clearing multiple depth attachments

Christoph · December 20, 2016, 6:52am

Hi,

I want to render a shadow cubemap using a cube compatible/ layerered image and 6 views/attachments.

I thought I might achieve this via subpasses but if I render, only the last attachment is written.
Are multiple depth attachments possible? Or rather can I use multiple depthreferences and swithch between them?
And what am I missing?

Best Regards
Christoph

github.com

Chrjstoph/Vulkan/blob/cpp/examples/offscreen/shadowmappingomniSubpasses.cpp

/*
* Vulkan Example - Omni directional shadows using a dynamic cube map
*
* Copyright (C) 2016 by Sascha Willems - www.saschawillems.de
*
* This code is licensed under the MIT license (MIT) (http://opensource.org/licenses/MIT)
*/



#include "../offscreen/vulkanOffscreenExampleBase.hpp"


// Texture properties
#define TEX_DIM 1024
#define TEX_FILTER vk::Filter::eLinear
// Offscreen frame buffer properties
#define FB_DIM TEX_DIM
#define FB_COLOR_FORMAT

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Sascha_Willems · December 21, 2016, 10:02am

A frame buffer can have an arbitrary number of depth and color attachments, so yes, you can create a frame buffer with multiple depth attachments.

Are you using preserve attachments of a subpass to ensure that the depth attachment that has been written by the former subpass is preserved?

I’m not 100% sure what you want to achieve, but since you’re doing cubemap rendering you may want to do this in a single pass with a geometry shaders.

Other than that some additional info would be useful.

Christoph · December 24, 2016, 3:43am

Hi and thank you for your reply.

I have a geometry shader sample that renders the scene directly into a cube map:

github.com

Chrjstoph/Vulkan/blob/cpp/examples/offscreen/shadowmappingomniLayered.cpp

/*
* Vulkan Example - Omni directional shadows using a dynamic cube map
*
* Copyright (C) 2016 by Sascha Willems - www.saschawillems.de
*
* This code is licensed under the MIT license (MIT) (http://opensource.org/licenses/MIT)
*/



#include "../offscreen/vulkanOffscreenExampleBase.hpp"


// Texture properties
#define TEX_DIM 1024
#define TEX_FILTER vk::Filter::eLinear

// Offscreen frame buffer properties
#define FB_DIM TEX_DIM
#define FB_COLOR_FORMAT

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Now I want to implement your omni sample without the copying and it was suggested that subpasses might be the way to do this, I was not aware of preservation attachments.
Thank you very much, I will educate myself in that direction.