p5.js | ambientMaterial() Function

The ambientMaterial() function in p5.js is used to create a ambient material for a geometry with the given color. The ambient material is used to define the color that the object reflects under any light. If the ambient material is set to reflect only red and the lights reflect only blue, then the object would not reflect any light.

Syntax:

ambientMaterial( v1, [v2], [v3] )

OR

ambientMaterial( color )

Parameters: This function accept four parameters as mentioned above and described below:

• v1: It is a number which determines the gray value, or the red or hue value relative to the current color range.
• v2: It is a number which determines the green or saturation value relative to the current color range. It is an optional parameter.
• v3: It is a number which determines the blue or brightness value relative to the current color range. It is an optional parameter.
• color: It is a p5.Color or color string which defines the color of the ambient material.

The examples below illustrates the ambientMaterial() function in p5.js:

Example 1:

let newFont;
let currentLightColor = "red";
let currentAmbientColor = "red";

function preload() {
  newFont = loadFont('fonts/Montserrat.otf');
}

function setup() {
  createCanvas(600, 300, WEBGL);
  textFont(newFont, 16);

  // Create a selector for selecting
  // the ambient material color
  materialColorSel = createSelect();
  materialColorSel.position(30, 70);
  materialColorSel.option('red');
  materialColorSel.option('green');
  materialColorSel.option('blue');
  materialColorSel.changed(() => {
    currentLightColor = materialColorSel.value();
  });

  // Create a selector for selecting
  // the directional light color
  lightColorSel = createSelect();
  lightColorSel.position(30, 120);
  lightColorSel.option('red');
  lightColorSel.option('green');
  lightColorSel.option('blue');
  lightColorSel.changed(() => {
    currentAmbientColor = lightColorSel.value();
  });
}

function draw() {
  background('white');
  fill('black');

  text("Select an option below to set the light "
        + "and ambient material color", -285, -125);
  text("Select directional light color", -285, -100);
  text("Select ambient material color", -285, -50);
  shininess(10);
  noStroke();

  // Set the ambient material to the selected color
  ambientMaterial(currentAmbientColor);

  // Set the directional to the selected color
  directionalLight(color(currentLightColor),
               height / 2, width / 2, -250);

  // Draw the sphere
  translate(100, 0, 0);
  sphere(100);
  translate(-100, 0, 0);
}

Output:

Example 2:

let newFont;
let currentLightColor = "yellow";
let hasRed = false;
let hasGreen = false;
let hasBlue = false;

function preload() {
  newFont = loadFont('fonts/Montserrat.otf');
}

function setup() {
  createCanvas(600, 300, WEBGL);
  textFont(newFont, 16);

  // Create 3 checkboxes for mixing 3 colors
  redCheckbox = createCheckbox('Red', false);
  redCheckbox.position(30, 70);
  redCheckbox.changed(() => hasRed = !hasRed);

  greenCheckbox = createCheckbox('Green', false);
  greenCheckbox.position(90, 70);
  greenCheckbox.changed(() => hasGreen = !hasGreen);

  blueCheckbox = createCheckbox('Blue', false);
  blueCheckbox.position(170, 70);
  blueCheckbox.changed(() => hasBlue = !hasBlue);

  // Create a selector for selecting
  // the directional light color
  lightColorSel = createSelect();
  lightColorSel.position(30, 120);
  lightColorSel.option('yellow');
  lightColorSel.option('magenta');
  lightColorSel.option('cyan');
  lightColorSel.changed(() => {
    currentLightColor = lightColorSel.value();
  });
}

function draw() {
  background('white');
  fill('black');

  text("Select an option below to set the light "
      + "and ambient material color", -285, -125);
  text("Select directional light color", -285, -100);
  text("Select ambient material color", -285, -50);
  shininess(10);
  noStroke();

  // Define the color based on the checkboxes
  let currentAmbientColor = color(hasRed ? 255 : 0,
            hasGreen ? 255 : 0, hasBlue ? 255 : 0);

  // Set the ambient material to the defined color
  ambientMaterial(currentAmbientColor);

  // Set the directional to the selected color
  directionalLight(color(currentLightColor),
              height / 2, width / 2, -250);

  // Draw the sphere
  translate(100, 0, 0);
  sphere(100);
  translate(-100, 0, 0);
}

Output:

Online editor: https://editor.p5js.org/

Environment Setup: https://www.geeksforgeeks.org/p5-js-soundfile-object-installation-and-methods/

Reference: https://p5js.org/reference/#/p5/ambientMaterial