[Mesa3d-dev] [ mesa3d-Bugs-694546 ] OSMesa/SWRast/ChanBits=32: error in s_aaline.c

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Bugs item #694546, was opened at 2003-02-27 19:17
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Category: mesa-core
Group: Rendering Error
>Status: Closed
>Resolution: Fixed
Priority: 5
Submitted By: Thomas Zeier (tzeier)
Assigned to: Brian Paul (brianp)
Summary: OSMesa/SWRast/ChanBits=32: error in s_aaline.c

Initial Comment:
file: s_aaline.c

A:

in static INLINE GLchan solve_plane_chan(GLfloat x, GLfloat y, 
const GLfloat plane[4])

actual:
return (GLchan) (GLint) z;

if wrong if GLchan==GLfloat

better: return (GLchan) z;

B:
in compute_plane(...)
#if 0
	/* original */
...
#else
	/* simplified */
...
#endif

The original version works better ;-) if GLchan==GLfloat

aws

TZ

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>Comment By: Brian Paul (brianp)
Date: 2003-02-28 15:19

Message:
Logged In: YES 
user_id=983

OK, fixed that.  it was actually fixed in the CVS trunk code
for AA triangles, but not for AA lines.
Closing this report now.


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Comment By: Thomas Zeier (tzeier)
Date: 2003-02-28 11:49

Message:
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user_id=722338

the error is in solve_plane_chan(...)

z = (plane[3] + plane[0] * x + plane[1] * y) / -plane[2] + 0.5F;

is wrong. if chantype==float then bounding of colors are 0..1 not 0..255 
or so.

if chantype==float
 +0.5 ==> 50% of color
else
 +0.5 ==> 0.2% of color
end

Solution:

#if CHAN_TYPE == GL_FLOAT
	z = (plane[3] + plane[0] * x + plane[1] * y) / -plane[2];
#else
	z = (plane[3] + plane[0] * x + plane[1] * y) / -plane[2] + 0.5F;
#endif

aws

TZ

----------------------------------------------------------------------

Comment By: Brian Paul (brianp)
Date: 2003-02-27 23:47

Message:
Logged In: YES 
user_id=983

I'm fixing the first casting problem.

I don't understand your comment about compute_plane().


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