[Impeller] Add blit pass

ci/licenses_golden/licenses_flutter

@@ -671,6 +671,10 @@ FILE: ../../../flutter/impeller/renderer/allocator.cc
 FILE: ../../../flutter/impeller/renderer/allocator.h
 FILE: ../../../flutter/impeller/renderer/backend/gles/allocator_gles.cc
 FILE: ../../../flutter/impeller/renderer/backend/gles/allocator_gles.h
+FILE: ../../../flutter/impeller/renderer/backend/gles/blit_command_gles.cc
+FILE: ../../../flutter/impeller/renderer/backend/gles/blit_command_gles.h
+FILE: ../../../flutter/impeller/renderer/backend/gles/blit_pass_gles.cc
+FILE: ../../../flutter/impeller/renderer/backend/gles/blit_pass_gles.h
 FILE: ../../../flutter/impeller/renderer/backend/gles/buffer_bindings_gles.cc
 FILE: ../../../flutter/impeller/renderer/backend/gles/buffer_bindings_gles.h
 FILE: ../../../flutter/impeller/renderer/backend/gles/capabilities_gles.cc
@@ -712,6 +716,10 @@ FILE: ../../../flutter/impeller/renderer/backend/gles/texture_gles.cc
 FILE: ../../../flutter/impeller/renderer/backend/gles/texture_gles.h
 FILE: ../../../flutter/impeller/renderer/backend/metal/allocator_mtl.h
 FILE: ../../../flutter/impeller/renderer/backend/metal/allocator_mtl.mm
+FILE: ../../../flutter/impeller/renderer/backend/metal/blit_command_mtl.h
+FILE: ../../../flutter/impeller/renderer/backend/metal/blit_command_mtl.mm
+FILE: ../../../flutter/impeller/renderer/backend/metal/blit_pass_mtl.h
+FILE: ../../../flutter/impeller/renderer/backend/metal/blit_pass_mtl.mm
 FILE: ../../../flutter/impeller/renderer/backend/metal/command_buffer_mtl.h
 FILE: ../../../flutter/impeller/renderer/backend/metal/command_buffer_mtl.mm
 FILE: ../../../flutter/impeller/renderer/backend/metal/context_mtl.h
@@ -742,6 +750,8 @@ FILE: ../../../flutter/impeller/renderer/backend/metal/vertex_descriptor_mtl.h
 FILE: ../../../flutter/impeller/renderer/backend/metal/vertex_descriptor_mtl.mm
 FILE: ../../../flutter/impeller/renderer/backend/vulkan/allocator_vk.cc
 FILE: ../../../flutter/impeller/renderer/backend/vulkan/allocator_vk.h
+FILE: ../../../flutter/impeller/renderer/backend/vulkan/blit_pass_vk.cc
+FILE: ../../../flutter/impeller/renderer/backend/vulkan/blit_pass_vk.h
 FILE: ../../../flutter/impeller/renderer/backend/vulkan/capabilities_vk.cc
 FILE: ../../../flutter/impeller/renderer/backend/vulkan/capabilities_vk.h
 FILE: ../../../flutter/impeller/renderer/backend/vulkan/command_buffer_vk.cc
@@ -773,6 +783,10 @@ FILE: ../../../flutter/impeller/renderer/backend/vulkan/texture_vk.h
 FILE: ../../../flutter/impeller/renderer/backend/vulkan/vertex_descriptor_vk.cc
 FILE: ../../../flutter/impeller/renderer/backend/vulkan/vertex_descriptor_vk.h
 FILE: ../../../flutter/impeller/renderer/backend/vulkan/vk.h
+FILE: ../../../flutter/impeller/renderer/blit_command.cc
+FILE: ../../../flutter/impeller/renderer/blit_command.h
+FILE: ../../../flutter/impeller/renderer/blit_pass.cc
+FILE: ../../../flutter/impeller/renderer/blit_pass.h
 FILE: ../../../flutter/impeller/renderer/buffer.cc
 FILE: ../../../flutter/impeller/renderer/buffer.h
 FILE: ../../../flutter/impeller/renderer/buffer_view.cc

impeller/display_list/display_list_dispatcher.cc

@@ -22,6 +22,7 @@
 #include "impeller/geometry/path_builder.h"
 #include "impeller/geometry/scalar.h"
 #include "impeller/geometry/vertices.h"
+#include "impeller/renderer/formats.h"
 #include "impeller/typographer/backends/skia/text_frame_skia.h"
 
