Vulkan's VertexIndex and InstanceIndex don't match with hardware. This
is because Nvidia implements gl_VertexID and gl_InstanceID. The math
that relates these is:
gl_VertexIndex = gl_BaseVertex + gl_VertexID
gl_InstanceIndex = gl_InstanceIndex + gl_InstanceID
To emulate it using what Vulkan's SPIR-V offers (the *Index variants)
this commit substracts gl_Base* from gl_*Index to obtain the OpenGL and
hardware's equivalent.
ATOM operates atomically on global memory. For now only add ATOM.ADD
since that's what was found in commercial games.
This asserts for ATOM.ADD.S32 (handling the others as unimplemented),
although ATOM.ADD.U32 shouldn't be any different.
This change forces us to change the default type on SPIR-V storage
buffers from float to uint. We could also alias the buffers, but it's
simpler for now to just use uint. While we are at it, abstract the code
to avoid repetition.
Some games like The Legend of Zelda: Breath of the Wild assign
render targets without writing them from the fragment shader. This
generates Vulkan validation errors, so silence these I previously
introduced a commit to set "vec4(0, 0, 0, 1)" for these attachments. The
problem is that this is not what games expect. This commit reverts that
change.
Front face was being forced to a certain value when cull face is
disabled. Set a default value on initialization and drop the forcefully
set front facing value with culling disabled.
Nvidia's driver defaults invalid enumerations to GL_CLAMP. Vulkan
doesn't expose GL_CLAMP through its API, but we can hack it on Nvidia's
driver using the internal driver defaults.
This currently only supports quad arrays and u8 indices.
In the future we can remove quad arrays with a table written from the
CPU, but this was used to bootstrap the other passes helpers and it
was left in the code.
The blob code is generated from the "shaders/" directory. Read the
instructions there to know how to generate the SPIR-V.
This abstractio represents the state of the 3D engine at a given draw.
Instead of changing individual bits of the pipeline how it's done in
APIs like D3D11, OpenGL and NVN; on Vulkan we are forced to put
everything together into a single, immutable object.
It takes advantage of the few dynamic states Vulkan offers.
The update descriptor is used to store in flat memory a large chunk of
staging data used to update descriptor sets through templates. It
provides a push interface to easily insert descriptors following the
current pipeline. The order used in the descriptor update template has
to be implicitly followed. We can catch bugs here using validation
layers.
