diff --git a/app/render/backend/dynamicrenderer.h b/app/render/backend/dynamicrenderer.h
index 95b92bf2d..772c44f2a 100644
--- a/app/render/backend/dynamicrenderer.h
+++ b/app/render/backend/dynamicrenderer.h
@@ -17,6 +17,8 @@ public:
 	explicit DynamicRenderer(const QString &backend, QObject *parent = nullptr);
 	virtual ~DynamicRenderer() override;
 
+	using Renderer::Blit;
+
 	bool Load();
 	bool InitWithOpenGLContext(QOpenGLContext *context);
 	bool GetBackendInfo(OakRenderBackendInfo *out_info) const;
diff --git a/app/render/opengl/openglrenderer.cpp b/app/render/opengl/openglrenderer.cpp
index 2059e6c77..253920869 100644
--- a/app/render/opengl/openglrenderer.cpp
+++ b/app/render/opengl/openglrenderer.cpp
@@ -987,6 +987,11 @@ bool OpenGLRenderer::EnsureContextCurrent(const char *caller)
 		return false;
 	}
 
+	if (context_->thread() != QThread::currentThread()) {
+		qWarning() << caller << "called from the wrong thread for this OpenGL context";
+		return false;
+	}
+
 	if (QOpenGLContext::currentContext() != context_) {
 		if (context_->parent() == this && surface_.isValid()) {
 			if (!context_->makeCurrent(&surface_)) {
diff --git a/app/render/vulkan/vulkanrenderer.cpp b/app/render/vulkan/vulkanrenderer.cpp
index 7a186f19c..9e7c6bcad 100644
--- a/app/render/vulkan/vulkanrenderer.cpp
+++ b/app/render/vulkan/vulkanrenderer.cpp
@@ -3,6 +3,7 @@
 #include <QDebug>
 #include <QFile>
 #include <QRegularExpression>
+#include <algorithm>
 #include <cstdio>
 
 #include "node/value.h"
@@ -857,6 +858,106 @@ VkFormat VulkanRenderer::PickRenderableFormat(PixelFormat format,
 	return VK_FORMAT_UNDEFINED;
 }
 
+int VulkanRenderer::GetVkFormatBytesPerPixel(VkFormat format) const
+{
+	switch (format) {
+	case VK_FORMAT_R8_UNORM:
+	case VK_FORMAT_R8_UINT:
+	case VK_FORMAT_R8_SINT:
+		return 1;
+	case VK_FORMAT_R8G8_UNORM:
+		return 2;
+	case VK_FORMAT_R8G8B8_UNORM:
+		return 3;
+	case VK_FORMAT_R8G8B8A8_UNORM:
+		return 4;
+	case VK_FORMAT_R16_UNORM:
+	case VK_FORMAT_R16_SFLOAT:
+		return 2;
+	case VK_FORMAT_R16G16_UNORM:
+	case VK_FORMAT_R16G16_SFLOAT:
+		return 4;
+	case VK_FORMAT_R16G16B16_UNORM:
+	case VK_FORMAT_R16G16B16_SFLOAT:
+		return 6;
+	case VK_FORMAT_R16G16B16A16_UNORM:
+	case VK_FORMAT_R16G16B16A16_SFLOAT:
+		return 8;
+	case VK_FORMAT_R32_SFLOAT:
+		return 4;
+	case VK_FORMAT_R32G32_SFLOAT:
+		return 8;
+	case VK_FORMAT_R32G32B32_SFLOAT:
+		return 12;
+	case VK_FORMAT_R32G32B32A32_SFLOAT:
+		return 16;
+	default:
+		// For packed or compressed formats, return 0 and let callers fall back
+		// to the requested channel count.
+		return 0;
+	}
+}
+
+float VulkanRenderer::GetFormatMaxAlpha(PixelFormat format) const
+{
+	if (format == PixelFormat::U8) {
+		return 255.0f;
+	} else if (format == PixelFormat::U16) {
+		return 65535.0f;
+	}
+	return 1.0f;
+}
+
+void VulkanRenderer::CopyPixelsWithChannelConversion(const void *src, void *dst,
+												 int width, int height, int depth,
+												 int src_channels, int dst_channels,
+												 PixelFormat format) const
+{
+	int src_bpc = VideoParams::GetBytesPerChannel(format);
+	int dst_bpc = src_bpc;
+	float alpha = GetFormatMaxAlpha(format);
+
+	int plane_pixels = width * height;
+	int total_pixels = plane_pixels * depth;
+
+	const char *src_ptr = static_cast<const char *>(src);
+	char *dst_ptr = static_cast<char *>(dst);
+
+	for (int i = 0; i < total_pixels; ++i) {
+		for (int c = 0; c < dst_channels; ++c) {
+			if (c < src_channels) {
+				memcpy(dst_ptr + (i * dst_channels + c) * dst_bpc,
+					   src_ptr + (i * src_channels + c) * src_bpc,
+					   dst_bpc);
+			} else {
+				// Fill missing channels with 0 (color) or max alpha.
+				if (c == 3) {
+					if (format == PixelFormat::U8) {
+						*reinterpret_cast<uint8_t *>(dst_ptr +
+												   (i * dst_channels + c) * dst_bpc) =
+							static_cast<uint8_t>(alpha);
+					} else if (format == PixelFormat::U16) {
+						*reinterpret_cast<uint16_t *>(dst_ptr +
+													 (i * dst_channels + c) * dst_bpc) =
+							static_cast<uint16_t>(alpha);
+					} else if (format == PixelFormat::F16) {
+						// Half-float 1.0: 0x3C00
+						*reinterpret_cast<uint16_t *>(dst_ptr +
+													 (i * dst_channels + c) * dst_bpc) =
+							0x3C00;
+					} else {
+						*reinterpret_cast<float *>(dst_ptr +
+													 (i * dst_channels + c) * dst_bpc) =
+							alpha;
+					}
+				} else {
+					memset(dst_ptr + (i * dst_channels + c) * dst_bpc, 0, dst_bpc);
+				}
+			}
+		}
+	}
+}
+
 VkDeviceSize VulkanRenderer::AlignSize(VkDeviceSize size,
 									   VkDeviceSize alignment) const
 {
@@ -982,11 +1083,15 @@ QVariant VulkanRenderer::CreateNativeTexture(int width, int height, int depth,
 
 	// Upload initial data if provided
 	if (data) {
-		int bytes_per_pixel = VideoParams::GetBytesPerPixel(format, channel_count);
+		int cpu_bytes_per_pixel = VideoParams::GetBytesPerPixel(format, channel_count);
+		int gpu_bytes_per_pixel = GetVkFormatBytesPerPixel(vk_format);
+		if (gpu_bytes_per_pixel == 0) {
+			gpu_bytes_per_pixel = cpu_bytes_per_pixel;
+		}
 		VkDeviceSize image_size = static_cast<VkDeviceSize>(width) * height * depth *
-								  bytes_per_pixel;
+								  gpu_bytes_per_pixel;
 		if (linesize == 0) {
-			linesize = width * bytes_per_pixel;
+			linesize = width * cpu_bytes_per_pixel;
 		}
 
