This week, I continued my work on Director ImGui debugger from last week. Working on ImGui has been bit of a fun exercise since, it is an open canvas. There are a lot of opportunities to improve upon, and it all depends on what a developer might find useful while working on Director engine.
First of all, there were a bunch of impurities with the ImGui debugger. e.g.
- Many child widgets have the same problem as the breakpoint window error pop-up from last week. i.e. widgets having the same label and id causing the ImGui throw an pop-up error saying changes made to one widget will be reflected to the other. I solved the same problem in the following places:
- i. Vars Window
ii. Watched Variables
iii. Scripts handler widget - I also improved the search for handler in the
getHandlerfunction. Instead of searching for the handler in all casts, we can single out the cast that has the handler in it. - When displaying Prop list in the execution handler window, there was a missing line, which I promptly added.
And a bunch of other small stuff, too small to be worth noting here.
Another feature that was stubbed in the debugger was being able to load and save the current state of the debugger into a persistent file. So, we can save a position in the game we are currently working on, and load the same position every time we start a debugging session.
We went with the JSON format to store the state. We are currently storing the following things (and loading them back):
1) Window Positions
2) Score frame number
3) Windows that are open/closed
4) Global, Local and Watched Variables
5) Breakpoints
6) Log
7) Colors
Here, @OMGThePizzaGuy and @lephilousophe showed me `ImGui::SaveIniSettingsToMemory/ImGui::LoadIniSettingsFromMemory` which made my job much easier.
In the Watched Vars window, I am also showing Local Variables and Global Variables with different colors. On top of that, Local Variables that are out of scope are shown with different color.
All variables are now shown with `renderVariable()` which allows variables to be clicked on to add them to the WatchedVars list and also show their current value.
Previously, the Scripts window only showed the handler being executed at that moment. However, for better navigation, @sev suggested that all the scripts from the same lingo context should be shown in the same window. This took me a while. Since, now not only was I rendering multiple (ImGui) widgets for multiple (Director) windows, I was also showing rendering multiple handler in the same Scripts widget. This caused a bunch of problems with stepping over e.g. pressing step over caused the script to move multiple steps forward, and with showing the current line in the handler (with a little yellow arrow), because the _state->_dbg._isScriptDirty was getting set to false immediately after the first script was rendered. Also, the scroll to the current line was also not working. This took some time and debugging to fix.
When @sev started review on my PR, he immediately pointed out that I was making a separate ImGuiState::state for each window, which in hindsight I realized was a mistake. So, I reworked it to only make a separate instances of the objects that are needed to hold the execution context of a window. This also took a while to get right. There was a bunch of unexpected behavior including, the scripts were not showing up the first time the ‘step’ button was pressed in the control panel.
I also fixed a deprecation warning that occurred while compiling the Director engine. I had to create a custom copy constructor for the MacWindow class since the synthesized copy constructor was calling a deprecated copy constructor for the ManagedSurface class. Instead I had to use a copyFrom method as suggested.
There was another instance of use of deprecated method operator= for the ManagedSurface class, used copyFrom there as well.
Overall, a somewhat normal week. I hope to make even more improvements to the ImGui debugger. e.g. Adding a trace for watched variables is next on the list.