scons: Add support for GLES.

GLES can be enabled by running scons with

  $ scons gles=yes

When gles=yes is given, the build is changed in three ways.  First,
libmesa.a will be built with FEATURE_ES1 and FEATURE_ES2.  This makes
DRI drivers and libEGL support and advertise GLES support.  Second, GLES
libraries will be created.  They are libGLESv1_CM, libGLESv2, and
libglapi.  Last, libGL or opengl32 will link to libglapi.  This change
is required as _glapi_* will be declared as __declspec(dllimport) in
libmesa.a on windows.  libmesa.a expects those symbols to be defined in
another DLL.  Due to this change to GL, GLES support is marked
experimental.

Note that GLES requires libxml2-python to generate some of its sources.

SConstruct

@@ -56,6 +56,12 @@ else:
 
 Help(opts.GenerateHelpText(env))
 
+# fail early for a common error on windows
+if env['gles']:
+    try:
+        import libxml2
+    except ImportError:
+        raise SCons.Errors.UserError, "GLES requires libxml2-python to build"
 
 #######################################################################
 # Environment setup

common.py

@@ -90,6 +90,7 @@ def AddOptions(opts):
 	opts.Add(EnumOption('platform', 'target platform', host_platform,
 											 allowed_values=('linux', 'cell', 'windows', 'winddk', 'wince', 'darwin', 'embedded', 'cygwin', 'sunos5', 'freebsd8')))
 	opts.Add('toolchain', 'compiler toolchain', default_toolchain)
+	opts.Add(BoolOption('gles', 'EXPERIMENTAL: enable OpenGL ES support', 'no'))
 	opts.Add(BoolOption('llvm', 'use LLVM', default_llvm))
 	opts.Add(BoolOption('debug', 'DEPRECATED: debug build', 'yes'))
 	opts.Add(BoolOption('profile', 'DEPRECATED: profile build', 'no'))

src/SConscript

@@ -8,6 +8,10 @@ else:
     Export('talloc')
 
 SConscript('glsl/SConscript')
+# When env['gles'] is set, the targets defined in mapi/glapi/SConscript are not
+# used.  libgl-xlib and libgl-gdi adapt themselves to use the targets defined
+# in mapi/glapi-shared/SConscript.  mesa/SConscript also adapts itself to
+# enable OpenGL ES support.
 SConscript('mapi/glapi/SConscript')
 SConscript('mesa/SConscript')
 
@@ -17,5 +21,8 @@ if env['platform'] != 'embedded':
     SConscript('egl/main/SConscript')
     SConscript('glut/glx/SConscript')
 
+    if env['gles']:
+        SConscript('mapi/shared-glapi/SConscript')
+
 SConscript('gallium/SConscript')
 

src/gallium/state_trackers/wgl/SConscript

@@ -15,6 +15,9 @@ env.AppendUnique(CPPDEFINES = [
     'BUILD_GL32', # declare gl* as __declspec(dllexport) in Mesa headers 
     'WIN32_LEAN_AND_MEAN', # http://msdn2.microsoft.com/en-us/library/6dwk3a1z.aspx
 ])
+if not env['gles']:
+    # prevent _glapi_* from being declared __declspec(dllimport)
+    env.Append(CPPDEFINES = ['_GLAPI_NO_EXPORTS'])
 
 sources = [
     'stw_context.c',

src/gallium/state_trackers/wgl/stw_device.c

@@ -170,7 +170,10 @@ stw_cleanup(void)
 
    _glthread_DESTROY_MUTEX(OneTimeLock);
 
+   /* glapi is statically linked: we can call the local destroy function. */
+#ifdef _GLAPI_NO_EXPORTS
    _glapi_destroy_multithread();
+#endif
 
 #ifdef DEBUG
    debug_memory_end(stw_dev->memdbg_no);

src/gallium/targets/egl-static/SConscript

@@ -58,10 +58,18 @@ if env['platform'] == 'windows':
     env.Prepend(LIBS = [
         ws_gdi,
     ])
-else:
-    # OpenGL
-    env.Append(CPPDEFINES = ['FEATURE_GL=1'])
-    env.Prepend(LIBS = ['GL', 'talloc', glsl, mesa])
+
+# OpenGL ES and OpenGL
+if env['gles']:
+    env.Append(CPPDEFINES = [
+        'FEATURE_GL=1',
+        'FEATURE_ES1=1',
+        'FEATURE_ES2=1'
+    ])
+    env.Prepend(LIBPATH = [shared_glapi.dir])
+    # manually add LIBPREFIX on windows
+    glapi_name = 'glapi' if env['platform'] != 'windows' else 'libglapi'
+    env.Prepend(LIBS = [glapi_name, talloc, glsl, mesa])
 
