[Impeller] Vulkan runtime effects/fragment program API (#49543)

Fixes flutter/flutter#122823
Fixes flutter/flutter#129659
Fixes flutter/flutter#123741

This patch makes runtime stage/fragment program stuff work on Vulkan for Android.

It will need flutter/flutter#140976 for that to become a reality for flutter_tools users.

Compiling with relaxed Vulkan semantics still has an issue: shaders that use `sampler2D` with an explicitly set `location` on the `layout` will fail to compile with an error documented in flutter/flutter#141219.

I think there might still be some issues with fragment programs on Vulkan, but this should at least be a good starting point and unblocks ink_sparkle.frag usage in the framework.

I've deleted some runtime_stage related code that would never get used - for example, enum related code that indicates we might support a bunch of data types that we do not and probably never will support in this API.

Author: dnfield

impeller/aiks/aiks_unittests.cc

@@ -2704,10 +2704,6 @@ TEST_P(AiksTest, CanRenderForegroundAdvancedBlendWithMaskBlur) {
 
 // Regression test for https://github.com/flutter/flutter/issues/126701 .
 TEST_P(AiksTest, CanRenderClippedRuntimeEffects) {
-  if (!BackendSupportsFragmentProgram()) {
-    GTEST_SKIP_("This backend doesn't support runtime effects.");
-  }
-
   auto runtime_stages =
       OpenAssetAsRuntimeStage("runtime_stage_example.frag.iplr");
 
@@ -2741,10 +2737,6 @@ TEST_P(AiksTest, CanRenderClippedRuntimeEffects) {
 }
 
 TEST_P(AiksTest, DrawPaintTransformsBounds) {
-  if (!BackendSupportsFragmentProgram()) {
-    GTEST_SKIP_("This backend doesn't support runtime effects.");
-  }
-
   auto runtime_stages = OpenAssetAsRuntimeStage("gradient.frag.iplr");
   auto runtime_stage = runtime_stages[RuntimeStageBackend::kMetal];
   ASSERT_TRUE(runtime_stage);

impeller/compiler/compiler.cc

@@ -19,6 +19,7 @@
 #include "impeller/compiler/includer.h"
 #include "impeller/compiler/logger.h"
 #include "impeller/compiler/spirv_compiler.h"
+#include "impeller/compiler/types.h"
 #include "impeller/compiler/uniform_sorter.h"
 #include "impeller/compiler/utilities.h"
 
@@ -122,15 +123,13 @@ static CompilerBackend CreateMSLCompiler(
 static CompilerBackend CreateVulkanCompiler(
     const spirv_cross::ParsedIR& ir,
     const SourceOptions& source_options) {
-  // TODO(dnfield): It seems like what we'd want is a CompilerGLSL with
-  // vulkan_semantics set to true, but that has regressed some things on GLES
-  // somehow. In the mean time, go back to using CompilerMSL, but set the Metal
-  // Language version to something really high so that we don't get weird
-  // complaints about using Metal features while trying to build Vulkan shaders.
-  // https://github.com/flutter/flutter/issues/123795
-  return CreateMSLCompiler(
-      ir, source_options,
-      spirv_cross::CompilerMSL::Options::make_msl_version(3, 0, 0));
+  auto gl_compiler = std::make_shared<spirv_cross::CompilerGLSL>(ir);
+  spirv_cross::CompilerGLSL::Options sl_options;
+  sl_options.force_zero_initialized_variables = true;
+  sl_options.vertex.fixup_clipspace = true;
+  sl_options.vulkan_semantics = true;
+  gl_compiler->set_common_options(sl_options);
+  return CompilerBackend(gl_compiler);
 }
 
 static CompilerBackend CreateGLSLCompiler(const spirv_cross::ParsedIR& ir,
@@ -302,18 +301,23 @@ Compiler::Compiler(const std::shared_ptr<const fml::Mapping>& source_mapping,
     } break;
     case TargetPlatform::kOpenGLES:
     case TargetPlatform::kOpenGLDesktop:
-    case TargetPlatform::kVulkan: {
+    case TargetPlatform::kVulkan:
+    case TargetPlatform::kRuntimeStageVulkan: {
       SPIRVCompilerTargetEnv target;
 
       target.env = shaderc_target_env::shaderc_target_env_vulkan;
       target.version = shaderc_env_version::shaderc_env_version_vulkan_1_1;
       target.spirv_version = shaderc_spirv_version::shaderc_spirv_version_1_3;
 
