Revert D50436128: Multisect successfully blamed "D50436125: [IGL] Sim…

…plify `ShaderUniforms::setFloat3x3`" for test or build failures

Summary:
This diff is reverting D50436128
Depends on D50483445
D50436125: [IGL] Simplify `ShaderUniforms::setFloat3x3` by AmesingFlank has been identified to be causing the following test or build failures:

Tests affected:
- [//fbandroid/instrumentation_tests/com/facebook/msqrd:block_inputs_every_type_via_patches-64bit - testDefault[base_gles2_hermes_vEffect_uncompressed] (com.facebook.msqrd.unified_runner.AREngineScreenshotTest)](https://www.internalfb.com/intern/test/281475070193663/)

Here's the Multisect link:
https://www.internalfb.com/multisect/3348209
Here are the tasks that are relevant to this breakage:

We're generating a revert to back out the changes in this diff, please note the backout may land if someone accepts it.

If you believe this diff has been generated in error you may Commandeer and Abandon it.

Reviewed By: syeh1

Differential Revision: D50483453

fbshipit-source-id: 7052e647820c558d7df6b85bae1969823d9b748e

IGLU/simple_renderer/ShaderUniforms.cpp

@@ -516,7 +516,26 @@ void ShaderUniforms::setFloat3x3Array(const igl::NameHandle& uniformName,
                                       const iglu::simdtypes::float3x3* value,
                                       size_t count,
                                       size_t arrayIndex) {
-  setUniformBytes(uniformName, value, sizeof(iglu::simdtypes::float3x3), count, arrayIndex);
+  if (device_.getBackendType() == igl::BackendType::Metal ||
+      device_.getBackendType() == igl::BackendType::Vulkan) {
+    setUniformBytes(uniformName, value, sizeof(iglu::simdtypes::float3x3), count, arrayIndex);
+  } else {
+    // simdtypes::float3x3 has an extra float per float-vector.
+    // Remove it so we can send the packed version to OpenGL
+    auto paddedMatrixPtr = reinterpret_cast<const float*>(value);
+    auto packedMatrix = new float[9 * count];
+    auto packedMatrixPtr = packedMatrix;
+    for (int n = 0; n < count; n++) {
+      for (int i = 0; i < 3; i++) {
+        for (int j = 0; j < 3; j++) {
+          *packedMatrixPtr++ = *paddedMatrixPtr++;
+        }
+        paddedMatrixPtr++; // skip over padded float
+      }
+    }
+    setUniformBytes(uniformName, packedMatrix, sizeof(float) * 9, count, arrayIndex);
+    delete[] packedMatrix;
+  }
 }
 
 void ShaderUniforms::setFloat4x4(const igl::NameHandle& uniformName,