check if texture alpha channel exists

[Kesshi]

Hi,

 

after loading a texture how can i check if the source image (PNG) has an alpha channel/transparent pixels or not?

I need to know this to set the flags material.diffuseTexture.hasAlpha and material.useAlphaFromDiffuseTexture to true.

In my scenario the images/textures which will be used later in the application are not predefined.

The only way is that i automatically detect if i need to enable the alpha flags.

[RaananW]

There is always a way!

 

In this case, not with BabylonJS, but there is a way :-)

 

You will have to download the image on your own, then check the 25's byte of the data. This byte contains the PNG type: Possible values are:

• 0 - grey
• 2 - RGB
• 3 - RGB with palette
• 4 - grey + alpha
• 6 - RGB + alpha

So, you will need to check the 25th byte

var alpha = downloadedData[25] >=4;

After downloading the image yourself, you can convert it to Base64 and use it as data for a texture.

 

Does it make sense?

[Kesshi]

Yes it makes sense :-)
I will try this later. Thank you.