Implement MSAA properly for Vulkan.

UnleashedRecomp/gpu/shader/.gitignore

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+*.hlsl.*.h

UnleashedRecomp/gpu/shader/copy_vs.hlsl

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+void main(in uint vertexId : SV_VertexID, out float4 position : SV_Position, out float2 texCoord : TEXCOORD)
+{
+    texCoord = float2((vertexId << 1) & 2, vertexId & 2);
+    position = float4(texCoord * float2(2.0, -2.0) + float2(-1.0, 1.0), 0.0, 1.0);
+}

UnleashedRecomp/gpu/shader/resolve_msaa_depth.hlsli

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+struct PushConstants
+{
+    uint ResourceDescriptorIndex;
+};
+
+[[vk::push_constant]] ConstantBuffer<PushConstants> g_PushConstants : register(b3, space4);
+
+Texture2DMS<float, SAMPLE_COUNT> g_Texture2DMSDescriptorHeap[] : register(t0, space0);
+
+float main(in float4 position : SV_Position) : SV_Depth
+{
+    float result = g_Texture2DMSDescriptorHeap[g_PushConstants.ResourceDescriptorIndex].Load(int2(position.xy), 0);
+    
+    [unroll] for (int i = 1; i < SAMPLE_COUNT; i++)
+        result = max(result, g_Texture2DMSDescriptorHeap[g_PushConstants.ResourceDescriptorIndex].Load(int2(position.xy), i));
+
+    return result;
+}

UnleashedRecomp/gpu/shader/resolve_msaa_depth_2x.hlsl

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+#define SAMPLE_COUNT 2
+#include "resolve_msaa_depth.hlsli"

UnleashedRecomp/gpu/shader/resolve_msaa_depth_4x.hlsl

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+#define SAMPLE_COUNT 4
+#include "resolve_msaa_depth.hlsli"

UnleashedRecomp/gpu/shader/resolve_msaa_depth_8x.hlsl

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+#define SAMPLE_COUNT 8
+#include "resolve_msaa_depth.hlsli"