alberthuang96 / vkrenderertools

RenderTools

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Updated 10.16

The first goal on the TODO list has been accomplished.

• Fill the depth/stencil attachment and set it as input attachment in the first subpass
• Read the input attachment in the second subpass.
  I will upload the code after I fix the blurry panel.

This project is based on Sascha Willems's demo framework which is in the base directory.

Debug overdraw

Rendering scene with multiple lights may lead to severe overdraw problems in forward rendering.
To count the number of times that fragment shader shade a pixel when rendering the scene,
setting up stencil test for the Sponza scene rendering pipeline as the following:

depthStencilStateCI.stencilTestEnable = VK_TRUE;
depthStencilStateCI.front.compareOp = VK_COMPARE_OP_ALWAYS;
depthStencilStateCI.front.compareMask = 0xff;
depthStencilStateCI.front.writeMask = 0xff;
depthStencilStateCI.front.depthFailOp = VK_STENCIL_OP_INCREMENT_AND_CLAMP;
depthStencilStateCI.front.passOp = VK_STENCIL_OP_INCREMENT_AND_CLAMP;

TODOs

• Visualize different stencil values on the screen
• Use the same renderpass when rendering shadow map?

ZPrepass

To investigate the methods to reduce overdraw,
enabling the early fragment test in the scene rendering fragment shader by

layout (early_fragment_tests) in;

Add a depth prepass as well before scene rendering with an empty fragment shader to fill the depth buffer. By turning the prepass on, the framerate gets increased stably to 180-190fps as shown in the screenshot.

Notice

You can select your GPU in the line 1022 by modifying the code in .\base\vulkanexamplebase.cpp.

        ...
1022    uint32_t selectedDevice  = 1;
        ...

The variable selectedDevice is 1 for default. You can change it to 0 in case:

• You want to switch to another GPU
• You only have only one GPU and the program crashes at the GPU selection.