Show density/noise value at cursor (#282)

* Fix #277 WIP show density at cursor

* Correctly implement hovered value for noise and df previews

src/app/components/previews/DensityFunctionPreview.tsx

@@ -1,7 +1,7 @@
 import { useEffect, useRef, useState } from 'preact/hooks'
 import { useLocale, useProject } from '../../contexts/index.js'
 import { useCanvas } from '../../hooks/index.js'
-import { densityFunction } from '../../previews/index.js'
+import { densityFunction, densityPoint } from '../../previews/index.js'
 import { randomSeed } from '../../Utils.js'
 import { Btn, BtnMenu } from '../index.js'
 import type { PreviewProps } from './index.js'
@@ -10,19 +10,21 @@ export const DensityFunctionPreview = ({ data, shown, version }: PreviewProps) =
 	const { locale } = useLocale()
 	const { project } = useProject()
 	const [seed, setSeed] = useState(randomSeed())
+	const [minY] = useState(0)
+	const [height] = useState(256)
 	const [autoScroll, setAutoScroll] = useState(false)
-	const [focused, setFocused] = useState<string | undefined>(undefined)
+	const [focused, setFocused] = useState<string[]>([])
 	const offset = useRef(0)
 	const scrollInterval = useRef<number | undefined>(undefined)
 	const state = JSON.stringify([data])
 
-	const size = data?.noise?.height ?? 256
+	const size = 256
 	const { canvas, redraw } = useCanvas({
 		size() {
 			return [size, size]
 		},
 		async draw(img) {
-			const options = { offset: offset.current, width: img.width, seed, version, project }
+			const options = { offset: offset.current, width: img.width, seed, version, project, minY, height }
 			await densityFunction(data, img, options)
 		},
 		async onDrag(dx) {
@@ -30,14 +32,16 @@ export const DensityFunctionPreview = ({ data, shown, version }: PreviewProps) =
 			redraw()
 		},
 		async onHover(x, y) {
-			const worldX = Math.floor(x * size - offset.current)
-			const worldY = size - Math.max(1, Math.ceil(y * size)) + (data?.noise?.min_y ?? 0)
-			setFocused(`X=${worldX} Y=${worldY}`)
+			const worldX = Math.floor(x * size)
+			const worldY = Math.floor(y * (height - minY))
+			const options = { offset: offset.current, width: size, seed, version, project, minY, height }
+			const density = await densityPoint(data, worldX, worldY, options)
+			setFocused([density.toPrecision(3), `X=${Math.floor(worldX - offset.current)} Y=${(height - minY) - worldY}`])
 		},
 		onLeave() {
-			setFocused(undefined)
+			setFocused([])
 		},
-	}, [version, state, seed, project])
+	}, [version, state, seed, minY, height, project])
 
 	useEffect(() => {
 		if (scrollInterval.current) {
@@ -52,11 +56,11 @@ export const DensityFunctionPreview = ({ data, shown, version }: PreviewProps) =
 				}, 100) as any
 			}
 		}
-	}, [version, state, seed, project, shown, autoScroll])
+	}, [version, state, seed, minY, height, project, shown, autoScroll])
 
 	return <>
 		<div class="controls preview-controls">
-			{focused && <Btn label={focused} class="no-pointer" />}
+			{focused.map(s => <Btn label={s} class="no-pointer" /> )}
 			<BtnMenu icon="gear" tooltip={locale('terrain_settings')}>
 				<Btn icon={autoScroll ? 'square_fill' : 'square'} label={locale('preview.auto_scroll')} onClick={() => setAutoScroll(!autoScroll)} />
 			</BtnMenu>

src/app/components/previews/NoisePreview.tsx

@@ -1,7 +1,7 @@
 import { useEffect, useRef, useState } from 'preact/hooks'
 import { useLocale } from '../../contexts/index.js'
 import { useCanvas } from '../../hooks/index.js'
-import { normalNoise } from '../../previews/index.js'
+import { normalNoise, normalNoisePoint } from '../../previews/index.js'
 import { randomSeed } from '../../Utils.js'
 import { Btn } from '../index.js'
 import type { PreviewProps } from './index.js'
@@ -10,6 +10,7 @@ export const NoisePreview = ({ data, shown, version }: PreviewProps) => {
 	const { locale } = useLocale()
 	const [seed, setSeed] = useState(randomSeed())
 	const [scale, setScale] = useState(2)
+	const [focused, setFocused] = useState<string[]>([])
 	const offset = useRef<[number, number]>([0, 0])
 	const state = JSON.stringify([data])
 
@@ -26,6 +27,21 @@ export const NoisePreview = ({ data, shown, version }: PreviewProps) => {
 			offset.current[1] = offset.current[1] + dy * 256
 			redraw()
 		},
+		onHover(x, y) {
+			const x2 = Math.floor(x * 256)
+			const y2 = Math.floor(y * 256)
+			const options = { offset: offset.current, scale, seed, version }
+			const value = normalNoisePoint(data, x2, y2, options)
+			
+			const ox = -options.offset[0] - 100
+			const oy = -options.offset[1] - 100
+			const xx = (x2 + ox) * options.scale
+			const yy = (y2 + oy) * options.scale
+			setFocused([value.toPrecision(3), `X=${Math.floor(xx)} Y=${Math.floor(yy)}`])
+		},
+		onLeave() {
+			setFocused([])
+		},
 	}, [version, state, scale, seed])
 
 	useEffect(() => {
@@ -42,6 +58,7 @@ export const NoisePreview = ({ data, shown, version }: PreviewProps) => {
 
