vk_buffer_cache: Add support for null index buffers

Games can bind a null index buffer (size=0) where all indices are
evaluated as zero. VK_EXT_robustness2 doesn't support this and all
drivers segfault when a null index buffer is passed to
vkCmdBindIndexBuffer.

Workaround this by creating a 4 byte buffer and filling it with zeroes.
If it's read out of bounds, robustness takes care of returning zeroes as
indices.
This commit is contained in:
ReinUsesLisp 2021-01-23 17:15:42 -03:00
parent 0b8b961442
commit 3a2eefb16c
2 changed files with 40 additions and 4 deletions

View File

@ -140,16 +140,22 @@ void BufferCacheRuntime::BindIndexBuffer(PrimitiveTopology topology, IndexFormat
u32 offset, [[maybe_unused]] u32 size) {
VkIndexType vk_index_type = MaxwellToVK::IndexFormat(index_format);
VkDeviceSize vk_offset = offset;
VkBuffer vk_buffer = buffer;
if (topology == PrimitiveTopology::Quads) {
vk_index_type = VK_INDEX_TYPE_UINT32;
std::tie(buffer, vk_offset) =
std::tie(vk_buffer, vk_offset) =
quad_index_pass.Assemble(index_format, num_indices, base_vertex, buffer, offset);
} else if (vk_index_type == VK_INDEX_TYPE_UINT8_EXT && !device.IsExtIndexTypeUint8Supported()) {
vk_index_type = VK_INDEX_TYPE_UINT16;
std::tie(buffer, vk_offset) = uint8_pass.Assemble(num_indices, buffer, offset);
std::tie(vk_buffer, vk_offset) = uint8_pass.Assemble(num_indices, buffer, offset);
}
scheduler.Record([buffer, vk_offset, vk_index_type](vk::CommandBuffer cmdbuf) {
cmdbuf.BindIndexBuffer(buffer, vk_offset, vk_index_type);
if (vk_buffer == VK_NULL_HANDLE) {
// Vulkan doesn't support null index buffers. Replace it with our own null buffer.
ReserveNullIndexBuffer();
vk_buffer = *null_index_buffer;
}
scheduler.Record([vk_buffer, vk_offset, vk_index_type](vk::CommandBuffer cmdbuf) {
cmdbuf.BindIndexBuffer(vk_buffer, vk_offset, vk_index_type);
});
}
@ -276,4 +282,29 @@ void BufferCacheRuntime::ReserveQuadArrayLUT(u32 num_indices, bool wait_for_idle
});
}
void BufferCacheRuntime::ReserveNullIndexBuffer() {
if (null_index_buffer) {
return;
}
null_index_buffer = device.GetLogical().CreateBuffer(VkBufferCreateInfo{
.sType = VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO,
.pNext = nullptr,
.flags = 0,
.size = 4,
.usage = VK_BUFFER_USAGE_INDEX_BUFFER_BIT | VK_BUFFER_USAGE_TRANSFER_DST_BIT,
.sharingMode = VK_SHARING_MODE_EXCLUSIVE,
.queueFamilyIndexCount = 0,
.pQueueFamilyIndices = nullptr,
});
if (device.HasDebuggingToolAttached()) {
null_index_buffer.SetObjectNameEXT("Null index buffer");
}
null_index_buffer_commit = memory_allocator.Commit(null_index_buffer, MemoryUsage::DeviceLocal);
scheduler.RequestOutsideRenderPassOperationContext();
scheduler.Record([buffer = *null_index_buffer](vk::CommandBuffer cmdbuf) {
cmdbuf.FillBuffer(buffer, 0, VK_WHOLE_SIZE, 0);
});
}
} // namespace Vulkan

View File

@ -90,6 +90,8 @@ private:
void ReserveQuadArrayLUT(u32 num_indices, bool wait_for_idle);
void ReserveNullIndexBuffer();
const Device& device;
MemoryAllocator& memory_allocator;
VKScheduler& scheduler;
@ -101,6 +103,9 @@ private:
VkIndexType quad_array_lut_index_type{};
u32 current_num_indices = 0;
vk::Buffer null_index_buffer;
MemoryCommit null_index_buffer_commit;
Uint8Pass uint8_pass;
QuadIndexedPass quad_index_pass;
};