 		VkBuffer staging_buffer;
@@ -994,16 +1099,41 @@ QVariant VulkanRenderer::CreateNativeTexture(int width, int height, int depth,
 		if (CreateStagingBuffer(image_size, &staging_buffer, &staging_memory)) {
 			void *mapped;
 			vkMapMemory(device_, staging_memory, 0, image_size, 0, &mapped);
-			if (linesize == width * bytes_per_pixel) {
-				memcpy(mapped, data, static_cast<size_t>(image_size));
-			} else {
-				char *dst = static_cast<char *>(mapped);
-				const char *src = static_cast<const char *>(data);
-				for (int row = 0; row < height * depth; row++) {
-					memcpy(dst + row * width * bytes_per_pixel,
-						   src + row * linesize,
-						   static_cast<size_t>(width * bytes_per_pixel));
+			if (cpu_bytes_per_pixel == gpu_bytes_per_pixel) {
+				if (linesize == width * cpu_bytes_per_pixel) {
+					memcpy(mapped, data, static_cast<size_t>(image_size));
+				} else {
+					char *dst = static_cast<char *>(mapped);
+					const char *src = static_cast<const char *>(data);
+					for (int row = 0; row < height * depth; row++) {
+						memcpy(dst + row * width * cpu_bytes_per_pixel,
+							   src + row * linesize,
+							   static_cast<size_t>(width * cpu_bytes_per_pixel));
+					}
 				}
+			} else {
+				// The GPU format has a different channel count than the CPU data
+				// (e.g. 3-channel RGB fallback to 4-channel RGBA). Repack the data
+				// in the staging buffer so the copy uses the GPU texel layout.
+				QByteArray tmp(width * height * depth * cpu_bytes_per_pixel,
+							   Qt::Uninitialized);
+				if (linesize == width * cpu_bytes_per_pixel) {
+					memcpy(tmp.data(), data, static_cast<size_t>(tmp.size()));
+				} else {
+					char *dst = tmp.data();
+					const char *src = static_cast<const char *>(data);
+					for (int row = 0; row < height * depth; row++) {
+						memcpy(dst + row * width * cpu_bytes_per_pixel,
+							   src + row * linesize,
+							   static_cast<size_t>(width * cpu_bytes_per_pixel));
+					}
+				}
+				int gpu_channels = gpu_bytes_per_pixel /
+								   VideoParams::GetBytesPerChannel(format);
+				CopyPixelsWithChannelConversion(tmp.constData(), mapped,
+											width, height, depth,
+											channel_count, gpu_channels,
+											format);
 			}
 			vkUnmapMemory(device_, staging_memory);
 
@@ -1071,12 +1201,16 @@ void VulkanRenderer::UploadToTexture(const QVariant &handle,
 	int width = params.effective_width();
 	int height = params.effective_height();
 	int depth = params.effective_depth();
-	int bytes_per_pixel = VideoParams::GetBytesPerPixel(params.format(),
-													params.channel_count());
+	int cpu_bytes_per_pixel = VideoParams::GetBytesPerPixel(params.format(),
+														params.channel_count());
+	int gpu_bytes_per_pixel = GetVkFormatBytesPerPixel(tex->vk_format);
+	if (gpu_bytes_per_pixel == 0) {
+		gpu_bytes_per_pixel = cpu_bytes_per_pixel;
+	}
 	VkDeviceSize image_size =
-		static_cast<VkDeviceSize>(width) * height * depth * bytes_per_pixel;
+		static_cast<VkDeviceSize>(width) * height * depth * gpu_bytes_per_pixel;
 	if (linesize == 0) {
-		linesize = width * bytes_per_pixel;
+		linesize = width * cpu_bytes_per_pixel;
 	}
 
 	VkBuffer staging_buffer;
@@ -1087,16 +1221,38 @@ void VulkanRenderer::UploadToTexture(const QVariant &handle,
 
 	void *mapped;
 	vkMapMemory(device_, staging_memory, 0, image_size, 0, &mapped);
-	if (linesize == width * bytes_per_pixel) {
-		memcpy(mapped, data, static_cast<size_t>(image_size));
-	} else {
-		char *dst = static_cast<char *>(mapped);
-		const char *src = static_cast<const char *>(data);
-		for (int row = 0; row < height * depth; row++) {
-			memcpy(dst + row * width * bytes_per_pixel,
-				   src + row * linesize,
-				   static_cast<size_t>(width * bytes_per_pixel));
+	if (cpu_bytes_per_pixel == gpu_bytes_per_pixel) {
+		if (linesize == width * cpu_bytes_per_pixel) {
+			memcpy(mapped, data, static_cast<size_t>(image_size));
+		} else {
+			char *dst = static_cast<char *>(mapped);
+			const char *src = static_cast<const char *>(data);
+			for (int row = 0; row < height * depth; row++) {
+				memcpy(dst + row * width * cpu_bytes_per_pixel,
+					   src + row * linesize,
+					   static_cast<size_t>(width * cpu_bytes_per_pixel));
+			}
 		}
+	} else {
+		QByteArray tmp(width * height * depth * cpu_bytes_per_pixel,
+					   Qt::Uninitialized);
+		if (linesize == width * cpu_bytes_per_pixel) {
+			memcpy(tmp.data(), data, static_cast<size_t>(tmp.size()));
+		} else {
+			char *dst = tmp.data();
+			const char *src = static_cast<const char *>(data);
+			for (int row = 0; row < height * depth; row++) {
+				memcpy(dst + row * width * cpu_bytes_per_pixel,
+					   src + row * linesize,
+					   static_cast<size_t>(width * cpu_bytes_per_pixel));
+			}
+		}
+		int gpu_channels = gpu_bytes_per_pixel /
+						   VideoParams::GetBytesPerChannel(params.format());
+		CopyPixelsWithChannelConversion(tmp.constData(), mapped,
+									width, height, depth,
+									params.channel_count(), gpu_channels,
+									params.format());
 	}
 	vkUnmapMemory(device_, staging_memory);
 
@@ -1130,13 +1286,17 @@ void VulkanRenderer::DownloadFromTexture(const QVariant &handle,
 
 	int width = params.effective_width();
 	int height = params.effective_height();
-	int bytes_per_pixel = VideoParams::GetBytesPerPixel(params.format(),
-													params.channel_count());
+	int cpu_bytes_per_pixel = VideoParams::GetBytesPerPixel(params.format(),
+														params.channel_count());
+	int gpu_bytes_per_pixel = GetVkFormatBytesPerPixel(tex->vk_format);
+	if (gpu_bytes_per_pixel == 0) {
+		gpu_bytes_per_pixel = cpu_bytes_per_pixel;
+	}
 	if (linesize == 0) {
-		linesize = width * bytes_per_pixel;
+		linesize = width * cpu_bytes_per_pixel;
 	}
 	VkDeviceSize image_size =
-		static_cast<VkDeviceSize>(width) * height * bytes_per_pixel;
+		static_cast<VkDeviceSize>(width) * height * gpu_bytes_per_pixel;
 
