Refactor assignment target overlap check into a function

[libs/gl.git] / source / glsl / syntax.cpp

diff --git a/source/glsl/syntax.cpp b/source/glsl/syntax.cpp
index 8b00e82e46eae73f397c599f6a9e3ea0008b4e3a..ccdb7197e570d7f786b65129b12e9196a884ccb4 100644 (file)
--- a/source/glsl/syntax.cpp
+++ b/source/glsl/syntax.cpp
@@ -414,6 +414,32 @@ void add_to_chain(Assignment::Target &target, Assignment::Target::ChainType type
        ++target.chain_len;
 }
 
+bool targets_overlap(const Assignment::Target &target1, const Assignment::Target &target2)
+{
+       bool overlap = (target1.declaration==target2.declaration);
+       for(unsigned i=0; (overlap && i<target1.chain_len && i<target2.chain_len); ++i)
+       {
+               Assignment::Target::ChainType type1 = static_cast<Assignment::Target::ChainType>(target1.chain[i]&0xC0);
+               Assignment::Target::ChainType type2 = static_cast<Assignment::Target::ChainType>(target2.chain[i]&0xC0);
+               unsigned index1 = target1.chain[i]&0x3F;
+               unsigned index2 = target2.chain[i]&0x3F;
+               if(type1==Assignment::Target::SWIZZLE || type2==Assignment::Target::SWIZZLE)
+               {
+                       if(type1==Assignment::Target::SWIZZLE && type2==Assignment::Target::SWIZZLE)
+                               overlap = index1&index2;
+                       else if(type1==Assignment::Target::ARRAY && index1<4)
+                               overlap = index2&(1<<index1);
+                       else if(type2==Assignment::Target::ARRAY && index2<4)
+                               overlap = index1&(1<<index2);
+                       // Treat other combinations as overlapping (shouldn't happen)
+               }
+               else
+                       overlap = (type1==type2 && (index1==index2 || index1==0x3F || index2==0x3F));
+       }
+
+       return overlap;
+}
+
 } // namespace SL
 } // namespace GL
 } // namespace Msp