 #include "third_party/skia/include/core/SkColor.h"
@@ -778,6 +779,11 @@ static impeller::SamplerDescriptor ToSamplerDescriptor(
       desc.min_filter = desc.mag_filter = impeller::MinMagFilter::kLinear;
       desc.label = "Linear Sampler";
       break;
+    case flutter::DlImageSampling::kMipmapLinear:
+      desc.min_filter = desc.mag_filter = impeller::MinMagFilter::kLinear;
+      desc.mip_filter = impeller::MipFilter::kLinear;
+      desc.label = "Mipmap Linear Sampler";
+      break;
     default:
       break;
   }

impeller/fixtures/BUILD.gn

@@ -16,6 +16,8 @@ impeller_shaders("shader_fixtures") {
     "impeller.vert",
     "instanced_draw.frag",
     "instanced_draw.vert",
+    "mipmaps.frag",
+    "mipmaps.vert",
     "simple.vert",
     "test_texture.frag",
     "test_texture.vert",

impeller/fixtures/mipmaps.frag

@@ -0,0 +1,18 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+uniform FragInfo {
+  float lod;
+}
+frag_info;
+
+uniform sampler2D tex;
+
+in vec2 v_uv;
+
+out vec4 frag_color;
+
+void main() {
+  frag_color = textureLod(tex, v_uv, frag_info.lod);
+}

impeller/fixtures/mipmaps.vert

@@ -0,0 +1,18 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+uniform VertInfo {
+  mat4 mvp;
+}
+vert_info;
+
+in vec2 vertex_position;
+in vec2 uv;
+
+out vec2 v_uv;
+
+void main() {
+  gl_Position = vert_info.mvp * vec4(vertex_position, 0.0, 1.0);
+  v_uv = uv;
+}

impeller/playground/playground.cc

@@ -334,7 +334,8 @@ std::optional<DecompressedImage> Playground::LoadFixtureImageRGBA(
 }
 
 std::shared_ptr<Texture> Playground::CreateTextureForFixture(
-    const char* fixture_name) const {
+    const char* fixture_name,
+    bool enable_mipmapping) const {
   auto image = LoadFixtureImageRGBA(fixture_name);
   if (!image.has_value()) {
     return nullptr;
@@ -343,7 +344,8 @@ std::shared_ptr<Texture> Playground::CreateTextureForFixture(
   auto texture_descriptor = TextureDescriptor{};
   texture_descriptor.format = PixelFormat::kR8G8B8A8UNormInt;
   texture_descriptor.size = image->GetSize();
-  texture_descriptor.mip_count = 1u;
+  texture_descriptor.mip_count =
+      enable_mipmapping ? image->GetSize().MipCount() : 1u;
 
   auto texture =
       renderer_->GetContext()->GetPermanentsAllocator()->CreateTexture(

impeller/playground/playground.h

@@ -57,7 +57,8 @@ class Playground : public ::testing::TestWithParam<PlaygroundBackend> {
       const char* fixture_name) const;
 
   std::shared_ptr<Texture> CreateTextureForFixture(
-      const char* fixture_name) const;
+      const char* fixture_name,
+      bool enable_mipmapping = false) const;
 
   std::shared_ptr<Texture> CreateTextureCubeForFixture(
       std::array<const char*, 6> fixture_names) const;

