Fix a depth texture read back issue.
Fix a depth texture read back issue.

Fixes #2740

pmuetschard/gapid,google/gapid,google/gapid,google/gapid,pmuetschard/gapid,google/gapid,google/gapid,google/agi,google/agi,pmuetschard/gapid,google/agi,google/gapid,google/gapid,google/agi,pmuetschard/gapid,google/agi,pmuetschard/gapid,pmuetschard/gapid,google/agi,pmuetschard/gapid,pmuetschard/gapid,google/gapid,google/agi,google/agi