What is the best way to ensure a texture is always facing the camera?

Question

What is the best way to ensure a texture is always facing the camera?

Latest Update:

We have created a new demo to showcase the desired outcome. The demo includes an invisible skydome, a cubecamera, and an environment map. However, it is important to note that these techniques should not be utilized for the reasons previously mentioned.

var MatcapTransformer = function(uvs, face) {
  for (var i = uvs.length; i-- > 0;) {
    uvs[i].x = face.vertexNormals[i].x * 0.5 + 0.5;
    uvs[i].y = face.vertexNormals[i].y * 0.5 + 0.5;
  }
};

var TransformUv = function(geometry, xformer) {
  // Handle uv transformations
};

var SetResizeHandler = function(renderer, camera) {
  // Resize handler function
};

// Other functions and setup code
...

body {
  background-color: #000;
  margin: 0px;
  overflow: hidden;
}

<script src="https://threejs.org/build/three.min.js"></script>
<script src="https://threejs.org/examples/js/controls/TrackballControls.js"></script>

<div id='container1'></div>

Previous Updates:

Just to clarify, the reflective plane in the demo serves a specific purpose to check texture binding and is not directly related to the main issue being addressed.

Update:

We have introduced new methods and functions to assist in solving the problem. Despite our efforts, the issue with getting the textures to align perfectly with camera movement persists. Any assistance in resolving this would be greatly appreciated.

The main goal is to ensure the texture of a mesh always faces the active perspective camera, regardless of their relative positions. We have provided a simplified example to demonstrate this concept while avoiding complex real-world scenarios.

Sample Code

var MatcapTransformer=function(uvs, face) {
// Handle matcap transformations
};

var TransformUv=function(geometry, xformer) {
// The first argument is also used as an array in the recursive calls
// Callback functions and array transformations
};

var SetResizeHandler=function(renderer, camera) {
// Function to handle resizing of elements
};

// Other functions and setup code
...

body {
background-color: #000;
margin: 0px;
overflow: hidden;
}

<script src="https://threejs.org/build/three.min.js"></script>
<script src="https://threejs.org/examples/js/controls/TrackballControls.js"></script>

<div id='container1'></div>

Our objective is to have the texture align with the camera's movement, especially when orbiting around the mesh. We have added wireframes to enhance visibility during demonstration. Your help in addressing the complex rotation issue is greatly appreciated.

While we have made progress in rotating the texture around the y-axis, we are struggling with achieving the same effect across all axes. Any insights or guidance on this matter would be highly valued.

javascript three.js geometry texture-mapping uv-mapping

Answer 1

Answer №1

When facing the camera, the appearance will be as follows:

https://i.sstatic.net/tITkm.gif

For an even more impressive result, check out this question, where the opposite solution is sought:

https://i.sstatic.net/7t3Vr.gif

To achieve this effect, it is necessary to set up a simple fragment shader (similar to what the OP accidentally did):

Vertex shader

void main() {
  gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;
}

Fragment shader

uniform vec2 size;
uniform sampler2D texture;

void main() {
  gl_FragColor = texture2D(texture, gl_FragCoord.xy / size.xy);
}

A functional example of the shader using Three.js

function main() {
  // Uniform texture setting
  const uniforms = {
    texture1: { type: "t", value: new THREE.TextureLoader().load( "https://threejsfundamentals.org/threejs/resources/images/wall.jpg" ) }
  };
  // Material by shader
   const myMaterial = new THREE.ShaderMaterial({
        uniforms: uniforms,
        vertexShader: document.getElementById('vertexShader').textContent,
        fragmentShader: document.getElementById('fragmentShader').textContent
      });
  const canvas = document.querySelector('#c');
  const renderer = new THREE.WebGLRenderer({canvas});

  const fov = 75;
  const aspect = 2;  // the canvas default
  const near = 0.1;
  const far = 5;
  const camera = new THREE.PerspectiveCamera(fov, aspect, near, far);
  camera.position.z = 2;

  const scene = new THREE.Scene();

  const boxWidth = 1;
  const boxHeight = 1;
  const boxDepth = 1;
  const geometry = new THREE.BoxGeometry(boxWidth, boxHeight, boxDepth);

