Png fix for vulkan rhi (#962)

* Add supported formats for pngs in frame capture system. Add conversion logic from bgra to rgba.

Gems/Atom/Feature/Common/Code/Source/FrameCaptureSystemComponent.cpp

@@ -21,6 +21,8 @@
 #include <Atom/Utils/PpmFile.h>
 
 #include <AtomCore/Serialization/Json/JsonUtils.h>
+#include <AzCore/Jobs/JobFunction.h>
+#include <AzCore/Jobs/JobCompletion.h>
 
 #include <AzCore/IO/SystemFile.h>
 #include <AzCore/RTTI/BehaviorContext.h>
@@ -55,6 +57,43 @@ namespace AZ
         FrameCaptureOutputResult PngFrameCaptureOutput(
             const AZStd::string& outputFilePath, const AZ::RPI::AttachmentReadback::ReadbackResult& readbackResult)
         {
+            AZStd::shared_ptr<AZStd::vector<uint8_t>> buffer = readbackResult.m_dataBuffer;
+
+            // convert bgra to rgba by swapping channels
+            const int numChannels = AZ::RHI::GetFormatComponentCount(readbackResult.m_imageDescriptor.m_format);
+            if (readbackResult.m_imageDescriptor.m_format == RHI::Format::B8G8R8A8_UNORM)
+            {
+                buffer = AZStd::make_shared<AZStd::vector<uint8_t>>(readbackResult.m_dataBuffer->size());
+                AZStd::copy(readbackResult.m_dataBuffer->begin(), readbackResult.m_dataBuffer->end(), buffer->begin());
+
+                AZ::JobCompletion jobCompletion;
+                const int numThreads = 8;
+                const int numPixelsPerThread = buffer->size() / numChannels / numThreads;
+                for (int i = 0; i < numThreads; ++i)
+                {
+                    int startPixel = i * numPixelsPerThread;
+
+                    AZ::Job* job = AZ::CreateJobFunction(
+                        [&, startPixel, numPixelsPerThread]()
+                        {
+                            for (int pixelOffset = 0; pixelOffset < numPixelsPerThread; ++pixelOffset)
+                            {
+                                if (startPixel * numChannels + numChannels < buffer->size())
+                                {
+                                    AZStd::swap(
+                                        buffer->data()[(startPixel + pixelOffset) * numChannels],
+                                        buffer->data()[(startPixel + pixelOffset) * numChannels + 2]
+                                    );
+                                }
+                            }
+                        }, true, nullptr);
+
+                    job->SetDependent(&jobCompletion);
+                    job->Start();
+                }
+                jobCompletion.StartAndWaitForCompletion();
+            }
+
             using namespace OIIO;
             AZStd::unique_ptr<ImageOutput> out = ImageOutput::create(outputFilePath.c_str());
             if (out)
@@ -62,13 +101,13 @@ namespace AZ
                 ImageSpec spec(
                     readbackResult.m_imageDescriptor.m_size.m_width,
                     readbackResult.m_imageDescriptor.m_size.m_height,
-                    AZ::RHI::GetFormatComponentCount(readbackResult.m_imageDescriptor.m_format)
+                    numChannels
                 );
                 spec.attribute("png:compressionLevel", r_pngCompressionLevel);
 
                 if (out->open(outputFilePath.c_str(), spec))
                 {
-                    out->write_image(TypeDesc::UINT8, readbackResult.m_dataBuffer->data());
+                    out->write_image(TypeDesc::UINT8, buffer->data());
                     out->close();
                     return FrameCaptureOutputResult{FrameCaptureResult::Success, AZStd::nullopt};
                 }
@@ -460,13 +499,23 @@ namespace AZ
 #if defined(OPEN_IMAGE_IO_ENABLED)
                     else if (extension == "png")
                     {
-                        AZStd::string folderPath;
-                        AzFramework::StringFunc::Path::GetFolderPath(m_outputFilePath.c_str(), folderPath);
-                        AZ::IO::SystemFile::CreateDir(folderPath.c_str());
+                        if (readbackResult.m_imageDescriptor.m_format == RHI::Format::R8G8B8A8_UNORM ||
+                            readbackResult.m_imageDescriptor.m_format == RHI::Format::B8G8R8A8_UNORM)
+                        {
+                            AZStd::string folderPath;
+                            AzFramework::StringFunc::Path::GetFolderPath(m_outputFilePath.c_str(), folderPath);
+                            AZ::IO::SystemFile::CreateDir(folderPath.c_str());
 
-                        const auto frameCaptureResult = PngFrameCaptureOutput(m_outputFilePath, readbackResult);
-                        m_result = frameCaptureResult.m_result;
-                        m_latestCaptureInfo = frameCaptureResult.m_errorMessage.value_or("");
+                            const auto frameCaptureResult = PngFrameCaptureOutput(m_outputFilePath, readbackResult);
+                            m_result = frameCaptureResult.m_result;
+                            m_latestCaptureInfo = frameCaptureResult.m_errorMessage.value_or("");
+                        }
+                        else
+                        {
+                            m_latestCaptureInfo = AZStd::string::format(
+                                "Can't save image with format %s to a png file", RHI::ToString(readbackResult.m_imageDescriptor.m_format));
+                            m_result = FrameCaptureResult::UnsupportedFormat;
+                        }
                     }
 #endif
                     else