gl-renderer: move vertex shader into new file

This patch adds the tooling for incorporating files as C data, so that
files can be built into the binaries. The tool is in Python to avoid
adding extra dependencies like xxd.

xxd.py is copied from Mesa as-is, from commit
b729cd58d76f97f3fc04a67569535ee5ef2f5278 (master branch on 2021-01-26),
a.k.a 21.0-branchpoint-635-gb729cd58d76.

Moving the GLSL vertex shader into a separate file is not that
interesting, the purpose of this commit is to provide a simple
demonstration of the tooling. The real benefits come in a following
patch where the fragment shaders are re-written and externalized.

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>

libweston/renderer-gl/gl-shaders.c

@@ -32,16 +32,8 @@
 #include "gl-renderer.h"
 #include "gl-renderer-internal.h"
 
-static const char vertex_shader[] =
-	"uniform mat4 proj;\n"
-	"attribute vec2 position;\n"
-	"attribute vec2 texcoord;\n"
-	"varying vec2 v_texcoord;\n"
-	"void main()\n"
-	"{\n"
-	"   gl_Position = proj * vec4(position, 0.0, 1.0);\n"
-	"   v_texcoord = texcoord;\n"
-	"}\n";
+/* static const char vertex_shader[]; vertex.glsl */
+#include "vertex-shader.h"
 
 /* Declare common fragment shader uniforms */
 #define FRAGMENT_CONVERT_YUV						\

libweston/renderer-gl/meson.build

@@ -4,12 +4,20 @@ endif
 
 config_h.set('ENABLE_EGL', '1')
 
+vertex_glsl = custom_target(
+	'vertex-shader.h',
+	command: cmd_xxd + [ '-n', 'vertex_shader' ],
+	input: 'vertex.glsl',
+	output: 'vertex-shader.h',
+)
+
 srcs_renderer_gl = [
 	'egl-glue.c',
 	'gl-renderer.c',
 	'gl-shaders.c',
 	linux_dmabuf_unstable_v1_protocol_c,
 	linux_dmabuf_unstable_v1_server_protocol_h,
+	vertex_glsl,
 ]
 
 deps_renderer_gl = [

libweston/renderer-gl/vertex.glsl

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2012 Intel Corporation
+ * Copyright 2015,2019 Collabora, Ltd.
+ * Copyright 2016 NVIDIA Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial
+ * portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+uniform mat4 proj;
+attribute vec2 position;
+attribute vec2 texcoord;
+varying vec2 v_texcoord;
+
+void main()
+{
+	gl_Position = proj * vec4(position, 0.0, 1.0);
+	v_texcoord = texcoord;
+}

meson.build

@@ -149,6 +149,10 @@ dep_libdrm = dependency('libdrm', version: '>= 2.4.95')
 dep_libdrm_headers = dep_libdrm.partial_dependency(compile_args: true)
 dep_threads = dependency('threads')
 
+prog_python = import('python').find_installation('python3')
+files_xxd_py = files('tools/xxd.py')
+cmd_xxd = [ prog_python, files_xxd_py, '@INPUT@', '@OUTPUT@' ]
+
 subdir('include')
 subdir('protocol')
 subdir('shared')

tools/xxd.py

@@ -0,0 +1,100 @@
+# encoding=utf-8
+# Copyright © 2018 Intel Corporation
+#
+# Permission is hereby granted, free of charge, to any person obtaining a
+# copy of this software and associated documentation files (the "Software"),
+# to deal in the Software without restriction, including without limitation
+# the rights to use, copy, modify, merge, publish, distribute, sublicense,
+# and/or sell copies of the Software, and to permit persons to whom the
+# Software is furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice (including the next
+# paragraph) shall be included in all copies or substantial portions of the
+# Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+# THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+# IN THE SOFTWARE.
+
+# Converts a file to a C/C++ #include containing a string
+
+from __future__ import unicode_literals
+import argparse
+import io
+import os
+
+
+def get_args():
+    parser = argparse.ArgumentParser()
+    parser.add_argument('input', help="Name of input file")
+    parser.add_argument('output', help="Name of output file")
+    parser.add_argument("-n", "--name",
+                        help="Name of C variable")
+    parser.add_argument("-b", "--binary", dest='binary', action='store_const',
+                        const=True, default=False)
+    args = parser.parse_args()
+    return args
+
+
+def filename_to_C_identifier(n):
+    if n[0] != '_' and not n[0].isalpha():
+        n = "_" + n[1:]
+
+    return "".join([c if c.isalnum() or c == "_" else "_" for c in n])
+
+
+def emit_byte(f, b):
+    f.write("0x{:02x}, ".format(ord(b)).encode('utf-8'))
+
+
+def process_file(args):
+    with io.open(args.input, "rb") as infile:
+        try:
+            with io.open(args.output, "wb") as outfile:
+                # If a name was not specified on the command line, pick one based on the
+                # name of the input file.  If no input filename was specified, use
+                # from_stdin.
+                if args.name is not None:
+                    name = args.name
+                else:
+                    name = filename_to_C_identifier(args.input)
+
+                outfile.write("static const char {}[] = {{\n".format(name).encode('utf-8'))
+
+                linecount = 0
+                while True:
+                    byte = infile.read(1)
+                    if byte == b"":
+                        break
+
+                    if not args.binary:
+                        assert(ord(byte) != 0)
+
+                    emit_byte(outfile, byte)
+                    linecount = linecount + 1
+                    if linecount > 20:
+                        outfile.write(b"\n ")
+                        linecount = 0
+                if not args.binary:
+                    outfile.write(b"\n0")
+                outfile.write(b"\n};\n\n")
+        except Exception:
+            # In the event that anything goes wrong, delete the output file,
+            # then re-raise the exception. Deleteing the output file should
+            # ensure that the build system doesn't try to use the stale,
+            # half-generated file.
+            os.unlink(args.output)
+            raise
+
+
+def main():
+    args = get_args()
+    process_file(args)
+
+
+if __name__ == "__main__":
+    main()