Video texture incorporated into Three.js

Question

Video texture incorporated into Three.js

I'm currently experimenting with using a specific section of a video as a texture on a Three.js mesh.

The video in question can be found at this link: . It features a fisheye lens, and I am only interested in incorporating the central circular portion into my mesh while ignoring the surrounding black areas.

My goal is to find a way to mask, crop, or reposition the video on the mesh so that only the desired content is displayed, excluding the extraneous parts.

Incorporated within the video code, I create a new 'video' element and apply settings such as loop, crossOrigin, and preload before linking it to the source file. Upon playback initiation, a VideoTexture based on this video is created with specified filter and format properties. This texture is then utilized in generating a MeshBasicMaterial for visualization on the mesh.

To enhance the immersive VR experience, the video is projected onto a 220-degree sphere shape via specified geometry parameters.

For reference and further exploration, a demo showcasing the implementation can be accessed through this CodePen link: http://codepen.io/bknill/pen/vXBWGv.

If anyone has suggestions or insights on optimizing this process, I would greatly appreciate any guidance provided.

javascript three.js

Answer 1

Answer №1

Utilize the texture.repeat method to adjust the size of the texture

For instance, to double the scale on both axes, you can use: texture.repeat.set(0.5, 0.5);

Answer 2

Utilize the texture.repeat method to adjust the size of the texture

For instance, to double the scale on both axes, you can use: texture.repeat.set(0.5, 0.5);

Answer 3

Answer №2

Simply put, updating the UV-Map of the sphere is essential to ensure that the appropriate area of your texture is assigned to the corresponding vertices of the sphere.

Each vertex's UV-coordinates determine the specific coordinates within the texture that are linked to that vertex (within a range of [0..1], with coordinates (0, 0) representing the top left corner and (1,1) denoting the bottom right corner of your video). Check out this example for a better understanding.

These UV-coordinates can be found in your geometry as geometry.faceVertexUvs[0], where each vertex of every face possesses a THREE.Vector2 value for the UV-coordinate. It's structured as a two-dimensional array, with the first index referring to the face-index and the second one indicating the vertex-index for the face (as shown in the example).

There are at least two methods for generating the UV-map. The simpler approach would involve creating the UV-map using 3D editing tools like blender and then exporting the object using the three.js exporter-plugin.

The alternative method is manually computing the values. Initially, you could try utilizing an orthographic projection of the sphere. Essentially, if you have a unit-sphere centered at the origin, you can disregard the z-coordinate of the vertices and utilize u = x/2 + 0.5 and v = y/2 + 0.5 as UV-coordinates.

In JavaScript, this might look something like:

// create the geometry
const geometry = new THREE.SphereGeometry(1, 18, 18, Math.PI, Math.PI)
const uvs = geometry.faceVertexUvs[0];
const vertices = geometry.vertices;

// calculate UV from sphere vertices
for(let i = 0; i<geometry.faces.length; i++) {
  const face = geometry.faces[i];
  const faceVertices = [vertices[face.a], vertices[face.b], vertices[face.c]];

  for(let j = 0; j<3; j++) {
    const vertex = faceVertices[j];
    uvs[i][j].set(vertex.x/2 + 0.5, vertex.y/2 + 0.5);
  }
}
geometry.uvsNeedUpdate = true;

(Feel free to ask for more details in either direction, and I'll provide further explanations.)

Answer 4

Simply put, updating the UV-Map of the sphere is essential to ensure that the appropriate area of your texture is assigned to the corresponding vertices of the sphere.

Each vertex's UV-coordinates determine the specific coordinates within the texture that are linked to that vertex (within a range of [0..1], with coordinates (0, 0) representing the top left corner and (1,1) denoting the bottom right corner of your video). Check out this example for a better understanding.

These UV-coordinates can be found in your geometry as geometry.faceVertexUvs[0], where each vertex of every face possesses a THREE.Vector2 value for the UV-coordinate. It's structured as a two-dimensional array, with the first index referring to the face-index and the second one indicating the vertex-index for the face (as shown in the example).

There are at least two methods for generating the UV-map. The simpler approach would involve creating the UV-map using 3D editing tools like blender and then exporting the object using the three.js exporter-plugin.

The alternative method is manually computing the values. Initially, you could try utilizing an orthographic projection of the sphere. Essentially, if you have a unit-sphere centered at the origin, you can disregard the z-coordinate of the vertices and utilize u = x/2 + 0.5 and v = y/2 + 0.5 as UV-coordinates.

In JavaScript, this might look something like:

// create the geometry
const geometry = new THREE.SphereGeometry(1, 18, 18, Math.PI, Math.PI)
const uvs = geometry.faceVertexUvs[0];
const vertices = geometry.vertices;

// calculate UV from sphere vertices
for(let i = 0; i<geometry.faces.length; i++) {
  const face = geometry.faces[i];
  const faceVertices = [vertices[face.a], vertices[face.b], vertices[face.c]];

  for(let j = 0; j<3; j++) {
    const vertex = faceVertices[j];
    uvs[i][j].set(vertex.x/2 + 0.5, vertex.y/2 + 0.5);
  }
}
geometry.uvsNeedUpdate = true;

(Feel free to ask for more details in either direction, and I'll provide further explanations.)

Video texture incorporated into Three.js

Answer №1

Answer №2

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