solved Alpha Blend Mode Help

[MackeyK24]

Yo @Deltakosh and @Sebavan ... I need your help yet again in trying to understand the correct Alpha Blend Mode I should be using for each of the blend mode that unity uses (Opaque - Cutout - Fade - Transparent)

I need help in translating what _SrcBlend and _DstBlend values should equal for babylon. Here is the shader code that hey use to enable the various ALPHABLEND, ALPHATEST, etc...

public static void SetupMaterialWithBlendMode(Material material, BlendMode blendMode)

{

switch (blendMode)

{

case BlendMode.Opaque:

material.SetOverrideTag("RenderType", "");

material.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.One);

material.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.Zero);

material.SetInt("_ZWrite", 1);

material.DisableKeyword("_ALPHATEST_ON");

material.DisableKeyword("_ALPHABLEND_ON");

material.DisableKeyword("_ALPHAPREMULTIPLY_ON");

material.renderQueue = -1;

break;

case BlendMode.Cutout:

material.SetOverrideTag("RenderType", "TransparentCutout");

material.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.One);

material.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.Zero);

material.SetInt("_ZWrite", 1);

material.EnableKeyword("_ALPHATEST_ON");

material.DisableKeyword("_ALPHABLEND_ON");

material.DisableKeyword("_ALPHAPREMULTIPLY_ON");

material.renderQueue = (int)UnityEngine.Rendering.RenderQueue.AlphaTest;

break;

case BlendMode.Fade:

material.SetOverrideTag("RenderType", "Transparent");

material.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.SrcAlpha);

material.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.OneMinusSrcAlpha);

material.SetInt("_ZWrite", 0);

material.DisableKeyword("_ALPHATEST_ON");

material.EnableKeyword("_ALPHABLEND_ON");

material.DisableKeyword("_ALPHAPREMULTIPLY_ON");

material.renderQueue = (int)UnityEngine.Rendering.RenderQueue.Transparent;

break;

case BlendMode.Transparent:

material.SetOverrideTag("RenderType", "Transparent");

material.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.One);

material.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.OneMinusSrcAlpha);

material.SetInt("_ZWrite", 0);

material.DisableKeyword("_ALPHATEST_ON");

material.DisableKeyword("_ALPHABLEND_ON");

material.EnableKeyword("_ALPHAPREMULTIPLY_ON");

material.renderQueue = (int)UnityEngine.Rendering.RenderQueue.Transparent;

break;

}

}

 

Here is my code to setup transparency for babylon for the export:

 

private static void DumpTransparency(Texture2D texture, Material material, BabylonSystemMaterial babylonPbrMaterial)

{

// Standard Alpha Transparency Mode

babylonPbrMaterial.alpha = 1.0f;

if (babylonPbrMaterial.albedo != null && babylonPbrMaterial.albedo.Length >= 4) {

babylonPbrMaterial.alpha = babylonPbrMaterial.albedo[3];

}

if (texture != null && texture.alphaIsTransparency == true) {

babylonPbrMaterial.backFaceCulling = false;

babylonPbrMaterial.useAlphaFromAlbedoTexture = true;

if (babylonPbrMaterial.albedoTexture != null) {

babylonPbrMaterial.albedoTexture.hasAlpha = true;

}

} else {

babylonPbrMaterial.useAlphaFromAlbedoTexture = false;

if (babylonPbrMaterial.albedoTexture != null) {

babylonPbrMaterial.albedoTexture.hasAlpha = false;

}

}

babylonPbrMaterial.alphaCutoff = 0.4f;

babylonPbrMaterial.transparencyMode = (int)BabylonTransparencyMode.Opaque;

if (material.HasProperty("_Mode")) {

var blendMode = (BlendMode)material.GetFloat("_Mode");

if (blendMode == BlendMode.Transparent) {

babylonPbrMaterial.alphaMode = 7; // PreMultiply

babylonPbrMaterial.alphaCutoff = 0.4f;

babylonPbrMaterial.transparencyMode = null;

} else if (blendMode == BlendMode.Cutout) {

babylonPbrMaterial.alphaMode = 2; // Default combine - but what should it be ???

babylonPbrMaterial.alphaCutoff = material.HasProperty("_Cutoff") ? material.GetFloat("_Cutoff") : 0.4f;

babylonPbrMaterial.transparencyMode = (int)BabylonTransparencyMode.AlphaTest;

