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Fri Sep 2 15:24:15 PDT 2011

 =A0 =A0&quot;Additionally, vertex and geometry shaders can operate in two-=
 =A0 =A0 color mode. When a vertex or geometry shader is active, front and<=
 =A0 =A0 back colors can be computed by the shader and written to the<br>
 =A0 =A0 gl_FrontColor, gl_BackColor, gl_FrontSecondaryColor and<br>
 =A0 =A0 gl_BackSecondaryColor outputs. If VERTEX_PROGRAM_TWO_SIDE is<br>
 =A0 =A0 enabled, the GL chooses between front and back colors, as describe=
 =A0 =A0 below. Otherwise, the front color output is always<br>
 =A0 =A0 selected. Two-sided color mode is enabled and disabled by calling<=
 =A0 =A0 Enable or Disable with the symbolic value VERTEX_PROGRAM_TWO_SIDE.=
</blockquote></div><br>Agreed--we definitely have bugs in this area, and th=
is patch is not going to make those bugs any easier to fix.=A0 IIRC, Mesa d=
oesn&#39;t even pay attention to VERTEX_PROGRAM_TWO_SIDE.=A0 If you want to=
 get two-sided color behavior in your vertex shader, you need to enable GL_=
LIGHTING and set GL_LIGHT_MODEL_TWO_SIDE to 1, both of which seem unnecessa=
ry.=A0 Getting VERTEX_PROGRAM_TWO_SIDE to work properly is going to require=
 delving into some areas of Mesa I&#39;m not familiar with yet, so I think =
I&#39;d like to postpone it to a future patch series.<br>
<br>Unless you have an alternate suggestion, I&#39;ll change this code so t=
hat it only does the swizzle if two_side_color is set.=A0 There won&#39;t b=
e any functional change for now, but that way it will be easier to find wha=
t code needs changing when we go back later to implement VERTEX_PROGRAM_TWO=
_SIDE properly.=A0 And I&#39;ll file a bug to remind us about the VERTEX_PR=
OGRAM_TWO_SIDE problem, since I may not have time to get to it for a while.=


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