preserve DB_DEPTH_SIZE_XY and add tiled readback

src/graphics/host_gpu/renderer/depthRenderTarget.cpp

@@ -126,7 +126,10 @@ void ResolveRenderDepthTarget(uint64_t submit_id, CommandBuffer* buffer, const H
 	    z.htile_surface.prefetch_height == 0 && z.htile_surface.dst_outside_zero_to_one == 0 &&
 	    z.z_read_base_addr == 0 && z.z_write_base_addr == 0 && z.stencil_read_base_addr == 0 &&
 	    z.stencil_write_base_addr == 0 && z.htile_data_base_addr == 0 &&
-	    !z.z_info.tile_surface_enable && !z.size.valid && !z.width_height_valid &&
+	    // DB_DEPTH_SIZE_XY is independent state and may remain programmed after the attachment
+	    // formats and addresses are unbound. A zero encoding is the valid 1x1 value, so its
+	    // presence alone must not manufacture a depth attachment.
+	    !z.z_info.tile_surface_enable && !z.width_height_valid &&
 	    !z.pitch_height_valid && z.size.x_max == 0 && z.size.y_max == 0 &&
 	    z.pitch_div8_minus1 == 0 && z.height_div8_minus1 == 0 && z.slice_div64_minus1 == 0 &&
 	    z.width == 0 && z.height == 0;
@@ -215,7 +218,7 @@ void ResolveRenderDepthTarget(uint64_t submit_id, CommandBuffer* buffer, const H
 	} else if (z.htile_data_base_addr != 0) {
 		DepthFatal("HTile address without an enabled tile surface");
 	}
-	const bool size_xy_valid = z.size.valid && (z.size.x_max != 0 || z.size.y_max != 0);
+	const bool size_xy_valid = z.size.valid;
 	const bool wh_valid      = z.width_height_valid && z.width != 0 && z.height != 0;
 	if (!size_xy_valid && !wh_valid) {
 		DepthFatal("missing depth extent");

src/graphics/host_gpu/renderer/tiler.cpp

@@ -2,6 +2,7 @@
 
 #include "common/assert.h"
 #include "graphics/guest_gpu/gpu_defs.h"
+#include "graphics/guest_gpu/gpu_format.h"
 #include "graphics/guest_gpu/tile.h"
 #include "graphics/host_gpu/graphicContext.h"
 #include "graphics/host_gpu/objects/textureCommon.h"
@@ -170,6 +171,38 @@ void Tiler::TileImage(void* dst, const void* src, const RenderTargetInfo& info)
 	}
 }
 
+void Tiler::TileImage(void* dst, const void* src, const ImageInfo& info) const {
+	const bool image_2d = info.type == Prospero::GpuEnumValue(Prospero::ImageType::kColor2D) &&
+	                      info.depth == 1;
+	const auto bytes_per_element = Prospero::RenderTargetBytesPerElement(info.format);
+	if (!image_2d || info.levels == 0 || info.levels > 16 ||
+	    info.tile != Prospero::GpuEnumValue(Prospero::TileMode::kRenderTarget) ||
+	    bytes_per_element == 0) {
+		EXIT("Tiler: unsupported storage-texture tile, addr=0x%016" PRIx64
+		     "+0x%016" PRIx64 " extent=%ux%ux%u levels=%u tile=%u format=%u\n",
+		     info.address, info.size, info.width, info.height, info.depth, info.levels, info.tile,
+		     info.format);
+	}
+	auto layout = TextureCalcUploadLayout(info.format, info.width, info.height, info.levels,
+	                                      info.depth, info.pitch, info.tile, info.size, true, false,
+	                                      false, "StorageTextureReadback");
+	auto regions = TextureBuildUploadRegions(
+	    layout, Prospero::SurfaceFormat(info.format), info.width, info.height, info.depth,
+	    info.levels, false, false, TextureUploadDestination::MipLevels,
+	    TextureUploadSliceLayout::MipChainPerSlice);
+	std::memset(dst, 0, info.size);
+	for (uint32_t level = 0; level < info.levels; level++) {
+		const auto& level_size = layout.level_sizes[level];
+		const auto  guest_offset = level_size.src_size != 0 ? level_size.src_offset
+		                                                   : level_size.offset;
+		auto* guest = static_cast<uint8_t*>(dst) + guest_offset;
+		const auto* linear = static_cast<const uint8_t*>(src) + regions[level].offset;
+		TileConvertLinearToTiledRenderTarget(
+		    guest, linear, regions[level].width, regions[level].height, regions[level].pitch,
+		    bytes_per_element, level_size.size, level_size.src_size, level_size.x, level_size.y);
+	}
+}
+
 void Tiler::TileImage(void* dst, const void* src, const DepthTargetInfo& info) const {
 	if (info.stencil_address != 0 || info.stencil_size != 0 ||
 	    info.tile_mode != Prospero::GpuEnumValue(Prospero::TileMode::kDepth) ||

src/graphics/host_gpu/renderer/tiler.h

@@ -25,6 +25,7 @@ public:
 	                   const DepthTargetInfo& info, const BufferImageCopySource& source,
 	                   bool refresh, uint32_t base_layer = 0) const;
 	void TileImage(void* dst, const void* src, const RenderTargetInfo& info) const;
+	void TileImage(void* dst, const void* src, const ImageInfo& info) const;
 	void TileImage(void* dst, const void* src, const DepthTargetInfo& info) const;
 };