Skip to content

Handle mobile touch gestures for scene controls #72

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
unkcpz merged 3 commits into from
Mar 4, 2026
Merged

Handle mobile touch gestures for scene controls #72

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
ab98614
feat: add mobile touch gesture control and zoom direction fix
syzer Mar 4, 2026
085b648
ui: show mobile-only control hint on touch
syzer Mar 4, 2026
7038893
separete out gesture.js to be load for gh deployment
unkcpz Mar 4, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
1 change: 1 addition & 0 deletions .github/workflows/deploy.yml
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -47,6 +47,7 @@ jobs:
run: |
cp ../../wasm/* .
cp ../../vizmat-app/index.html .
cp ../../vizmat-app/mobile-gesture.js .
cp ../../vizmat-app/style.css .
npm install
npm run build
Expand Down
7 changes: 6 additions & 1 deletion vizmat-app/index.html
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,10 @@
<head>
<meta charset="UTF-8">
<title>vizmat: a cross platform crystal visualizer</title>
<meta name="viewport" content="width=device-width, initial-scale=1">
<meta
name="viewport"
content="width=device-width, initial-scale=1, maximum-scale=1, minimum-scale=1, user-scalable=no"
>
<link rel="preconnect" href="https://fonts.googleapis.com">
<link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
<link href="https://fonts.googleapis.com/css2?family=Space+Grotesk:wght@400;500;700&display=swap" rel="stylesheet">
Expand All @@ -18,9 +21,11 @@
data-cargo-no-default-features="true" />
<link data-trunk rel="copy-dir" href="assets" />
<link data-trunk rel="copy-file" href="index.js" />
<link data-trunk rel="copy-file" href="mobile-gesture.js" />
<link data-trunk rel="copy-file" href="style.css" />
<link href="style.css" rel="stylesheet" />
<script type="module" src="./index.js"></script>
<script type="module" src="./mobile-gesture.js"></script>
<h1 class="site-title">vizmat <span>molecule / crystal</span> visual lab</h1>
<header>
<a href="https://github.com/rs4rse/vizmat" target="_blank">
Expand Down
268 changes: 268 additions & 0 deletions vizmat-app/mobile-gesture.js
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,268 @@
(function () {
const canvas = document.getElementById("bevy-canvas");

const emitTouchGesture = (gesture) => {
window.dispatchEvent(
new CustomEvent("vizmat-touch-gesture", {
detail: gesture,
}),
);
};

const toVec = (touch) => ({ x: touch.clientX, y: touch.clientY });

const touchPanState = {
one: null,
two: {
active: false,
midpoint: null,
distance: null,
},
};

const getMidpoint = (a, b) => ({
x: (a.x + b.x) * 0.5,
y: (a.y + b.y) * 0.5,
});

const getDistance = (a, b) => {
const dx = a.x - b.x;
const dy = a.y - b.y;
return Math.hypot(dx, dy);
};

const clearTouchState = () => {
touchPanState.one = null;
touchPanState.two = {
active: false,
midpoint: null,
distance: null,
};
};

const emitIf = (condition, payload) => {
if (!condition) return false;
emitTouchGesture(payload);
return true;
};

if (canvas) {
canvas.style.touchAction = "none";

if (window.PointerEvent) {
const pointerState = new Map();

const removePointer = (event) => {
if (event.pointerType !== "touch") return;
if (!event.currentTarget || !pointerState.has(event.pointerId)) return;
pointerState.delete(event.pointerId);

if (pointerState.size === 0) {
clearTouchState();
return;
}

if (pointerState.size === 1) {
touchPanState.one = [...pointerState.values()][0];
touchPanState.two = {
active: false,
midpoint: null,
distance: null,
};
return;
}

const points = [...pointerState.values()];
touchPanState.two = {
active: true,
midpoint: getMidpoint(points[0], points[1]),
distance: getDistance(points[0], points[1]),
};
};

const updateSinglePointer = (point) => {
if (!touchPanState.one) {
touchPanState.one = point;
return;
}

const dx = point.x - touchPanState.one.x;
const dy = point.y - touchPanState.one.y;
const emitted = emitIf(dx !== 0 || dy !== 0, {
gesture: "Rotate",
dx,
dy,
scale_delta: 0,
});
if (emitted) {
touchPanState.one = point;
}
};

const updateTwoPointer = (a, b) => {
if (!touchPanState.two.active) {
touchPanState.two = {
active: true,
midpoint: getMidpoint(a, b),
distance: getDistance(a, b),
};
return;
}

const midpoint = getMidpoint(a, b);
const distance = getDistance(a, b);
const panDx = midpoint.x - touchPanState.two.midpoint.x;
const panDy = midpoint.y - touchPanState.two.midpoint.y;
const scaleDelta = touchPanState.two.distance > 0
? (distance - touchPanState.two.distance) / touchPanState.two.distance
: 0;

const emitted = emitIf(panDx !== 0 || panDy !== 0 || scaleDelta !== 0, {
gesture: "TwoFinger",
dx: panDx,
dy: panDy,
scale_delta: scaleDelta,
});

