/// <summary>
/// Scan a texture looking for transparent pixels and trying to guess the correct blend mode needed.
/// </summary>
/// <param name="texture">input rexture (it must be set to readable)</param>
/// <param name="mode">blend mode set to FADE or CUTOUT if transparent pixels are found.</param>
/// <returns>Return true if transparent pixels were found.</returns>
public static bool ScanTransparentPixels(Texture2D texture, ref MtlBlendMode mode)
{
bool texCanBeTransparent = texture != null &&
(texture.format == TextureFormat.ARGB32 ||
texture.format == TextureFormat.RGBA32 ||
texture.format == TextureFormat.DXT5 ||
texture.format == TextureFormat.ARGB4444 ||
texture.format == TextureFormat.BGRA32 ||
texture.format == TextureFormat.DXT5Crunched
//|| texture.format == ... (all alpha formats)
);
if (texCanBeTransparent)
{
bool stop = false;
int pixelScanFrequency = 1;
for (int x = 0; x < texture.width && !stop; x += pixelScanFrequency)
{
for (int y = 0; y < texture.height && !stop; y += pixelScanFrequency)
{
float a = texture.GetPixel(x, y).a;
DetectMtlBlendFadeOrCutout(a, ref mode, ref stop);
if (stop)
{
return(mode == MtlBlendMode.FADE || mode == MtlBlendMode.CUTOUT);
}
}
}
}
return(mode == MtlBlendMode.FADE || mode == MtlBlendMode.CUTOUT);
}
/// <summary>
/// Set up a Material for the given mode.
/// </summary>
/// <remarks>Here is replicated what is done when choosing a blend mode from Inspector.</remarks>
/// <param name="mtl">material to be changed</param>
/// <param name="mode">mode to be set</param>
public static void SetupMaterialWithBlendMode(Material mtl, MtlBlendMode mode)
{
switch (mode)
{
case MtlBlendMode.OPAQUE:
mtl.SetOverrideTag("RenderType", "Opaque");
mtl.SetFloat("_Mode", 0);
mtl.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.One);
mtl.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.Zero);
mtl.SetInt("_ZWrite", 1);
mtl.DisableKeyword("_ALPHATEST_ON");
mtl.DisableKeyword("_ALPHABLEND_ON");
mtl.DisableKeyword("_ALPHAPREMULTIPLY_ON");
mtl.renderQueue = -1;
break;
case MtlBlendMode.CUTOUT:
mtl.SetOverrideTag("RenderType", "TransparentCutout");
mtl.SetFloat("_Mode", 1);
mtl.SetFloat("_Mode", 1);
mtl.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.One);
mtl.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.Zero);
mtl.SetInt("_ZWrite", 1);
mtl.EnableKeyword("_ALPHATEST_ON");
mtl.DisableKeyword("_ALPHABLEND_ON");
mtl.DisableKeyword("_ALPHAPREMULTIPLY_ON");
mtl.renderQueue = 2450;
break;
case MtlBlendMode.FADE:
mtl.SetOverrideTag("RenderType", "Transparent");
mtl.SetFloat("_Mode", 2);
mtl.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.SrcAlpha);
mtl.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.OneMinusSrcAlpha);
mtl.SetInt("_ZWrite", 0);
mtl.DisableKeyword("_ALPHATEST_ON");
mtl.EnableKeyword("_ALPHABLEND_ON");
mtl.DisableKeyword("_ALPHAPREMULTIPLY_ON");
mtl.renderQueue = 3000;
break;
case MtlBlendMode.TRANSPARENT:
mtl.SetOverrideTag("RenderType", "Transparent");
mtl.SetFloat("_Mode", 3);
mtl.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.One);
mtl.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.OneMinusSrcAlpha);
mtl.SetInt("_ZWrite", 0);
mtl.DisableKeyword("_ALPHATEST_ON");
mtl.DisableKeyword("_ALPHABLEND_ON");
mtl.EnableKeyword("_ALPHAPREMULTIPLY_ON");
mtl.renderQueue = 3000;
break;
}
}
/// <summary>
/// Detect if the blend mode must be set to FADE or CUTOUT
/// according to the given alpha value and the current value of mode.
/// </summary>
/// <param name="alpha">input alpha value</param>
/// <param name="mode">blend mode set to FADE or CUTOUT</param>
/// <param name="noDoubt">flag set to true if the mode is finally detected (it can be used to break from a scan loop)</param>
public static void DetectMtlBlendFadeOrCutout(float alpha, ref MtlBlendMode mode, ref bool noDoubt)
{
if (noDoubt)
{
return;
}
if (alpha < 1.0f)
{
//mode = MtlBlendMode.TRANSPARENT;
if (alpha == 0.0f)
{
// assume there is a "cutout texture"
mode = MtlBlendMode.CUTOUT;
} // else 0<alpha<1
else if (mode != MtlBlendMode.FADE)
{
// assume there is a "fade texture"
mode = MtlBlendMode.FADE;
noDoubt = true;
}
}
}
