Fix splash screen upside down on Android

Fixes an issue introduced in #96439 (see
https://github.com/godotengine/godot/pull/96439#issuecomment-2447288702)

Godot was relying on Java's
activity.getWindowManager().getDefaultDisplay().getRotation(); to apply
pre-rotation but this is wrong.

First, getRotation() may temporarily return a different value from the
correct one; which is what was causing the splash screen to be upside
down. It would return -90 instead of 90 for the first rendered frame.

But unfortunately, the splash screen is just one frame rendered for a
very long time, so the error lingered for a long time for everyone to
see.

Second, to determine what rotation to use, we should be looking at what
Vulkan told us, which is the value we pass to
VkSurfaceTransformFlagBitsKHR::preTransform.

This commit removes the now-unnecessary
screen_get_internal_current_rotation() function (which was introduced by
#96439) and now saves the preTransform value in the swapchain.

drivers/vulkan/rendering_device_driver_vulkan.cpp

@@ -2996,6 +2996,24 @@ Error RenderingDeviceDriverVulkan::swap_chain_resize(CommandQueueID p_cmd_queue,
 	swap_create_info.imageUsage = VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT;
 	swap_create_info.imageSharingMode = VK_SHARING_MODE_EXCLUSIVE;
 	swap_create_info.preTransform = surface_transform_bits;
+	switch (swap_create_info.preTransform) {
+		case VK_SURFACE_TRANSFORM_IDENTITY_BIT_KHR:
+			swap_chain->pre_transform_rotation_degrees = 0;
+			break;
+		case VK_SURFACE_TRANSFORM_ROTATE_90_BIT_KHR:
+			swap_chain->pre_transform_rotation_degrees = 90;
+			break;
+		case VK_SURFACE_TRANSFORM_ROTATE_180_BIT_KHR:
+			swap_chain->pre_transform_rotation_degrees = 180;
+			break;
+		case VK_SURFACE_TRANSFORM_ROTATE_270_BIT_KHR:
+			swap_chain->pre_transform_rotation_degrees = 270;
+			break;
+		default:
+			WARN_PRINT("Unexpected swap_create_info.preTransform = " + itos(swap_create_info.preTransform) + ".");
+			swap_chain->pre_transform_rotation_degrees = 0;
+			break;
+	}
 	swap_create_info.compositeAlpha = composite_alpha;
 	swap_create_info.presentMode = present_mode;
 	swap_create_info.clipped = true;
@@ -3167,6 +3185,13 @@ RDD::RenderPassID RenderingDeviceDriverVulkan::swap_chain_get_render_pass(SwapCh
 	return swap_chain->render_pass;
 }
 
+int RenderingDeviceDriverVulkan::swap_chain_get_pre_rotation_degrees(SwapChainID p_swap_chain) {
+	DEV_ASSERT(p_swap_chain.id != 0);
+
+	SwapChain *swap_chain = (SwapChain *)(p_swap_chain.id);
+	return swap_chain->pre_transform_rotation_degrees;
+}
+
 RDD::DataFormat RenderingDeviceDriverVulkan::swap_chain_get_format(SwapChainID p_swap_chain) {
 	DEV_ASSERT(p_swap_chain.id != 0);
 

drivers/vulkan/rendering_device_driver_vulkan.h

@@ -359,6 +359,7 @@ private:
 		LocalVector<CommandQueue *> command_queues_acquired;
 		LocalVector<uint32_t> command_queues_acquired_semaphores;
 		RenderPassID render_pass;
+		int pre_transform_rotation_degrees = 0;
 		uint32_t image_index = 0;
 #ifdef ANDROID_ENABLED
 		uint64_t refresh_duration = 0;
@@ -373,6 +374,7 @@ public:
 	virtual Error swap_chain_resize(CommandQueueID p_cmd_queue, SwapChainID p_swap_chain, uint32_t p_desired_framebuffer_count) override final;
 	virtual FramebufferID swap_chain_acquire_framebuffer(CommandQueueID p_cmd_queue, SwapChainID p_swap_chain, bool &r_resize_required) override final;
 	virtual RenderPassID swap_chain_get_render_pass(SwapChainID p_swap_chain) override final;
+	virtual int swap_chain_get_pre_rotation_degrees(SwapChainID p_swap_chain) override final;
 	virtual DataFormat swap_chain_get_format(SwapChainID p_swap_chain) override final;
 	virtual void swap_chain_set_max_fps(SwapChainID p_swap_chain, int p_max_fps) override final;
 	virtual void swap_chain_free(SwapChainID p_swap_chain) override final;

platform/android/display_server_android.cpp

@@ -229,14 +229,6 @@ DisplayServer::ScreenOrientation DisplayServerAndroid::screen_get_orientation(in
 	return (ScreenOrientation)orientation;
 }
 
