graphics: write small GPU-written tiled images back to guest memory behind --readback-tiled-images

Co-authored-by: Dimitar Vagalinski <275970482+overlordxrz-source@users.noreply.github.com>
Co-authored-by: Mr. Big Britches <111622360+MrBigBritches@users.noreply.github.com>

src/common/emulatorConfig.cpp

@@ -185,6 +185,10 @@ bool ReadbackLinearImagesEnabled() {
 	return g_config->readback_linear_images;
 }
 
+bool ReadbackTiledImagesEnabled() {
+	return g_config->readback_tiled_images;
+}
+
 bool SyncRawImageBuffersEnabled() {
 	return g_config->sync_raw_image_buffers;
 }

src/common/emulatorConfig.h

@@ -85,6 +85,7 @@ struct ConfigOptions {
 	bool                   gpu_assisted_validation_enabled = false;
 	bool                   renderdoc_enabled           = false;
 	bool                   readback_linear_images      = false;
+	bool                   readback_tiled_images       = false;
 	bool                   sync_raw_image_buffers      = false;
 	bool                   tessellation_enabled        = false;
 	bool                   trophy_enabled              = true;
@@ -150,6 +151,7 @@ bool GpuAssistedValidationEnabled();
 
 bool RenderDocEnabled();
 bool ReadbackLinearImagesEnabled();
+bool ReadbackTiledImagesEnabled();
 bool SyncRawImageBuffersEnabled();
 bool TessellationEnabled();
 bool TrophyEnabled();

src/graphics/host_gpu/renderer/cache/textureCache.cpp

@@ -34,6 +34,8 @@ namespace Libs::Graphics {
 namespace {
 
 constexpr uint64_t NumFramesBeforeRemoval = 32;
+// Largest GPU-written tiled image (in texels) that is written back to guest memory on submit.
+constexpr uint64_t SmallTiledReadbackTexels = 64 * 64;
 
 [[nodiscard]] bool DecodeColorClear(const TextureCache::ImageDesc& desc, uint8_t code,
                                   vk::ClearColorValue& clear) {
@@ -122,7 +124,8 @@ TextureCache::TextureCache(GraphicContext& graphics, CommandScheduler& scheduler
       m_blit_helper(graphics, scheduler),
       m_tiler(graphics, scheduler, buffer_cache.GetUtilityBuffer(MemoryUsage::Stream)),
       m_buffer_cache(buffer_cache),
-      m_readback_linear_images(Config::ReadbackLinearImagesEnabled()) {
+      m_readback_linear_images(Config::ReadbackLinearImagesEnabled()),
+      m_readback_tiled_images(Config::ReadbackTiledImagesEnabled()) {
 	if (m_graphics.CanReportMemoryUsage()) {
 		constexpr int64_t GiB = 1024ll * 1024 * 1024;
 		const auto        budget =
@@ -401,7 +404,14 @@ void TextureCache::UntrackImageTail(ImageId id) {
 }
 
 void TextureCache::TrackImageDownload(ImageId id, Image& image) {
-	if (m_readback_linear_images && !image.info.IsTiled()) {
+	// Small tiled targets are written back too: games read GPU results such as reductions and
+	// simulation state from them on the CPU (PPSA04263 keeps the origin of its ocean wave grid
+	// in a 1x1 R32G32 target, and its water physics read it to sample the wave heights).
+	const auto& info   = image.info;
+	const auto  texels = static_cast<uint64_t>(info.extent.width) * info.extent.height *
+	                     info.extent.depth * info.resources.layers;
+	if (info.IsTiled() ? m_readback_tiled_images && texels <= SmallTiledReadbackTexels
+	                   : m_readback_linear_images) {
 		if (!image.IsGpuModified()) {
 			EXIT("TextureCache: cannot enroll a non-GPU-owned image for download\n");
 		}
@@ -1956,7 +1966,7 @@ void TextureCache::RunGarbageCollector() {
 }
 
 void TextureCache::ProcessDownloadImages() {
-	if (!m_readback_linear_images) {
+	if (!m_readback_linear_images && !m_readback_tiled_images) {
 		return;
 	}
 	std::scoped_lock lock {m_lock};

src/graphics/host_gpu/renderer/cache/textureCache.h

@@ -180,6 +180,7 @@ private:
 	uint64_t         m_gc_tick                = 0;
 	mutable uint32_t m_image_query_epoch      = 0;
 	bool             m_readback_linear_images = false;
+	bool             m_readback_tiled_images  = false;
 
 	friend struct TextureCacheTestAccess;
 	friend class BufferCache;

src/launcher/forms/configuration_edit_dialog.ui

@@ -168,12 +168,18 @@
              </widget>
             </item>
             <item row="6" column="1">
+             <widget class="QCheckBox" name="checkBox_readback_tiled">
+              <property name="toolTip"><string>Read back small writable tiled images</string></property>
+              <property name="text"><string>Enable tiled readback</string></property>
+             </widget>
+            </item>
+            <item row="7" column="1">
              <widget class="QCheckBox" name="checkBox_tessellation">
               <property name="toolTip"><string>Draw tessellated geometry. Disabled by default; unsupported tessellation may cause crashes.</string></property>
               <property name="text"><string>Enable tessellation support (experimental)</string></property>
              </widget>
             </item>
-            <item row="7" column="1">
+            <item row="8" column="1">
              <widget class="QCheckBox" name="checkBox_hdr">
               <property name="toolTip"><string>Enable HDR10 output for supported games. Requires HDR enabled on the host display.</string></property>
               <property name="text"><string>Enable HDR display support</string></property>