} else if (blendMode == BlendMode.Fade) {

babylonPbrMaterial.alphaMode = 2; // Default combine - but what should it be ???

babylonPbrMaterial.alphaCutoff = material.HasProperty("_FadeCutoff") ? material.GetFloat("_FadeCutoff") : 0.4f;

babylonPbrMaterial.transparencyMode = (int)BabylonTransparencyMode.AlphaBlend;

}

}

}

 

 

From looking at the _SrcBlend and _DstBlend from unity, the only one I can tell for sure is TRANSPARENT... IT SAYS PREMULTIPLY

But what should I use for CUTOUT and FADE

Should FADE be Babylon Alpha Blend Mode Subtractive ()

material.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.SrcAlpha);

material.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.OneMinusSrcAlpha);

Can anyone PLEASE try to interpret the Unity Blend Info to what that would be in babylon

PRETTY PLEASE  

 

 

 

 

[MackeyK24]

This is a better DumpTransparency... I just need to know what to set material.alphaMode for the four different mode...

 

I have included the Unity _SrcBlend and _DstBlend and _ALPHAPREMULIPLY as REMARKS to use a guide to try and figure what is the best mode we should use for alpha mode based on the KIND OF properties they are using. Please take a look at the code and try tell me what I should put for material.alphaMode

 

private static void DumpTransparency(Texture2D texture, Material material, BabylonSystemMaterial babylonPbrMaterial)

{

// Standard Alpha Transparency Mode

bool alphaIsTransparency = false;

babylonPbrMaterial.alpha = 1.0f;

babylonPbrMaterial.alphaCutoff = 0.4f;

babylonPbrMaterial.transparencyMode = null;

if (babylonPbrMaterial.albedo != null && babylonPbrMaterial.albedo.Length >= 4) {

babylonPbrMaterial.alpha = babylonPbrMaterial.albedo[3];

}

if (texture != null && texture.alphaIsTransparency == true) {

alphaIsTransparency = true;

babylonPbrMaterial.backFaceCulling = false;

babylonPbrMaterial.useAlphaFromAlbedoTexture = true;

if (babylonPbrMaterial.albedoTexture != null) {

babylonPbrMaterial.albedoTexture.hasAlpha = true;

}

} else {

babylonPbrMaterial.useAlphaFromAlbedoTexture = false;

if (babylonPbrMaterial.albedoTexture != null) {

babylonPbrMaterial.albedoTexture.hasAlpha = false;

}

}

if (material.HasProperty("_Mode")) {

var blendMode = (BlendMode)material.GetFloat("_Mode");

if (blendMode == BlendMode.Opaque) {

//material.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.One);

//material.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.Zero);

//babylonPbrMaterial.alphaMode = 2;

 

babylonPbrMaterial.alphaCutoff = 0.4f;

babylonPbrMaterial.transparencyMode = (int)BabylonTransparencyMode.Opaque;

} else if (blendMode == BlendMode.Cutout) {

//material.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.One);

//material.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.Zero);

//babylonPbrMaterial.alphaMode = 2;

 

babylonPbrMaterial.alphaCutoff = material.HasProperty("_Cutoff") ? material.GetFloat("_Cutoff") : 0.4f;

babylonPbrMaterial.transparencyMode = (alphaIsTransparency) ? (int)BabylonTransparencyMode.AlphaTestAndBlend : (int)BabylonTransparencyMode.AlphaTest;

} else if (blendMode == BlendMode.Fade) {

//material.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.SrcAlpha);

//material.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.OneMinusSrcAlpha);

//babylonPbrMaterial.alphaMode = 2;

 

babylonPbrMaterial.alphaCutoff = material.HasProperty("_FadeCutoff") ? material.GetFloat("_FadeCutoff") : 0.4f;

babylonPbrMaterial.transparencyMode = (alphaIsTransparency) ? (int)BabylonTransparencyMode.AlphaBlend : (int)BabylonTransparencyMode.Opaque;

} else if (blendMode == BlendMode.Transparent) {

//material.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.One);

//material.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.OneMinusSrcAlpha);

//material.EnableKeyword("_ALPHAPREMULTIPLY_ON");

