added glad generator and a glad runtime

tools/glad-0.1.14a0/glad/lang/volt/loader/gl.py

@@ -0,0 +1,60 @@
+from glad.lang.common.loader import BaseLoader
+from glad.lang.volt.loader import LOAD_OPENGL_DLL
+from glad.lang.d.loader.gl import _OPENGL_HAS_EXT as _D_OPENGL_HAS_EXT
+
+
+_OPENGL_LOADER = \
+    LOAD_OPENGL_DLL % {'pre':'private', 'init':'open_gl',
+                       'proc':'get_proc', 'terminate':'close_gl'} + '''
+bool gladLoadGL() {
+    StructToDg structToDg;
+    structToDg.func = cast(void*)get_proc;
+    auto dg = *cast(Loader*)&structToDg;
+
+    bool status = false;
+
+    if(open_gl()) {
+        status = gladLoadGL(dg);
+        close_gl();
+    }
+
+    return status;
+}
+'''
+
+_OPENGL_HAS_EXT = (
+    'global int GL_MAJOR = 0;\nglobal int GL_MINOR = 0;' +
+    '\n'.join(l for l in _D_OPENGL_HAS_EXT.replace('@nogc', '').splitlines() if 'struct' not in l)
+        .replace('GLVersion.major', 'GL_MAJOR') +
+    '\n\n'
+)
+
+
+class OpenGLVoltLoader(BaseLoader):
+    def write_header_end(self, fobj):
+        pass
+
+    def write_header(self, fobj):
+        pass
+
+    def write(self, fobj):
+        fobj.write('import watt.library;\n')
+        if not self.disabled and 'gl' in self.apis:
+            fobj.write(_OPENGL_LOADER)
+
+    def write_begin_load(self, fobj):
+        fobj.write('\tglGetString = cast(typeof(glGetString))load("glGetString");\n')
+        fobj.write('\tif(glGetString is null) { return false; }\n')
+        fobj.write('\tif(glGetString(GL_VERSION) is null) { return false; }\n\n')
+
+    def write_end_load(self, fobj):
+        fobj.write('\treturn GL_MAJOR != 0 || GL_MINOR != 0;\n')
+
+    def write_find_core(self, fobj):
+        fobj.write('\tconst(char)* v = cast(const(char)*)glGetString(GL_VERSION);\n')
+        fobj.write('\tint major = v[0] - \'0\';\n')
+        fobj.write('\tint minor = v[2] - \'0\';\n')
+        fobj.write('\tGL_MAJOR = major; GL_MINOR = minor;\n')
+
+    def write_has_ext(self, fobj):
+        fobj.write(_OPENGL_HAS_EXT)