Discussion about software development for the old-school Gameboys, ranging from the "Gray brick" to Gameboy Color
(Launched in 2008)
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Hello everyone. I’m encountering a glitch in my Game Boy game where the screen flickers. What debugging techniques do you suggest for tracking down the issue?
Can someone help!!
Looking forward to your responses.
Thanks in advance!
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Hardware and Emulator Considerations
Test on both hardware (if possible) and emulators (e.g., BGB, Visual Boy Advance) to isolate the problem.
Verify that the issue persists across different emulators and hardware configurations.
Code Review
Check your video memory (VRAM) updates: Ensure you're not writing to VRAM during vblank.
Verify your LCD controller settings: Confirm that the LCD controller is properly configured.
Review your interrupt handlers: Ensure they're not interfering with video rendering.
Debugging Tools
Use a debugger (e.g., BGB's built-in debugger): Step through code, inspect registers, and set breakpoints.
Add debug prints or logging: Monitor variables and code execution.
Utilize visual debugging tools (e.g., tile viewers, VRAM editors).
Common Culprits
Incorrect vblank timing.
VRAM corruption or misuse.
LCD controller misconfiguration.
Interrupt conflicts.
Incorrect palette or color usage.
Methodical Approach
Isolate the problem area: Identify the specific code or scenario causing the flicker.
Simplify and minimize: Reduce code complexity to isolate the issue.
Divide and conquer: Split code into sections and test each independently.
Game Boy-Specific Considerations
Understand the Game Boy's video timing and LCD controller.
Familiarize yourself with the Game Boy's memory layout and VRAM.
Some recommended resources:
Game Boy Programming Manual (GBDev Wiki)
BGB Debugger Documentation
Visual Boy Advance Debugger Documentation
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