added glad generator and a glad runtime

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

@@ -0,0 +1,118 @@
+from glad.lang.common.loader import BaseLoader
+from glad.lang.d.loader import LOAD_OPENGL_DLL
+
+
+_OPENGL_LOADER = \
+    LOAD_OPENGL_DLL % {'pre':'private', 'init':'open_gl',
+                       'proc':'get_proc', 'terminate':'close_gl'} + '''
+bool gladLoadGL() {
+    bool status = false;
+
+    if(open_gl()) {
+        status = gladLoadGL(x => get_proc(x));
+        close_gl();
+    }
+
+    return status;
+}
+'''
+
+_OPENGL_HAS_EXT = '''
+static struct GLVersion { static int major = 0; static int minor = 0; }
+private extern(C) char* strstr(const(char)*, const(char)*) @nogc;
+private extern(C) int strcmp(const(char)*, const(char)*) @nogc;
+private extern(C) int strncmp(const(char)*, const(char)*, size_t) @nogc;
+private extern(C) size_t strlen(const(char)*) @nogc;
+private bool has_ext(const(char)* ext) @nogc {
+    if(GLVersion.major < 3) {
+        const(char)* extensions = cast(const(char)*)glGetString(GL_EXTENSIONS);
+        const(char)* loc;
+        const(char)* terminator;
+
+        if(extensions is null || ext is null) {
+            return false;
+        }
+
+        while(1) {
+            loc = strstr(extensions, ext);
+            if(loc is null) {
+                return false;
+            }
+
+            terminator = loc + strlen(ext);
+            if((loc is extensions || *(loc - 1) == ' ') &&
+                (*terminator == ' ' || *terminator == '\\0')) {
+                return true;
+            }
+            extensions = terminator;
+        }
+    } else {
+        int num;
+        glGetIntegerv(GL_NUM_EXTENSIONS, &num);
+
+        for(uint i=0; i < cast(uint)num; i++) {
+            if(strcmp(cast(const(char)*)glGetStringi(GL_EXTENSIONS, i), ext) == 0) {
+                return true;
+            }
+        }
+    }
+
+    return false;
+}
+'''
+
+_FIND_VERSION = '''
+    // Thank you @elmindreda
+    // https://github.com/elmindreda/greg/blob/master/templates/greg.c.in#L176
+    // https://github.com/glfw/glfw/blob/master/src/context.c#L36
+    int i;
+    const(char)* glversion;
+    const(char)*[] prefixes = [
+        "OpenGL ES-CM ".ptr,
+        "OpenGL ES-CL ".ptr,
+        "OpenGL ES ".ptr,
+    ];
+
+    glversion = cast(const(char)*)glGetString(GL_VERSION);
+    if (glversion is null) return;
+
+    foreach(prefix; prefixes) {
+        size_t length = strlen(prefix);
+        if (strncmp(glversion, prefix, length) == 0) {
+            glversion += length;
+            break;
+        }
+    }
+
+    int major = glversion[0] - \'0\';
+    int minor = glversion[2] - \'0\';
+    GLVersion.major = major; GLVersion.minor = minor;
+'''
+
+
+class OpenGLDLoader(BaseLoader):
+    def write_header_end(self, fobj):
+        pass
+
+    def write_header(self, fobj):
+        pass
+
+    def write(self, fobj):
+        fobj.write('alias Loader = void* delegate(const(char)*);\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 GLVersion.major != 0 || GLVersion.minor != 0;\n')
+
+    def write_find_core(self, fobj):
+        fobj.write(_FIND_VERSION)
+
+    def write_has_ext(self, fobj):
+        fobj.write(_OPENGL_HAS_EXT)
+