Add support for bayer images to Ogre and Ogre2

[tejalbarnwal]

🎉 New feature

Closes gz-sensors issue 299

Sub-Tasks

• Support simulation for BAYER_RGGB8 with OGRE
• Extend the functionality to support all bayer types with OGRE
• Extend the functionality to support with OGRE2

Summary and Related PRs

The functionality reads the user input and renders an RGB image, which is later converted into a single channel 8bit Bayer image using ConvertRGBToBayer() added to Utils.cc inside gz-rendering.

• gz-sensors : Adds a switch case for RGGB bayer format inside CameraSensor.cc and passes the R8G8B8 format to render the image.
• gz-redering : Adds ConvertRGBToBayer() to Utils.cc, modifies OgreRenderTarget.cc to call the conversion function, and handles image format conversion functions with if-else statements.
• gz-gui : Adds switch cases to display Bayer images in Gazebo GUI inside. It treats them as single-channel 8-bit images.
• gz-common : Modifies Image::SetFromData inside Image.cc to support saving of Bayer images. In order to save it It treats them as single-channel 8-bit images.

Test it

In order to test this, one can modify camera_sensor.sdf inside gz-sim here. Would have just to replace the part with the following snippet.

<image>
   <width>320</width>
   <height>240</height>
   <format>BAYER_RGGB8</format>
</image>
<clip>
   <near>0.1</near>
   <far>100</far>
</clip>
<save enabled="true">
    <path>path to the folder</path>
</save>

Checklist

• Signed all commits for DCO
• Added tests
• Added example and/or tutorial
• Updated documentation (as needed)
• Updated migration guide (as needed)
• Consider updating Python bindings (if the library has them)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
• While waiting for a review on your PR, please help review another open pull request to support the maintainers

Note to maintainers: Remember to use Squash-Merge and edit the commit message to match the pull request summary while retaining Signed-off-by messages.

[azeey]

Since the title of the PR ends up in the changelog, mind changing it to maybe just "Add support for bayer images to Ogre and Ogre2". Feel free to reword, but "Pr" and "gzrendering7" should not be in the title.

[iche033]

for global functions, we use a lowercase first letter for the function name. Can you also make this return a copy of the image instead of modifying the source image, i.e. Image convertRGBToBayer(const Image &_image);

[tejalbarnwal]

Sure, I will return the destination image aka the variable destImageData and use memcpy() to actually modify the source image inside OgreRenderTarget.cc. That seems good, right?

[tejalbarnwal]

Hey @iche033, I have made the changes to the enum elements corresponding to bayer formats so that they are consistent with gazebo-classic. As you suggested, we could now review the outcomes of the ABI build.

[tejalbarnwal]

Update: The ABI compatibility failed :(

[iche033]

yes but looking closely at the report, the compatibility is 100%. It did catch the behavior change, which I'm leaning towards letting it slide since Bayer format was not working before.

[iche033]

yes but looking closely at the report, the compatibility is 100%. It did catch the behavior change, which I'm leaning towards letting it slide since Bayer format was not working before.

[iche033]

updated channel count of bayer image format from to 4 to 1 and fixed crash in 79a83c6

[codecov]

Codecov Report

Merging #838 (2ddecda) into gz-rendering7 (a9e2aba) will decrease coverage by 0.28%.
The diff coverage is 17.46%.

❗ Current head 2ddecda differs from pull request most recent head 40a10b9. Consider uploading reports for the commit 40a10b9 to get more accurate results

@@                Coverage Diff                @@
##           gz-rendering7     #838      +/-   ##
=================================================
- Coverage          77.37%   77.09%   -0.28%     
=================================================
  Files                164      164              
  Lines              14459    14521      +62     
=================================================
+ Hits               11187    11195       +8     
- Misses              3272     3326      +54     

Impacted Files	Coverage Δ
src/PixelFormat.cc	100.00% <ø> (ø)
src/Utils.cc	63.63% <0.00%> (-35.19%)	⬇️
ogre2/src/Ogre2RenderTarget.cc	83.44% <68.75%> (-0.67%)	⬇️

... and 1 file with indirect coverage changes