Refactor Shader::compareVarying to use a table instead of nested switch statements.

TRAC #23081 Signed-off-by: Geoff Lang Signed-off-by: Shannon Woods Author: Jamie Madill git-svn-id: https://angleproject.googlecode.com/svn/branches/es3proto@2393 736b8ea6-26fd-11df-bfd4-992fa37f6226

Refactor Shader::compareVarying to use a table instead of nested switch statements.
4f35fdf6 · shannonwoods@chromium.org · 09e09884 · 4f35fdf6
Commit 4f35fdf6 authored May 30, 2013 by shannonwoods@chromium.org
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Showing with 25 additions and 72 deletions

Shader.cpp src/libGLESv2/Shader.cpp +25 -72

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--- a/src/libGLESv2/Shader.cpp
+++ b/src/libGLESv2/Shader.cpp
@@ -498,87 +498,40 @@ GLenum Shader::parseType(const std::string &type)
    return GL_NONE;
 }
+typedef std::map<GLenum, int> VaryingPriorityMap;
+static VaryingPriorityMap varyingPriorities;
+static void makeVaryingPriorityMap()
+{
+    varyingPriorities[GL_FLOAT_MAT4]    = 0;
+    varyingPriorities[GL_FLOAT_MAT2]    = 50;
+    varyingPriorities[GL_FLOAT_VEC4]    = 60;
+    varyingPriorities[GL_FLOAT_MAT3]    = 70;
+    varyingPriorities[GL_FLOAT_VEC3]    = 100;
+    varyingPriorities[GL_FLOAT_VEC2]    = 110;
+    varyingPriorities[GL_FLOAT]         = 120;
+}
 // true if varying x has a higher priority in packing than y
 bool Shader::compareVarying(const Varying &x, const Varying &y)
 {
-    if(x.type == y.type)
+    if (varyingPriorities.empty())
    {
-        return x.size > y.size;
+        makeVaryingPriorityMap();
    }
-    switch (x.type)
+    if(x.type == y.type)
    {
-      case GL_FLOAT_MAT4: return true;
+        return x.size > y.size;
-      case GL_FLOAT_MAT2:
-        switch(y.type)
-        {
-          case GL_FLOAT_MAT4: return false;
-          case GL_FLOAT_MAT2: return true;
-          case GL_FLOAT_VEC4: return true;
-          case GL_FLOAT_MAT3: return true;
-          case GL_FLOAT_VEC3: return true;
-          case GL_FLOAT_VEC2: return true;
-          case GL_FLOAT:      return true;
-          default: UNREACHABLE();
-        }
-        break;
-      case GL_FLOAT_VEC4:
-        switch(y.type)
-        {
-          case GL_FLOAT_MAT4: return false;
-          case GL_FLOAT_MAT2: return false;
-          case GL_FLOAT_VEC4: return true;
-          case GL_FLOAT_MAT3: return true;
-          case GL_FLOAT_VEC3: return true;
-          case GL_FLOAT_VEC2: return true;
-          case GL_FLOAT:      return true;
-          default: UNREACHABLE();
-        }
-        break;
-      case GL_FLOAT_MAT3:
-        switch(y.type)
-        {
-          case GL_FLOAT_MAT4: return false;
-          case GL_FLOAT_MAT2: return false;
-          case GL_FLOAT_VEC4: return false;
-          case GL_FLOAT_MAT3: return true;
-          case GL_FLOAT_VEC3: return true;
-          case GL_FLOAT_VEC2: return true;
-          case GL_FLOAT:      return true;
-          default: UNREACHABLE();
-        }
-        break;
-      case GL_FLOAT_VEC3:
-        switch(y.type)
-        {
-          case GL_FLOAT_MAT4: return false;
-          case GL_FLOAT_MAT2: return false;
-          case GL_FLOAT_VEC4: return false;
-          case GL_FLOAT_MAT3: return false;
-          case GL_FLOAT_VEC3: return true;
-          case GL_FLOAT_VEC2: return true;
-          case GL_FLOAT:      return true;
-          default: UNREACHABLE();
-        }
-        break;
-      case GL_FLOAT_VEC2:
-        switch(y.type)
-        {
-          case GL_FLOAT_MAT4: return false;
-          case GL_FLOAT_MAT2: return false;
-          case GL_FLOAT_VEC4: return false;
-          case GL_FLOAT_MAT3: return false;
-          case GL_FLOAT_VEC3: return false;
-          case GL_FLOAT_VEC2: return true;
-          case GL_FLOAT:      return true;
-          default: UNREACHABLE();
-        }
-        break;
-      case GL_FLOAT: return false;
-      default: UNREACHABLE();
    }
-    return false;
+    VaryingPriorityMap::iterator xPriority = varyingPriorities.find(x.type);
+    VaryingPriorityMap::iterator yPriority = varyingPriorities.find(y.type);
+    ASSERT(xPriority != varyingPriorities.end());
+    ASSERT(yPriority != varyingPriorities.end());
+    return xPriority->second <= yPriority->second;
 }
 int Shader::getShaderVersion() const