Render shadows only in a new version

RyuSoHyeong · June 15, 2025, 6:57pm

Hi everyone! I’m facing an issue… I need to render shadows without displaying the object itself. I used a script that worked with version 1 of the engine, but in version 2.7.4 this approach no longer works. I’ve searched through various forums but haven’t found a working implementation for the new version yet.

var ArGround = pc.createScript('ar-ground');
ArGround.attributes.add('material', { type: 'asset' });
ArGround.attributes.add('intensity', { type: 'number', min: 0, max: 1, default: 1 });

ArGround.prototype.initialize = function () {
    // Attach a shader to a material that makes it appear transparent while still receiving shadows.
    const materialResource = this.material.resource;
    materialResource.chunks.APIVersion = pc.CHUNKAPI_1_62;
    materialResource.chunks.endPS = `
            litArgs_opacity = mix(light0_shadowIntensity, 0.0, shadow0);
            gl_FragColor.rgb = vec3(0.0);
        `;

    materialResource.blendType = pc.BLEND_PREMULTIPLIED;
    materialResource.update();
};

mvaligursky · June 16, 2025, 7:43am

You can use the new shadow catcher from here:

github.com

playcanvas/engine/blob/main/scripts/esm/shadow-catcher.mjs

import {
    Script,
    Entity,
    StandardMaterial,
    BLEND_MULTIPLICATIVE,
    Vec3
} from 'playcanvas';

/**
 * Implementations of shadow catcher functionality, which allows a shadow from directional lights to
 * be rendered using a transparent material. This is a common way to add a shadow to the scene where
 * the background is just a skydome.
 *
 * This implementation uses all directional lights in the scene to cast shadows onto the shadow.
 * Other light types are not supported.
 * If you want the light to not affect your scene, you can set the intensity of the light to 0 - this
 * way it will be only used to cast shadows.
 *
 * Additionally, at creation time, you can provide a geometry entity that will be used as the shadow
 * catcher. If you don't provide one, the script will create a plane geometry.

This file has been truncated. show original

See the example of its use here:
https://playcanvas.vercel.app/#/graphics/shadow-catcher