 	VkBuffer staging_buffer;
 	VkDeviceMemory staging_memory;
@@ -1156,20 +1316,43 @@ void VulkanRenderer::DownloadFromTexture(const QVariant &handle,
 
 	void *mapped;
 	vkMapMemory(device_, staging_memory, 0, image_size, 0, &mapped);
-	if (linesize == width * bytes_per_pixel) {
-		memcpy(data, mapped, static_cast<size_t>(image_size));
+	if (cpu_bytes_per_pixel == gpu_bytes_per_pixel) {
+		if (linesize == width * cpu_bytes_per_pixel) {
+			memcpy(data, mapped, static_cast<size_t>(image_size));
+		} else {
+			char *dst = static_cast<char *>(data);
+			const char *src = static_cast<const char *>(mapped);
+			for (int row = 0; row < height; row++) {
+				memcpy(dst + row * linesize,
+					   src + row * width * cpu_bytes_per_pixel,
+					   static_cast<size_t>(width * cpu_bytes_per_pixel));
+			}
+		}
 	} else {
-		char *dst = static_cast<char *>(data);
-		const char *src = static_cast<const char *>(mapped);
-		for (int row = 0; row < height; row++) {
-			memcpy(dst + row * linesize,
-				   src + row * width * bytes_per_pixel,
-				   static_cast<size_t>(width * bytes_per_pixel));
+		int gpu_channels = gpu_bytes_per_pixel /
+						   VideoParams::GetBytesPerChannel(params.format());
+		QByteArray tmp(width * height * gpu_bytes_per_pixel, Qt::Uninitialized);
+		memcpy(tmp.data(), mapped, static_cast<size_t>(tmp.size()));
+		CopyPixelsWithChannelConversion(tmp.constData(), data,
+									width, height, 1,
+									gpu_channels, params.channel_count(),
+									params.format());
+		if (linesize != width * cpu_bytes_per_pixel) {
+			// Repack from tight CPU layout to caller's stride in-place.
+			QByteArray tight(static_cast<const char *>(data),
+							 width * height * cpu_bytes_per_pixel);
+			char *dst = static_cast<char *>(data);
+			for (int row = 0; row < height; row++) {
+				memcpy(dst + row * linesize,
+					   tight.constData() + row * width * cpu_bytes_per_pixel,
+					   static_cast<size_t>(width * cpu_bytes_per_pixel));
+			}
 		}
 	}
 	vkUnmapMemory(device_, staging_memory);
 
 	DestroyStagingBuffer(staging_buffer, staging_memory);
+	tex->current_layout = VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL;
 }
 
 void VulkanRenderer::Flush()
@@ -1222,9 +1405,9 @@ Color VulkanRenderer::GetPixelFromTexture(olive::Texture *texture,
 	if (!texture) {
 		return Color();
 	}
-	int bytes_per_pixel = VideoParams::GetBytesPerPixel(texture->format(),
-													texture->channel_count());
-	QByteArray data(bytes_per_pixel, Qt::Uninitialized);
+	int cpu_bytes_per_pixel = VideoParams::GetBytesPerPixel(texture->format(),
+														texture->channel_count());
+	QByteArray data(cpu_bytes_per_pixel, Qt::Uninitialized);
 
 	quint64 id = texture->id().value<quint64>();
 	QMutexLocker lock(&mutex_);
@@ -1236,9 +1419,14 @@ Color VulkanRenderer::GetPixelFromTexture(olive::Texture *texture,
 	uint32_t px = static_cast<uint32_t>(qBound(0.0, pt.x(), double(tex->width - 1)));
 	uint32_t py = static_cast<uint32_t>(qBound(0.0, pt.y(), double(tex->height - 1)));
 
+	int gpu_bytes_per_pixel = GetVkFormatBytesPerPixel(tex->vk_format);
+	if (gpu_bytes_per_pixel == 0) {
+		gpu_bytes_per_pixel = cpu_bytes_per_pixel;
+	}
+
 	VkBuffer staging_buffer;
 	VkDeviceMemory staging_memory;
-	if (!CreateStagingBuffer(bytes_per_pixel, &staging_buffer, &staging_memory)) {
+	if (!CreateStagingBuffer(gpu_bytes_per_pixel, &staging_buffer, &staging_memory)) {
 		return Color();
 	}
 
@@ -1251,11 +1439,23 @@ Color VulkanRenderer::GetPixelFromTexture(olive::Texture *texture,
 	EndOneTimeCommands(cmd);
 
 	void *mapped;
-	vkMapMemory(device_, staging_memory, 0, bytes_per_pixel, 0, &mapped);
-	memcpy(data.data(), mapped, static_cast<size_t>(bytes_per_pixel));
+	vkMapMemory(device_, staging_memory, 0, gpu_bytes_per_pixel, 0, &mapped);
+	if (cpu_bytes_per_pixel == gpu_bytes_per_pixel) {
+		memcpy(data.data(), mapped, static_cast<size_t>(cpu_bytes_per_pixel));
+	} else {
+		int gpu_channels = gpu_bytes_per_pixel /
+						   VideoParams::GetBytesPerChannel(texture->format());
+		QByteArray gpu_pixel(gpu_bytes_per_pixel, Qt::Uninitialized);
+		memcpy(gpu_pixel.data(), mapped, static_cast<size_t>(gpu_bytes_per_pixel));
+		CopyPixelsWithChannelConversion(gpu_pixel.constData(), data.data(),
+									1, 1, 1,
+									gpu_channels, texture->channel_count(),
+									texture->format());
+	}
 	vkUnmapMemory(device_, staging_memory);
 
 	DestroyStagingBuffer(staging_buffer, staging_memory);
+	tex->current_layout = VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL;
 
 	return Color::fromData(data.data(), texture->format(),
 						   texture->channel_count());
@@ -1845,36 +2045,15 @@ bool VulkanRenderer::CreatePipelineForShader(VulkanShader *shader,
 	return true;
 }
 
-void VulkanRenderer::Blit(QVariant shader_variant, olive::AcceleratedJob &a_job,
-							  olive::Texture *destination,
-							  VideoParams destination_params,
-							  bool clear_destination)
+void VulkanRenderer::BlitPass(VulkanShader *shader, VulkanTexture *dest_tex,
+							  const QVector<TextureBinding> &bindings,
+							  const QByteArray &ubo_data,
+							  const VideoParams &destination_params,
+							  bool clear_destination, int iteration)
 {
-	QMutexLocker lock(&mutex_);
+	(void)iteration;
 
-	ShaderJob *s_job = dynamic_cast<ShaderJob *>(&a_job);
-	if (!s_job) {
-		return;
-	}
-	ShaderJob job(*s_job);
-
-	quint64 shader_id = shader_variant.value<quint64>();
-	VulkanShader *shader = shaders_.value(shader_id);
-	if (!shader) {
-		return;
-	}
-
-	VulkanTexture *dest_tex = nullptr;
-	if (destination) {
-		quint64 dest_id = destination->id().value<quint64>();
-		dest_tex = textures_.value(dest_id);
-		if (!dest_tex) {
-			return;
-		}
-	} else {
-		// TODO: support rendering to a temporary offscreen texture when the
-		// caller requests the default output (used by OpenGL direct-to-widget).
-		qWarning() << "VulkanRenderer::Blit with null destination is not implemented";
+	if (!dest_tex) {
 		return;
 	}
 
@@ -1890,145 +2069,26 @@ void VulkanRenderer::Blit(QVariant shader_variant, olive::AcceleratedJob &a_job,
 
 	VkPipeline pipeline = shader->pipeline_cache.value(render_pass_format);
 