+      if (source_options.target_platform ==
+          TargetPlatform::kRuntimeStageVulkan) {
+        spirv_options.macro_definitions.push_back("IMPELLER_GRAPHICS_BACKEND");
+        spirv_options.relaxed_vulkan_rules = true;
+      }
       spirv_options.target = target;
     } break;
     case TargetPlatform::kRuntimeStageMetal:
-    case TargetPlatform::kRuntimeStageGLES:
-    case TargetPlatform::kRuntimeStageVulkan: {
+    case TargetPlatform::kRuntimeStageGLES: {
       SPIRVCompilerTargetEnv target;
 
       target.env = shaderc_target_env::shaderc_target_env_opengl;
@@ -398,7 +402,8 @@ Compiler::Compiler(const std::shared_ptr<const fml::Mapping>& source_mapping,
   // If the target is Vulkan, our shading language is SPIRV which we already
   // have. We just need to strip it of debug information. If it isn't, we need
   // to invoke the appropriate compiler to compile the SPIRV to the target SL.
-  if (source_options.target_platform == TargetPlatform::kVulkan) {
+  if (source_options.target_platform == TargetPlatform::kVulkan ||
+      source_options.target_platform == TargetPlatform::kRuntimeStageVulkan) {
     auto stripped_spirv_options = spirv_options;
     stripped_spirv_options.generate_debug_info = false;
     sl_mapping_ = spv_compiler.CompileToSPV(

impeller/compiler/compiler_backend.cc

@@ -13,7 +13,10 @@ CompilerBackend::CompilerBackend(MSLCompiler compiler)
     : CompilerBackend(Type::kMSL, compiler) {}
 
 CompilerBackend::CompilerBackend(GLSLCompiler compiler)
-    : CompilerBackend(Type::kGLSL, compiler) {}
+    : CompilerBackend(compiler->get_common_options().vulkan_semantics
+                          ? Type::kGLSLVulkan
+                          : Type::kGLSL,
+                      compiler) {}
 
 CompilerBackend::CompilerBackend(SkSLCompiler compiler)
     : CompilerBackend(Type::kSkSL, compiler) {}

impeller/compiler/compiler_backend.h

@@ -27,6 +27,7 @@ struct CompilerBackend {
   enum class Type {
     kMSL,
     kGLSL,
+    kGLSLVulkan,
     kSkSL,
   };
 

impeller/compiler/reflector.cc

@@ -12,6 +12,7 @@
 #include <sstream>
 
 #include "flutter/fml/logging.h"
+#include "fml/backtrace.h"
 #include "impeller/base/strings.h"
 #include "impeller/base/validation.h"
 #include "impeller/compiler/code_gen_template.h"
@@ -23,54 +24,12 @@
 #include "impeller/geometry/half.h"
 #include "impeller/geometry/matrix.h"
 #include "impeller/geometry/scalar.h"
+#include "impeller/runtime_stage/runtime_stage.h"
+#include "spirv_common.hpp"
 
 namespace impeller {
 namespace compiler {
 
-static std::string BaseTypeToString(spirv_cross::SPIRType::BaseType type) {
-  using Type = spirv_cross::SPIRType::BaseType;
-  switch (type) {
-    case Type::Void:
-      return "ShaderType::kVoid";
-    case Type::Boolean:
-      return "ShaderType::kBoolean";
-    case Type::SByte:
-      return "ShaderType::kSignedByte";
-    case Type::UByte:
-      return "ShaderType::kUnsignedByte";
-    case Type::Short:
-      return "ShaderType::kSignedShort";
-    case Type::UShort:
-      return "ShaderType::kUnsignedShort";
-    case Type::Int:
-      return "ShaderType::kSignedInt";
-    case Type::UInt:
-      return "ShaderType::kUnsignedInt";
-    case Type::Int64:
-      return "ShaderType::kSignedInt64";
-    case Type::UInt64:
-      return "ShaderType::kUnsignedInt64";
-    case Type::AtomicCounter:
-      return "ShaderType::kAtomicCounter";
-    case Type::Half:
-      return "ShaderType::kHalfFloat";
-    case Type::Float:
-      return "ShaderType::kFloat";
-    case Type::Double:
-      return "ShaderType::kDouble";
-    case Type::Struct:
-      return "ShaderType::kStruct";
-    case Type::Image:
-      return "ShaderType::kImage";
-    case Type::SampledImage:
-      return "ShaderType::kSampledImage";
-    case Type::Sampler:
-      return "ShaderType::kSampler";
-    default:
-      return "ShaderType::kUnknown";
-  }
-}
-
 static std::string ExecutionModelToString(spv::ExecutionModel model) {
   switch (model) {
     case spv::ExecutionModel::ExecutionModelVertex:
@@ -370,7 +329,6 @@ std::shared_ptr<RuntimeStageData::Shader> Reflector::GenerateRuntimeStageData()
   // Sort the IR so that the uniforms are in declaration order.
   std::vector<spirv_cross::ID> uniforms =
       SortUniforms(ir_.get(), compiler_.GetCompiler());
-
   for (auto& sorted_id : uniforms) {
     auto var = ir_->ids[sorted_id].get<spirv_cross::SPIRVariable>();
     const auto spir_type = compiler_->get_type(var.basetype);
@@ -383,9 +341,69 @@ std::shared_ptr<RuntimeStageData::Shader> Reflector::GenerateRuntimeStageData()
     uniform_description.columns = spir_type.columns;
     uniform_description.bit_width = spir_type.width;
     uniform_description.array_elements = GetArrayElements(spir_type);
+    FML_CHECK(data->backend != RuntimeStageBackend::kVulkan ||
+              spir_type.basetype ==
+                  spirv_cross::SPIRType::BaseType::SampledImage)
+        << "Vulkan runtime effect had unexpected uniforms outside of the "
+           "uniform buffer object.";
     data->uniforms.emplace_back(std::move(uniform_description));
   }
 
