ASTC Texture Appears Vertically Flipped When Rendered

Originator:wcmiii
Number:rdar://20755603 Date Originated:04/29/2015
Status:Closed Resolved:Fixed
Product:iOS Product Version:8.3
Classification:Other Bug Reproducible:Always
 
Summary:
When loading ASTC textures into Metal, the texture appears upright in the frame debugger (Capture GPU Frame), but vertically flipped when rendered. Other texture formats appear upright both in the debugger and when rendered.

Steps to Reproduce:
1. Run the attached sample app on a Metal-capable iOS device.
2. Select an ASTC texture from the menu (4x4 or 8x8 block size)
3. (Optional) Define MBE_WORKAROUND_INVERTED_ASTC to be 1 to enable a texture matrix that inverts the y axis of the texture coordinate system and results in correct rendering.

Expected Results:
ASTC textures render as they appear in the debugger, similar to how other compressed formats render (the sample app includes PVRTC and ETC2 textures for comparison).

Actual Results:
ASTC textures appear vertically flipped when rendered.

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