[Drape] Introduce developer sandbox app for rendering debugging and developement #10052

AndrewShkrob · 2025-01-10T20:51:36Z

renderexpert commented

2025-01-10 20:51:36 +00:00

(Migrated from github.com)

Current problem

The existing Qt-based desktop app supports only OpenGL rendering, while mobile clients use Metal and Vulkan mostly. More than that, the Qt-based app injects its own OpenGL code and mixes rendering with Qt's OpenGL. It increases the distance between desktop and mobile clients even more. Thus, the development and debugging of graphics features can be reliably done only on mobile devices. It's much more tricky because of the lack of good tooling, especially for Vulkan.
The latest versions of Qt provide support for Metal and Vulkan on desktop (not supported by OMaps at the moment, though). However, Qt still does its own Vulkan/Metal API calls there and requires a lot of additional code to be compatible with OMaps approach - execute business logic in the main thread and do rendering in a separate thread(s).

My approach

There are two popular and well-known libraries in the community of game and rendering developers

GLFW - https://github.com/glfw/glfw
Dear imGui - https://github.com/ocornut/imgui

These libraries do OS-level window management and simplistic GUI for tons of graphics demos and games. I created a separate app in the OMaps repository that utilises them.

How it looks (click to open video):

Features

All rendering is done by the Drape, no external graphics API calls
Simplistic UI allows to do map manipulations, to download maps, to work with location, to enable hidden rendering features (like SMAA and POI displacement debugging visualisation) and can be easily extended for other features in the future (3D, routing, elevation maps and so on)
Graphics API can be switched without app re-run! (It is hard to implement the same in Qt)
All API works on macOS (Vulkan via MoltenVK - https://github.com/KhronosGroup/MoltenVK)
Vulkan and OpenGL work natively on Linux (tested on Ubuntu)

How to use

Just build and run dev_sandbox project

# Current problem The existing Qt-based desktop app supports only OpenGL rendering, while mobile clients use Metal and Vulkan mostly. More than that, the Qt-based app injects its own OpenGL code and mixes rendering with Qt's OpenGL. It increases the distance between desktop and mobile clients even more. Thus, the development and debugging of graphics features can be reliably done only on mobile devices. It's much more tricky because of the lack of good tooling, especially for Vulkan. The latest versions of Qt provide support for Metal and Vulkan on desktop (not supported by OMaps at the moment, though). However, Qt still does its own Vulkan/Metal API calls there and requires a lot of additional code to be compatible with OMaps approach - execute business logic in the main thread and do rendering in a separate thread(s). # My approach There are two popular and well-known libraries in the community of game and rendering developers 1. GLFW - https://github.com/glfw/glfw 2. Dear imGui - https://github.com/ocornut/imgui These libraries do OS-level window management and simplistic GUI for tons of graphics demos and games. I created a separate app in the OMaps repository that utilises them. How it looks (click to open video): [![video 1](https://img.youtube.com/vi/2o73QoAqZFA/0.jpg)](https://www.youtube.com/watch?v=2o73QoAqZFA) [![video 2](https://img.youtube.com/vi/cy88pk9tPW0/0.jpg)](https://www.youtube.com/watch?v=cy88pk9tPW0) # Features 1. All rendering is done by the Drape, no external graphics API calls 2. Simplistic UI allows to do map manipulations, to download maps, to work with location, to enable hidden rendering features (like SMAA and POI displacement debugging visualisation) and can be easily extended for other features in the future (3D, routing, elevation maps and so on) 3. Graphics API can be switched without app re-run! (It is hard to implement the same in Qt) 4. All API works on macOS (Vulkan via MoltenVK - https://github.com/KhronosGroup/MoltenVK) 5. Vulkan and OpenGL work natively on Linux (tested on Ubuntu) # How to use Just build and run `dev_sandbox` project #

👍 3 🚀 5

vng (Migrated from github.com) approved these changes 2025-02-22 10:40:44 +00:00

dev_sandbox/main.cpp

vng (Migrated from github.com) commented

2025-02-22 10:27:32 +00:00

nit: I'd prefer to make one Window or App instance here that holds all these callbacks. To have one global object instead of many.

dev_sandbox/main.cpp

					
				@ -0,0 +537,4 @@

				#if defined(OMIM_OS_MAC)

				    x *= visualScale;

				    y *= visualScale;

				#endif

vng (Migrated from github.com) commented

2025-02-22 10:32:53 +00:00

This stuff here and above is a bit mind-blowing :) Why do we multiply coordinates on Mac and divide on Linux.

dev_sandbox/main_linux.cpp

vng (Migrated from github.com) commented

2025-02-22 10:39:40 +00:00

nit: I suppose static is redundant here

renderexpert (Migrated from github.com) reviewed 2025-02-22 17:36:06 +00:00

dev_sandbox/main.cpp

					
				@ -0,0 +537,4 @@

				#if defined(OMIM_OS_MAC)

				    x *= visualScale;

				    y *= visualScale;

				#endif

renderexpert (Migrated from github.com) commented

2025-02-22 17:36:06 +00:00

Unfortunately, OS are not consistent in terms of visual scale in glfw library (possibly it's native behaviour on this OS). macOS returns width/height in the same units regardless of screen scaling, while on Linux it returns width/height premultiplied to display scaling.

AndrewShkrob reviewed 2025-02-22 22:31:53 +00:00

dev_sandbox/CMakeLists.txt

AndrewShkrob commented

2025-02-22 22:31:53 +00:00

Is it needed? Shaders compiler is used only in tests

AndrewShkrob reviewed 2025-02-22 22:32:40 +00:00

dev_sandbox/CMakeLists.txt

					
				@ -0,0 +82,4 @@

				  endforeach()

				endfunction()

				copy_resources(

AndrewShkrob commented

2025-02-22 22:32:40 +00:00

How about vulkan shaders folder? Is the app going to support Vulkan?

rtsisyk approved these changes 2025-02-23 15:34:34 +00:00

rtsisyk left a comment

LGTM

renderexpert (Migrated from github.com) reviewed 2025-02-24 22:22:18 +00:00

dev_sandbox/CMakeLists.txt

					
				@ -0,0 +82,4 @@

				  endforeach()

				endfunction()

				copy_resources(

renderexpert (Migrated from github.com) commented

2025-02-24 22:22:18 +00:00

Good catch!

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Reference: organicmaps/organicmaps-tmp#10052

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