Detailed Analysis of Framebuffer Correspondence-Visualization

Summary

A quick test (30 seconds) was run with Tetris to generate framebuffer-display correspondence logs implemented in Step 0343. However, no renderer logs were found in the generated log file, indicating that the logs from Step 0343 are not running or are not being captured correctly. The problem found is documented and a plan is established for Step 0346 to verify and correct the situation.

Hardware Concept

Framebuffer-Display Correspondence:

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.

To verify that the correspondence is correct, it is necessary to compare:

• The framebuffer indices (values ​​0-3)
• Expected RGB colors based on palette
• Actual RGB colors on Pygame surface after drawing
• Final RGB colors after scaling

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

Analysis Performed

A quick test was run to generate framebuffer-display correspondence logs:

timeout 30 python3 main.py roms/tetris.gb 2>&1 | tee logs/test_tetris_step0345_analysis.log

Analysis Results

Problem Found:No renderer logs were found in the generated log file.

• No logs appear with the tag[Renderer-Entry]
• No logs appear with the tag[Renderer-Framebuffer-Size]
• No logs appear with the tag[Renderer-Pixel-Order-Verification]
• No logs appear with the tag[Renderer-Framebuffer-Visualization-Correspondence]

Verifications Made

It was verified that:

• ✅ The log code is present insrc/gpu/renderer.py
• ✅ The renderer is called fromsrc/viboy.py(lines 976 and 979)
• ✅ The logs have correct conditions (len(frame_indices) > 0)
• ❌ The logs do not appear in the generated log file

Possible Causes

The possible reasons why the logs do not appear are:

1. The renderer is not running:There may be a silent error preventing the renderer from running
2. Logs are not being captured:There may be a problem with the output redirection or the logging system
3. The log conditions are not met:Maybeframe_indicesbe None or empty when the logs are run
4. The renderer runs before the logs are configured:There may be an execution order problem

Scanned Files

• src/gpu/renderer.py- Verified that the logs are present
• src/viboy.py- Verified that the renderer is called correctly
• logs/test_tetris_step0345_analysis.log- Generated log file (without renderer logs)

Tests and Verification

Command executed:

timeout 30 python3 main.py roms/tetris.gb 2>&1 | tee logs/test_tetris_step0345_analysis.log

Result:

• ❌ No renderer logs were found in the log file
• ✅ Other logs were found (PPU, VRAM, etc.)
• ✅ The emulator runs correctly (the window is visible)

Log Analysis:

grep -E "\[Renderer-" logs/test_tetris_step0345_analysis.log

Result:No matches found.

Sources consulted

• Pan Docs: "LCD Timing", "Frame Rate", "Tile Data", "LCD Control Register"
• Python documentationloggingfor log system

Educational Integrity

Next Steps

Step 0346: Verification and Correction of Renderer Logs

• [ ] Add diagnostic logs to startuprender_frame()to verify that it is executed
• [ ] Verify that the logging system is configured correctly
• [ ] Verify that the output redirection captures all logs
• [ ] Check the conditions of the logs (ifframe_indicesis available)
• [ ] Run tests and analyze the generated logs
• [ ] If the logs appear, analyze the framebuffer-display correspondence
• [ ] If the logs do not appear, implement corrections