-	// Collect textures to bind and build UBO data
-	struct TextureBinding {
-		QString name;
-		VulkanTexture *tex;
-		Texture::Interpolation interp;
-	};
-	QVector<TextureBinding> bindings;
-
-	QByteArray ubo_data;
-	if (shader->ubo_size > 0) {
-		ubo_data.resize(static_cast<int>(shader->ubo_size));
-		ubo_data.fill(0);
-	}
-
-	for (auto it = job.GetValues().constBegin(); it != job.GetValues().constEnd();
-		 ++it) {
-		const NodeValue &value = it.value();
-		if (value.type() == NodeValue::kTexture) {
-			TexturePtr texture = value.toTexture();
-			VulkanTexture *vtex = nullptr;
-			if (texture) {
-				quint64 tid = texture->id().value<quint64>();
-				vtex = textures_.value(tid);
-			}
-			bindings.append({ it.key(), vtex,
-							  job.GetInterpolation(it.key()) });
-		} else if (!shader->uniforms.isEmpty() && shader->ubo_size > 0) {
-			// Find matching uniform
-			for (const UniformInfo &u : shader->uniforms) {
-				if (u.name != it.key())
-					continue;
-				char *dst = ubo_data.data() + static_cast<int>(u.offset);
-				switch (value.type()) {
-				case NodeValue::kFloat:
-					*reinterpret_cast<float *>(dst) = static_cast<float>(value.toDouble());
-					break;
-				case NodeValue::kInt:
-					*reinterpret_cast<int *>(dst) = static_cast<int>(value.toInt());
-					break;
-				case NodeValue::kBoolean:
-					*reinterpret_cast<int *>(dst) = value.toBool() ? 1 : 0;
-					break;
-				case NodeValue::kVec2: {
-					QVector2D v = value.toVec2();
-					memcpy(dst, &v, sizeof(float) * 2);
-					break;
-				}
-				case NodeValue::kVec3: {
-					QVector3D v = value.toVec3();
-					memcpy(dst, &v, sizeof(float) * 3);
-					break;
-				}
-				case NodeValue::kVec4: {
-					QVector4D v = value.toVec4();
-					memcpy(dst, &v, sizeof(float) * 4);
-					break;
-				}
-				case NodeValue::kMatrix: {
-					QMatrix4x4 m = value.toMatrix();
-					memcpy(dst, m.constData(), sizeof(float) * 16);
-					break;
-				}
-				case NodeValue::kColor: {
-					Color c = value.toColor();
-					float col[4] = { static_cast<float>(c.red()),
-									 static_cast<float>(c.green()),
-									 static_cast<float>(c.blue()),
-									 static_cast<float>(c.alpha()) };
-					memcpy(dst, col, sizeof(float) * 4);
-					break;
-				}
-				case NodeValue::kCombo:
-					*reinterpret_cast<int *>(dst) = value.toInt();
-					break;
-				default:
-					break;
-				}
-				break;
-			}
-		}
-	}
-
-	// Handle special uniforms that may not be in job values
-	if (shader->ubo_size > 0) {
-		for (const UniformInfo &u : shader->uniforms) {
-			char *dst = ubo_data.data() + static_cast<int>(u.offset);
-			if (u.name == QStringLiteral("ove_mvpmat")) {
-				QMatrix4x4 m = job.Get(QStringLiteral("ove_mvpmat")).toMatrix();
-				memcpy(dst, m.constData(), sizeof(float) * 16);
-			} else if (u.name == QStringLiteral("ove_cropmatrix")) {
-				QMatrix4x4 m = job.Get(QStringLiteral("ove_cropmatrix")).toMatrix();
-				memcpy(dst, m.constData(), sizeof(float) * 16);
-			} else if (u.name == QStringLiteral("ove_maintex_alpha")) {
-				*reinterpret_cast<int *>(dst) = job.Get(QStringLiteral("ove_maintex_alpha")).toInt();
-			} else if (u.name == QStringLiteral("ove_force_opaque")) {
-				*reinterpret_cast<int *>(dst) = job.Get(QStringLiteral("ove_force_opaque")).toBool() ? 1 : 0;
-			} else if (u.name == QStringLiteral("ove_iteration")) {
-				*reinterpret_cast<int *>(dst) = job.Get(QStringLiteral("ove_iteration")).toInt();
-			}
-		}
-	}
-
-	// Set texture-enable flags for shaders that declare uniform bool NAME_enabled.
-	if (shader->ubo_size > 0) {
-		for (const TextureBinding &tb : bindings) {
-			QString enabled_name = tb.name + QStringLiteral("_enabled");
-			for (const UniformInfo &u : shader->uniforms) {
-				if (u.name == enabled_name && u.size == sizeof(int)) {
-					char *dst = ubo_data.data() + static_cast<int>(u.offset);
-					*reinterpret_cast<int *>(dst) = tb.tex ? 1 : 0;
-					break;
-				}
-			}
-		}
-	}
-
 	// Lazily create a per-texture framebuffer. The framebuffer is compatible
 	// with any render pass that uses the same format and sample count, so we
 	// build it once with the non-clear variant and reuse it.
-	VkFramebuffer framebuffer = VK_NULL_HANDLE;
-	if (dest_tex) {
-		if (dest_tex->framebuffer == VK_NULL_HANDLE) {
-			VkFramebufferCreateInfo fb_info = {};
-			fb_info.sType = VK_STRUCTURE_TYPE_FRAMEBUFFER_CREATE_INFO;
-			fb_info.renderPass = GetOrCreateRenderPass(render_pass_format, false);
-			fb_info.attachmentCount = 1;
-			fb_info.pAttachments = &dest_tex->view;
-			fb_info.width = static_cast<uint32_t>(dest_tex->width);
-			fb_info.height = static_cast<uint32_t>(dest_tex->height);
-			fb_info.layers = 1;
-			VkResult fb_result = vkCreateFramebuffer(device_, &fb_info, nullptr,
-														 &dest_tex->framebuffer);
-			if (fb_result != VK_SUCCESS) {
-				qWarning() << "Failed to create Vulkan framebuffer:" << fb_result;
-				return;
-			}
+	if (dest_tex->framebuffer == VK_NULL_HANDLE) {
+		VkFramebufferCreateInfo fb_info = {};
+		fb_info.sType = VK_STRUCTURE_TYPE_FRAMEBUFFER_CREATE_INFO;
+		fb_info.renderPass = GetOrCreateRenderPass(render_pass_format, false);
+		fb_info.attachmentCount = 1;
+		fb_info.pAttachments = &dest_tex->view;
+		fb_info.width = static_cast<uint32_t>(dest_tex->width);
+		fb_info.height = static_cast<uint32_t>(dest_tex->height);
+		fb_info.layers = 1;
+		VkResult fb_result = vkCreateFramebuffer(device_, &fb_info, nullptr,
+											 &dest_tex->framebuffer);
+		if (fb_result != VK_SUCCESS) {
+			qWarning() << "Failed to create Vulkan framebuffer:" << fb_result;
+			return;
 		}
-		framebuffer = dest_tex->framebuffer;
 	}
+	VkFramebuffer framebuffer = dest_tex->framebuffer;
 
 	// Create UBO buffer if needed
 	VkBuffer ubo_buffer = VK_NULL_HANDLE;
@@ -2108,13 +2168,13 @@ void VulkanRenderer::Blit(QVariant shader_variant, olive::AcceleratedJob &a_job,
 
 		if (!writes.isEmpty()) {
 			vkUpdateDescriptorSets(device_, writes.size(), writes.constData(), 0,
-										nullptr);
+								   nullptr);
 		}
 	}
 
 	VkCommandBuffer cmd = BeginOneTimeCommands();
 
-	if (dest_tex && dest_tex->current_layout != VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL) {
+	if (dest_tex->current_layout != VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL) {
 		TransitionImageLayout(cmd, dest_tex->image, dest_tex->current_layout,
 							  VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL);
 		dest_tex->current_layout = VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL;
@@ -2175,7 +2235,6 @@ void VulkanRenderer::Blit(QVariant shader_variant, olive::AcceleratedJob &a_job,
 								nullptr);
 	}
 
-
 	// Draw
 	vkCmdDraw(cmd, 6, 1, 0, 0);
 
@@ -2183,12 +2242,10 @@ void VulkanRenderer::Blit(QVariant shader_variant, olive::AcceleratedJob &a_job,
 
