Vulkan: Add support for ETC1

The ETC2 format is backwards compatible with ETC1.  ETC1 RGB8 is thus
supported by implicitly using the ETC2 RGB8 Vulkan format.

Bug: angleproject:2670
Change-Id: I59a112da5ed3a0b90f90a8b4c350c94d43b31120
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1520987
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Tim Van Patten <timvp@google.com>

scripts/run_code_generation_hashes.json

@@ -14,9 +14,9 @@
   "ANGLE load functions table:src/libANGLE/renderer/gen_load_functions_table.py":
     "2dcc3aa0cd700165b588cf53441e243b",
   "ANGLE load functions table:src/libANGLE/renderer/load_functions_data.json":
-    "eaca9d5068380214c416bb8e23ca2f99",
+    "5f26e468153a98121f7a9c03eea9999e",
   "ANGLE load functions table:src/libANGLE/renderer/load_functions_table_autogen.cpp":
-    "da4924c3be631b8c2abed3023860299b",
+    "28991ca4bb52f7cce520d2fb4882eb0d",
   "D3D11 blit shader selection:src/libANGLE/renderer/d3d/d3d11/Blit11Helper_autogen.inc":
     "f69cf03a3d868a977fad9e9c0eb0652a",
   "D3D11 blit shader selection:src/libANGLE/renderer/d3d/d3d11/d3d11_blit_shaders_autogen.gni":
@@ -188,9 +188,9 @@
   "Vulkan format:src/libANGLE/renderer/vulkan/gen_vk_format_table.py":
     "9937d3c942f0a5fe08f1ca080d40d47e",
   "Vulkan format:src/libANGLE/renderer/vulkan/vk_format_map.json":
-    "992749b88763adb66003fe5d801b5ded",
+    "9b5a784d36ea31610e143d23860425d7",
   "Vulkan format:src/libANGLE/renderer/vulkan/vk_format_table_autogen.cpp":
-    "1d22113470fbe8506e1264923f1793d2",
+    "ef0ea80cf33e60f76391bcfed10b3c0a",
   "Vulkan internal shader programs:src/libANGLE/renderer/vulkan/gen_vk_internal_shaders.py":
     "e5fa1f79a91ff812f24b5755eba8e145",
   "Vulkan internal shader programs:src/libANGLE/renderer/vulkan/shaders/gen/BufferUtils.comp.00000000.inc":

src/libANGLE/renderer/load_functions_data.json

@@ -719,6 +719,9 @@
     },
     "ETC1_R8G8B8_UNORM_BLOCK": {
       "GL_UNSIGNED_BYTE": "LoadCompressedToNative<4, 4, 8>"
+    },
+    "ETC2_R8G8B8_UNORM_BLOCK": {
+      "GL_UNSIGNED_BYTE": "LoadCompressedToNative<4, 4, 8>"
     }
   },
   "GL_ETC1_RGB8_LOSSY_DECODE_ANGLE": {

src/libANGLE/renderer/load_functions_table_autogen.cpp

@@ -1184,6 +1184,18 @@ LoadImageFunctionInfo ETC1_RGB8_OES_to_ETC1_R8G8B8_UNORM_BLOCK(GLenum type)
     }
 }
 
+LoadImageFunctionInfo ETC1_RGB8_OES_to_ETC2_R8G8B8_UNORM_BLOCK(GLenum type)
+{
+    switch (type)
+    {
+        case GL_UNSIGNED_BYTE:
+            return LoadImageFunctionInfo(LoadCompressedToNative<4, 4, 8>, true);
+        default:
+            UNREACHABLE();
+            return LoadImageFunctionInfo(UnreachableLoadFunction, true);
+    }
+}
+
 LoadImageFunctionInfo ETC1_RGB8_OES_to_R8G8B8A8_UNORM(GLenum type)
 {
     switch (type)
@@ -3016,6 +3028,8 @@ LoadFunctionMap GetLoadFunctionsMap(GLenum internalFormat, FormatID angleFormat)
             {
                 case FormatID::ETC1_R8G8B8_UNORM_BLOCK:
                     return ETC1_RGB8_OES_to_ETC1_R8G8B8_UNORM_BLOCK;
+                case FormatID::ETC2_R8G8B8_UNORM_BLOCK:
+                    return ETC1_RGB8_OES_to_ETC2_R8G8B8_UNORM_BLOCK;
                 case FormatID::R8G8B8A8_UNORM:
                     return ETC1_RGB8_OES_to_R8G8B8A8_UNORM;
                 default:

src/libANGLE/renderer/vulkan/vk_format_map.json

@@ -224,6 +224,10 @@
             "buffer": "NONE",
             "texture": "D24_UNORM_S8_UINT"
         },
+        "ETC1_R8G8B8_UNORM_BLOCK": {
+            "buffer": "NONE",
+            "texture": "ETC2_R8G8B8_UNORM_BLOCK"
+        },
         "R32_FIXED": {
             "buffer": "R32_FLOAT"
         },

src/libANGLE/renderer/vulkan/vk_format_table_autogen.cpp

@@ -751,7 +751,15 @@ void Format::initialize(RendererVk *renderer, const angle::Format &angleFormat)
             break;
 
         case angle::FormatID::ETC1_R8G8B8_UNORM_BLOCK:
-            // This format is not implemented in Vulkan.
+            internalFormat               = GL_ETC1_RGB8_OES;
+            textureFormatID              = angle::FormatID::ETC2_R8G8B8_UNORM_BLOCK;
+            vkTextureFormat              = VK_FORMAT_ETC2_R8G8B8_UNORM_BLOCK;
+            textureInitializerFunction   = nullptr;
+            bufferFormatID               = angle::FormatID::NONE;
+            vkBufferFormat               = VK_FORMAT_UNDEFINED;
+            vkBufferFormatIsPacked       = false;
+            vertexLoadFunction           = nullptr;
+            vertexLoadRequiresConversion = true;
             break;
 
         case angle::FormatID::ETC2_R8G8B8A1_SRGB_BLOCK: