Uploaded May 2025 | Updated September 2026, 2 weeks ago

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💡 Normal maps simulate small surface details without adding geometry. But DirectX and OpenGL handle the Y-axis differently:

👉 DirectX Normal Maps:

Y-axis (Green channel) points down
Typically use left-handed coordinate system
Green areas on the normal map might look darker.

👉 OpenGL Normal Maps:

Y-axis (Green channel) points up
Uses a right-handed coordinate system
Green areas usually appear lighter.

🎯 Why it matters:
If you use the wrong format in your engine or shader, lighting will look off—like bumps are inverted. You can fix this by inverting the green channel if needed.