 	// Leave the destination in a shader-readable state so it can be sampled or
 	// downloaded without an extra layout transition on the caller side.
-	if (dest_tex) {
-		TransitionImageLayout(cmd, dest_tex->image,
-							  VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL,
-							  VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL);
-		dest_tex->current_layout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL;
-	}
+	TransitionImageLayout(cmd, dest_tex->image,
+						  VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL,
+						  VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL);
+	dest_tex->current_layout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL;
 
 	EndOneTimeCommands(cmd);
 
@@ -2200,4 +2257,225 @@ void VulkanRenderer::Blit(QVariant shader_variant, olive::AcceleratedJob &a_job,
 	}
 }
 
+void VulkanRenderer::Blit(QVariant shader_variant, olive::AcceleratedJob &a_job,
+						  olive::Texture *destination,
+						  VideoParams destination_params,
+						  bool clear_destination)
+{
+	ShaderJob *s_job = dynamic_cast<ShaderJob *>(&a_job);
+	if (!s_job) {
+		return;
+	}
+	ShaderJob job(*s_job);
+
+	quint64 shader_id = shader_variant.value<quint64>();
+
+	// Iterative shaders require ping-pong textures. Create them before locking
+	// the renderer mutex because CreateTexture also locks it.
+	int real_iteration_count = 1;
+	if (job.GetIterationCount() > 1 && !job.GetIterativeInput().isEmpty()) {
+		real_iteration_count = job.GetIterationCount();
+	}
+
+	struct PingPongTexture {
+		TexturePtr texture;
+		VulkanTexture *native = nullptr;
+	};
+
+	PingPongTexture output_tex, input_tex, final_tex;
+	if (real_iteration_count > 1) {
+		output_tex.texture = CreateTexture(destination_params);
+		if (real_iteration_count > 2) {
+			input_tex.texture = CreateTexture(destination_params);
+		}
+	}
+
+	if (!destination) {
+		final_tex.texture = CreateTexture(destination_params);
+	}
+
+	QMutexLocker lock(&mutex_);
+
+	VulkanShader *shader = shaders_.value(shader_id);
+	if (!shader) {
+		return;
+	}
+
+	VulkanTexture *dest_tex = nullptr;
+	if (destination) {
+		quint64 dest_id = destination->id().value<quint64>();
+		dest_tex = textures_.value(dest_id);
+		if (!dest_tex) {
+			return;
+		}
+	} else {
+		quint64 final_id = final_tex.texture->id().value<quint64>();
+		final_tex.native = textures_.value(final_id);
+		if (!final_tex.native) {
+			qWarning() << "VulkanRenderer::Blit failed to resolve temporary destination texture";
+			return;
+		}
+		dest_tex = final_tex.native;
+	}
+
+	if (output_tex.texture) {
+		quint64 id = output_tex.texture->id().value<quint64>();
+		output_tex.native = textures_.value(id);
+	}
+	if (input_tex.texture) {
+		quint64 id = input_tex.texture->id().value<quint64>();
+		input_tex.native = textures_.value(id);
+	}
+
+	// Collect textures to bind and build base UBO data
+	QVector<TextureBinding> base_bindings;
+	QByteArray base_ubo_data;
+	if (shader->ubo_size > 0) {
+		base_ubo_data.resize(static_cast<int>(shader->ubo_size));
+		base_ubo_data.fill(0);
+	}
+
+	for (auto it = job.GetValues().constBegin(); it != job.GetValues().constEnd();
+		 ++it) {
+		const NodeValue &value = it.value();
+		if (value.type() == NodeValue::kTexture) {
+			TexturePtr texture = value.toTexture();
+			VulkanTexture *vtex = nullptr;
+			if (texture) {
+				quint64 tid = texture->id().value<quint64>();
+				vtex = textures_.value(tid);
+			}
+			base_bindings.append({ it.key(), vtex,
+								   job.GetInterpolation(it.key()) });
+		} else if (!shader->uniforms.isEmpty() && shader->ubo_size > 0) {
+			// Find matching uniform
+			for (const UniformInfo &u : shader->uniforms) {
+				if (u.name != it.key())
+					continue;
+				char *dst = base_ubo_data.data() + static_cast<int>(u.offset);
+				switch (value.type()) {
+				case NodeValue::kFloat:
+					*reinterpret_cast<float *>(dst) = static_cast<float>(value.toDouble());
+					break;
+				case NodeValue::kInt:
+					*reinterpret_cast<int *>(dst) = static_cast<int>(value.toInt());
+					break;
+				case NodeValue::kBoolean:
+					*reinterpret_cast<int *>(dst) = value.toBool() ? 1 : 0;
+					break;
+				case NodeValue::kVec2: {
+					QVector2D v = value.toVec2();
+					memcpy(dst, &v, sizeof(float) * 2);
+					break;
+				}
+				case NodeValue::kVec3: {
+					QVector3D v = value.toVec3();
+					memcpy(dst, &v, sizeof(float) * 3);
+					break;
+				}
+				case NodeValue::kVec4: {
+					QVector4D v = value.toVec4();
+					memcpy(dst, &v, sizeof(float) * 4);
+					break;
+				}
+				case NodeValue::kMatrix: {
+					QMatrix4x4 m = value.toMatrix();
+					memcpy(dst, m.constData(), sizeof(float) * 16);
+					break;
+				}
+				case NodeValue::kColor: {
+					Color c = value.toColor();
+					float col[4] = { static_cast<float>(c.red()),
+									 static_cast<float>(c.green()),
+									 static_cast<float>(c.blue()),
+									 static_cast<float>(c.alpha()) };
+					memcpy(dst, col, sizeof(float) * 4);
+					break;
+				}
+				case NodeValue::kCombo:
+					*reinterpret_cast<int *>(dst) = value.toInt();
+					break;
+				default:
+					break;
+				}
+				break;
+			}
+		}
+	}
+
+	// Handle special uniforms that may not be in job values
+	if (shader->ubo_size > 0) {
+		for (const UniformInfo &u : shader->uniforms) {
+			char *dst = base_ubo_data.data() + static_cast<int>(u.offset);
+			if (u.name == QStringLiteral("ove_mvpmat")) {
+				QMatrix4x4 m = job.Get(QStringLiteral("ove_mvpmat")).toMatrix();
+				memcpy(dst, m.constData(), sizeof(float) * 16);
+			} else if (u.name == QStringLiteral("ove_cropmatrix")) {
+				QMatrix4x4 m = job.Get(QStringLiteral("ove_cropmatrix")).toMatrix();
+				memcpy(dst, m.constData(), sizeof(float) * 16);
+			} else if (u.name == QStringLiteral("ove_maintex_alpha")) {
+				*reinterpret_cast<int *>(dst) = job.Get(QStringLiteral("ove_maintex_alpha")).toInt();
+			} else if (u.name == QStringLiteral("ove_force_opaque")) {
+				*reinterpret_cast<int *>(dst) = job.Get(QStringLiteral("ove_force_opaque")).toBool() ? 1 : 0;
+			}
+		}
+	}
+
+	// Set texture-enable flags for shaders that declare uniform bool NAME_enabled.
+	if (shader->ubo_size > 0) {
+		for (const TextureBinding &tb : base_bindings) {
+			QString enabled_name = tb.name + QStringLiteral("_enabled");
+			for (const UniformInfo &u : shader->uniforms) {
+				if (u.name == enabled_name && u.size == sizeof(int)) {
+					char *dst = base_ubo_data.data() + static_cast<int>(u.offset);
+					*reinterpret_cast<int *>(dst) = tb.tex ? 1 : 0;
+					break;
+				}
+			}
+		}
+	}
+
+	for (int iteration = 0; iteration < real_iteration_count; ++iteration) {
+		QVector<TextureBinding> pass_bindings = base_bindings;
+		QByteArray pass_ubo_data = base_ubo_data;
+
+		// Set iteration number
+		if (shader->ubo_size > 0) {
+			for (const UniformInfo &u : shader->uniforms) {
+				if (u.name == QStringLiteral("ove_iteration")) {
+					char *dst = pass_ubo_data.data() + static_cast<int>(u.offset);
+					*reinterpret_cast<int *>(dst) = iteration;
+					break;
+				}
+			}
+		}
+
+		// Replace iterative input
+		VulkanTexture *pass_dest = dest_tex;
+		bool pass_clear = clear_destination;
+		if (iteration != real_iteration_count - 1) {
+			pass_dest = output_tex.native;
+			pass_clear = true;
+		}
+
+		if (iteration > 0) {
+			const QString &iterative_input = job.GetIterativeInput();
+			for (TextureBinding &tb : pass_bindings) {
+				if (tb.name == iterative_input) {
+					tb.tex = input_tex.native;
+					break;
+				}
+			}
+		}
+
+		BlitPass(shader, pass_dest, pass_bindings, pass_ubo_data,
+				 destination_params, pass_clear, iteration);
+
+		if (iteration != real_iteration_count - 1) {
+			std::swap(output_tex, input_tex);
+		}
+	}
+}
+
+
 } // namespace olive
diff --git a/app/render/vulkan/vulkanrenderer.h b/app/render/vulkan/vulkanrenderer.h
index 0815b498b..2a6accfb6 100644
--- a/app/render/vulkan/vulkanrenderer.h
+++ b/app/render/vulkan/vulkanrenderer.h
@@ -109,6 +109,12 @@ private:
 	VkFormat PixelFormatToVkFormat(PixelFormat format, int channel_count) const;
 	VkFormat PickRenderableFormat(PixelFormat format, int channel_count) const;
 	bool IsColorAttachmentSupported(VkFormat format) const;
+	int GetVkFormatBytesPerPixel(VkFormat format) const;
+	float GetFormatMaxAlpha(PixelFormat format) const;
+	void CopyPixelsWithChannelConversion(const void *src, void *dst,
+									 int width, int height, int depth,
+									 int src_channels, int dst_channels,
+									 PixelFormat format) const;
 	VkDeviceSize AlignSize(VkDeviceSize size, VkDeviceSize alignment) const;
 
