Add a helper function for making indexed vertex components

[libs/gl.git] / source / vertexformat.cpp

diff --git a/source/vertexformat.cpp b/source/vertexformat.cpp
index 0a26d94268847b94d443bcf6e9d47192936d1722..ea5845c5fc10f56cca9b217a6db5c405e9b0028c 100644 (file)
--- a/source/vertexformat.cpp
+++ b/source/vertexformat.cpp
@@ -77,9 +77,7 @@ VertexFormat VertexFormat::operator,(unsigned i) const
                throw invalid_operation("VertexFormat::operator,");
        VertexFormat r = *this;
        unsigned char *c = r.data+r.data[0];
-       if((*c<TEXCOORD1 && i>0) || (*c<ATTRIB1 && i>=8) || i>=53)
-               throw invalid_argument("VertexFormat::operator,");
-       *c += i*4;
+       *c = make_indexed_component(static_cast<VertexComponent>(*c), i);
 
        return r;
 }
@@ -92,12 +90,9 @@ unsigned VertexFormat::stride() const
        return s;
 }
 
-int VertexFormat::offset(VertexComponent comp, unsigned index) const
+int VertexFormat::offset(VertexComponent comp) const
 {
-       if((comp<TEXCOORD1 && index>0) || (comp<ATTRIB1 && index>=8) || index>=53)
-               throw out_of_range("VertexFormat::offset");
-
-       unsigned type = get_component_type(comp)+index;
+       unsigned type = get_component_type(comp);
        unsigned size = get_component_size(comp);
        unsigned offs = 0;
        for(const unsigned char *i=begin(); i!=end(); ++i)
@@ -116,6 +111,23 @@ int VertexFormat::offset(VertexComponent comp, unsigned index) const
        return -1;
 }
 
+VertexComponent make_indexed_component(VertexComponent comp, unsigned index)
+{
+       if(comp>=TEXCOORD1 && comp<=TEXCOORD4)
+       {
+               if(index>=4)
+                       throw out_of_range("make_indexed_component");
+       }
+       else if(comp>=ATTRIB1 && comp<=ATTRIB4)
+       {
+               if(index>=53)
+                       throw out_of_range("make_indexed_component");
+       }
+       else
+               throw invalid_argument("make_indexed_component");
+       return static_cast<VertexComponent>(comp+index*4);
+}
+
 void operator>>(const LexicalConverter &conv, VertexComponent &c)
 {
        const string &str = conv.get();