[D3D12] EDRAM storing and random cleanup

src/xenia/gpu/d3d12/shaders/edram_load_depth_float.cs.hlsl

@@ -0,0 +1,31 @@
+#include "edram_load_store.hlsli"
+#include "pixel_formats.hlsli"
+
+[numthreads(20, 16, 1)]
+void main(uint3 xe_group_id : SV_GroupID,
+          uint3 xe_group_thread_id : SV_GroupThreadID,
+          uint3 xe_thread_id : SV_DispatchThreadID) {
+  uint2 tile_dword_index = xe_group_thread_id.xy;
+  tile_dword_index.x *= 4u;
+  uint edram_offset = XeEDRAMOffset(xe_group_id.xy, tile_dword_index);
+  uint4 depth24_stencil = xe_edram_load_store_source.Load4(edram_offset);
+  uint4 depth24 = depth24_stencil & 0xFFFFFFu;
+  uint4 depth32 = xe_edram_load_store_source.Load4(10485760u + edram_offset);
+  // Depth. If the stored 32-bit depth converted to 24-bit is the same as the
+  // stored 24-bit depth, load the 32-bit value because it has more precision
+  // (and multipass rendering is possible), if it's not, convert the 24-bit
+  // depth because it was overwritten by aliasing.
+  uint4 depth24to32 = XeFloat20e4To32(depth24);
+  uint4 depth = depth24to32 + (depth32 - depth24to32) *
+                uint4(XeFloat32To20e4(depth32) == depth24);
+  uint rt_offset = xe_thread_id.y * xe_edram_rt_color_depth_pitch +
+                   xe_thread_id.x * 16u;
+  xe_edram_load_store_dest.Store4(rt_offset, depth);
+  // Stencil.
+  uint4 stencil = (depth24_stencil >> 24u) << uint4(0u, 8u, 16u, 24u);
+  stencil.xy |= stencil.zw;
+  stencil.x |= stencil.y;
+  rt_offset = xe_edram_rt_stencil_offset +
+              xe_thread_id.y * xe_edram_rt_stencil_pitch + xe_thread_id.x * 4u;
+  xe_edram_load_store_dest.Store(rt_offset, stencil.x);
+}