Hey this still works in Nim 1.2.
- Volumetric textures.
- Cube maps. I still don't have test textures for these.
- Images with widths or heights that are not powers of two. Makes the math inconvenient, and GPUs should be fed textures with powers of two anyway.
- Uncompressed textures. Anything which is not one of the usual DX-something codes (so, DXT compression) will be rejected as an unsupported file. Uncompressed formats are more complicated and application specific, and there are better formats for storing those (PNG, FLIF, WebP.)
proc base_width*(self: DdsReader): int
proc base_height*(self: DdsReader): int
Returns the base width or height of the image file. This does not change with the image's current mipmap level.
proc width*(self: DdsReader): int
proc height*(self: DdsReader): int
Returns the current width or height of the image. As smaller mipmap levels are encountered, this size shrinks progressivey.
proc current_mipmap*(self: DdsReader): int
Returns the current mip map encountered in the file, starting at zero.
proc total_mipmaps*(self: DdsReader): int
Returns total number of mipmaps in the file.
proc channel_count*(self: DdsReader): int
Makes an educated guess at the number of channels within this file. It does this by looking at whether the file is compressed or not, if certain flags are set, or certain FourCC codes are encountered. It may return -1, as there is no explicit channel count in a DDS file and unrecognized compression methods leave no way of knowing the proper size.
These are the basic procedures for getting your texture data out.
proc init*(self: var DdsReader; f: File): bool
Reads the header of a DDS from a file, storing it in the DDS reader. Returns true if a valid header could be read.
proc read*(self: var DdsReader; f: File; destination: var seq[uint8]): bool
Reads the current surface and/or mipmap level to destination, which will be setLen to the proper size. Returns true if data was read.
NOTE: DDS reader will not decode texel information. When reading compressed textures, you will receive the blob of compressed data for shipping to a decoder (or more likely, your GPU.)
proc skip*(self: var DdsReader; f: File): bool
Skips the current surface and/or mipmap level. Will seek forward in the file by the size of the image block. Returns true if skipping was successful. Skipping fails when the end of file is reached, such as the final mipmap in a mipmapped texture.