Alpha masking - Revision history

Windwalkr at 10:33, 24 October 2017

2017-10-24T10:33:38Z

← Older revision		Revision as of 10:33, 24 October 2017
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	=Control of alpha masking via texture.txt file=		=Control of alpha masking via texture.txt file=
	[[texture.txt file]]s may be created with masked alpha, either by using a perfectly black and white (as opposed to grayscale) alpha channel, or by forcing alpha masking using the appropriate tags. This controls the contents of the texture file, but does ~~NOT~~ affect the behavior of the material. The appropriate [[Material Types\|material type]] must be used to achieve the desired outcome.		[[texture.txt file]]s may be created with masked alpha, either by using a perfectly black and white (as opposed to grayscale) alpha channel, or by forcing alpha masking using the appropriate tags. This controls the contents of the texture file, but does not affect the behavior of the material (except for certain auto-switching legacy materials). The appropriate [[Material Types\|material type]] must be used to achieve the desired outcome.

	''TBD: alpha masking vs mip mapping''		''TBD: alpha masking vs mip mapping''

Windwalkr at 10:23, 24 October 2017

2017-10-24T10:23:56Z

← Older revision		Revision as of 10:23, 24 October 2017
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	[[Alpha masking]] refers to a special case of [[alpha blending]] where all pixels are rendered as either fully opaque (100% alpha) or fully transparent (0% alpha) with no partial transparency. This can be treated as a special case because it does not require alpha sorting in order to produce visually correct results. ~~This~~ provides a significant performance win over an equivalent alpha sorted material.		[[Alpha masking]] refers to a special case of [[alpha blending]] where all pixels are rendered as either fully opaque (100% alpha) or fully transparent (0% alpha) with no partial transparency. This can be treated as a special case because it does not require alpha sorting in order to produce visually correct results. On most hardware, this provides a significant performance win over an equivalent alpha sorted material. On some hardware, this is substantially slower than an opaque material. This technique also guarantees correct visual outcomes, whereas alpha sorting is inevitably an approximation which will show incorrect results in certain edge cases.

	''TBD: ~~Materials~~ which support alpha masking.''		= Materials which support alpha masking =
			The following materials support alpha masking:
			* [[m.pbrmetalmasked]]
			* TBD: legacy materials which optionally support alpha masking.

	~~''TBD:~~ Control of alpha masking via texture.txt file''		=Control of alpha masking via texture.txt file=
			[[texture.txt file]]s may be created with masked alpha, either by using a perfectly black and white (as opposed to grayscale) alpha channel, or by forcing alpha masking using the appropriate tags. This controls the contents of the texture file, but does NOT affect the behavior of the material. The appropriate [[Material Types\|material type]] must be used to achieve the desired outcome.

			''TBD: alpha masking vs mip mapping''

			=TBD=

	''TBD: Image of alpha mask and the in-game result, versus alpha blending.''		''TBD: Image of alpha mask and the in-game result, versus alpha blending.''
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	''TBD: Overdraw concerns''		''TBD: Overdraw concerns''

	~~''TBD: alpha masking vs mip mapping''~~

	[[Category:Texture mapping]]		[[Category:Texture mapping]]

Windwalkr at 11:01, 18 October 2017

2017-10-18T11:01:27Z

← Older revision		Revision as of 11:01, 18 October 2017
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	[[Alpha masking]] refers to a special case of [[alpha blending]] where all pixels are rendered as either fully opaque (100% alpha) or fully transparent (0% alpha) with no partial transparency. This can be treated as a special case because it does not require alpha sorting in order to produce visually correct results. This provides a significant performance win over an equivalent alpha sorted material.		[[Alpha masking]] refers to a special case of [[alpha blending]] where all pixels are rendered as either fully opaque (100% alpha) or fully transparent (0% alpha) with no partial transparency. This can be treated as a special case because it does not require alpha sorting in order to produce visually correct results. This provides a significant performance win over an equivalent alpha sorted material.

	When an alpha masked texture is recognized, Trainz will also compress [[texture file]]s using DXT1a compression rather than the DXT3 required for normal alpha blending. This provides a 50% reduction in texture memory usage.

	''TBD: Materials which support alpha masking.''		''TBD: Materials which support alpha masking.''
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	''TBD: Discussion of using alpha testing without a b&w texture.''		''TBD: Discussion of using alpha testing without a b&w texture.''

			''TBD: Overdraw concerns''

			''TBD: alpha masking vs mip mapping''

	[[Category:Texture mapping]]		[[Category:Texture mapping]]

Retro00064: Added Category:Texture mapping.

2011-09-05T02:03:50Z

Added Category:Texture mapping.

← Older revision		Revision as of 02:03, 5 September 2011
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	''TBD: Discussion of using alpha testing without a b&w texture.''		''TBD: Discussion of using alpha testing without a b&w texture.''

			[[Category:Texture mapping]]

Windwalkr: 1 revision

2010-02-03T13:58:21Z

1 revision

← Older revision	Revision as of 13:58, 3 February 2010
(No difference)

Windwalkr at 12:28, 16 September 2008

2008-09-16T12:28:27Z

New page

[[Alpha masking]] refers to a special case of [[alpha blending]] where all pixels are rendered as either fully opaque (100% alpha) or fully transparent (0% alpha) with no partial transparency. This can be treated as a special case because it does not require alpha sorting in order to produce visually correct results. This provides a significant performance win over an equivalent alpha sorted material.

When an alpha masked texture is recognized, Trainz will also compress [[texture file]]s using DXT1a compression rather than the DXT3 required for normal alpha blending. This provides a 50% reduction in texture memory usage.

''TBD: Materials which support alpha masking.''

''TBD: Control of alpha masking via texture.txt file''

''TBD: Image of alpha mask and the in-game result, versus alpha blending.''

''TBD: Discussion of using alpha testing without a b&w texture.''