From: Mikko Rasa <tdb@tdb.fi>
Date: Sun, 21 Feb 2021 23:39:30 +0000 (+0200)
Subject: Throw an exception if a feature required by a shader is missing
X-Git-Url: http://git.tdb.fi/?p=libs%2Fgl.git;a=commitdiff_plain;h=836eeb313874d4f0c406f154ecb0dff366f362c4

Throw an exception if a feature required by a shader is missing

Workarounds are not always available.
---

diff --git a/source/glsl/compatibility.cpp b/source/glsl/compatibility.cpp
index 2e13a5f6..34073862 100644
--- a/source/glsl/compatibility.cpp
+++ b/source/glsl/compatibility.cpp
@@ -2,6 +2,7 @@
 #include <msp/core/raii.h>
 #include <msp/strings/lexicalcast.h>
 #include "compatibility.h"
+#include "glsl_error.h"
 
 using namespace std;
 
@@ -259,8 +260,8 @@ void LegacyConverter::visit(VariableDeclaration &var)
 			}
 			else if(stage->type==Stage::FRAGMENT && var.interface=="out")
 			{
-				if(location!=0)
-					check_extension(&Features::ext_gpu_shader4);
+				if(location!=0 && !check_extension(&Features::ext_gpu_shader4))
+					throw unsupported_shader("EXT_gpu_shader4 is required");
 				stage->locations[var.name] = location;
 				var.layout->qualifiers.erase(i);
 			}
diff --git a/source/glsl/glsl_error.h b/source/glsl/glsl_error.h
index 1ae521ca..46ca49be 100644
--- a/source/glsl/glsl_error.h
+++ b/source/glsl/glsl_error.h
@@ -37,6 +37,13 @@ public:
 	virtual ~parse_error() throw() { }
 };
 
+class unsupported_shader: public std::runtime_error
+{
+public:
+	unsupported_shader(const std::string &w): runtime_error(w) { }
+	virtual ~unsupported_shader() throw() { }
+};
+
 } // namespace SL
 } // namespace GL
 } // namespace Msp