Recognize swizzles in GLSL

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

diff --git a/source/glsl/validate.cpp b/source/glsl/validate.cpp
index b0c6e3d67acb29cb178bbdeb1e7d2812ea16f5be..c4e0a9bda8aa6b21d80fca7e92a5b393217d4a53 100644 (file)
--- a/source/glsl/validate.cpp
+++ b/source/glsl/validate.cpp
@@ -1,3 +1,4 @@
+#include <algorithm>
 #include <cstring>
 #include <msp/core/raii.h>
 #include <msp/strings/format.h>
@@ -227,6 +228,44 @@ void ReferenceValidator::visit(FunctionDeclaration &func)
 }
 
 
+void ExpressionValidator::visit(Swizzle &swizzle)
+{
+       unsigned size = 0;
+       if(BasicTypeDeclaration *basic = dynamic_cast<BasicTypeDeclaration *>(swizzle.left->type))
+       {
+               if(basic->kind==BasicTypeDeclaration::INT || basic->kind==BasicTypeDeclaration::FLOAT)
+                       size = 1;
+               else if(basic->kind==BasicTypeDeclaration::VECTOR)
+                       size = basic->size;
+       }
+
+       if(size)
+       {
+               static const char component_names[] = { 'x', 'y', 'z', 'w', 'r', 'g', 'b', 'a', 's', 't', 'p', 'q' };
+               int flavour = -1;
+               for(unsigned i=0; i<swizzle.count; ++i)
+               {
+                       unsigned component_flavour = (find(component_names, component_names+12, swizzle.component_group[i])-component_names)/4;
+                       if(flavour==-1)
+                               flavour = component_flavour;
+                       else if(flavour>=0 && component_flavour!=static_cast<unsigned>(flavour))
+                       {
+                               error(swizzle, format("Flavour of swizzle component '%c' is inconsistent with '%c'",
+                                       swizzle.component_group[i], swizzle.component_group[0]));
+                               flavour = -2;
+                       }
+
+                       if(swizzle.components[i]>=size)
+                               error(swizzle, format("Access to component '%c' which is not present in '%s'",
+                                       swizzle.component_group[i], swizzle.left->type->name));
+               }
+       }
+       else if(swizzle.left->type)
+               error(swizzle, format("Swizzle applied to '%s' which is neither a scalar nor a vector", swizzle.left->type->name));
+
+       TraversingVisitor::visit(swizzle);
+}
+
 void ExpressionValidator::visit(UnaryExpression &unary)
 {
        if(unary.expression->type)