Rename README.md to AGENT.md for both D3D12 and OpenGL tests

tests/OpenGL/AGENT.md

@@ -0,0 +1,54 @@
+# OpenGL Test Agent Instructions
+
+## Quick Start
+
+```bash
+# Build
+cmake --build build --config Debug --target XCRender
+
+# Run test
+./build/tests/OpenGL/Debug/run.bat
+
+# Or manually:
+cd build/tests/OpenGL/Debug
+XCRender.exe
+python compare_ppm.py screenshot.ppm GT.ppm 5
+```
+
+## Test Details
+
+- **Resolution**: 1280x720
+- **Screenshot Frame**: 30
+- **Reference Image**: GT.ppm
+- **Comparison Threshold**: 5 pixels
+
+## Build Target
+
+- Target name: `XCRender`
+- Output: `build/tests/OpenGL/Debug/XCRender.exe`
+
+## Test Output
+
+- Log file: `OpenGL_engine_log.txt`
+- Screenshot: `screenshot.ppm`
+
+## Dependencies
+
+- GLFW 3.3
+- GLAD
+- Assimp
+- GLM
+- stb_image
+
+## Resources
+
+- Model: `res/models/backpack/backpack.obj`
+- Shaders: `Shaders/vertexshader.glsl`, `Shaders/fragmentshader.glsl`
+
+## Troubleshooting
+
+| Issue | Solution |
+|-------|----------|
+| Black screen | Check shader compilation errors in log |
+| No textures | Verify res/models/ directory exists |
+| Model not loading | Check model file path |