impeller/renderer/BUILD.gn

@@ -8,6 +8,10 @@ impeller_component("renderer") {
   sources = [
     "allocator.cc",
     "allocator.h",
+    "blit_command.cc",
+    "blit_command.h",
+    "blit_pass.cc",
+    "blit_pass.h",
     "buffer.cc",
     "buffer.h",
     "buffer_view.cc",

impeller/renderer/backend/gles/BUILD.gn

@@ -16,6 +16,10 @@ impeller_component("gles") {
   sources = [
     "allocator_gles.cc",
     "allocator_gles.h",
+    "blit_command_gles.cc",
+    "blit_command_gles.h",
+    "blit_pass_gles.cc",
+    "blit_pass_gles.h",
     "buffer_bindings_gles.cc",
     "buffer_bindings_gles.h",
     "capabilities_gles.cc",
@@ -60,8 +64,11 @@ impeller_component("gles") {
   if (!is_android && !is_fuchsia) {
     public_configs = [ ":gles_config" ]
     sources += [
-      "//third_party/angle/include/GLES2/gl2.h",
       "//third_party/angle/include/GLES2/gl2ext.h",
+
+      # The GLES3 API is a superset of GLES2. Although we target GLES2, we use
+      # some GLES3 features if the driver supports them.
+      "//third_party/angle/include/GLES3/gl3.h",
     ]
   }
 

impeller/renderer/backend/gles/blit_command_gles.cc

@@ -0,0 +1,134 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "impeller/renderer/backend/gles/blit_command_gles.h"
+
+#include "flutter/fml/closure.h"
+#include "impeller/base/validation.h"
+#include "impeller/renderer/backend/gles/texture_gles.h"
+
+namespace impeller {
+
+BlitEncodeGLES::~BlitEncodeGLES() = default;
+
+static void DeleteFBO(const ProcTableGLES& gl, GLuint fbo, GLenum type) {
+  if (fbo != GL_NONE) {
+    gl.BindFramebuffer(type, GL_NONE);
+    gl.DeleteFramebuffers(1u, &fbo);
+  }
+};
+
+static std::optional<GLuint> ConfigureFBO(
+    const ProcTableGLES& gl,
+    const std::shared_ptr<Texture>& texture,
+    GLenum fbo_type) {
+  auto handle = TextureGLES::Cast(texture.get())->GetGLHandle();
+  if (!handle.has_value()) {
+    return std::nullopt;
+  }
+
+  if (TextureGLES::Cast(*texture).IsWrapped()) {
+    // The texture is attached to the default FBO, so there's no need to
+    // create/configure one.
+    gl.BindFramebuffer(fbo_type, 0);
+    return 0;
+  }
+
+  GLuint fbo;
+  gl.GenFramebuffers(1u, &fbo);
+  gl.BindFramebuffer(fbo_type, fbo);
+
+  if (!TextureGLES::Cast(*texture).SetAsFramebufferAttachment(
+          fbo_type, fbo, TextureGLES::AttachmentPoint::kColor0)) {
+    VALIDATION_LOG << "Could not attach texture to framebuffer.";
+    DeleteFBO(gl, fbo, fbo_type);
+    return std::nullopt;
+  }
+
+  if (gl.CheckFramebufferStatus(fbo_type) != GL_FRAMEBUFFER_COMPLETE) {
+    VALIDATION_LOG << "Could not create a complete frambuffer.";
+    DeleteFBO(gl, fbo, fbo_type);
+    return std::nullopt;
+  }
+
+  return fbo;
+};
+
+BlitCopyTextureToTextureCommandGLES::~BlitCopyTextureToTextureCommandGLES() =
+    default;
+
+std::string BlitCopyTextureToTextureCommandGLES::GetLabel() const {
+  return label;
+}
+
+bool BlitCopyTextureToTextureCommandGLES::Encode(
+    const ReactorGLES& reactor) const {
+  const auto& gl = reactor.GetProcTable();
+
+  // glBlitFramebuffer is a GLES3 proc. Since we target GLES2, we need to
+  // emulate the blit when it's not available in the driver.
+  if (!gl.BlitFramebuffer.IsAvailable()) {
+    // TODO(bdero): Emulate the blit using a raster draw call here.
+    FML_LOG(ERROR) << "Texture blit fallback not implemented yet for GLES2.";
+    return false;
+  }
+
+  GLuint read_fbo = GL_NONE;
+  GLuint draw_fbo = GL_NONE;
+  fml::ScopedCleanupClosure delete_fbos([&gl, &read_fbo, &draw_fbo]() {
+    DeleteFBO(gl, read_fbo, GL_READ_FRAMEBUFFER);
+    DeleteFBO(gl, draw_fbo, GL_DRAW_FRAMEBUFFER);
+  });
+
+  {
+    auto read = ConfigureFBO(gl, source, GL_READ_FRAMEBUFFER);
+    if (!read.has_value()) {
+      return false;
+    }
+    read_fbo = read.value();
+  }
+
+  {
+    auto draw = ConfigureFBO(gl, destination, GL_DRAW_FRAMEBUFFER);
+    if (!draw.has_value()) {
+      return false;
+    }
+    draw_fbo = draw.value();
+  }
+
+  gl.Disable(GL_SCISSOR_TEST);
+  gl.Disable(GL_DEPTH_TEST);
+  gl.Disable(GL_STENCIL_TEST);
+
+  gl.BlitFramebuffer(source_region.origin.x,     // srcX0
+                     source_region.origin.y,     // srcY0
+                     source_region.size.width,   // srcX1
+                     source_region.size.height,  // srcY1
+                     destination_origin.x,       // dstX0
+                     destination_origin.y,       // dstY0
+                     source_region.size.width,   // dstX1
+                     source_region.size.height,  // dstY1
+                     GL_COLOR_BUFFER_BIT,        // mask
+                     GL_NEAREST                  // filter
+  );
+
+  return true;
+};
+
+BlitGenerateMipmapCommandGLES::~BlitGenerateMipmapCommandGLES() = default;
+
+std::string BlitGenerateMipmapCommandGLES::GetLabel() const {
+  return label;
+}
+
+bool BlitGenerateMipmapCommandGLES::Encode(const ReactorGLES& reactor) const {
+  auto texture_gles = TextureGLES::Cast(texture.get());
+  if (!texture_gles->GenerateMipmaps()) {
+    return false;
+  }
+
+  return true;
+};
+
+}  // namespace impeller