-int DisplayServerAndroid::screen_get_internal_current_rotation(int p_screen) const {
-	GodotIOJavaWrapper *godot_io_java = OS_Android::get_singleton()->get_godot_io_java();
-	ERR_FAIL_NULL_V(godot_io_java, 0);
-
-	const int rotation = godot_io_java->get_internal_current_screen_rotation();
-	return rotation;
-}
-
 int DisplayServerAndroid::get_screen_count() const {
 	return 1;
 }

platform/android/display_server_android.h

@@ -129,7 +129,6 @@ public:
 
 	virtual void screen_set_orientation(ScreenOrientation p_orientation, int p_screen = SCREEN_OF_MAIN_WINDOW) override;
 	virtual ScreenOrientation screen_get_orientation(int p_screen = SCREEN_OF_MAIN_WINDOW) const override;
-	virtual int screen_get_internal_current_rotation(int p_screen) const override;
 
 	virtual int get_screen_count() const override;
 	virtual int get_primary_screen() const override;

platform/android/java/lib/src/org/godotengine/godot/GodotIO.java

@@ -296,28 +296,6 @@ public class GodotIO {
 		}
 	}
 
-	/**
-	 This function is used by DisplayServer::screen_get_internal_current_rotation (C++)
-		and is used to implement a performance optimization in devices that do not offer
-		a HW rotator.
-	 @return
-		Rotation in degrees, in multiples of 90°
-	*/
-	public int getInternalCurrentScreenRotation() {
-		int rotation = activity.getWindowManager().getDefaultDisplay().getRotation();
-
-		switch (rotation) {
-			case Surface.ROTATION_90:
-				return 90;
-			case Surface.ROTATION_180:
-				return 180;
-			case Surface.ROTATION_270:
-				return 270;
-			default:
-				return 0;
-		}
-	}
-
 	public void setEdit(GodotEditText _edit) {
 		edit = _edit;
 	}

platform/android/java_godot_io_wrapper.cpp

@@ -66,7 +66,6 @@ GodotIOJavaWrapper::GodotIOJavaWrapper(JNIEnv *p_env, jobject p_godot_io_instanc
 		_has_hardware_keyboard = p_env->GetMethodID(cls, "hasHardwareKeyboard", "()Z");
 		_set_screen_orientation = p_env->GetMethodID(cls, "setScreenOrientation", "(I)V");
 		_get_screen_orientation = p_env->GetMethodID(cls, "getScreenOrientation", "()I");
-		_get_internal_current_screen_rotation = p_env->GetMethodID(cls, "getInternalCurrentScreenRotation", "()I");
 		_get_system_dir = p_env->GetMethodID(cls, "getSystemDir", "(IZ)Ljava/lang/String;");
 	}
 }
@@ -268,16 +267,6 @@ int GodotIOJavaWrapper::get_screen_orientation() {
 	}
 }
 
-int GodotIOJavaWrapper::get_internal_current_screen_rotation() {
-	if (_get_internal_current_screen_rotation) {
-		JNIEnv *env = get_jni_env();
-		ERR_FAIL_NULL_V(env, 0);
-		return env->CallIntMethod(godot_io_instance, _get_internal_current_screen_rotation);
-	} else {
-		return 0;
-	}
-}
-
 String GodotIOJavaWrapper::get_system_dir(int p_dir, bool p_shared_storage) {
 	if (_get_system_dir) {
 		JNIEnv *env = get_jni_env();

platform/android/java_godot_io_wrapper.h

@@ -61,7 +61,6 @@ private:
 	jmethodID _has_hardware_keyboard = 0;
 	jmethodID _set_screen_orientation = 0;
 	jmethodID _get_screen_orientation = 0;
-	jmethodID _get_internal_current_screen_rotation = 0;
 	jmethodID _get_system_dir = 0;
 
 public:
@@ -89,7 +88,6 @@ public:
 	void set_vk_height(int p_height);
 	void set_screen_orientation(int p_orient);
 	int get_screen_orientation();
-	int get_internal_current_screen_rotation();
 	String get_system_dir(int p_dir, bool p_shared_storage);
 };
 

servers/display_server.h

@@ -360,13 +360,6 @@ public:
 
 	virtual void screen_set_orientation(ScreenOrientation p_orientation, int p_screen = SCREEN_OF_MAIN_WINDOW);
 	virtual ScreenOrientation screen_get_orientation(int p_screen = SCREEN_OF_MAIN_WINDOW) const;
-	// Note: The "internal" current orientation is not necessarily the current orientation and will often be 0 for most platforms.
-	//
-	// Some Android GPUs come with a HW-based rotator which means the screen gets rotated for free to
-	// whatever orientation the device is currently facing. But many Android GPUs emulate it via SW instead,
-	// which costs performance and power. This value is an optimization that tells Godot's compositor how to
-	// rotate the render texture before presenting to screen so that Android's compositor doesn't have to.
-	virtual int screen_get_internal_current_rotation(int p_screen = SCREEN_OF_MAIN_WINDOW) const { return 0; }
 
