nvidia-texture-tools/ApiDesignIssues.md

General Issues

• does nvtt have state? should we have a context? Don't use globals/statics.

InputOptions

• Default mipmap filter should be Box instead of Kaiser. (Fixed)
• Remove Format_LATC, stop adding more aliases.

Alpha transparency

• alphaTransparency should not be specified in setFormat.
• Add setAlphaMode(AlphaMode mode)

Where AlphaMode could be:

• AlphaMode_None
• AlphaMode_Transparency
• AlphaMode_Premultiplied

None is the default (treats alpha as a regular channel) while Transparency and Premultiplied are hints. Currently there are some compressors that only support None, others that only support Transparency.

Mipmapping options

Option 1:

• Deprecate setMipmapping.
• Add setMipmapFilter(MipmapFilter filter)
• Add maxLevel argument to setTextureLayout
• To disable mipmap output set maxLevel = 0.

Option 2:

• Deprecate setMipmapping.
• Add setMipmapFilter(MipmapFilter filter)
• Add enableMipmaps(bool enable)
• Add setMipmapMaxLevel(int maxLevel)

Option 3:

• Add setMipmapFilter(MipmapFilter filter)
• Remove filter argument from setMipmapping: setMipmapping(bool enabled, int maxLevel)

Option 4:

• Leave things as is.

CompressionOptions

• enableHardwareCompressor, should be called enableCudaCompressor or enableGpuCompressor.
• Quantization should be a compression option.
• remove error threshold from setQuality, it's not used.
• setColorWeights should take an alpha weight, not used right now, but useful for future formats.

OutputOptions

• Should be a pimpl like InputOptions and CompressionOptions. Member attributes should be hidden.

• Add setFileName() member to output dds file directly instead of using output handler.

Output Handling

• OutputHandler::writeData should return false to signal a write error and stop processing.
• The mipmap method of OutputHandler should have been called image or beginImage.

Error Handling

• Error_Unknown should be 0
• Error_UserInterruption is not being used and could be removed.