Determine the hue of a specific location on a geometric surface

Question

Determine the hue of a specific location on a geometric surface

I'm currently working with THREE.js for my scene rendering and I have a complex question - how can I retrieve the color of a specific point on a geometry face?

When I mention color, it's not just the face or material color that I'm interested in. I want to extract the actual output color at that specific point, taking into account the material, face color, and texture color at that exact location. For instance, if the texture on the face at a certain point is red, and the material color is partially visible (with an alpha value of 0.5), I'm looking to obtain: (r=1.0, g=0.0, b=0.0, a=0.5).

Please keep in mind that performance is a crucial factor here.

Do you have any suggestions? Thank you!

javascript three.js

Answer 1

Answer №1

One effective method is to utilize the <canvas> element for this task.

var canvas = document.createElement( 'canvas' );
canvas.width = renderer.domElement.width;
canvas.height = renderer.domElement.height;

var context = canvas.getContext( '2d' );
context.drawImage( renderer.domElement, 0, 0 );

var imagedata = context.getImageData( 0, 0, canvas.width, canvas.height );
var data = imagedata.data;

var index = ( mouseX + ( mouseY * canvas.width ) ) * 4;

var red = data[ index ];
var green = data[ index + 1 ];
var blue = data[ index + 2 ];

var hex = red << 16 | green << 8 | blue << 0

Answer 2

One effective method is to utilize the <canvas> element for this task.

var canvas = document.createElement( 'canvas' );
canvas.width = renderer.domElement.width;
canvas.height = renderer.domElement.height;

var context = canvas.getContext( '2d' );
context.drawImage( renderer.domElement, 0, 0 );

var imagedata = context.getImageData( 0, 0, canvas.width, canvas.height );
var data = imagedata.data;

var index = ( mouseX + ( mouseY * canvas.width ) ) * 4;

var red = data[ index ];
var green = data[ index + 1 ];
var blue = data[ index + 2 ];

var hex = red << 16 | green << 8 | blue << 0

Answer 3

Answer №2

Engage your thinking You may be surprised to find that reality is not as straightforward as you think. The presence or absence of lights greatly affects how we perceive objects. Without light, everything appears black; but with strategically placed lighting, the results can vary. Even when using flat shading, the color of an object's surface is determined by its normal.

Answer 4

Engage your thinking You may be surprised to find that reality is not as straightforward as you think. The presence or absence of lights greatly affects how we perceive objects. Without light, everything appears black; but with strategically placed lighting, the results can vary. Even when using flat shading, the color of an object's surface is determined by its normal.

Determine the hue of a specific location on a geometric surface

Answer №1

Answer №2

Similar questions

Utilizing JQuery and AJAX to fetch a specific variable

What is the best way to verify async actions that update the UI in my React Native application?

Issue with the datepicker not toggling properly in Angular-UI 0.11.0, only opens

Retrieve the identification of elements with dynamically generated ids

It seems that an issue has occurred indicating that something is not defined in the current context

Why are my cursor and my drawing line on opposite sides?

Determine the presence of an element using its selector and retrieve a true or false value using jQuery or JavaScript

What is the best way to display the HTML content being received from the database in the DOM?

Displaying information in form using ajax within the laravel framework

What is the best method for creating a loop script within a widget using script?

Vuetify 3 now displays full text in v-autocomplete without an ellipsis

Trimming decimal points from large numbers using Javascript

JavaScript is failing to pass the argument value

The ajax request does not support this method (the keydown event is only active during debugging)

assign a JSON key to a variable

Determining when all promises have either been rejected or resolved using vanilla JavaScript promises

In Internet Explorer 11, the input event in VueJS may not be triggered upon the first input

Transform the object into an array of JSON with specified keys

Strategies for effectively handling errors in the requestAnimationFrame function

Implementing the use of a partial view in ASP.NET MVC with the help of JavaScript