/// <summary>
/// Resizes the texture. (If original texture has mipmaps, all mipmap levels are automatically
/// recreated.)
/// </summary>
/// <param name="width">The new width.</param>
/// <param name="height">The new height.</param>
/// <param name="depth">The new depth. Must be 1 for 2D textures and cube map textures.</param>
/// <param name="filter">The filter to use for resizing.</param>
/// <param name="alphaTransparency">
/// <see langword="true"/> if the image contains uses non-premultiplied alpha; otherwise,
/// <see langword="false"/> if the image uses premultiplied alpha or has no alpha.
/// </param>
/// <param name="wrapMode">
/// The texture address mode that will be used for sampling the at runtime.
/// </param>
/// <returns>The resized texture.</returns>
public Texture Resize(int width, int height, int depth, ResizeFilter filter, bool alphaTransparency, TextureAddressMode wrapMode)
{
var description = Description;
description.Width = width;
description.Height = height;
description.Depth = depth;
var resizedTexture = new Texture(description);
// Resize mipmap level 0.
for (int arrayIndex = 0; arrayIndex < description.ArraySize; arrayIndex++)
TextureHelper.Resize(this, 0, arrayIndex, resizedTexture, 0, arrayIndex, filter, alphaTransparency, wrapMode);
// Regenerate mipmap levels, if necessary.
if (description.MipLevels > 1)
resizedTexture.GenerateMipmaps(filter, alphaTransparency, wrapMode);
return resizedTexture;
}
/// <summary>
/// (Re-)Generates all mipmap levels.
/// </summary>
/// <param name="filter">The filter to use for resizing.</param>
/// <param name="alphaTransparency">
/// <see langword="true"/> if the image contains uses non-premultiplied alpha; otherwise,
/// <see langword="false"/> if the image uses premultiplied alpha or has no alpha.
/// </param>
/// <param name="wrapMode">
/// The texture address mode that will be used for sampling the at runtime.
/// </param>
public void GenerateMipmaps(ResizeFilter filter, bool alphaTransparency, TextureAddressMode wrapMode)
{
var oldDescription = Description;
var newDescription = Description;
// Determine number of mipmap levels.
if (oldDescription.Dimension == TextureDimension.Texture3D)
newDescription.MipLevels = TextureHelper.CalculateMipLevels(oldDescription.Width, oldDescription.Height, oldDescription.Depth);
else
newDescription.MipLevels = TextureHelper.CalculateMipLevels(oldDescription.Width, oldDescription.Height);
if (oldDescription.MipLevels != newDescription.MipLevels)
{
// Update Description and Images.
var oldImages = Images;
Description = newDescription;
ValidateTexture(newDescription);
// Recreate image collection. (Mipmap level 0 is copied from existing image collection.)
Images = CreateImageCollection(newDescription, true);
for (int arrayIndex = 0; arrayIndex < newDescription.ArraySize; arrayIndex++)
{
for (int zIndex = 0; zIndex < newDescription.Depth; zIndex++)
{
int oldIndex = oldDescription.GetImageIndex(0, arrayIndex, zIndex);
int newIndex = newDescription.GetImageIndex(0, arrayIndex, zIndex);
Images[newIndex] = oldImages[oldIndex];
}
}
}
// Downsample mipmap levels.
for (int arrayIndex = 0; arrayIndex < newDescription.ArraySize; arrayIndex++)
for (int mipIndex = 0; mipIndex < newDescription.MipLevels - 1; mipIndex++)
TextureHelper.Resize(this, mipIndex, arrayIndex, this, mipIndex + 1, arrayIndex, filter, alphaTransparency, wrapMode);
}