XXX. Conversion from DOM element into WebGLTexture internal format

Any DOM element whose source format is not in RGB colorspace (e.g CYMK) is initially converted into RGB colorspace as usually performed by browsers [REF?] if access to at least one of R, G or B component is required.

Table XXX.Y summarizes the supported conversions with :

• Every component having a value represented between 0.0 (min) and 1.0 (max).
• A representing the alpha-channel component value, when it is unspecified the default value 1.0 is used.
• R representing the red color-channel component value, if available, or the luminance-channel component value otherwise.
• A source column being given for completeness only, as browsers traditionally do not support image formats that can define just one alpha-channel.

internalformat parameter	Storage representation	RGBA source	RGB  source	RA   source	R    source	A    source
ALPHA	A	0, 0, 0, A	0, 0, 0, 1	0, 0, 0, A	0, 0, 0, R	0, 0, 0, A
LUMINANCE	R	R, R, R, 1	R, R, R, 1	R, R, R, 1	R, R, R, 1	A, A, A, 1
LUMINANCE_ALPHA	RA	R, R, R, A	R, R, R, 1	R, R, R, A	R, R, R, 1	0, 0, 0, A
RGB	RGB	R, G, B, 1	R, G, B, 1	R, R, R, 1	R, R, R, 1	A, A, A, 1
RGBA	RGBA	R, G, B, A	R, G, B, 1	R, R, R, A	R, R, R, 1	0, 0, 0, A

Example 1: If internalformat is ALPHA and the DOM source is RGBA, texture will be stored as a sequence of A pixels with A the value of the alpha-channel for every source pixel.
Example 2: If internalformat is LUMINANCE_ALPHA and the DOM source is RGB, texture will be stored as a sequence of RA pixels with R the value of the red-color channel and A equal to 1.0.