 	uint32_t FindMemoryType(uint32_t type_filter,
@@ -134,6 +140,18 @@ private:
 
 	VkRenderPass GetOrCreateRenderPass(VkFormat format, bool clear);
 
+	struct TextureBinding {
+		QString name;
+		VulkanTexture *tex;
+		Texture::Interpolation interp;
+	};
+
+	void BlitPass(VulkanShader *shader, VulkanTexture *dest_tex,
+				  const QVector<TextureBinding> &bindings,
+				  const QByteArray &ubo_data,
+				  const VideoParams &destination_params,
+				  bool clear_destination, int iteration);
+
 	VkInstance instance_ = VK_NULL_HANDLE;
 	VkPhysicalDevice physical_device_ = VK_NULL_HANDLE;
 	uint32_t physical_device_count_ = 0;
diff --git a/app/widget/viewer/viewerdisplay.cpp b/app/widget/viewer/viewerdisplay.cpp
index 7037cf1fe..f7730601c 100644
--- a/app/widget/viewer/viewerdisplay.cpp
+++ b/app/widget/viewer/viewerdisplay.cpp
@@ -429,18 +429,22 @@ void ViewerDisplayWidget::OnPaint()
 				// This is a GPU texture, switch to it directly when possible.
 				if (texture && texture->renderer() &&
 					texture->renderer() != renderer()) {
-					// Cross-renderer texture: download and re-upload
-					FramePtr frame = Frame::Create();
-					frame->set_video_params(texture->params());
-					if (frame->allocate()) {
-						texture->renderer()->DownloadFromTexture(
-							texture->id(), texture->params(),
-							frame->data(), frame->linesize_pixels());
-						texture_ = renderer()->CreateTexture(
-							frame->video_params(), frame->data(),
-							frame->linesize_pixels());
-					} else {
+					if (texture->renderer()->IsOpenGL() && renderer()->IsOpenGL()) {
 						texture_ = texture;
+					} else {
+						// Cross-backend texture: download and re-upload
+						FramePtr frame = Frame::Create();
+						frame->set_video_params(texture->params());
+						if (frame->allocate()) {
+							texture->renderer()->DownloadFromTexture(
+								texture->id(), texture->params(),
+								frame->data(), frame->linesize_pixels());
+							texture_ = renderer()->CreateTexture(
+								frame->video_params(), frame->data(),
+								frame->linesize_pixels());
+						} else {
+							texture_ = texture;
+						}
 					}
 				} else {
 					texture_ = texture;
diff --git a/docs/zh/render-backend-dynamic-plan.md b/docs/zh/render-backend-dynamic-plan.md
index 5dd2a9fef..96bc3b80c 100644
--- a/docs/zh/render-backend-dynamic-plan.md
+++ b/docs/zh/render-backend-dynamic-plan.md
@@ -59,7 +59,7 @@
   - 动态适配器：`DynamicRenderer`、`renderbackend_c.h`。
   - 必要的 value/config/工具：`node/value`、`node/param`、`node/valuedatabase`、`config/config`、`common/filefunctions`、`common/qtutils`、`common/avframeptr`。
 - `oakgl`/`oakvulkan` 现在只链接 `libolive-rendercore`，不再链接完整 `libolive-editor`。
-- `liboakgl.so` / `liboakvulkan.so` 体积从约 21 MB 降至约 600 KB。
+- `liboakgl.so` / `liboakvulkan.so` 不再链接完整 editor 对象库；实际体积取决于构建类型、符号表和系统依赖链接方式，当前 debug 构建仍会显著大于 release/strip 后体积。
 - 为隔离依赖做的头文件清理：
   - `renderer.h` 移除 `node/node.h`、`render/colorprocessor.h`、`render/job/colortransformjob.h`、`job/pluginjob.h`，改为前向声明。
   - `videoparams.h` 移除 `ofxImageEffect.h`，OFX 字符串 setter 实现下移到 `videoparams.cpp`。
@@ -70,7 +70,7 @@
 剩余优化空间：
 - 长远可将 `libolive-editor` 也改为依赖 `libolive-rendercore`，彻底消除渲染核心代码在主程序与后端库之间的重复编译/重复链接。当前阶段先保证后端边界干净、主程序保持兼容。
 
-## 阶段 3：Vulkan 后端（原型实现，运行时验证待完成）
+## 阶段 3：Vulkan 后端（offscreen 核心已实现，运行时依赖可用 Vulkan ICD）
 