  const cubes = [];  // just an array we can use to rotate the cubes
  
  const cube = new THREE.Mesh(geometry, myMaterial);
  scene.add(cube);
  cubes.push(cube);  // add to our list of cubes to rotate

  function resizeRendererToDisplaySize(renderer) {
    const canvas = renderer.domElement;
    const width = canvas.clientWidth;
    const height = canvas.clientHeight;
    const needResize = canvas.width !== width || canvas.height !== height;
    if (needResize) {
      renderer.setSize(width, height, false);
    }
    return needResize;
  }

  function render(time) {
    time *= 0.001;
    
    if (resizeRendererToDisplaySize(renderer)) {
      const canvas = renderer.domElement;
      camera.aspect = canvas.clientWidth / canvas.clientHeight;
      camera.updateProjectionMatrix();
    }

    cubes.forEach((cube, ndx) => {
      const speed = .2 + ndx * .1;
      const rot = time * speed;
      
      
      cube.rotation.x = rot;
      cube.rotation.y = rot;      
    });
   

    renderer.render(scene, camera);

    requestAnimationFrame(render);
  }

  requestAnimationFrame(render);
}

main();

body {
  margin: 0;
}
#c {
  width: 100vw;
  height: 100vh;
  display: block;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/109/three.min.js"></script>
<script id="vertexShader" type="x-shader/x-vertex">
  void main() {
    gl_Position =   projectionMatrix * 
                    modelViewMatrix * 
                    vec4(position,1.0);
  }
</script>

<script id="fragmentShader" type="x-shader/x-fragment">
  uniform sampler2D texture1;
  const vec2  size = vec2(1024, 512);
  
  void main() {
    gl_FragColor = texture2D(texture1,gl_FragCoord.xy/size.xy); 
  }
</script>
<canvas id="c"></canvas>

An alternative method: Cube Mapping

In this instance, I have made modifications to a jsfiddle demonstrating cube mapping, which might be more aligned with what you are seeking:

https://jsfiddle.net/v8efxdo7/

The cube projects its face texture onto the underlying object and maintains alignment with the camera.

Note: The lighting changes as the object rotates due to the fixed positions of the light and inner object, while the camera and projection cube both rotate around the scene's center.

Upon closer inspection of the example, this technique, though not flawless, addresses the complexities involved in applying this effect to a box. The UV unwrap of a cube's texture is cross-shaped, rotating the UV itself would not suffice, and using projection techniques presents its own challenges, as the shapes of the projector object and projection subject are crucial factors.

For better comprehension: where in real-world 3D space do we observe this effect on boxes? The only instance that comes to mind is a 2D projection onto a 3D surface (similar to projection mapping in visual design).

Answer 2

When facing the camera, the appearance will be as follows:

https://i.sstatic.net/tITkm.gif

For an even more impressive result, check out this question, where the opposite solution is sought:

https://i.sstatic.net/7t3Vr.gif

To achieve this effect, it is necessary to set up a simple fragment shader (similar to what the OP accidentally did):

Vertex shader

void main() {
  gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;
}

Fragment shader

uniform vec2 size;
uniform sampler2D texture;

void main() {
  gl_FragColor = texture2D(texture, gl_FragCoord.xy / size.xy);
}

A functional example of the shader using Three.js

function main() {
  // Uniform texture setting
  const uniforms = {
    texture1: { type: "t", value: new THREE.TextureLoader().load( "https://threejsfundamentals.org/threejs/resources/images/wall.jpg" ) }
  };
  // Material by shader
   const myMaterial = new THREE.ShaderMaterial({
        uniforms: uniforms,
        vertexShader: document.getElementById('vertexShader').textContent,
        fragmentShader: document.getElementById('fragmentShader').textContent
      });
  const canvas = document.querySelector('#c');
  const renderer = new THREE.WebGLRenderer({canvas});

  const fov = 75;
  const aspect = 2;  // the canvas default
  const near = 0.1;
  const far = 5;
  const camera = new THREE.PerspectiveCamera(fov, aspect, near, far);
  camera.position.z = 2;

  const scene = new THREE.Scene();

