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Front-ends: Non-functional: Rationalize vector and matrix swizzles.

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This reduces code duplication in a few ways, and better encapsulates
vector swizzle representation.
This commit is contained in:
John Kessenich 2017-01-13 19:34:22 -07:00
parent 0a76a1870c
commit c142c88967
12 changed files with 269 additions and 340 deletions
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102
glslang/MachineIndependent/ParseContextBase.cpp
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@ -433,6 +433,108 @@ const TFunction* TParseContextBase::selectFunction(
return incumbent;
}
//
// Look at a '.' field selector string and change it into numerical selectors
// for a vector or scalar.
//
// Always return some form of swizzle, so the result is always usable.
//
void TParseContextBase::parseSwizzleSelector(const TSourceLoc& loc, const TString& compString, int vecSize,
TSwizzleSelectors<TVectorSelector>& selector)
{
// Too long?
if (compString.size() > TSwizzleSelectors<TVectorSelector>::maxSelectors)
error(loc, "vector swizzle too long", compString.c_str(), "");
// Use this to test that all swizzle characters are from the same swizzle-namespace-set
enum {
exyzw,
ergba,
estpq,
} fieldSet[TSwizzleSelectors<TVectorSelector>::maxSelectors];
// Decode the swizzle string.
int size = std::min(TSwizzleSelectors<TVectorSelector>::maxSelectors, (int)compString.size());
for (int i = 0; i < size; ++i) {
switch (compString[i]) {
case 'x':
selector.push_back(0);
fieldSet[i] = exyzw;
break;
case 'r':
selector.push_back(0);
fieldSet[i] = ergba;
break;
case 's':
selector.push_back(0);
fieldSet[i] = estpq;
break;
case 'y':
selector.push_back(1);
fieldSet[i] = exyzw;
break;
case 'g':
selector.push_back(1);
fieldSet[i] = ergba;
break;
case 't':
selector.push_back(1);
fieldSet[i] = estpq;
break;
case 'z':
selector.push_back(2);
fieldSet[i] = exyzw;
break;
case 'b':
selector.push_back(2);
fieldSet[i] = ergba;
break;
case 'p':
selector.push_back(2);
fieldSet[i] = estpq;
break;
case 'w':
selector.push_back(3);
fieldSet[i] = exyzw;
break;
case 'a':
selector.push_back(3);
fieldSet[i] = ergba;
break;
case 'q':
selector.push_back(3);
fieldSet[i] = estpq;
break;
default:
error(loc, "unknown swizzle selection", compString.c_str(), "");
break;
}
}
// Additional error checking.
for (int i = 0; i < selector.size(); ++i) {
if (selector[i] >= vecSize) {
error(loc, "vector swizzle selection out of range", compString.c_str(), "");
selector.resize(i);
break;
}
if (i > 0 && fieldSet[i] != fieldSet[i-1]) {
error(loc, "vector swizzle selectors not from the same set", compString.c_str(), "");
selector.resize(i);
break;
}
}
// Ensure it is valid.
if (selector.size() == 0)
selector.push_back(0);
}
//
// Make the passed-in variable information become a member of the
// global uniform block. If this doesn't exist yet, make it.