 # OpenVG
 if True:

src/gallium/targets/libgl-gdi/SConscript

@@ -37,6 +37,12 @@ drivers += [trace, rbug]
 
 env['no_import_lib'] = 1
 
+# when GLES is enabled, gl* and _glapi_* belong to bridge_glapi and
+# shared_glapi respectively
+if env['gles']:
+    env.Prepend(LIBPATH = [shared_glapi.dir])
+    glapi = [bridge_glapi, 'libglapi']
+
 opengl32 = env.SharedLibrary(
     target ='opengl32',
     source = sources,

src/gallium/targets/libgl-xlib/SConscript

@@ -16,6 +16,12 @@ env.Append(CPPDEFINES = ['USE_XSHM'])
 
 env.Prepend(LIBS = env['X11_LIBS'])
 
+# when GLES is enabled, gl* and _glapi_* belong to bridge_glapi and
+# shared_glapi respectively
+if env['gles']:
+    env.Prepend(LIBPATH = [shared_glapi.dir])
+    glapi = [bridge_glapi, 'glapi']
+
 env.Prepend(LIBS = [
     st_xlib,
     ws_xlib,

src/mapi/glapi/SConscript

@@ -17,6 +17,11 @@ if env['platform'] != 'winddk':
             '_GDI32_', # prevent gl* being declared __declspec(dllimport) in MS headers
             'BUILD_GL32', # declare gl* as __declspec(dllexport) in Mesa headers
         ])
+        if env['gles']:
+            env.Append(CPPDEFINES = ['_GLAPI_DLL_EXPORTS'])
+        else:
+            # prevent _glapi_* from being declared __declspec(dllimport)
+            env.Append(CPPDEFINES = ['_GLAPI_NO_EXPORTS'])
 
     env.Append(CPPPATH = [
         '#/src/mapi',

src/mapi/glapi/glapi.h

@@ -45,11 +45,6 @@
 #define _GLAPI_H
 
 
-/* opengl.dll does not export _glapi_* */
-#if defined(_WIN32)
-#define _GLAPI_NO_EXPORTS
-#endif
-
 #ifdef _GLAPI_NO_EXPORTS
 #  define _GLAPI_EXPORT
 #else /* _GLAPI_NO_EXPORTS */

src/mapi/shared-glapi/SConscript

@@ -0,0 +1,116 @@
+#######################################################################
+# SConscript for shared-glapi/es1api/es2api
+
+from sys import executable as python_cmd
+
+Import('*')
+
+def mapi_objects(env, printer, mode):
+    """Return mapi objects built for the given printer and mode."""
+    mapi_sources = {
+        'glapi': ['entry.c', 'mapi_glapi.c', 'stub.c', 'table.c',
+                  'u_current.c', 'u_execmem.c', 'u_thread.c'],
+        'bridge': ['entry.c'],
+    }
+    mapi_defines = {
+        'glapi': ['MAPI_MODE_GLAPI'],
+        'bridge': ['MAPI_MODE_BRIDGE'],
+    }
+
+    header_name = '%s-tmp.h' % (printer)
+
+    # generate ABI header
+    header = env.CodeGenerate(
+        target = header_name,
+        script = '../mapi/mapi_abi.py',
+        source = '../glapi/gen/gl_and_es_API.xml',
+        command = python_cmd + ' $SCRIPT ' + \
+                '--printer %s --mode lib $SOURCE > $TARGET' % (printer),
+    )
+
+    cpppath = [
+        header[0].dir,
+        '#/include',
+        '#/src/mapi',
+    ]
+    
+    cppdefines = mapi_defines[mode] + [
+        'MAPI_ABI_HEADER=\\"%s\\"' % (header_name),
+    ]
+
+    if env['platform'] == 'windows':
+        if mode == 'glapi':
+            cppdefines += [
+                '_GLAPI_DLL_EXPORTS', # declare _glapi_* as __declspec(dllexport) in glapi.h
+            ]
+        else:
+            cppdefines += [
+                '_GDI32_', # prevent gl* being declared __declspec(dllimport) in MS headers
+                'BUILD_GL32', # declare gl* as __declspec(dllexport) in Mesa headers
+            ]
+
+    objects = []
+    for s in mapi_sources[mode]:
+        o = env.SharedObject(
+            target = '%s-%s' % (printer, s[:-2]),
+            source = '../mapi/' + s,
+            CPPPATH = cpppath,
+            CPPDEFINES = cppdefines,
+        )
+        objects.append(o[0])
+
+    env.Depends(objects, header)
+
+    return objects
+
+if env['platform'] != 'winddk':
+    env = env.Clone()
+
+    env['SHLIBPREFIX'] = 'lib'
+    env['LIBPREFIX'] = 'lib'
+
+    shared_glapi_objects = mapi_objects(env, 'shared-glapi', 'glapi')
+    shared_glapi = env.SharedLibrary(
+        target = 'glapi',
+        source = shared_glapi_objects,
+    )
+
+    # manually add LIBPREFIX on windows
+    if env['platform'] == 'windows':
+        libs = ['libglapi']
+    else:
+        libs = ['glapi']
+
+    es1api_objects = mapi_objects(env, 'es1api', 'bridge')
+    es1api = env.SharedLibrary(
+        target = 'GLESv1_CM',
+        source = es1api_objects,
+        LIBPATH = ['.'],
+        LIBS = libs,
+    )
+
+    es2api_objects = mapi_objects(env, 'es2api', 'bridge')
+    es2api = env.SharedLibrary(
+        target = 'GLESv2',
+        source = es2api_objects,
+        LIBPATH = ['.'],
+        LIBS = libs,
+    )
+
+    env.InstallSharedLibrary(shared_glapi, version=(0, 0, 0))
+    env.InstallSharedLibrary(es1api, version=(1, 0, 0))
+    env.InstallSharedLibrary(es2api, version=(2, 0, 0))
+
+    if env['platform'] == 'windows':
+        shared_glapi = env.FindIxes(shared_glapi, 'LIBPREFIX', 'LIBSUFFIX')
+    else:
+        shared_glapi = env.FindIxes(shared_glapi, 'SHLIBPREFIX', 'SHLIBSUFFIX')
+
+    # build glapi bridge as a convenience libarary for libgl-xlib/libgl-gdi
+    bridge_glapi_objects = mapi_objects(env, 'glapi', 'bridge')
+    bridge_glapi = env.ConvenienceLibrary(
+        target = 'glapi_bridge',
+        source = bridge_glapi_objects,
+    )
+
+    Export(['shared_glapi', 'bridge_glapi'])