 	virtual void screen_set_keep_on(bool p_enable); //disable screensaver
 	virtual bool screen_is_kept_on() const;

servers/rendering/renderer_rd/renderer_compositor_rd.cpp

@@ -67,7 +67,7 @@ void RendererCompositorRD::blit_render_targets_to_screen(DisplayServer::WindowID
 		RD::get_singleton()->draw_list_bind_uniform_set(draw_list, render_target_descriptors[rd_texture], 0);
 
 		// We need to invert the phone rotation.
-		int screen_rotation_degrees = -DisplayServer::get_singleton()->screen_get_internal_current_rotation();
+		const int screen_rotation_degrees = -RD::get_singleton()->screen_get_pre_rotation_degrees(p_screen);
 		float screen_rotation = Math::deg_to_rad((float)screen_rotation_degrees);
 
 		blit.push_constant.rotation_cos = Math::cos(screen_rotation);
@@ -238,7 +238,7 @@ void RendererCompositorRD::set_boot_image(const Ref<Image> &p_image, const Color
 	RD::get_singleton()->draw_list_bind_index_array(draw_list, blit.array);
 	RD::get_singleton()->draw_list_bind_uniform_set(draw_list, uset, 0);
 
-	int screen_rotation_degrees = DisplayServer::get_singleton()->screen_get_internal_current_rotation();
+	const int screen_rotation_degrees = -RD::get_singleton()->screen_get_pre_rotation_degrees(DisplayServer::MAIN_WINDOW_ID);
 	float screen_rotation = Math::deg_to_rad((float)screen_rotation_degrees);
 	blit.push_constant.rotation_cos = Math::cos(screen_rotation);
 	blit.push_constant.rotation_sin = Math::sin(screen_rotation);

servers/rendering/rendering_device.cpp

@@ -3757,6 +3757,15 @@ int RenderingDevice::screen_get_height(DisplayServer::WindowID p_screen) const {
 	return context->surface_get_height(surface);
 }
 
+int RenderingDevice::screen_get_pre_rotation_degrees(DisplayServer::WindowID p_screen) const {
+	_THREAD_SAFE_METHOD_
+
+	HashMap<DisplayServer::WindowID, RDD::SwapChainID>::ConstIterator it = screen_swap_chains.find(p_screen);
+	ERR_FAIL_COND_V_MSG(it == screen_swap_chains.end(), ERR_CANT_CREATE, "A swap chain was not created for the screen.");
+
+	return driver->swap_chain_get_pre_rotation_degrees(it->value);
+}
+
 RenderingDevice::FramebufferFormatID RenderingDevice::screen_get_framebuffer_format(DisplayServer::WindowID p_screen) const {
 	_THREAD_SAFE_METHOD_
 

servers/rendering/rendering_device.h

@@ -1083,6 +1083,7 @@ public:
 	Error screen_prepare_for_drawing(DisplayServer::WindowID p_screen = DisplayServer::MAIN_WINDOW_ID);
 	int screen_get_width(DisplayServer::WindowID p_screen = DisplayServer::MAIN_WINDOW_ID) const;
 	int screen_get_height(DisplayServer::WindowID p_screen = DisplayServer::MAIN_WINDOW_ID) const;
+	int screen_get_pre_rotation_degrees(DisplayServer::WindowID p_screen = DisplayServer::MAIN_WINDOW_ID) const;
 	FramebufferFormatID screen_get_framebuffer_format(DisplayServer::WindowID p_screen = DisplayServer::MAIN_WINDOW_ID) const;
 	Error screen_free(DisplayServer::WindowID p_screen = DisplayServer::MAIN_WINDOW_ID);
 

servers/rendering/rendering_device_driver.h

@@ -454,6 +454,9 @@ public:
 	// Retrieve the render pass that can be used to draw on the swap chain's framebuffers.
 	virtual RenderPassID swap_chain_get_render_pass(SwapChainID p_swap_chain) = 0;
 
+	// Retrieve the rotation in degrees to apply as a pre-transform. Usually 0 on PC. May be 0, 90, 180 & 270 on Android.
+	virtual int swap_chain_get_pre_rotation_degrees(SwapChainID p_swap_chain) { return 0; }
+
 	// Retrieve the format used by the swap chain's framebuffers.
 	virtual DataFormat swap_chain_get_format(SwapChainID p_swap_chain) = 0;