+  const auto ubos = compiler_->get_shader_resources().uniform_buffers;
+  if (data->backend == RuntimeStageBackend::kVulkan && !ubos.empty()) {
+    if (ubos.size() != 1 && ubos[0].name != RuntimeStage::kVulkanUBOName) {
+      VALIDATION_LOG << "Expected a single UBO resource named "
+                        "'"
+                     << RuntimeStage::kVulkanUBOName
+                     << "' "
+                        "for Vulkan runtime stage backend.";
+      return nullptr;
+    }
+
+    const auto& ubo = ubos[0];
+
+    auto members = ReadStructMembers(ubo.type_id);
+    std::vector<uint8_t> struct_layout;
+    size_t float_count = 0;
+
+    for (size_t i = 0; i < members.size(); i += 1) {
+      const auto& member = members[i];
+      std::vector<int> bytes;
+      switch (member.underlying_type) {
+        case StructMember::UnderlyingType::kPadding: {
+          size_t padding_count =
+              (member.size + sizeof(float) - 1) / sizeof(float);
+          while (padding_count > 0) {
+            struct_layout.push_back(0);
+            padding_count--;
+          }
+          break;
+        }
+        case StructMember::UnderlyingType::kFloat: {
+          size_t member_float_count = member.byte_length / sizeof(float);
+          float_count += member_float_count;
+          while (member_float_count > 0) {
+            struct_layout.push_back(1);
+            member_float_count--;
+          }
+          break;
+        }
+        case StructMember::UnderlyingType::kOther:
+          VALIDATION_LOG << "Non-floating-type struct member " << member.name
+                         << " is not supported.";
+          return nullptr;
+      }
+    }
+    data->uniforms.emplace_back(UniformDescription{
+        .name = ubo.name,
+        .location = 64,  // Magic constant that must match the descriptor set
+                         // location for fragment programs.
+        .type = spirv_cross::SPIRType::Struct,
+        .struct_layout = std::move(struct_layout),
+        .struct_float_count = float_count,
+    });
+  }
+
   // We only need to worry about storing vertex attributes.
   if (entrypoints.front().execution_model == spv::ExecutionModelVertex) {
     const auto inputs = compiler_->get_shader_resources().stage_inputs;
@@ -532,6 +550,8 @@ static std::string ToString(CompilerBackend::Type type) {
       return "Metal Shading Language";
     case CompilerBackend::Type::kGLSL:
       return "OpenGL Shading Language";
+    case CompilerBackend::Type::kGLSLVulkan:
+      return "OpenGL Shading Language (Relaxed Vulkan Semantics)";
     case CompilerBackend::Type::kSkSL:
       return "SkSL Shading Language";
   }
@@ -627,7 +647,7 @@ std::optional<nlohmann::json::object_t> Reflector::ReflectType(
 
   const auto type = compiler_->get_type(type_id);
 
-  result["type_name"] = BaseTypeToString(type.basetype);
+  result["type_name"] = StructMember::BaseTypeToString(type.basetype);
   result["bit_width"] = type.width;
   result["vec_size"] = type.vecsize;
   result["columns"] = type.columns;
@@ -637,7 +657,8 @@ std::optional<nlohmann::json::object_t> Reflector::ReflectType(
       auto member = nlohmann::json::object_t{};
       member["name"] = struct_member.name;
       member["type"] = struct_member.type;
-      member["base_type"] = BaseTypeToString(struct_member.base_type);
+      member["base_type"] =
+          StructMember::BaseTypeToString(struct_member.base_type);
       member["offset"] = struct_member.offset;
       member["size"] = struct_member.size;
       member["byte_length"] = struct_member.byte_length;
@@ -1117,7 +1138,8 @@ nlohmann::json::object_t Reflector::EmitStructDefinition(
     auto& member = members.emplace_back(nlohmann::json::object_t{});
     member["name"] = struct_member.name;
     member["type"] = struct_member.type;
-    member["base_type"] = BaseTypeToString(struct_member.base_type);
+    member["base_type"] =
+        StructMember::BaseTypeToString(struct_member.base_type);
     member["offset"] = struct_member.offset;
     member["byte_length"] = struct_member.byte_length;
     if (struct_member.array_elements.has_value()) {
@@ -1142,7 +1164,7 @@ static VertexType VertexTypeFromInputResource(
     const spirv_cross::Resource* resource) {
   VertexType result;
   result.variable_name = resource->name;
-  const auto type = compiler.get_type(resource->type_id);
+  const auto& type = compiler.get_type(resource->type_id);
   result.base_type = type.basetype;
   const auto total_size = type.columns * type.vecsize * type.width / 8u;
   result.byte_length = total_size;