 - 新增 Vulkan 后端库 `liboakvulkan.so`（当系统安装了 Vulkan 头文件/库时构建；无 Vulkan 环境时 CMake 自动跳过）。
 - 新增 `VulkanRenderer` 类，继承 `Renderer`，使用原生 Vulkan API 实现 offscreen 渲染管线；代码已合入，并在本机 NVIDIA Vulkan 驱动上通过了基础端到端渲染测试。
@@ -99,11 +99,19 @@
   - framebuffer / sampler 缓存：每张纹理延迟创建并复用 framebuffer；按插值模式复用 linear/nearest sampler。
   - 单通道纹理 swizzle：image view 组件映射为 R→RGB、A=1，匹配 OpenGL 灰度行为。
   - 纹理启用标志：为声明 `NAME_enabled` 的 shader 自动设置 0/1。
-- **已知限制 / 待完善**：
+- **已修复 / 已实现**：
   - 链接边界已最小化，`liboakvulkan.so` 现在只依赖 `libolive-rendercore`。
-  - 单通道/3-channel 格式的上传/下载 CPU 侧对齐、回退格式与请求格式不一致时的数据转换仍待完善。
-  - `Blit` 尚未实现 iterative/pin-pong 多 pass（如 blur/glow 等依赖 `ShaderJob::GetIterationCount` 的效果目前只渲染第一 pass）。
-  - 尚未在 viewer、proxy、thumbnail/cache、导出等完整渲染路径上验证 Vulkan 输出一致性；需要在真实 GPU 上手工测试并记录结果。
+  - 单通道/3-channel 格式的上传/下载 CPU 侧对齐：当 GPU 回退格式（如 3→4 channel）与请求格式不一致时，staging buffer 按实际 `VkFormat` 大小分配，并在 CPU 侧进行通道数转换（alpha 填最大值）。
+  - `Blit` 已实现 iterative/pin-pong 多 pass：根据 `ShaderJob::GetIterationCount` / `GetIterativeInput` 创建临时 ping-pong 纹理，每 pass 更新 `ove_iteration` 并替换迭代输入；最后一 pass 写入目标纹理。
+  - null-destination Blit 实现为渲染到临时 offscreen texture，保证调用不崩溃。
+  - 新增自动化测试：
+    - `VulkanNullDestinationBlitDoesNotCrash`
+    - `VulkanIterativeBlitPingPong`（2 pass 折半，验证 ping-pong 结果）
+    - `VulkanUploadDownloadThreeChannel`（验证 3-channel RGB 上传/下载与回退格式转换）
+- **当前验证状态**：
+  - 自动化测试已覆盖 Vulkan 后端加载、texture upload/download、Blit、null-destination fallback、iterative ping-pong、3-channel upload/download fallback；这些测试会在运行环境存在可用 Vulkan ICD 时执行。
+  - 当前开发环境可找到 Vulkan loader/headers，但运行时 loader 只发现不可用的 NVIDIA ICD，`vkCreateInstance` 报 `Found no drivers`；因此 Vulkan 用例会按设计 SKIP，不能作为 Vulkan 渲染通过的证据。
+  - Viewer / proxy / 导出的完整交互流程仍需具备显示环境和可用 Vulkan runtime 的项目做最终验证；当前已在代码路径层面确认 backend-neutral viewer readback、proxy/export 渲染入口均使用 `Renderer` 抽象，无硬编码 OpenGL 依赖。
 
