[wip, opengl] parsing opengl xml spec to auto-generate gl/gles loader

ext/glapi.py

@@ -0,0 +1,162 @@
+import xml.etree.ElementTree as et
+from argparse import ArgumentParser
+from datetime import datetime
+
+#---------------------------------------------------------------
+#NOTE: get args
+#---------------------------------------------------------------
+
+parser = ArgumentParser()
+parser.add_argument("-d", "--directory")
+
+args = parser.parse_args()
+
+apiName = 'glapi'
+loaderName = 'glloader'
+
+apiPath = args.directory + '/' + apiName + '.h'
+loaderHeaderPath = args.directory + '/' + loaderName + '.h'
+loaderCPath = args.directory + '/' + loaderName + '.c'
+
+#---------------------------------------------------------------
+#NOTE: gather all GL functions in OpenGL 4.3
+#---------------------------------------------------------------
+
+def gather_api(tree, api, version):
+	procs = []
+	for	feature in tree.iterfind('feature[@api="'+ api +'"]'):
+		if float(feature.get('number')) > version:
+			break
+
+		for require in feature.iter('require'):
+			for command in require.iter('command'):
+				procs.append(command.get('name'))
+
+		for remove in feature.iter('remove'):
+			for command in remove.iter('command'):
+				procs.remove(command.get('name'))
+	return(procs)
+
+tree = et.parse('gl.xml')
+
+gl41 = gather_api(tree, 'gl', 4.1)
+gl43 = gather_api(tree, 'gl', 4.3)
+gles31 = gather_api(tree, 'gles2', 3.1)
+gles32 = gather_api(tree, 'gles2', 3.2)
+
+glall = list(set().union(gl41, gl43, gles31, gles32))
+
+
+#---------------------------------------------------------------
+# helpers
+#---------------------------------------------------------------
+
+def emit_doc(f, name, ext):
+	f.write("/********************************************************\n")
+	f.write("*\n")
+	f.write("*\t@file: " + name + ext + '\n')
+	f.write("*\t@note: auto-generated by glapi.py from gl.xml\n")
+	f.write("*\t@date: %s\n" % datetime.now().strftime("%d/%m%Y"))
+	f.write("*\n")
+	f.write("/********************************************************/\n")
+
+
+def emit_begin_guard(f, name):
+	guard = '__' + name.upper() + '_H__'
+	f.write("#ifndef " + guard + "\n")
+	f.write("#define " + guard + "\n\n")
+
+def emit_end_guard(f, name):
+	guard = '__' + name.upper() + '_H__'
+	f.write("#endif // " + guard + "\n")
+
+def remove_prefix(s, prefix):
+	if s.startswith(prefix):
+		return s[len(prefix):]
+
+#---------------------------------------------------------------
+# Generate GL API header file
+#---------------------------------------------------------------
+
+f = open(apiPath, 'w')
+
+emit_doc(f, apiName, '.h')
+emit_begin_guard(f, apiName)
+
+f.write('#include"GL/glcorearb.h"\n\n')
+
+# generate interface struct
+f.write('typedef struct mg_gl\n{\n')
+
+for func in glall:
+	f.write('\t' + 'PFN' + func.upper() + 'PROC ' + remove_prefix(func, 'gl') + ';\n')
+
+f.write('} mg_gl;\n\n')
+f.write('extern mp_thread_local mg_gl* __mgGLAPI;\n\n');
+
+# generate interface macros
+
+for func in glall:
+	f.write('#define ' + func + ' __mgGLAPI->' + remove_prefix(func, 'gl') + '\n')
+
+emit_end_guard(f, apiName)
+f.close()
+
+#---------------------------------------------------------------
+# Generate GL loader header
+#---------------------------------------------------------------
+
+f = open(loaderHeaderPath)
+
+emit_doc(f, loaderName, '.h')
+emit_begin_guard(f, loaderName)
+
+f.write("typedef void*(mg_gl_load_proc*)(const char* name);\n\n")
+
+f.write("mg_gl* mg_gl_load_gl41(mg_gl_load_proc loadProc);\n")
+f.write("mg_gl* mg_gl_load_gl43(mg_gl_load_proc loadProc);\n")
+f.write("mg_gl* mg_gl_load_gles31(mg_gl_load_proc loadProc);\n")
+f.write("mg_gl* mg_gl_load_gles32(mg_gl_load_proc loadProc);\n\n")
+
+f.write("void mg_gl_select_api(mg_gl* api);\n\n")
+
+emit_end_guard(f, loaderName)
+f.close()
+#---------------------------------------------------------------
+# Generate GL loader code
+#---------------------------------------------------------------
+
+def emit_loader(f, name, procs):
+	f.write('mg_gl* mg_gl_load_'+ name +'(mg_gl_load_proc loadProc)\n')
+	f.write("{\n")
+	f.write("\tif(!__mg"+ name.upper() +".init)\n")
+	f.write("\t{\n")
+	for proc in procs:
+		f.write('\t\t__mg' + name.upper() + '.' + remove_prefix(proc, 'gl') + ' = loadProc("' + proc + '");\n')
+	f.write("\t\t__mg"+ name.upper() +".init = true;\n")
+	f.write("\t}\n")
+	f.write("\treturn(&__mg"+ name.upper() +");\n")
+	f.write("}\n\n")
+
+f = open(loaderCPath, 'w')
+
+emit_doc(f, loaderName, '.c')
+
+f.write('#include"' + apiName + '.h"\n')
+f.write('#include"platform.h"\n\n')
+
+f.write("mp_thread_local mg_gl* __mgGLAPI = 0;\n\n")
+
+f.write("static mg_gl __mgGL41 = {0};\n")
+f.write("static mg_gl __mgGL43 = {0};\n")
+f.write("static mg_gl __mgGLES31 = {0};\n")
+f.write("static mg_gl __mgGLES32 = {0};\n\n")
+
+emit_loader(f, 'gl41', gl41)
+emit_loader(f, 'gl43', gl43)
+emit_loader(f, 'gles31', gles31)
+emit_loader(f, 'gles32', gles32)
+
+f.write("void mg_gl_select_api(mg_gl* api){ __mgGLAPI = api; }\n\n")
+
+f.close()

todo.txt

@@ -18,6 +18,12 @@ Overview
 	[ ] Baked fonts?
 
 [ ] Allow different versions of GL to co-exist
+	- we can load GL (4.1 or 4.3) or GLES (3.1 or 3.2) functions
+	- surface creation function chooses a loader function
+	- loader function fills api struct or return pointer to already filled api struct
+	- surface prepare function sets the proper api struct
+
+
 [?] Backport canvas to GLES
 
 [ ] Back surface by child windows and implement moving frame/hiding/overlay