Log Execution Verification and Correspondence Analysis Framebuffer-Visualization

Summary

Verification that new diagnostic logs run correctly after rebuilding the module. Added additional diagnostic logs to investigate why log blocks were not running and verified that all logs appear correctly in tests. The logs confirm that the framebuffer is the correct size (23040 pixels) and that the framebuffer-display mapping logs run correctly.

Hardware Concept

Framebuffer-Display Mapping

The framebuffer contains color indices (0-3) for each pixel in 1D format[y * 160 + x]. These indices are converted to RGB using the palette, the RGB colors are drawn on the Pygame surface, and the surface is scaled to the screen resolution. The final content must match the original framebuffer.

Fountain:Pan Docs - "LCD Timing", "Frame Rate", "Tile Data", "LCD Control Register"

Implementation

Verified that the log code is present and added additional diagnostic logs insrc/gpu/renderer.py.

Log Code Verification

It was verified that the following tags are present in the code:

• [Renderer-Framebuffer-Size]- Framebuffer size check
• [Renderer-Pixel-Order-Verification]- Pixel order check
• [Renderer-Framebuffer-Visualization-Correspondence]- Correspondence verification

It was confirmed that the conditions uselen(frame_indices) > 0ratherlen(frame_indices) == 23040.

Additional Diagnostic Logs

Added additional logs at the start ofrender_frame()to verify that the function is executed and thatframe_indicesis available:

• Tag: [Renderer-Entry]
• Registered information:Frame number, yesframebuffer_datais None, yesframe_indicesis None, and the length offrame_indiceseitherframebuffer_data
• Limit:First 20 frames

These logs were added in both the blockif framebuffer_data is not None:like on the blockelse:to ensure that they are executed in both cases.

Log Location Correction

Initially, the logs for Step 0343 were outside the block whereframe_indicesis defined, which caused them to not be executed. They moved inside the blockif self.use_cpp_ppu and self.cpp_ppu is not None:afterframe_indicesis defined.

Added Prints for Debugging

Prints were added along with the logs to facilitate debugging and verify that the code is executed correctly. The prints were added to:

• Logs of[Renderer-Entry]
• Logs of[Renderer-Framebuffer-Size]
• Logs of[Renderer-Pixel-Order-Verification]
• Logs of[Renderer-Framebuffer-Visualization-Correspondence]

Affected Files

• src/gpu/renderer.py- Added additional diagnostic logs and corrected log location

Tests and Verification

Quick tests (30 seconds) were run with Tetris to verify that the logs appear correctly.

Test Results

Command executed: timeout 30 python3 main.py roms/tetris.gb 2>&1 | tee logs/test_tetris_step0343_quick.log

Verified logs:

• ✅ [Renderer-Entry]- Appears correctly, shows thatframe_indicesIt has length 23040
• ✅ [Renderer-Framebuffer-Size]- Appears correctly, confirm the size is 23040 pixels
• ✅ [Renderer-Pixel-Order-Verification]- Appears correctly
• ✅ [Renderer-Framebuffer-Visualization-Correspondence]- Appears correctly

Key Findings

• Framebuffer size:Confirmed that the framebuffer always has 23040 pixels (160x144)
• Log execution:All logs run correctly after moving them into the correct block
• Frame indices: frame_indicesis available and the correct size when the logs are run

Complete Tests Pending

The complete tests with the 5 ROMs (2.5 minutes each) are pending execution. These tests will allow:

• Analyze patterns in framebuffer behavior between different ROMs
• Identify differences in framebuffer-display correspondence between ROMs
• Check if the display issue (vertical stripes, white screen, checkerboard) is related to the content of the framebuffer or the conversion/display

Next Steps

If the cause is identified:

• Step 0344:Implement correction based on findings
• Step 0345:Final display check

If the problem persists:

• Step 0344:Deeper analysis and workaround