 ## 阶段 4：Viewer 双后端（backend-neutral 路径已落地，Vulkan viewer 为原型）
 
@@ -146,7 +154,8 @@
 - [x] OpenGL 后端库可单独构建、加载、初始化、销毁。
 - [x] 用户能在配置中选择 OpenGL/Vulkan。
 - [x] Vulkan 不可用时自动回退到 OpenGL，不崩溃；`RenderManager::backend()` 会在 `DynamicRenderer` 内部回退后同步为实际运行后端。
-- [x] 链接边界已最小化：`oakgl` / `oakvulkan` 现在只链接独立的 `libolive-rendercore`，不再拉入完整 editor 代码；库体积从约 21 MB 降至约 600 KB。
-- [x] Vulkan / backend-neutral viewer readback display 路径已搭建（offscreen texture → download → QImage → QPainter）；单 pass Blit 已在真实 Vulkan 驱动上验证，完整 UI/导出流程待验证。
+- [x] 链接边界已最小化：`oakgl` / `oakvulkan` 现在只链接独立的 `libolive-rendercore`，不再拉入完整 editor 代码；库体积需按 release/strip 构建重新记录。
+- [ ] Vulkan / backend-neutral viewer readback display 路径已搭建（offscreen texture → download → QImage → QPainter）；仍需在可用 Vulkan runtime 和显示环境下验证完整 Viewer/proxy/导出流程。
 - [x] OpenFX 插件渲染边界已处理：`PluginRenderer` 后端无关化，非 OpenGL 渲染器自动回退 CPU 路径，动态 OpenGL 后端通过 C ABI 支持 OFX OpenGL 输出绑定。
-- [ ] 手工测试计划覆盖 viewer、proxy、scope、导出等完整路径。
+- [x] 自动化测试覆盖 device init、texture create/upload/download（含 3-channel fallback）、shader compilation、Blit with destination、null-destination fallback、iterative shaders；无可用 Vulkan ICD 时相关用例按设计 SKIP。
+- [ ] 手工测试计划覆盖 viewer、proxy、scope、导出等完整路径；`ScopeBase` 当前在 backend-neutral 时仍是安全跳过，不是完整 Vulkan scope display。
diff --git a/tests/gtest/dynamic_render_backend_test.cpp b/tests/gtest/dynamic_render_backend_test.cpp
index ad03cdbee..9ad797035 100644
--- a/tests/gtest/dynamic_render_backend_test.cpp
+++ b/tests/gtest/dynamic_render_backend_test.cpp
@@ -146,3 +146,186 @@ TEST(DynamicRenderBackend, VulkanUploadBlitDownload)
 	EXPECT_EQ(static_cast<uint8_t>(dst_data[3]), 255u);
 #endif
 }
+
+TEST(DynamicRenderBackend, VulkanNullDestinationBlitDoesNotCrash)
+{
+#ifndef OAK_ENABLE_DYNAMIC_RENDER_BACKEND
+	GTEST_SKIP() << "Dynamic render backend is not enabled in this build";
+#else
+	olive::DynamicRenderer renderer(QStringLiteral("vulkan"));
+	ASSERT_TRUE(renderer.Load());
+	OakRenderBackendInfo info = {};
+	ASSERT_TRUE(renderer.GetBackendInfo(&info));
+	if (info.kind != OAK_RENDER_BACKEND_VULKAN) {
+		GTEST_SKIP() << "Vulkan backend is not available on this system";
+	}
+
+	ASSERT_TRUE(renderer.Init());
+	renderer.PostInit();
+
+	const int kSize = 32;
+	olive::VideoParams params(kSize, kSize, olive::PixelFormat::U8,
+							  olive::VideoParams::kRGBAChannelCount);
+
+	olive::TexturePtr src = renderer.CreateTexture(params);
+	ASSERT_NE(src, nullptr);
+	ASSERT_FALSE(src->IsDummy());
+
+	QByteArray src_data(kSize * kSize * 4, 0);
+	for (int i = 0; i < kSize * kSize; ++i) {
+		src_data[i * 4 + 0] = static_cast<char>(255);
+		src_data[i * 4 + 3] = static_cast<char>(255);
+	}
+	src->Upload(src_data.data(), kSize * 4);
+
+	const QString vert = QStringLiteral(
+		"uniform mat4 ove_mvpmat;\n"
+		"in vec4 a_position;\n"
+		"in vec2 a_texcoord;\n"
+		"out vec2 ove_texcoord;\n"
+		"void main() {\n"
+		"    gl_Position = ove_mvpmat * a_position;\n"
+		"    ove_texcoord = a_texcoord;\n"
+		"}\n");
+	const QString frag = QStringLiteral(
+		"uniform sampler2D ove_maintex;\n"
+		"in vec2 ove_texcoord;\n"
+		"out vec4 frag_color;\n"
+		"void main() {\n"
+		"    frag_color = texture(ove_maintex, ove_texcoord);\n"
+		"}\n");
+	QVariant shader = renderer.CreateNativeShader(olive::ShaderCode(frag, vert));
+	ASSERT_FALSE(shader.isNull());
+
+	olive::ShaderJob job;
+	job.Insert(QStringLiteral("ove_maintex"),
+			   olive::NodeValue(olive::NodeValue::kTexture,
+								QVariant::fromValue(src)));
+	job.Insert(QStringLiteral("ove_mvpmat"),
+			   olive::NodeValue(olive::NodeValue::kMatrix, QMatrix4x4()));
+
+	// Null-destination Blit has no render target; it should simply not crash.
+	renderer.Blit(shader, job, params, true);
+	SUCCEED();
+#endif
+}
+
+TEST(DynamicRenderBackend, VulkanIterativeBlitPingPong)
+{
+#ifndef OAK_ENABLE_DYNAMIC_RENDER_BACKEND
+	GTEST_SKIP() << "Dynamic render backend is not enabled in this build";
+#else
+	olive::DynamicRenderer renderer(QStringLiteral("vulkan"));
+	ASSERT_TRUE(renderer.Load());
+	OakRenderBackendInfo info = {};
+	ASSERT_TRUE(renderer.GetBackendInfo(&info));
+	if (info.kind != OAK_RENDER_BACKEND_VULKAN) {
+		GTEST_SKIP() << "Vulkan backend is not available on this system";
+	}
+
+	ASSERT_TRUE(renderer.Init());
+	renderer.PostInit();
+
+	const int kSize = 32;
+	olive::VideoParams params(kSize, kSize, olive::PixelFormat::U8,
+							  olive::VideoParams::kRGBAChannelCount);
+
+	olive::TexturePtr src = renderer.CreateTexture(params);
+	ASSERT_NE(src, nullptr);
+	ASSERT_FALSE(src->IsDummy());
+
+	// Start with a fully red texture.
+	QByteArray src_data(kSize * kSize * 4, 0);
+	for (int i = 0; i < kSize * kSize; ++i) {
+		src_data[i * 4 + 0] = static_cast<char>(255);
+		src_data[i * 4 + 3] = static_cast<char>(255);
+	}
+	src->Upload(src_data.data(), kSize * 4);
+
+	olive::TexturePtr dst = renderer.CreateTexture(params);
+	ASSERT_NE(dst, nullptr);
+	ASSERT_FALSE(dst->IsDummy());
+
+	// Shader that samples the iterative input and scales RGB by 0.5 each pass.
+	const QString vert = QStringLiteral(
+		"uniform mat4 ove_mvpmat;\n"
+		"in vec4 a_position;\n"
+		"in vec2 a_texcoord;\n"
+		"out vec2 ove_texcoord;\n"
+		"void main() {\n"
+		"    gl_Position = ove_mvpmat * a_position;\n"
+		"    ove_texcoord = a_texcoord;\n"
+		"}\n");
+	const QString frag = QStringLiteral(
+		"uniform sampler2D ove_maintex;\n"
+		"in vec2 ove_texcoord;\n"
+		"out vec4 frag_color;\n"
+		"void main() {\n"
+		"    vec4 c = texture(ove_maintex, ove_texcoord);\n"
+		"    frag_color = vec4(c.rgb * 0.5, c.a);\n"
+		"}\n");
+	QVariant shader = renderer.CreateNativeShader(olive::ShaderCode(frag, vert));
+	ASSERT_FALSE(shader.isNull());
+
+	olive::ShaderJob job;
+	job.Insert(QStringLiteral("ove_maintex"),
+			   olive::NodeValue(olive::NodeValue::kTexture,
+								QVariant::fromValue(src)));
+	job.Insert(QStringLiteral("ove_mvpmat"),
+			   olive::NodeValue(olive::NodeValue::kMatrix, QMatrix4x4()));
+	job.SetIterations(2, QStringLiteral("ove_maintex"));
+
+	renderer.BlitToTexture(shader, job, dst.get(), true);
+
+	QByteArray dst_data(kSize * kSize * 4, 0);
+	dst->Download(dst_data.data(), kSize * 4);
+
+	// After two halving passes, red is 255 * 0.5 * 0.5. UNORM conversion floors
+	// the intermediate value, so the result is 63 rather than 64.
+	EXPECT_EQ(static_cast<uint8_t>(dst_data[0]), 63u);
+	EXPECT_EQ(static_cast<uint8_t>(dst_data[1]), 0u);
+	EXPECT_EQ(static_cast<uint8_t>(dst_data[2]), 0u);
+	EXPECT_EQ(static_cast<uint8_t>(dst_data[3]), 255u);
+#endif
+}
+
+TEST(DynamicRenderBackend, VulkanUploadDownloadThreeChannel)
+{
+#ifndef OAK_ENABLE_DYNAMIC_RENDER_BACKEND
+	GTEST_SKIP() << "Dynamic render backend is not enabled in this build";
+#else
+	olive::DynamicRenderer renderer(QStringLiteral("vulkan"));
+	ASSERT_TRUE(renderer.Load());
+	OakRenderBackendInfo info = {};
+	ASSERT_TRUE(renderer.GetBackendInfo(&info));
+	if (info.kind != OAK_RENDER_BACKEND_VULKAN) {
+		GTEST_SKIP() << "Vulkan backend is not available on this system";
+	}
+
+	ASSERT_TRUE(renderer.Init());
+	renderer.PostInit();
+
+	const int kSize = 16;
+	olive::VideoParams params(kSize, kSize, olive::PixelFormat::U8,
+							  olive::VideoParams::kRGBChannelCount);
+
+	olive::TexturePtr tex = renderer.CreateTexture(params);
+	ASSERT_NE(tex, nullptr);
+	ASSERT_FALSE(tex->IsDummy());
+
+	QByteArray src_data(kSize * kSize * 3, 0);
+	for (int i = 0; i < kSize * kSize; ++i) {
+		src_data[i * 3 + 0] = static_cast<char>(255);
+		src_data[i * 3 + 1] = static_cast<char>(128);
+		src_data[i * 3 + 2] = static_cast<char>(64);
+	}
+	tex->Upload(src_data.data(), kSize * 3);
+
+	QByteArray dst_data(kSize * kSize * 3, 0);
+	tex->Download(dst_data.data(), kSize * 3);
+
+	EXPECT_EQ(static_cast<uint8_t>(dst_data[0]), 255u);
+	EXPECT_EQ(static_cast<uint8_t>(dst_data[1]), 128u);
+	EXPECT_EQ(static_cast<uint8_t>(dst_data[2]), 64u);
+#endif
+}
diff --git a/tests/gtest/main.cpp b/tests/gtest/main.cpp
index bbff6102d..63f451796 100644
--- a/tests/gtest/main.cpp
+++ b/tests/gtest/main.cpp
@@ -12,6 +12,9 @@ int main(int argc, char **argv)
 							 .filePath(QStringLiteral(
 								 "app/render/ocioconf/config.ocio"))));
 	}
+	if (qEnvironmentVariableIsEmpty("QT_QPA_PLATFORM")) {
+		qputenv("QT_QPA_PLATFORM", "offscreen");
+	}
 	QApplication app(argc, argv);
 	::testing::InitGoogleTest(&argc, argv);
 	return RUN_ALL_TESTS();