From 3f18c5e0f18a0cf117287f02b02849ba61722c7a Mon Sep 17 00:00:00 2001
From: Stenzek <stenzek@gmail.com>
Date: Sun, 16 Apr 2017 20:53:38 +1000
Subject: [PATCH] D3D12: Support native compressed textures

---
 Source/Core/VideoBackends/D3D12/D3DBase.cpp   | 17 +++++++
 .../Core/VideoBackends/D3D12/TextureCache.cpp | 50 +++++++++++++++++--
 2 files changed, 63 insertions(+), 4 deletions(-)

diff --git a/Source/Core/VideoBackends/D3D12/D3DBase.cpp b/Source/Core/VideoBackends/D3D12/D3DBase.cpp
index 9f1da4042e..56c5bc6534 100644
--- a/Source/Core/VideoBackends/D3D12/D3DBase.cpp
+++ b/Source/Core/VideoBackends/D3D12/D3DBase.cpp
@@ -262,6 +262,21 @@ std::vector<DXGI_SAMPLE_DESC> EnumAAModes(ID3D12Device* device)
   return aa_modes;
 }
 
+static bool SupportsS3TCTextures(ID3D12Device* device)
+{
+  auto CheckForFormat = [](ID3D12Device* device, DXGI_FORMAT format) {
+    D3D12_FEATURE_DATA_FORMAT_SUPPORT data = {format};
+    if (FAILED(device->CheckFeatureSupport(D3D12_FEATURE_FORMAT_SUPPORT, &data, sizeof(data))))
+      return false;
+
+    return (data.Support1 & D3D12_FORMAT_SUPPORT1_TEXTURE2D) != 0;
+  };
+
+  return CheckForFormat(device, DXGI_FORMAT_BC1_UNORM) &&
+         CheckForFormat(device, DXGI_FORMAT_BC2_UNORM) &&
+         CheckForFormat(device, DXGI_FORMAT_BC3_UNORM);
+}
+
 HRESULT Create(HWND wnd)
 {
   hWnd = wnd;
@@ -478,6 +493,8 @@ HRESULT Create(HWND wnd)
   SAFE_RELEASE(factory);
   SAFE_RELEASE(adapter);
 
+  g_Config.backend_info.bSupportsST3CTextures = SupportsS3TCTextures(device12);
+
   return S_OK;
 }
 
diff --git a/Source/Core/VideoBackends/D3D12/TextureCache.cpp b/Source/Core/VideoBackends/D3D12/TextureCache.cpp
index 77009112cd..cf0f237575 100644
--- a/Source/Core/VideoBackends/D3D12/TextureCache.cpp
+++ b/Source/Core/VideoBackends/D3D12/TextureCache.cpp
@@ -33,6 +33,42 @@ static u32 s_efb_copy_last_cbuf_id = UINT_MAX;
 static ID3D12Resource* s_texture_cache_entry_readback_buffer = nullptr;
 static size_t s_texture_cache_entry_readback_buffer_size = 0;
 
+static u32 GetLevelPitch(HostTextureFormat format, u32 row_length)
+{
+  switch (format)
+  {
+  case HostTextureFormat::DXT1:
+    return row_length / 4 * 8;
+
+  case HostTextureFormat::DXT3:
+  case HostTextureFormat::DXT5:
+    return row_length / 4 * 16;
+
+  case HostTextureFormat::RGBA8:
+  default:
+    return row_length * 4;
+  }
+}
+
+static DXGI_FORMAT GetDXGIFormatForHostFormat(HostTextureFormat format)
+{
+  switch (format)
+  {
+  case HostTextureFormat::DXT1:
+    return DXGI_FORMAT_BC1_UNORM;
+
+  case HostTextureFormat::DXT3:
+    return DXGI_FORMAT_BC2_UNORM;
+
+  case HostTextureFormat::DXT5:
+    return DXGI_FORMAT_BC3_UNORM;
+
+  case HostTextureFormat::RGBA8:
+  default:
+    return DXGI_FORMAT_R8G8B8A8_UNORM;
+  }
+}
+
 TextureCache::TCacheEntry::~TCacheEntry()
 {
   m_texture->Release();
@@ -51,6 +87,11 @@ bool TextureCache::TCacheEntry::Save(const std::string& filename, unsigned int l
       Common::AlignUp(level_width * sizeof(u32), D3D12_TEXTURE_DATA_PITCH_ALIGNMENT);
   size_t required_readback_buffer_size = level_pitch * level_height;
 
+  // We can't dump compressed textures currently (it would mean drawing them to a RGBA8
+  // framebuffer, and saving that). TextureCache does not call Save for custom textures
+  // anyway, so this is fine for now.
+  _assert_(config.format == HostTextureFormat::RGBA8);
+
   // Check if the current readback buffer is large enough
   if (required_readback_buffer_size > s_texture_cache_entry_readback_buffer_size)
   {
@@ -178,19 +219,20 @@ void TextureCache::TCacheEntry::CopyRectangleFromTexture(const TCacheEntryBase*
 void TextureCache::TCacheEntry::Load(u32 level, u32 width, u32 height, u32 row_length,
                                      const u8* buffer, size_t buffer_size)
 {
-  u32 src_pitch = 4 * row_length;
+  u32 src_pitch = GetLevelPitch(config.format, row_length);
   D3D::ReplaceRGBATexture2D(m_texture->GetTex12(), buffer, width, height, src_pitch, level,
                             m_texture->GetResourceUsageState());
 }
 
 TextureCacheBase::TCacheEntryBase* TextureCache::CreateTexture(const TCacheEntryConfig& config)
 {
+  DXGI_FORMAT dxgi_format = GetDXGIFormatForHostFormat(config.format);
   if (config.rendertarget)
   {
     D3DTexture2D* texture =
         D3DTexture2D::Create(config.width, config.height,
                              TEXTURE_BIND_FLAG_SHADER_RESOURCE | TEXTURE_BIND_FLAG_RENDER_TARGET,
-                             DXGI_FORMAT_R8G8B8A8_UNORM, 1, config.layers);
+                             dxgi_format, 1, config.layers);
 
     TCacheEntry* entry = new TCacheEntry(config, texture);
 
@@ -204,8 +246,8 @@ TextureCacheBase::TCacheEntryBase* TextureCache::CreateTexture(const TCacheEntry
   {
     ID3D12Resource* texture_resource = nullptr;
 
-    D3D12_RESOURCE_DESC texture_resource_desc = CD3DX12_RESOURCE_DESC::Tex2D(
-        DXGI_FORMAT_R8G8B8A8_UNORM, config.width, config.height, 1, config.levels);
+    D3D12_RESOURCE_DESC texture_resource_desc =
+        CD3DX12_RESOURCE_DESC::Tex2D(dxgi_format, config.width, config.height, 1, config.levels);
 
     CheckHR(D3D::device12->CreateCommittedResource(
         &CD3DX12_HEAP_PROPERTIES(D3D12_HEAP_TYPE_DEFAULT), D3D12_HEAP_FLAG_NONE,