  const boxWidth = 1;
  const boxHeight = 1;
  const boxDepth = 1;
  const geometry = new THREE.BoxGeometry(boxWidth, boxHeight, boxDepth);

  const cubes = [];  // just an array we can use to rotate the cubes
  
  const cube = new THREE.Mesh(geometry, myMaterial);
  scene.add(cube);
  cubes.push(cube);  // add to our list of cubes to rotate

  function resizeRendererToDisplaySize(renderer) {
    const canvas = renderer.domElement;
    const width = canvas.clientWidth;
    const height = canvas.clientHeight;
    const needResize = canvas.width !== width || canvas.height !== height;
    if (needResize) {
      renderer.setSize(width, height, false);
    }
    return needResize;
  }

  function render(time) {
    time *= 0.001;
    
    if (resizeRendererToDisplaySize(renderer)) {
      const canvas = renderer.domElement;
      camera.aspect = canvas.clientWidth / canvas.clientHeight;
      camera.updateProjectionMatrix();
    }

    cubes.forEach((cube, ndx) => {
      const speed = .2 + ndx * .1;
      const rot = time * speed;
      
      
      cube.rotation.x = rot;
      cube.rotation.y = rot;      
    });
   

    renderer.render(scene, camera);

    requestAnimationFrame(render);
  }

  requestAnimationFrame(render);
}

main();

body {
  margin: 0;
}
#c {
  width: 100vw;
  height: 100vh;
  display: block;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/109/three.min.js"></script>
<script id="vertexShader" type="x-shader/x-vertex">
  void main() {
    gl_Position =   projectionMatrix * 
                    modelViewMatrix * 
                    vec4(position,1.0);
  }
</script>

<script id="fragmentShader" type="x-shader/x-fragment">
  uniform sampler2D texture1;
  const vec2  size = vec2(1024, 512);
  
  void main() {
    gl_FragColor = texture2D(texture1,gl_FragCoord.xy/size.xy); 
  }
</script>
<canvas id="c"></canvas>

An alternative method: Cube Mapping

In this instance, I have made modifications to a jsfiddle demonstrating cube mapping, which might be more aligned with what you are seeking:

https://jsfiddle.net/v8efxdo7/

The cube projects its face texture onto the underlying object and maintains alignment with the camera.

Note: The lighting changes as the object rotates due to the fixed positions of the light and inner object, while the camera and projection cube both rotate around the scene's center.

Upon closer inspection of the example, this technique, though not flawless, addresses the complexities involved in applying this effect to a box. The UV unwrap of a cube's texture is cross-shaped, rotating the UV itself would not suffice, and using projection techniques presents its own challenges, as the shapes of the projector object and projection subject are crucial factors.

For better comprehension: where in real-world 3D space do we observe this effect on boxes? The only instance that comes to mind is a 2D projection onto a 3D surface (similar to projection mapping in visual design).

What is the best way to ensure a texture is always facing the camera?

Answer №1

Similar questions

A guide to using select2.js to activate a selection based on a data attribute

Unable to access a frame inside an iframe and frameset using JavaScript when both domains are identical

Tips for shortening extra text in a non-wrapping HTML table cell and adding "..." at the end

Creating markers for every value in a table using Google Maps API v3

JavaScript form validation involves using client-side scripting to ensure that

Utilizing JSON parse/stringify for data manipulation

Retrieve the attributes associated with a feature layer to display in a Pop-up Template using ArcGIS Javascript

Guide on setting the dropdown's selected index through JavaScript

Transmitting information to the service array through relentless perseverance

Using JavaScript to fetch HTML and apply CSS dynamically

Instructions on utilizing module.exports to export an async function

Modify the ColVis Appearance in Datatable Using JavaScript

Configuring route for serving static files in an Express server

Integrating PHP code into a React.js application can provide

When using AngularJS, the templateUrl feature delays the initialization of the controller, causing issues with dependent code

Refreshing jQuery via Ajax Response

Ordering an Array of JavaScript Objects in a Custom Sequence (utilizing pre-existing methods)

Vue - Implementing plugin as a prototype functionality

An error popped up: "argument list is missing) after"

Encountered difficulties while attempting to use keyboard input and received a null value when attempting to retrieve a data-* attribute using Python and Selenium