if (emitted) {
touchPanState.two.midpoint = midpoint;
touchPanState.two.distance = distance;
}
};

canvas.addEventListener(
"pointerdown",
(event) => {
if (event.pointerType !== "touch") return;
if (!event.target) return;
const point = toVec(event);
pointerState.set(event.pointerId, point);
event.currentTarget.setPointerCapture(event.pointerId);
touchPanState.one = point;
touchPanState.two = {
active: false,
midpoint: null,
distance: null,
};
event.preventDefault();
},
{ passive: false },
);

canvas.addEventListener(
"pointermove",
(event) => {
if (event.pointerType !== "touch") return;
if (!pointerState.has(event.pointerId)) return;

const point = toVec(event);
pointerState.set(event.pointerId, point);

if (pointerState.size === 1) {
updateSinglePointer(point);
} else if (pointerState.size >= 2) {
const points = [...pointerState.values()];
const a = points[0];
const b = points[1];
updateTwoPointer(a, b);
}

event.preventDefault();
},
{ passive: false },
);

canvas.addEventListener(
"pointerup",
removePointer,
{ passive: false },
);
canvas.addEventListener("pointercancel", removePointer, {
passive: false,
});
canvas.addEventListener("pointerleave", removePointer, {
passive: false,
});
canvas.addEventListener("pointerout", removePointer, { passive: false });
canvas.addEventListener("pointerlostcapture", removePointer);
} else {
canvas.addEventListener(
"touchstart",
(event) => {
if (!event.target) return;
if (event.touches.length === 1) {
touchPanState.one = toVec(event.touches[0]);
touchPanState.two.active = false;
} else if (event.touches.length === 2) {
const a = toVec(event.touches[0]);
const b = toVec(event.touches[1]);
touchPanState.two = {
active: true,
midpoint: getMidpoint(a, b),
distance: getDistance(a, b),
};
touchPanState.one = null;
}
event.preventDefault();
},
{ passive: false },
);

canvas.addEventListener(
"touchmove",
(event) => {
if (event.touches.length === 1 && touchPanState.one) {
const current = toVec(event.touches[0]);
const dx = current.x - touchPanState.one.x;
const dy = current.y - touchPanState.one.y;

if (dx !== 0 || dy !== 0) {
emitTouchGesture({
gesture: "Rotate",
dx,
dy,
scale_delta: 0,
});
touchPanState.one = current;
}
event.preventDefault();
return;
}

if (event.touches.length === 2 && touchPanState.two.active) {
const a = toVec(event.touches[0]);
const b = toVec(event.touches[1]);
const midpoint = getMidpoint(a, b);
const distance = getDistance(a, b);

const panDx = midpoint.x - touchPanState.two.midpoint.x;
const panDy = midpoint.y - touchPanState.two.midpoint.y;
const scaleDelta = touchPanState.two.distance > 0
? (distance - touchPanState.two.distance) /
touchPanState.two.distance
: 0;

if (panDx !== 0 || panDy !== 0 || scaleDelta !== 0) {
emitTouchGesture({
gesture: "TwoFinger",
dx: panDx,
dy: panDy,
scale_delta: scaleDelta,
});
touchPanState.two.midpoint = midpoint;
touchPanState.two.distance = distance;
}

event.preventDefault();
}
},
{ passive: false },
);
}

const clearTouch = () => clearTouchState();
canvas.addEventListener("touchend", clearTouch, { passive: false });
canvas.addEventListener("touchcancel", clearTouch, { passive: false });
canvas.addEventListener("touchleave", clearTouch, { passive: false });
}
})();
16 changes: 16 additions & 0 deletions vizmat-app/style.css
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -47,6 +47,11 @@ html[data-theme="light"] {
html, body {
width: 100%;
height: 100%;
touch-action: none;
overscroll-behavior: none;
user-select: none;
-webkit-user-select: none;
-webkit-touch-callout: none;
}
body {
margin: 0;
Expand All @@ -70,6 +75,7 @@ body {
color: var(--accent);
}
header {
touch-action: none;
position: fixed;
top: 10px;
right: 10px;
Expand Down Expand Up @@ -97,6 +103,7 @@ header a img {
height: 20px;
}
.hint {
touch-action: none;
position: fixed;
left: 12px;
bottom: 12px;
Expand Down Expand Up @@ -124,6 +131,11 @@ canvas {
height: 100%;
display: block;
background: transparent;
touch-action: none;
overscroll-behavior: none;
user-select: none;
-webkit-user-select: none;
-webkit-touch-callout: none;
}
.canvas-shell {
position: fixed;
Expand All @@ -137,6 +149,10 @@ canvas {
border: 1px solid var(--line);
box-shadow: 0 24px 80px rgba(0, 0, 0, 0.45);
background: var(--canvas-bg);
touch-action: none;
overscroll-behavior: none;
user-select: none;
-webkit-user-select: none;
}
.loader {
position: fixed;
Expand Down
Loading