//babylonPbrMaterial.alphaMode = 7;

 

babylonPbrMaterial.alphaCutoff = 0.4f;

babylonPbrMaterial.transparencyMode = (alphaIsTransparency) ? (int)BabylonTransparencyMode.AlphaBlend : (int)BabylonTransparencyMode.Opaque;

}

}

}

 

 

 

 

[Guest]

You can find here how we deal with glBlend which is the same as the value you have in unity:

https://github.com/BabylonJS/Babylon.js/blob/master/src/Engine/babylon.engine.ts#L3958

Pick the one that works for you

[Sebavan]

looks like fade is combine and transparent is premultiply at a first glance.

[MackeyK24]

Thats what i thought, but i dont know what Cutoff and opaque should be ... combine also or additive or subtractive

[MackeyK24]

4 hours ago, Deltakosh said:

You can find here how we deal with glBlend which is the same as the value you have in unity:

https://github.com/BabylonJS/Babylon.js/blob/master/src/Engine/babylon.engine.ts#L3958

Pick the one that works for you

I am not trying to pick one... i sm trying to match the four options that unity uses for alpha mode... i just dont know means SrcBlend One and DstBlend Zero... would tbat be additive or subtractive or combine or what...

And should fade be combine

And should transparent be premultply

[MackeyK24]

4 hours ago, Sebavan said:

looks like fade is combine and transparent is premultiply at a first glance.

Thanks Sebastian 

[MackeyK24]

This is what I finalized on Dumping Transparency ... this should be a pretty good match to what unity is doing for Alpha Blending. Please review and tell me what you think:

        private static void DumpTransparency(Texture2D texture, Material material, BabylonSystemMaterial babylonPbrMaterial)
        {
            // Standard Alpha Transparency Mode
            bool alphaIsTransparency = false;
            babylonPbrMaterial.alpha = 1.0f;
            babylonPbrMaterial.alphaMode = 2;
            babylonPbrMaterial.alphaCutoff = material.HasProperty("_Cutoff") ? material.GetFloat("_Cutoff") : 0.4f;
            if (babylonPbrMaterial.albedo != null && babylonPbrMaterial.albedo.Length >= 4) {
                babylonPbrMaterial.alpha = babylonPbrMaterial.albedo[3];
            }
            if (texture != null && texture.alphaIsTransparency == true) {
                alphaIsTransparency = true;
                babylonPbrMaterial.backFaceCulling = false;
                babylonPbrMaterial.useAlphaFromAlbedoTexture = true;
                if (babylonPbrMaterial.albedoTexture != null) {
                    babylonPbrMaterial.albedoTexture.hasAlpha = true;
                }
            } else {
                babylonPbrMaterial.useAlphaFromAlbedoTexture = false;
                if (babylonPbrMaterial.albedoTexture != null) {
                    babylonPbrMaterial.albedoTexture.hasAlpha = false;
                }
            }
            if (material.HasProperty("_Mode")) {
                var blendMode = (BlendMode)material.GetFloat("_Mode");
                if (blendMode == BlendMode.Opaque) {
                    babylonPbrMaterial.alphaMode = 2; // Note: Alpha Not Used For Blending
                    babylonPbrMaterial.transparencyMode = (int)BabylonTransparencyMode.Opaque;
                } else if (blendMode == BlendMode.Cutout) {
                    babylonPbrMaterial.alphaMode = 2; // Note: Alpha Not Used For Blending
                    babylonPbrMaterial.transparencyMode = (int)BabylonTransparencyMode.AlphaTest;
                } else if (blendMode == BlendMode.Fade) {
                    babylonPbrMaterial.alphaMode = 2; // Note: Alpha Combine Blending Mode
                    babylonPbrMaterial.transparencyMode = (alphaIsTransparency) ? (int)BabylonTransparencyMode.AlphaBlend : (int)BabylonTransparencyMode.Opaque;
                } else if (blendMode == BlendMode.Transparent) {
                    babylonPbrMaterial.alphaMode = 7; // Note: Alpha Pre Multiply Blending Mode
                    babylonPbrMaterial.transparencyMode = (alphaIsTransparency) ? (int)BabylonTransparencyMode.AlphaBlend : (int)BabylonTransparencyMode.Opaque;
                }
            }
        }