createFromFiles now traverses the dot hierarchy to find shaders

src/glow/common/str_utils.hh

 #pragma once
 
-#include <string>
 #include <algorithm>
+#include <string>
 
 namespace glow
 {
@@ -68,5 +68,25 @@ inline std::string pathOf(std::string const &filename)
         return "";
     return filename.substr(0, minPos);
 }
+
+/// strips everything after (and including) the last dot of the filename
+/// returns "" otherwise
+/// e.g. "a.b.c" -> "a.b" but "a.b/c" -> ""
+inline std::string stripFileDot(std::string const &filename)
+{
+    auto dotPos = filename.rfind('.');
+    if (dotPos == std::string::npos)
+        return "";
+
+    auto slashPosA = filename.rfind('/');
+    if (slashPosA != std::string::npos && slashPosA > dotPos)
+        return "";
+
+    auto slashPosB = filename.rfind('\\');
+    if (slashPosB != std::string::npos && slashPosB > dotPos)
+        return "";
+
+    return filename.substr(0, dotPos);
+}
 }
 }

src/glow/objects/Program.cc

@@ -473,6 +473,7 @@ SharedProgram Program::createFromFile(const std::string &fileOrBaseName)
     std::string content;
     std::string realFileName;
 
+    // try to resolve file directly
     if (Shader::resolveFile(fileOrBaseName, type, content, realFileName))
     {
         if (!realFileName.empty())
@@ -480,14 +481,27 @@ SharedProgram Program::createFromFile(const std::string &fileOrBaseName)
         else
             program->attachShader(Shader::createFromSource(type, content));
     }
-    else
+    else // otherwise check endings
+    {
         for (auto const &kvp : glow::shaderEndingToType)
-            if (Shader::resolveFile(fileOrBaseName + kvp.first, type, content, realFileName))
+        {
+            auto fname = fileOrBaseName;
+            while (fname != "")
+            {
+                if (Shader::resolveFile(fname + kvp.first, type, content, realFileName))
                 {
                     if (!realFileName.empty())
                         program->attachShader(Shader::createFromFile(type, realFileName));
                     else
                         program->attachShader(Shader::createFromSource(type, content));
+
+                    break; // found file
+                }
+
+                // try to find "base" versions
+                fname = util::stripFileDot(fname);
+            }
+        }
     }
 
     if (program->mShader.empty())

src/glow/objects/Program.hh

@@ -406,6 +406,9 @@ public: // static construction
     /// E.g. createFromFile("mesh");
     ///   will use mesh.vsh as vertex shader and mesh.fsh as fragment shader if available
     /// See common/shader_endings.cc for a list of available endings
+    /// Will also traverse "dots" if file not found to check for base versions
+    /// E.g. createFromFile("mesh.opaque");
+    ///   might find mesh.opaque.fsh and mesh.vsh
     static SharedProgram createFromFile(std::string const& fileOrBaseName);
     /// Creates a program from a list of explicitly named files
     /// Shader type is determined by common/shader_endings.cc

src/glow/objects/Shader.cc

@@ -170,6 +170,7 @@ bool Shader::resolveFile(const std::string &name, GLenum &shaderType, std::strin
         if (util::endswith(name, kvp.first))
         {
             shaderType = kvp.second;
+            found = true;
             break;
         }