPos = rl.NewVector2(-1, -1)
+				tex = texSync{rectBuf: tex.rectBuf}
+			}
 		}
 
+		// Tool Selector (text must be "opt1;opt2;..." — raygui splits on ';' and needs 2+ items)
+		rg.Label(rl.NewRectangle(sidebarX+(10*scale), (75*scale), (180*scale), (30*scale)), "Tool:")
+		if rg.DropdownBox(rl.NewRectangle(sidebarX+(10*scale), (100*scale), (180*scale), (30*scale)), toolOptionsText, &activeTool, toolDropdownOpen) {
+			toolDropdownOpen = !toolDropdownOpen
+		}
+
+		// Heuristic Selector
+		if !toolDropdownOpen {
+			rg.Label(rl.NewRectangle(sidebarX+(10*scale), (135*scale), (180*scale), (30*scale)), "Heuristic:")
+			if rg.DropdownBox(rl.NewRectangle(sidebarX+(10*scale), (160*scale), (180*scale), (30*scale)), heuristicOptionsText, &activeHeuristic, heuristicDropdownOpen) {
+				heuristicDropdownOpen = !heuristicDropdownOpen
+			}
+		}
+
+		// Reset Visualization Button
+		if !toolDropdownOpen && !heuristicDropdownOpen {
+			if rg.Button(rl.NewRectangle(sidebarX+(10*scale), (200*scale), (180*scale), (30*scale)), "Reset Visualization") {
+				astar.ResetGrid(false) // keep grid types, otherwise it will delete the board before simulating
+				gridTypes := astar.GetGridTypes()
+				for i, gridType := range gridTypes {
+					// reset the map image
+					switch gridType {
+					case 0:
+						rl.ImageDrawPixel(mapImage, int32(i%width), int32(i/width), rl.NewColor(240, 240, 240, 255))
+					case 1:
+						rl.ImageDrawPixel(mapImage, int32(i%width), int32(i/width), rl.NewColor(0, 0, 0, 255))
+					case 2:
+						rl.ImageDrawPixel(mapImage, int32(i%width), int32(i/width), rl.NewColor(0, 255, 0, 255))
+					case 3:
+						rl.ImageDrawPixel(mapImage, int32(i%width), int32(i/width), rl.NewColor(255, 0, 0, 255))
+					}
+				}
+				tex.markFull()
+			}
+		}
+
+		// AutoCompute
+		autoCompute = rg.CheckBox(rl.NewRectangle(sidebarX+(160*scale), (screenHeight-(40*scale)), (30*scale), (30*scale)), "", autoCompute) // no title because it would overlap the button
+
+		// Calculate Path Button
+		if rg.Button(rl.NewRectangle(sidebarX+(10*scale), (screenHeight-(40*scale)), (140*scale), (30*scale)), "Calculate Path") {
+			if int(startPos.X) < 0 || int(startPos.X) >= width || int(startPos.Y) < 0 || int(startPos.Y) >= height || int(endPos.X) < 0 || int(endPos.X) >= width || int(endPos.Y) < 0 || int(endPos.Y) >= height {
+				posError = true
+			} else {
+				astar.ResetGrid(false) // keep grid types, otherwise it will delete the board before simulating
+				astar.SetHeuristic(activeHeuristic)
+				gridTypes := astar.GetGridTypes()
+				for i, gridType := range gridTypes {
+					// reset the map image
+					switch gridType {
+					case 0:
+						rl.ImageDrawPixel(mapImage, int32(i%width), int32(i/width), rl.NewColor(240, 240, 240, 255))
+					case 1:
+						rl.ImageDrawPixel(mapImage, int32(i%width), int32(i/width), rl.NewColor(0, 0, 0, 255))
+					case 2:
+						rl.ImageDrawPixel(mapImage, int32(i%width), int32(i/width), rl.NewColor(0, 255, 0, 255))
+					case 3:
+						rl.ImageDrawPixel(mapImage, int32(i%width), int32(i/width), rl.NewColor(255, 0, 0, 255))
+					}
+				}
+				path := astar.CalculatePath(int(startPos.X), int(startPos.Y), int(endPos.X), int(endPos.Y))
+				closedSet := astar.GetClosedSet()
+				for i, closed := range closedSet {
+					if closed {
+						x := i % width
+						y := i / width
+						if x != int(startPos.X) || y != int(startPos.Y) {
+							rl.ImageDrawPixel(mapImage, int32(x), int32(y), rl.NewColor(0, 0, 255, 255))
+						}
+					}
+				}
+				for _, p := range path {
+					if p[0] != int(startPos.X) || p[1] != int(startPos.Y) { // we want to keep the start position green
+						rl.ImageDrawPixel(mapImage, int32(p[0]), int32(p[1]), rl.NewColor(255, 255, 0, 255))
+					}
+				}
+				tex.markFull()
+			}
+		}
+
+		// Status Label
+		rg.Label(rl.NewRectangle((10*scale), (screenHeight-(30*scale)), (canvasWidth-(20*scale)), (30*scale)), "Evaluated "+strconv.Itoa(astar.GetEvaluatedCells())+" cells in "+astar.GetTimeTaken().String())
+
 		rl.EndDrawing()
 	}
 }