http://bugs.freedesktop.org/show_bug.cgi?id=20626
raoxianhong <raoxianh...@163.net> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|RESOLVED |REOPENED
Resolution|FIXED |
--- Comment #9 from raoxianhong <raoxianh...@163.net> 2009-03-17 04:57:23 PST
---
(In reply to comment #8)
> (In reply to comment #7)
> > (In reply to comment #6)
> > > The problem is solved by update mesa version. But I must DISABLE
> > > GL_TEXTURE_GEN_R and GL_TEXTURE_GEN_Q to do it. If GL_TEXTURE_GEN_R or
> > > GL_TEXTURE_GEN_Q is enabled, R200 looks line to object coord to normalized
> > > (x/w, y/w, z/w, 1.0), it is same when I use with ATI's driver under
> > > windows XP,
> > > so it must be a limitation of R200. (and I get the same result on RADEON
> > > X300,
> > > X1300)
> > I'm not sure I follow you there. If you get the same results on X300 and
> > X1300
> > then possibly the results might be correct. Clearly if you disable
> > GL_TEXTURE_GEN_R and GL_TEXTURE_GEN_Q results are expected to be different.
> > In the example you gave, what coords do you get?
> > The coords after texgen for your four vertices should be
> > (1.0, 0.0, 2.0, 2.0)
> > (1.0, 2.0, 2.0, 2.0)
> > (0.5, 2.0, 2.0, 2.0)
> > (0.25, 0.0, 1.0, 1.0)
> > hence after the q divide (and ignoring the unused r coord)
> > (0.5, 0.0)
> > (0.5, 1.0)
> > (0.25, 1.0)
> > (0.25, 0.0)
> > Is that different to what you get?
> > Note that if you disable some of the texgen coords, the r200 _will_ produce
> > bogus results in some cases, and I think it's generally a good idea to stay
> > away from doing this
> Oh, I forget the texture coordinates is homogeneous coordinates too, so the
> texture corrdinates is used with TEXTURE_2D is (s/q, t/q) actually.
> with object coordinate (x, y, z, w), the s, q texture coord is:
> s = s1 * x + s2 * y + s3 * z + s4 * w
> q = q1 * x + q2 * y + q3 * z + q4 * w
> if we normalized object coordinate to (x/w, y/w, z/w, 1.0)
> s' = s1 * x / w + s2 * y / w + s3 * z / w + s4
> q' = q1 * x / w + q2 * y / w + q3 * z / w + q4
> s/q = s'/q'
> R200 is correct, and you. The real world is 3D world, we can only use three
> indenpendent parameters talk with it.
> But can I set q coordinate to 1.0f when I disable texgen Q?
The bit R200_TEXGEN_FORCE_W_TO_ONE of the register R200_SE_TCL_TEX_PROC_CTL_0
may be used to set different Object coordinate for texgen.
for vertex coordinate (x, y, z, w), if R200_TEXGEN_FORCE_W_TO_ONE is set,
texgen
get the texture coordinate as
s = s1 * x + s2 * y + s3 * z + s4;
q = q1 * x + q2 * y + q3 * z + q4;
we set q1 = q2 = q3 = 0.0f and q4 = 1.0f and get q = 1.0f, thus we generate
texture
coordinate to s = s1 * x + s2 * y + s3 * z + s4; and vertex coordinate as
(x, y, z, w).
to do that, replace line 2421 of r200_state.c(mesa ver 7.2):
tpc = (rmesa->TexMatEnabled | rmesa->TexGenEnabled);
with
tpc = (rmesa->TexMatEnabled | rmesa->TexGenEnabled) |
R200_TEXGEN_FORCE_W_TO_ONE;
any better result?
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