src/launcher/include/configuration.h

@@ -126,6 +126,7 @@ public:
 	bool                   hdr_enabled                 = false;
 	bool                   hide_cursor_enabled         = false;
 	bool                   readback_linear_images      = false;
+	bool                   readback_tiled_images       = false;
 	bool                   sync_raw_image_buffers      = false;
 	bool                   tessellation_enabled        = false;
 	bool                   trophy_enabled              = true;
@@ -165,6 +166,7 @@ public:
 		hdr_enabled                 = other.hdr_enabled;
 		hide_cursor_enabled         = other.hide_cursor_enabled;
 		readback_linear_images      = other.readback_linear_images;
+		readback_tiled_images       = other.readback_tiled_images;
 		sync_raw_image_buffers      = other.sync_raw_image_buffers;
 		tessellation_enabled        = other.tessellation_enabled;
 		trophy_enabled              = other.trophy_enabled;

src/launcher/src/configuration.cpp

@@ -13,6 +13,7 @@ QVariantMap Configuration::GameSettings() const {
 	KYTY_CFG_SET(hdr_enabled);
 	KYTY_CFG_SET(hide_cursor_enabled);
 	KYTY_CFG_SET(readback_linear_images);
+	KYTY_CFG_SET(readback_tiled_images);
 	KYTY_CFG_SET(sync_raw_image_buffers);
 	KYTY_CFG_SET(tessellation_enabled);
 	KYTY_CFG_SET(trophy_enabled);
@@ -62,6 +63,7 @@ void Configuration::ReadGameSettingsValues(const Settings& s) {
 	KYTY_CFG_GET(hdr_enabled);
 	KYTY_CFG_GET(hide_cursor_enabled);
 	KYTY_CFG_GET(readback_linear_images);
+	KYTY_CFG_GET(readback_tiled_images);
 	KYTY_CFG_GET(sync_raw_image_buffers);
 	KYTY_CFG_GET(tessellation_enabled);
 	trophy_enabled   = s.value("trophy_enabled", trophy_enabled).toBool();

src/launcher/src/configurationEditDialog.cpp

@@ -286,6 +286,7 @@ void ConfigurationEditDialog::Init(const Configuration& info) {
 	m_ui->checkBox_hdr->setChecked(info.hdr_enabled);
 	m_ui->checkBox_hide_cursor->setChecked(info.hide_cursor_enabled);
 	m_ui->checkBox_readback->setChecked(info.readback_linear_images);
+	m_ui->checkBox_readback_tiled->setChecked(info.readback_tiled_images);
 	m_ui->checkBox_sync_raw_image_buffers->setChecked(info.sync_raw_image_buffers);
 	m_ui->checkBox_tessellation->setChecked(info.tessellation_enabled);
 	m_ui->checkBox_skip_notice_screen->setChecked(info.skip_notice_screen);
@@ -479,6 +480,7 @@ static void UpdateInfo(Configuration& info, Ui::ConfigurationEditDialog& ui, boo
 	info.hdr_enabled               = ui.checkBox_hdr->isChecked();
 	info.hide_cursor_enabled       = ui.checkBox_hide_cursor->isChecked();
 	info.readback_linear_images    = ui.checkBox_readback->isChecked();
+	info.readback_tiled_images     = ui.checkBox_readback_tiled->isChecked();
 	info.sync_raw_image_buffers    = ui.checkBox_sync_raw_image_buffers->isChecked();
 	info.tessellation_enabled      = ui.checkBox_tessellation->isChecked();
 	info.skip_notice_screen        = ui.checkBox_skip_notice_screen->isChecked();

src/launcher/src/mainDialog.cpp

@@ -279,6 +279,7 @@ static QStringList CreateEmulatorArgs(const Configuration& info) {
 	AddFlag(args, info.hdr_enabled, "--hdr");
 	AddFlag(args, info.hide_cursor_enabled, "--hide-cursor");
 	AddFlag(args, info.readback_linear_images, "--readback-linear-images");
+	AddFlag(args, info.readback_tiled_images, "--readback-tiled-images");
 	AddFlag(args, info.sync_raw_image_buffers, "--sync-raw-image-buffers");
 	AddFlag(args, !info.trophy_enabled, "--no-trophy-notifications");
 	args << "--trophy-duration" << QString::number(info.trophy_duration_seconds);

src/main.cpp

@@ -89,6 +89,7 @@ static void PrintUsage() {
 	::printf("  --profile                            Enable the Tracy profiler.\n");
 	::printf("  --spirv-debug-printf                 Enable SPIR-V debug printf.\n");
 	::printf("  --readback-linear-images             Read back writable linear images on submit.\n");
+	::printf("  --readback-tiled-images              Read back small writable tiled images on submit.\n");
 	::printf("  --sync-raw-image-buffers             Synchronize raw reads of GPU images.\n");
 	::printf("  --no-trophy-notifications            Disable trophy unlock toasts and their sound.\n");
 	::printf(
@@ -206,6 +207,7 @@ static constexpr Flag FLAGS[] = {
     {"--profile", &ConfigOptions::profiler_enabled},
     {"--spirv-debug-printf", &ConfigOptions::spirv_debug_printf_enabled},
     {"--readback-linear-images", &ConfigOptions::readback_linear_images},
+    {"--readback-tiled-images", &ConfigOptions::readback_tiled_images},
     {"--sync-raw-image-buffers", &ConfigOptions::sync_raw_image_buffers},
     {"--no-trophy-notifications", &ConfigOptions::trophy_enabled, false},
     {"--perf-overlay", &ConfigOptions::perf_overlay_enabled},