meson: Automatically generate glsl_shaders.h from specified shader programs

Encode the bayer shader files into a header as part of the build process.
Qcam already compiles the shader files down into a QT resource file which
it references internally.

In order to share the debayering shader programs outside of qcam create a
generic header which both qcam and libcamera can operate from.

Acked-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Milan Zamazal <mzamazal@redhat.com>
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

src/libcamera/meson.build

@@ -76,6 +76,7 @@ subdir('ipa')
 subdir('pipeline')
 subdir('proxy')
 subdir('sensor')
+subdir('shaders')
 subdir('software_isp')
 
 libdl = dependency('dl')
@@ -182,6 +183,16 @@ libcamera_deps += [
     libyaml,
 ]
 
+# Generate headers from shaders
+libcamera_shader_headers = custom_target(
+    'gen-shader-headers',
+    input : [shader_files],
+    output : 'glsl_shaders.h',
+    command : [gen_shader_headers, meson.project_source_root(), meson.project_build_root(), '@OUTPUT@', '@INPUT@'],
+)
+
+libcamera_internal_headers += libcamera_shader_headers
+
 # We add '/' to the build_rpath as a 'safe' path to act as a boolean flag.
 # The build_rpath is stripped at install time by meson, so we determine at
 # runtime if the library is running from an installed location by checking

src/libcamera/shaders/meson.build

@@ -0,0 +1,10 @@
+# SPDX-License-Identifier: CC0-1.0
+
+# List of shader files to convert to header hex
+# for the purposes of inclusion in OpenGL debayering
+shader_files = files([
+    'bayer_1x_packed.frag',
+    'bayer_8.frag',
+    'bayer_8.vert',
+    'identity.vert',
+])

utils/meson.build

@@ -3,5 +3,7 @@
 subdir('codegen')
 subdir('ipu3')
 
+gen_shader_headers = files('gen-shader-headers.sh')
+
 ## Module signing
 gen_ipa_priv_key = files('gen-ipa-priv-key.sh')