Skybox smooth transition / Skybox blending

Gradess · November 19, 2020, 10:21am

Hi!
I want to make day/night transition like in UE4
Demo video
Is there any solution?

yaustar · November 19, 2020, 10:51am

We don’t have that particular feature.

I’m thinking you might be write something custom using an inverted sphere and a shader to transition between textures/colours.

mvaligursky · November 19, 2020, 11:17am

See how skybox is implemented in the engine here:

github.com

playcanvas/engine/blob/d5d091dac979414a81c1a3f57a66e221c4c38c6d/src/scene/scene.js#L383-L465


Scene.prototype._updateSkybox = function (device) {
    // Create skybox
    if (!this.skyboxModel) {

        // skybox selection for some reason has always skipped the 32x32 mipmap, presumably a bug.
        // we can't simply fix this and map 3 to the correct level, since doing so has the potential
        // to change the look of existing scenes dramatically.
        // NOTE: the table skips the 32x32 mipmap
        var skyboxMapping = [0, 1, 3, 4, 5, 6];

        // select which texture to use for the backdrop
        var usedTex =
            this._skyboxMip ?
                this._skyboxPrefiltered[skyboxMapping[this._skyboxMip]] || this._skyboxPrefiltered[0] || this._skyboxCubeMap :
                this._skyboxCubeMap || this._skyboxPrefiltered[0];
        if (!usedTex) {
            return;
        }

        if (usedTex._isRenderTarget) {

This file has been truncated. show original

you could use similar code, and implement what @yaustar suggested.

Cain_Quigley · November 20, 2020, 8:03pm

I suppose you could also enable alpha blending, and lerp the ‘Intensity’ of the material down to zero.