 	return <>
 		<div class="controls preview-controls">
+			{focused.map(s => <Btn label={s} class="no-pointer" /> )}
 			<Btn icon="dash" tooltip={locale('zoom_out')}
 				onClick={() => changeScale(scale * 1.5)} />
 			<Btn icon="plus" tooltip={locale('zoom_in')}

src/app/previews/Deepslate.ts

@@ -299,12 +299,12 @@ export class Deepslate {
 		}
 	}
 
-	public loadDensityFunction(state: unknown, seed: bigint) {
+	public loadDensityFunction(state: unknown, minY: number, height: number, seed: bigint) {
 		if (this.isVersion('1.19')) {
 			const settings = this.d.NoiseGeneratorSettings.create({
 				noise: {
-					minY: -64,
-					height: 384,
+					minY: minY,
+					height: height,
 					xzSize: 1,
 					ySize: 2,
 				},
@@ -318,8 +318,8 @@ export class Deepslate {
 		} else {
 			const random = this.d.XoroshiroRandom.create(seed).forkPositional()
 			const settings = this.d.NoiseSettings.fromJson({
-				min_y: -64,
-				height: 384,
+				min_y: minY,
+				height: height,
 				size_horizontal: 1,
 				size_vertical: 2,
 				sampling: { xz_scale: 1, y_scale: 1, xz_factor: 80, y_factor: 160 },

src/app/previews/NoiseSettings.ts

@@ -15,6 +15,8 @@ export type NoiseSettingsOptions = {
 	seed: bigint,
 	version: VersionId,
 	project: Project,
+	minY?: number,
+	height?: number,
 }
 
 const colors: Record<string, [number, number, number]> = {
@@ -82,22 +84,22 @@ export function getNoiseBlock(x: number, y: number) {
 
 export async function densityFunction(state: any, img: ImageData, options: NoiseSettingsOptions) {
 	await DEEPSLATE.loadVersion(options.version, getProjectData(options.project))
-	const fn = DEEPSLATE.loadDensityFunction(DataModel.unwrapLists(state), options.seed)
+	const fn = DEEPSLATE.loadDensityFunction(DataModel.unwrapLists(state), options.minY ?? 0, options.height ?? 256, options.seed)
 	const noise = DEEPSLATE.getNoiseSettings()
 
 	const arr = Array(options.width * noise.height)
-	let min = Infinity
-	let max = -Infinity
+	let limit = 0
 	for (let x = 0; x < options.width; x += 1) {
-		for (let y = 0; y < noise.height; y += 1) {
-			const i = x + (noise.height-y-1) * options.width
-			const density = fn.compute(DensityFunction.context(x - options.offset, y, 0))
-			min = Math.min(min, density)
-			max = Math.max(max, density)
+		for (let y = 0; y < noise.height - noise.minY; y += 1) {
+			const i = x + y * options.width
+			const density = fn.compute(DensityFunction.context(x - options.offset, noise.height - y - 1, 0))
+			limit = Math.max(limit, Math.abs(density))
 			arr[i] = density
 		}
 	}
 
+	const min = -limit
+	const max = limit
 	const data = img.data
 	for (let i = 0; i < options.width * noise.height; i += 1) {
 		const color = Math.floor(clampedMap(arr[i], min, max, 0, 256))
@@ -108,6 +110,13 @@ export async function densityFunction(state: any, img: ImageData, options: Noise
 	}
 }
 
+export async function densityPoint(state: any, x: number, y: number, options: NoiseSettingsOptions) {
+	await DEEPSLATE.loadVersion(options.version, getProjectData(options.project))
+	const fn = DEEPSLATE.loadDensityFunction(DataModel.unwrapLists(state), options.minY ?? 0, options.height ?? 256, options.seed)
+
+	return fn.compute(DensityFunction.context(Math.floor(x - options.offset), (options.height ?? 256) - y, 0))
+}
+
 export function getProjectData(project: Project) {
 	return Object.fromEntries(['worldgen/noise_settings', 'worldgen/noise', 'worldgen/density_function'].map(type => {
 		const resources = Object.fromEntries(

src/app/previews/NormalNoise.ts

@@ -15,13 +15,13 @@ export function normalNoise(state: any, img: ImageData, options: NoiseOptions) {
 	const noise = new NormalNoise(random, params)
 
 	const ox = -options.offset[0] - 100
-	const oz = -options.offset[1] - 100
+	const oy = -options.offset[1] - 100
 	const data = img.data
 	for (let x = 0; x < 256; x += 1) {
 		for (let y = 0; y < 256; y += 1) {
 			const i = x * 4 + y * 4 * 256
 			const xx = (x + ox) * options.scale
-			const yy = (y + oz) * options.scale
+			const yy = (y + oy) * options.scale
 			const color = (noise.sample(xx, yy, 0) + 1) * 128
 			data[i] = color
 			data[i + 1] = color
@@ -30,3 +30,15 @@ export function normalNoise(state: any, img: ImageData, options: NoiseOptions) {
 		}
 	}
 }
+
+export function normalNoisePoint(state: any, x: number, y: number, options: NoiseOptions) {
+	const random = XoroshiroRandom.create(options.seed)
+	const params = NoiseParameters.fromJson(DataModel.unwrapLists(state))
+	const noise = new NormalNoise(random, params)
+	
+	const ox = -options.offset[0] - 100
+	const oy = -options.offset[1] - 100
+	const xx = (x + ox) * options.scale
+	const yy = (y + oy) * options.scale
+	return noise.sample(xx, yy, 0)
+}

src/locales/en.json

@@ -139,6 +139,8 @@
   "preview.weather.rain": "Rain",
   "preview.weather.thunder": "Thunder",
   "preview.width": "Width",
+  "preview.height": "Height",
+  "preview.min_y": "Min Y",
   "project.new": "New project",
   "project.cancel": "Cancel",
   "project.create": "Create a new project",