/// <summary>
/// Processes a texture.
/// </summary>
/// <param name="input">The texture content to process.</param>
/// <param name="context">Context for the specified processor.</param>
/// <returns>The converted texture content.</returns>
/// <exception cref="ArgumentNullException">
/// <paramref name="input"/> or <paramref name="context"/> is <see langword="null"/>.
/// </exception>
public override TextureContent Process(TextureContent input, ContentProcessorContext context)
{
if (input == null)
throw new ArgumentNullException("input");
if (context == null)
throw new ArgumentNullException("context");
// Linear vs. sRGB:
// XNA does not support _SRGB texture formats. Texture processing is designed
// for non-sRGB formats. (sRGB formats require a different order of operations!
// See section "Alpha Blending" in DigitalRune KB.)
try
{
var mipmapChain = input.Faces[0]; // Mipmap chain.
var level0 = mipmapChain[0]; // Most detailed mipmap level.
int width = level0.Width;
int height = level0.Height;
// Early out?
if (!ColorKeyEnabled
&& (!GenerateMipmaps || (width == 1 && height == 1) // Does not need mipmaps
|| mipmapChain.Count > 1) // or already has mipmaps.
&& !PremultiplyAlpha
&& (!ResizeToPowerOfTwo || (MathHelper.IsPowerOf2(width) && MathHelper.IsPowerOf2(height)))
&& !ScaleAlphaToCoverage)
{
if (Format == DRTextureFormat.NoChange)
{
// No processing required.
return input;
}
SurfaceFormat surfaceFormat;
if (!level0.TryGetFormat(out surfaceFormat))
throw new InvalidContentException("Surface format is not supported.", input.Identity);
if ((Format == DRTextureFormat.Color && surfaceFormat == SurfaceFormat.Color)
|| (Format == DRTextureFormat.Dxt && IsDxt(surfaceFormat)))
{
// No processing required.
return input;
}
}
var texture = TextureHelper.ToTexture(input);
var sourceFormat = texture.Description.Format;
// Apply color keying.
if (ColorKeyEnabled)
{
// Apply color keying in RGBA 8:8:8:8.
texture = texture.ConvertTo(DataFormat.R8G8B8A8_UNORM);
TextureHelper.ApplyColorKey(texture, ColorKeyColor.R, ColorKeyColor.G, ColorKeyColor.B, ColorKeyColor.A);
}
// Normal maps require special treatment (no sRGB, etc.).
bool isNormalMap = (Format == DRTextureFormat.Normal || Format == DRTextureFormat.NormalInvertY);
if (isNormalMap)
{
InputGamma = 1.0f;
OutputGamma = 1.0f;
PremultiplyAlpha = false;
}
// Check whether alpha channel is used.
bool hasAlpha = false; // true if alpha channel != 1.
bool hasFractionalAlpha = false; // true if alpha channel has 0 < alpha < 1.
if (!isNormalMap)
{
if (GenerateMipmaps || ResizeToPowerOfTwo || PremultiplyAlpha || Format == DRTextureFormat.Dxt)
{
try
{
TextureHelper.HasAlpha(texture, out hasAlpha, out hasFractionalAlpha);
}
catch (NotSupportedException)
{
// HasAlpha() does not support the current format. Convert and try again.
texture = texture.ConvertTo(DataFormat.R32G32B32A32_FLOAT);
TextureHelper.HasAlpha(texture, out hasAlpha, out hasFractionalAlpha);
}
}
}
// Convert to high-precision, floating-point format for processing.
texture = texture.ConvertTo(DataFormat.R32G32B32A32_FLOAT);
if (!isNormalMap)
{
// Convert texture from gamma space to linear space.
TextureHelper.GammaToLinear(texture, InputGamma);
}
else
{
// Convert normal map from [0, 1] to [-1, 1].