impeller/renderer/backend/gles/blit_command_gles.h

@@ -0,0 +1,41 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#pragma once
+
+#include "impeller/base/backend_cast.h"
+#include "impeller/renderer/backend/gles/reactor_gles.h"
+#include "impeller/renderer/blit_command.h"
+
+namespace impeller {
+
+/// Mixin for dispatching GLES commands.
+struct BlitEncodeGLES : BackendCast<BlitEncodeGLES, BlitCommand> {
+  virtual ~BlitEncodeGLES();
+
+  virtual std::string GetLabel() const = 0;
+
+  [[nodiscard]] virtual bool Encode(const ReactorGLES& reactor) const = 0;
+};
+
+struct BlitCopyTextureToTextureCommandGLES
+    : public BlitEncodeGLES,
+      public BlitCopyTextureToTextureCommand {
+  ~BlitCopyTextureToTextureCommandGLES() override;
+
+  std::string GetLabel() const override;
+
+  [[nodiscard]] bool Encode(const ReactorGLES& reactor) const override;
+};
+
+struct BlitGenerateMipmapCommandGLES : public BlitEncodeGLES,
+                                       public BlitGenerateMipmapCommand {
+  ~BlitGenerateMipmapCommandGLES() override;
+
+  std::string GetLabel() const override;
+
+  [[nodiscard]] bool Encode(const ReactorGLES& reactor) const override;
+};
+
+}  // namespace impeller