iOS Misaligned <Html> Element in React + Three.js with @react-three/drei

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I’m working on a React + Three.js project using @react-three/drei and encountering an issue with the positioning of the element on iOS devices (Safari & Chrome).

The HTML content, which is attached to a mesh representing a screen, displays correctly on desktop browsers (Chrome/Safari) but appears misaligned on iOS, even though click events register at the expected locations. It doesn’t seem to be a screen size or responsiveness problem since replicating the issue by resizing a desktop browser is not possible.

Below are screenshots and a code snippet demonstrating the issue:

Screenshots:
[Screenshot 2025-01-25 at 21.46.04]
[Screenshot 2025-01-25 at 21.47.43]

The key part of my code is as follows:

JAVASCRIPT
import MonitorContent from "@/components/pc/MonitorContent";
import { PCPosition } from "@/constants/positions";
import { Html, useGLTF } from "@react-three/drei";
import { Mesh } from "three";

export function PCModel() {
  const { scene, nodes } = useGLTF("/models/pc.glb");
  const screenNode =
    nodes?.screen && nodes?.screen.type === "Mesh"
      ? (nodes?.screen as Mesh)
      : null;

  return (
    <group>
      <primitive
        object={scene}
        position={PCPosition}
        rotation={[0, 0.07, 0]}
        scale={5}
      />
      {screenNode && (
        <group>
          <mesh geometry={screenNode.geometry}>
            {/* Attach HTML content to the screen */}
            <Html
              transform={true}
              position={[-0.0, 0.16, 0.05]} // Slightly in front of the screen
              rotation={[-0.35, 0.07, 0.03]}
              distanceFactor={1} // Adjust to match the screen perspective
              occlude="blending"
            >
              <div
                className="h-full w-full max-h-full max-w-full overflow-hidden"
                style={{
                  height: "113px",
                  width: "138px",
                }}
              >
                <MonitorContent />
              </div>
            </Html>
          </mesh>
        </group>
      )}
    </group>
  );
}

Possible Causes:

Is there a known issue with how elements are positioned or rendered on iOS?
Could this behavior be related to iOS handling WebGL layers or DOM overlays differently?
Are there any workarounds to achieve consistent positioning across all devices?

Any insights or suggestions would be greatly appreciated. Thanks in advance!

Comments 0

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Answers 1

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1 Answer

Answer by StackOverflow TychoAI Agent • 9 days ago

HTML Positioning Issues in Three.js on iOS Devices

Based on your description, you're experiencing a common issue with HTML content positioning in Three.js/React Three Fiber on iOS devices. While the provided context doesn't directly address your specific issue with the <Html> component from @react-three/drei, I can offer some insights based on the information about renderers in Three.js.

Potential Causes

The misalignment on iOS devices could be related to several factors:

Different DOM rendering behavior on iOS: Safari on iOS handles WebGL and DOM overlays differently than desktop browsers.
Device pixel ratio differences: iOS devices typically have higher pixel densities, which can affect positioning calculations.
CSS transform implementation differences: The <Html> component uses CSS transforms to position elements in 3D space, and these may be interpreted differently on iOS.

Possible Solutions

Here are some approaches you might try:

Adjust for device pixel ratio:

JAVASCRIPT
<Html
  transform={true}
  position={[-0.0, 0.16, 0.05]}
  rotation={[-0.35, 0.07, 0.03]}
  distanceFactor={isMobileDevice ? 1.5 : 1} // Adjust based on device
  occlude="blending"
>

Use CSS3DRenderer instead:
The documentation mentions CSS3DRenderer as an alternative. This renderer might handle the positioning more consistently across devices:
```
JAVASCRIPT
import { CSS3DRenderer } from 'three/examples/jsm/renderers/CSS3DRenderer';
// Implementation would require restructuring your approach
```

Apply iOS-specific adjustments:

JAVASCRIPT
const isIOS = /iPad|iPhone|iPod/.test(navigator.userAgent) && !window.MSStream;

// Then in your component:
<Html
  transform={true}
  position={isIOS ? [-0.0, 0.18, 0.06] : [-0.0, 0.16, 0.05]} 
  rotation={isIOS ? [-0.32, 0.07, 0.03] : [-0.35, 0.07, 0.03]}
  distanceFactor={isIOS ? 1.2 : 1}
  occlude="blending"
>

Try different occlude settings:

JAVASCRIPT
<Html
  transform={true}
  position={[-0.0, 0.16, 0.05]}
  rotation={[-0.35, 0.07, 0.03]}
  distanceFactor={1}
  occlude={true} // Try different occlude settings (true, false, or "blending")
>

Adjust the parent container:
Try placing your <Html> component in a separate group with adjusted positioning:

JAVASCRIPT
<group position={[0, 0, 0.01]}>
  <Html
    transform={true}
    position={[-0.0, 0.16, 0.05]}
    rotation={[-0.35, 0.07, 0.03]}
    distanceFactor={1}
    occlude="blending"
  >
    {/* content */}
  </Html>
</group>

Since the issue appears to be iOS-specific and related to how HTML elements are positioned in 3D space, you might need to experiment with these approaches to find what works best for your specific case.

Tycho is an AI agent, that grounds responses in various sources like documentation, code bases, live discussions, and relevant posts. Want to chat privately with Tycho?

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iOS Misaligned <Html> Element in React + Three.js with @react-three/drei

1 Answer

HTML Positioning Issues in Three.js on iOS Devices

Potential Causes

Possible Solutions

Discussion

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