Add helpers to add/modulate glsl vec4s.

[bsalomon, 2012-08-28 21:59:55]

Some cleanup on the way to getting rid of fSwizzle and fModulate on
GrGLShaderBuilder.

[robertphillips, 2012-08-29 10:47:27]

LGTM + 1 question & 1 comment change request

https://codereview.appspot.com/6497046/diff/2001/src/gpu/gl/GrGLSL.cpp
File src/gpu/gl/GrGLSL.cpp (right):

https://codereview.appspot.com/6497046/diff/2001/src/gpu/gl/GrGLSL.cpp#newcod...
src/gpu/gl/GrGLSL.cpp:117: } else {
// Both defaults are kOnes

https://codereview.appspot.com/6497046/diff/2001/src/gpu/gl/GrGLSL.cpp#newcod...
src/gpu/gl/GrGLSL.cpp:144: 
Why not remove the default<i> params and just always assume they are zero?

https://codereview.appspot.com/6497046/diff/2001/src/gpu/gl/GrGLSL.h
File src/gpu/gl/GrGLSL.h (right):

https://codereview.appspot.com/6497046/diff/2001/src/gpu/gl/GrGLSL.h#newcode150
src/gpu/gl/GrGLSL.h:150: * The result is always a vec4. The inputs may be
expressions, not just identifier names. Either
in which _case_
params -> default<i>

[bsalomon, 2012-08-29 12:50:18]

https://codereview.appspot.com/6497046/diff/2001/src/gpu/gl/GrGLSL.cpp
File src/gpu/gl/GrGLSL.cpp (right):

https://codereview.appspot.com/6497046/diff/2001/src/gpu/gl/GrGLSL.cpp#newcod...
src/gpu/gl/GrGLSL.cpp:117: } else {
On 2012/08/29 10:47:27, robertphillips wrote:
> // Both defaults are kOnes

Done.

https://codereview.appspot.com/6497046/diff/2001/src/gpu/gl/GrGLSL.cpp#newcod...
src/gpu/gl/GrGLSL.cpp:144: 
On 2012/08/29 10:47:27, robertphillips wrote:
> Why not remove the default<i> params and just always assume they are zero?

I was thinking that a caller might not want this function to silently work when
an input is empty/null if that is an unexpected condition.

https://codereview.appspot.com/6497046/diff/2001/src/gpu/gl/GrGLSL.h
File src/gpu/gl/GrGLSL.h (right):

https://codereview.appspot.com/6497046/diff/2001/src/gpu/gl/GrGLSL.h#newcode150
src/gpu/gl/GrGLSL.h:150: * The result is always a vec4. The inputs may be
expressions, not just identifier names. Either
On 2012/08/29 10:47:27, robertphillips wrote:
> in which _case_
> params -> default<i>

Done.

[bsalomon, 2012-08-29 13:00:16]

Closed with r5332.