glsl framebuffer_fetch extension check at runtime

src/shader.cpp

@@ -4,6 +4,7 @@
 
 std::map<kShader, Shader> ShaderManager::m_shaders;
 Shader* ShaderManager::m_current;
+bool ShaderManager::ext_framebuffer_fetch = false;
 
 bool Shader::create(const char* vertex, const char* fragment)
 {
@@ -157,6 +158,7 @@ GLint Shader::GetAttribLocation(const char* name)
 {
     return glGetAttribLocation(prog, name);
 }
+
 bool ShaderManager::create(kShader id, const char* vertex, const char* fragment)
 {
     m_shaders[id].name = id;