gpu: preserve low-alpha 2/10/10/10 render-target storage

src/graphics/host_gpu/renderer/image/imageInfo.h

@@ -17,7 +17,7 @@
 
 namespace Libs::Graphics {
 
-enum class ColorTransform : uint32_t { None, SwapBgra16, Reverse10_11_11 };
+enum class ColorTransform : uint32_t { None, SwapBgra16, Reverse10_11_11, Rotate2_10_10_10 };
 
 enum class VideoOutCompression : uint8_t {
 	Uncompressed,
@@ -105,6 +105,8 @@ struct ImageInfo {
 		switch (guest_format) {
 			case Prospero::BufferFormat::k10_11_11Float:
 				return ColorTransform::Reverse10_11_11;
+			case Prospero::BufferFormat::k2_10_10_10UNorm:
+				return ColorTransform::Rotate2_10_10_10;
 			default: return ColorTransform::None;
 		}
 	}

src/graphics/host_gpu/renderer/image/textureCommon.cpp

@@ -32,8 +32,12 @@ struct HostFormatInfo {
 
 HostFormatInfo ResolveHostFormat(Prospero::BufferFormat guest_format,
                                  Prospero::ChannelOrder order) {
-	if (guest_format == Prospero::BufferFormat::k10_11_11Float) {
-		return {vk::Format::eB10G11R11UfloatPack32, Prospero::ColorMappingBgra};
+	switch (guest_format) {
+		case Prospero::BufferFormat::k10_11_11Float:
+			return {vk::Format::eB10G11R11UfloatPack32, Prospero::ColorMappingBgra};
+		case Prospero::BufferFormat::k2_10_10_10UNorm:
+			return {vk::Format::eA2R10G10B10UnormPack32, Prospero::ColorMappingAbgr};
+		default: break;
 	}
 	if (order == Prospero::ChannelOrder::kAlt) {
 		switch (guest_format) {

src/graphics/host_gpu/renderer/image/tiler.cpp

@@ -104,7 +104,8 @@ TileManager::Tiling TileManager::Prepare(bool tile, uint64_t tiled_capacity,
 	    block.block_depth == 0 || block.block_size == 0 || info.tiling.texel_width == 0 ||
 	    info.tiling.texel_height == 0 || info.tiled_slice_stride == 0);
 	EXIT_IF((transform == ColorTransform::SwapBgra16 && block.bytes_per_element != 8u) ||
-	        (transform == ColorTransform::Reverse10_11_11 && block.bytes_per_element != 4u));
+	        ((transform == ColorTransform::Reverse10_11_11 ||
+	          transform == ColorTransform::Rotate2_10_10_10) && block.bytes_per_element != 4u));
 	const auto checked_multiply = [](uint64_t left, uint64_t right, uint64_t& result) {
 		return (left == 0 || right <= UINT64_MAX / left) && (result = left * right, true);
 	};
@@ -560,7 +561,8 @@ void TileManager::TransformColor(Result input, Result output, ColorTransform tra
 	uint32_t element_bytes = 0;
 	switch (transform) {
 		case ColorTransform::SwapBgra16: element_bytes = 8; break;
-		case ColorTransform::Reverse10_11_11: element_bytes = 4; break;
+		case ColorTransform::Reverse10_11_11:
+		case ColorTransform::Rotate2_10_10_10: element_bytes = 4; break;
 		default: EXIT("invalid color transform\n");
 	}
 	EXIT_IF(input.size == 0 || input.size % element_bytes != 0 ||

src/graphics/host_gpu/shaders/gpu_tiler_color.inc

@@ -1,4 +1,4 @@
-// ColorTransform values match imageInfo.h. Preserve the floating-point bit fields exactly.
+// ColorTransform values match imageInfo.h. Preserve the component bit fields exactly.
 uvec2 transform_color(uvec2 value, uint transform, bool to_host) {
 	switch (transform) {
 		case 1u:
@@ -15,6 +15,13 @@ uvec2 transform_color(uvec2 value, uint transform, bool to_host) {
 			}
 			break;
 		}
+		case 3u:
+			if (to_host) {
+				value.x = (value.x >> 2u) | (value.x << 30u);
+			} else {
+				value.x = (value.x << 2u) | (value.x >> 30u);
+			}
+			break;
 	}
 	return value;
 }