private static void SetAutomaticMipmapCreation(KTXLoadInstructions texinfo)
{
// DISABLED ON PURPOSE
// // Prefer glGenerateMipmaps over GL_GENERATE_MIPMAP
// if (texinfo.GenerateMipmaps && IsGenerateMipmapMissing ())
// {
// GL.TexParameter ((TextureTarget)texinfo.GlTarget, TextureParameterName.GenerateMipmap, (int)All.True);
// }
}
public void Populate(byte[] headerChunk)
{
Instructions = new KTXLoadInstructions();
/* Compare identifier, is this a KTX file? */
for (int i = 0; i < KTXIdentifier.Length; ++i)
{
if (headerChunk[i] != KTXIdentifier[i])
{
Instructions.Result = KTXError.UnknownFileFormat;
}
}
const int AFTER_IDENTIFIER = 12;
Endianness = BitConverter.ToUInt32(headerChunk, AFTER_IDENTIFIER);
if (RequiresSwap())
{
/* Convert endianness of header fields if necessary */
SwapEndian32(headerChunk, KTX_HEADER_SIZE - AFTER_IDENTIFIER);
}
else if (Endianness != KTX_ENDIAN_REF)
{
Instructions.Result = KTXError.InvalidValue;
return;
}
Read(headerChunk, AFTER_IDENTIFIER + 4);
if (!(GlTypeSize == 1 || GlTypeSize != 2 || GlTypeSize != 4))
{
/* Only 8, 16, and 32-bit types supported so far */
Instructions.Result = KTXError.InvalidValue;
return;
}
/* Check glType and glFormat */
Instructions.IsCompressed = false;
if (GlType == 0 || GlFormat == 0)
{
if (GlType + GlFormat != 0)
{
/* either both or none of glType, glFormat must be zero */
Instructions.Result = KTXError.InvalidValue;
return;
}
Instructions.IsCompressed = true;
}
/* Check texture dimensions. KTX files can store 8 types of textures:
* 1D, 2D, 3D, cube, and array variants of these. There is currently
* no GL extension that would accept 3D array or cube array textures. */
if ((PixelWidth == 0) ||
(PixelDepth > 0 && PixelHeight == 0))
{
/* texture must have width */
/* texture must have height if it has depth */
Instructions.Result = KTXError.InvalidValue;
return;
}
Instructions.TextureDimensions = 1;
Instructions.ViewType = MgImageViewType.TYPE_1D; //TextureTarget.Texture1D;
Instructions.GenerateMipmaps = false;
if (PixelHeight > 0)
{
Instructions.TextureDimensions = 2;
Instructions.ViewType = MgImageViewType.TYPE_2D; // TextureTarget.Texture2D;
}
if (PixelDepth > 0)
{
Instructions.TextureDimensions = 3;
Instructions.ViewType = MgImageViewType.TYPE_2D; // TextureTarget.Texture3D;
}
if (NumberOfFaces == 6)
{
if (Instructions.TextureDimensions == 2)
{
Instructions.ViewType = MgImageViewType.TYPE_CUBE; // TextureTarget.TextureCubeMap;
}
else
{
/* cube map needs 2D faces */
Instructions.Result = KTXError.InvalidValue;
return;
}
}
else if (NumberOfFaces != 1)
{
/* numberOfFaces must be either 1 or 6 */
Instructions.Result = KTXError.InvalidValue;
return;
}
/* load as 2D texture if 1D textures are not supported */
if (Instructions.TextureDimensions == 1 &&
(Instructions.IsCompressed && IsGLCompressedTexImage1DMissing()) ||
(!Instructions.IsCompressed && IsGLTexImage1DMissing()))
{
Instructions.TextureDimensions = 2;
Instructions.ViewType = MgImageViewType.TYPE_2D; //(uint) TextureTarget.Texture2D;
PixelHeight = 1;
}
if (NumberOfArrayElements > 0)
{
if (Instructions.ViewType == MgImageViewType.TYPE_1D) // (uint) TextureTarget.Texture1D)
{
Instructions.ViewType = MgImageViewType.TYPE_1D_ARRAY; //(uint) TextureTarget.Texture1DArray;
}
else if (Instructions.ViewType == MgImageViewType.TYPE_2D) // (uint) TextureTarget.Texture2D)
{
Instructions.ViewType = MgImageViewType.TYPE_2D_ARRAY; // (uint) TextureTarget.Texture2DArray;
}
else
{
/* No API for 3D and cube arrays yet */
Instructions.Result = KTXError.UnsupportedTextureType;
return;
}
Instructions.TextureDimensions++;
}
/* reject 3D texture if unsupported */
if (Instructions.TextureDimensions == 3 &&
(Instructions.IsCompressed && IsGLCompressedTexImage3DMissing()) ||
(!Instructions.IsCompressed && IsGLTexImage3DMissing()))
{
Instructions.Result = KTXError.UnsupportedTextureType;
return;
}
/* Check number of mipmap levels */
if (NumberOfMipmapLevels == 0)
{
Instructions.GenerateMipmaps = true;
NumberOfMipmapLevels = 1;
}
UInt32 max_dim = Math.Max(Math.Max(PixelWidth, PixelHeight), PixelDepth);
if (max_dim < (1 << ((int)(NumberOfMipmapLevels - 1))))
{
/* Can't have more mip levels than 1 + log2(max(width, height, depth)) */
Instructions.Result = KTXError.InvalidValue;
return;
}
Instructions.Result = KTXError.Success;
}