TextureHelper.UnpackNormals(texture);
}
// The resize filter needs to consider alpha if the image is not already
// premultiplied. PremultiplyAlpha indicates that the source image has
// alpha, but is not yet premultiplied. (Premultiplication happen at the
// end.)
bool alphaTransparency = hasAlpha && PremultiplyAlpha;
if (ResizeToPowerOfTwo || context.TargetProfile == GraphicsProfile.Reach && Format == DRTextureFormat.Dxt)
{
// Resize to power-of-two.
int expectedWidth = RoundUpToPowerOfTwo(texture.Description.Width);
int expectedHeight = RoundUpToPowerOfTwo(texture.Description.Height);
if (expectedWidth != texture.Description.Width || expectedHeight != texture.Description.Height)
texture = texture.Resize(expectedWidth, expectedHeight, texture.Description.Depth, ResizeFilter.Kaiser, alphaTransparency, TextureAddressMode.Clamp);
}
if (Format == DRTextureFormat.Dxt || Format == DRTextureFormat.Normal || Format == DRTextureFormat.NormalInvertY)
{
// Resize to multiple of four.
int expectedWidth = RoundToMultipleOfFour(texture.Description.Width);
int expectedHeight = RoundToMultipleOfFour(texture.Description.Height);
if (expectedWidth != texture.Description.Width || expectedHeight != texture.Description.Height)
texture = texture.Resize(expectedWidth, expectedHeight, texture.Description.Depth, ResizeFilter.Kaiser, alphaTransparency, TextureAddressMode.Clamp);
}
if (GenerateMipmaps && texture.Description.MipLevels <= 1)
{
// Generate mipmaps.
texture.GenerateMipmaps(ResizeFilter.Box, alphaTransparency, TextureAddressMode.Repeat);
}
// For debugging:
// ColorizeMipmaps(texture);
if (!isNormalMap)
{
if (ScaleAlphaToCoverage)
TextureHelper.ScaleAlphaToCoverage(texture, ReferenceAlpha, /* data not yet premultiplied */ false);
// Convert texture from linear space to gamma space.
TextureHelper.LinearToGamma(texture, OutputGamma);
// Premultiply alpha.
if (hasAlpha && PremultiplyAlpha)
TextureHelper.PremultiplyAlpha(texture);
}
else
{
// Renormalize normal map and convert to DXT5nm.
TextureHelper.ProcessNormals(texture, Format == DRTextureFormat.NormalInvertY);
}
// No PVRTC in XNA build.
string mgPlatform = ContentHelper.GetMonoGamePlatform();
if (!string.IsNullOrEmpty(mgPlatform) && mgPlatform.ToUpperInvariant() == "IOS")
Format = DRTextureFormat.Color;
// Convert to from floating-point format to requested output format.
switch (Format)
{
case DRTextureFormat.NoChange:
texture = texture.ConvertTo(sourceFormat);
input = TextureHelper.ToContent(texture, input.Identity);
break;
case DRTextureFormat.Color:
texture = texture.ConvertTo(DataFormat.R8G8B8A8_UNORM);
input = TextureHelper.ToContent(texture, input.Identity);
break;
case DRTextureFormat.Dxt:
if (texture.Description.Dimension == TextureDimension.Texture3D)
{
texture = texture.ConvertTo(DataFormat.R8G8B8A8_UNORM);
input = TextureHelper.ToContent(texture, input.Identity);
}
else
{
input = Compress(context, texture, hasAlpha, hasFractionalAlpha, PremultiplyAlpha, input.Identity);
#else
if (hasFractionalAlpha)
texture = texture.ConvertTo(DataFormat.BC3_UNORM);
else
texture = texture.ConvertTo(DataFormat.BC1_UNORM);
input = TextureHelper.ToContent(texture, input.Identity);
}
break;
case DRTextureFormat.Normal:
case DRTextureFormat.NormalInvertY:
input = Compress(context, texture, true, true, false, input.Identity);
#else
texture = texture.ConvertTo(DataFormat.BC3_UNORM);
input = TextureHelper.ToContent(texture, input.Identity);
break;
default:
throw new NotSupportedException("The specified output format is not supported.");
}
}
catch (Exception ex)
{
throw new InvalidContentException(ex.Message, input.Identity);
}
return input;
}