[Openmsx-bugs] [ openmsx-Bugs-603675 ] Colors are wrong in SDLGL renderer

[<no...@so...>]

Bugs item #603675, was opened at 2002-09-02 22:10
You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=421861&aid=603675&group_id=38274

Category: Graphics
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: Manuel Bilderbeek (manuelbi)
Assigned to: Maarten ter Huurne (mthuurne)
Summary: Colors are wrong in SDLGL renderer

Initial Comment:
Wouter wrote:
The colors in SDLGLRenderer are wrong. You can best see
it in BASIC
when you type
	color 15,10,10
In all screen modes except screen0.40 the background
color is wrong,
the border color is correct.

Maarten replied:
The difference between SCREEN0.40 and the other
screens, is that SCREEN0.40 
uses a monochrome texture, while the other modes use a
coloured texture.

It seems the background colour is "amplified": when
bright, it becomes brighter, when dark it becomes
darker. Try "color=(4,2,0,0)" and you'll see the
background is darker than the border. At intensity 0 or
7 clipping occurs and as a result you cannot see the
difference with the border anymore.

Why it this happening? Some guesses:
1. Coloured textures use a different colour space than
the background.
2. When applying a texture to a quad, some setting is
wrong (maybe default value because it was never
initialised) and this causes the texture colour to be
amplified.

Guess 1 seems unlikely: I cannot see any reason why
this would be the case. 
Guess 2 sounds more likely, however I looked through
the GL spec and I cannot find any such setting. And
since the texture function is REPLACE, no setting
should have any effect.

(Still not solved though!)

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https://sourceforge.net/tracker/?func=detail&atid=421861&aid=603675&group_id=38274