Make backend idenfication more generic

[libs/gl.git] / source / core / backend.cpp

diff --git a/source/core/backend.cpp b/source/core/backend.cpp
new file mode 100644 (file)
index 0000000..c3e159f
--- /dev/null
+++ b/source/core/backend.cpp
@@ -0,0 +1,76 @@
+#include <stdexcept>
+#include <cstdlib>
+#include <msp/strings/lexicalcast.h>
+#include <msp/strings/utils.h>
+#include "backend.h"
+#include "gl.h"
+
+using namespace std;
+
+namespace Msp {
+namespace GL {
+
+Version::Version()
+{
+       major = 0;
+       minor = 0;
+}
+
+Version::Version(unsigned short a, unsigned short i)
+{
+       major = a;
+       minor = i;
+}
+
+Version::Version(const string &s)
+{
+       vector<string> parts = split(s, '.');
+       major = lexical_cast<unsigned>(parts[0]);
+       minor = lexical_cast<unsigned>(parts[1]);
+}
+
+bool Version::operator>=(const Version &other) const
+{
+       return major>other.major || (major==other.major && minor>=other.minor);
+}
+
+
+GraphicsApi get_backend_api()
+{
+#ifdef GL_ES_VERSION_2_0
+       return OPENGL_ES;
+#else
+       return OPENGL;
+#endif
+}
+
+inline Version get_gl_version()
+{
+       const char *gl_ver_ptr = reinterpret_cast<const char *>(glGetString(GL_VERSION));
+       if(!gl_ver_ptr)
+               throw runtime_error("OpenGL version not available");
+
+       string gl_ver = gl_ver_ptr;
+       if(!gl_ver.compare(0, 10, "OpenGL ES "))
+               gl_ver.erase(0, 10);
+
+       Version ver(gl_ver.substr(0, gl_ver.find(' ')));
+
+       if(const char *force_ver_ptr = getenv("MSPGL_FORCE_VERSION"))
+       {
+               Version force_ver(force_ver_ptr);
+               if(force_ver<ver)
+                       ver = force_ver;
+       }
+
+       return ver;
+}
+
+const Version &get_backend_version()
+{
+       static Version version = get_gl_version();
+       return version;
+}
+
+} // namespace GL
+} // namespace Msp