screenshot empty when running on android

[zhuker]

1 Fresh git checkout
2 Run on Android 13, 14, 15
3 Draws fine, click "Take screenshot"
4 screenshot.ppm is filled with zeros

[zhuker]

debugger shows zero-filled data after

		// Map image memory so we can start copying from it
		const char* data;
		vkMapMemory(device, dstImageMemory, 0, VK_WHOLE_SIZE, 0, (void**)&data);

[zhuker]

Also I see a bunch of messages like this in logcat

2025-02-06 01:41:47.194 26350-26449 BufferQueueProducer     de.saschawillems.vulkanScreenshot    D  [VRI[VulkanActivity]#0(BLAST Consumer)0](id:66ee00000000,api:1,p:26350,c:26350) connect: api=1 producerControlledByApp=true
2025-02-06 01:41:47.202 26350-26449 BufferQueueProducer     de.saschawillems.vulkanScreenshot    D  [VRI[VulkanActivity]#0(BLAST Consumer)0](id:66ee00000000,api:1,p:26350,c:26350) disconnect: api 1

[SaschaWillems]

I can reproduce this. Can't tell if this ever worked, at least on my Pixel 9 the current code can't even write out the file due to android file paths. Will try to fix.

[SaschaWillems]

Tried using an image to buffer copy instead and still no luck. Might be related to #1150.

[zhuker]

Added validation layer

2025-03-04 09:43:20.992 15493-15542 vulkanExample           de.saschawillems.vulkanScreenshot    E  ERROR: [1180184443][VUID-vkCmdDraw-None-09600] : Validation Error: [ VUID-vkCmdDraw-None-09600 ] Object 0: handle = 0x75086d4c40, type = VK_OBJECT_TYPE_COMMAND_BUFFER; Object 1: handle = 0xbe25490000018f76, type = VK_OBJECT_TYPE_IMAGE; | MessageID = 0x46582f7b | vkQueueSubmit(): pSubmits[0].pCommandBuffers[0] command buffer VkCommandBuffer 0x75086d4c40[] expects VkImage 0xbe25490000018f76[] (subresource: aspectMask = VK_IMAGE_ASPECT_COLOR_BIT, mipLevel = 0, arrayLayer = 0) to be in layout VK_IMAGE_LAYOUT_PRESENT_SRC_KHR--instead, current layout is VK_IMAGE_LAYOUT_UNDEFINED.
                                                                                                    The Vulkan spec states: If a descriptor with type equal to any of VK_DESCRIPTOR_TYPE_SAMPLE_WEIGHT_IMAGE_QCOM, VK_DESCRIPTOR_TYPE_BLOCK_MATCH_IMAGE_QCOM, VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE, VK_DESCRIPTOR_TYPE_STORAGE_IMAGE, or VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT is accessed as a result of this command, the image subresource identified by that descriptor must be in the image layout identified when the descriptor was written (https://docs.vul

[zhuker]

I can confirm it works fine when I force screen orientation to portrait

            android:screenOrientation="portrait"

also no validation errors

ie definitely related to #1150