src/mesa/SConscript

@@ -12,11 +12,19 @@ env.Append(CPPPATH = [
     '#/src/mesa',
 ])
 
+env.Append(CPPDEFINES = [
+    'FEATURE_GL=1',
+])
+
 if env['platform'] == 'windows':
     env.Append(CPPDEFINES = [
         '_GDI32_', # prevent gl* being declared __declspec(dllimport) in MS headers
         'BUILD_GL32', # declare gl* as __declspec(dllexport) in Mesa headers
     ])
+    if not env['gles']:
+        # prevent _glapi_* from being declared __declspec(dllimport)
+        env.Append(CPPDEFINES = ['_GLAPI_NO_EXPORTS'])
+
     env.Prepend(CPPPATH = ['#src/talloc'])
 else:
     env.Append(CPPDEFINES = [
@@ -240,6 +248,61 @@ mesa_sources = (
     statetracker_sources
 )
 
+if env['gles']:
+    from sys import executable as python_cmd
+
+    env.Append(CPPDEFINES = ['FEATURE_ES1=1', 'FEATURE_ES2=1'])
+
+    # generate GLES sources
+    gles_sources = []
+    gles_sources += env.CodeGenerate(
+        target = 'main/api_exec_es1.c',
+        script = 'main/es_generator.py',
+        source = 'main/APIspec.xml',
+        command = python_cmd + ' $SCRIPT -S $SOURCE -V GLES1.1 > $TARGET'
+    )
+    gles_sources += env.CodeGenerate(
+        target = 'main/api_exec_es2.c',
+        script = 'main/es_generator.py',
+        source = 'main/APIspec.xml',
+        command = python_cmd + ' $SCRIPT -S $SOURCE -V GLES2.0 > $TARGET'
+    )
+
+    # generate GLES headers
+    GLAPI = '#src/mapi/glapi/'
+    gles_headers = []
+    gles_headers += env.CodeGenerate(
+        target = 'es1api/main/glapidispatch.h',
+        script = GLAPI + 'gen/gl_table.py',
+        source = GLAPI + 'gen-es/es1_API.xml',
+        command = python_cmd + ' $SCRIPT -c -m remap_table -f $SOURCE > $TARGET',
+    )
+    gles_headers += env.CodeGenerate(
+        target = 'es1api/main/remap_helper.h',
+        script = GLAPI + 'gen/remap_helper.py',
+        source = GLAPI + 'gen-es/es1_API.xml',
+        command = python_cmd + ' $SCRIPT -f $SOURCE > $TARGET',
+    )
+    gles_headers += env.CodeGenerate(
+        target = 'es2api/main/glapidispatch.h',
+        script = GLAPI + 'gen/gl_table.py',
+        source = GLAPI + 'gen-es/es2_API.xml',
+        command = python_cmd + ' $SCRIPT -c -m remap_table -f $SOURCE > $TARGET',
+    )
+    gles_headers += env.CodeGenerate(
+        target = 'es2api/main/remap_helper.h',
+        script = GLAPI + 'gen/remap_helper.py',
+        source = GLAPI + 'gen-es/es2_API.xml',
+        command = python_cmd + ' $SCRIPT -f $SOURCE > $TARGET',
+    )
+
+    env.Depends(gles_sources, gles_headers)
+
+    # gles_sources #include gles_headers with full path
+    env.Append(CPPPATH = [gles_headers[0].dir.up().up()])
+
+    mesa_sources += gles_sources
+
 #
 # Assembly sources
 #