Cleanup ContextCreationAttribs

Bunch of attributes are not used anymore:
* buffer_preserved is not read, nothing sets it to not default value
* single_buffer nothing sets it to not default value
* samples/sample_buffers/stencil_size/depth_size are default inited to
  -1 and only overridden to 0. Command decoders check if they are > 0,
  so that code is never reached.
* gpu::Capabilities::num_stencil_bits is not used.
* red/green/blue_bits are used only on android [1] and alpha_size is
  set to only on android.

This CL removes unused attributes and code that sets it in the client.
Immediate affected code from GLES2 decoders is also removed, to make
this compile, but extensive cleanup will be done in follow-up.

Color attributes are not really needed on Android either, but it's not
trivial clean up, so for now put them under BUILDFLAG(IS_ANDROID).

[1] https://source.chromium.org/chromium/chromium/src/+/refs/heads/main:gpu/ipc/service/gles2_command_buffer_stub.cc;l=140-144;drc=b8a0323a84f483b25e94b3a24d80fda16c5dd1ae;bpv=0;bpt=1

Bug: 1445523
Change-Id: Icc4d63922eff5b2b4702692316ac3ab3c21bd4aa
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4582013
Commit-Queue: Vasiliy Telezhnikov <vasilyt@chromium.org>
Reviewed-by: Justin Novosad <junov@chromium.org>
Reviewed-by: Colin Blundell <blundell@chromium.org>
Reviewed-by: danakj <danakj@chromium.org>
Reviewed-by: Bo Liu <boliu@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1154072}

chrome/browser/vr/win/graphics_delegate_win.cc

@@ -31,14 +31,6 @@ bool GraphicsDelegateWin::InitializeOnMainThread() {
   scoped_refptr<gpu::GpuChannelHost> host = factory->EstablishGpuChannelSync();
 
   gpu::ContextCreationAttribs attributes;
-  attributes.alpha_size = -1;
-  attributes.red_size = 8;
-  attributes.green_size = 8;
-  attributes.blue_size = 8;
-  attributes.stencil_size = 0;
-  attributes.depth_size = 0;
-  attributes.samples = 0;
-  attributes.sample_buffers = 0;
   attributes.bind_generates_resource = false;
 
   context_provider_ = base::MakeRefCounted<viz::ContextProviderCommandBuffer>(

components/webxr/android/openxr_device_provider.cc

@@ -88,10 +88,6 @@ void OpenXrDeviceProvider::CreateContextProviderAsync(
             attributes.red_size = 8;
             attributes.green_size = 8;
             attributes.blue_size = 8;
-            attributes.stencil_size = 0;
-            attributes.depth_size = 0;
-            attributes.samples = 0;
-            attributes.sample_buffers = 0;
             attributes.bind_generates_resource = false;
             if (base::SysInfo::IsLowEndDevice()) {
               attributes.alpha_size = 0;

components/webxr/mailbox_to_surface_bridge_impl.cc

@@ -250,10 +250,6 @@ void MailboxToSurfaceBridgeImpl::CreateAndBindContextProvider(
                        attributes.red_size = 8;
                        attributes.green_size = 8;
                        attributes.blue_size = 8;
-                       attributes.stencil_size = 0;
-                       attributes.depth_size = 0;
-                       attributes.samples = 0;
-                       attributes.sample_buffers = 0;
                        attributes.bind_generates_resource = false;
                        if (base::SysInfo::IsLowEndDevice()) {
                          attributes.alpha_size = 0;

content/browser/compositor/viz_process_transport_factory.cc

@@ -72,14 +72,8 @@ scoped_refptr<viz::ContextProviderCommandBuffer> CreateContextProvider(
   constexpr bool kAutomaticFlushes = false;
 
   gpu::ContextCreationAttribs attributes;
-  attributes.alpha_size = -1;
-  attributes.depth_size = 0;
-  attributes.stencil_size = 0;
-  attributes.samples = 0;
-  attributes.sample_buffers = 0;
   attributes.bind_generates_resource = false;
   attributes.lose_context_when_out_of_memory = true;
-  attributes.buffer_preserved = false;
   attributes.enable_gles2_interface = supports_gles2_interface;
   attributes.enable_raster_interface = supports_raster_interface;
   attributes.enable_oop_rasterization = supports_gpu_rasterization;

content/browser/media/android/browser_gpu_video_accelerator_factories.cc

@@ -28,10 +28,6 @@ void OnGpuChannelEstablished(
   attributes.red_size = 8;
   attributes.green_size = 8;
   attributes.blue_size = 8;
-  attributes.stencil_size = 0;
-  attributes.depth_size = 0;
-  attributes.samples = 0;
-  attributes.sample_buffers = 0;
   attributes.bind_generates_resource = false;
   attributes.enable_raster_interface = true;
 

content/browser/renderer_host/compositor_impl_android.cc

@@ -116,10 +116,6 @@ gpu::ContextCreationAttribs GetCompositorContextAttributes(
   // background.
   gpu::ContextCreationAttribs attributes;
   attributes.alpha_size = -1;
-  attributes.stencil_size = 0;
-  attributes.depth_size = 0;
-  attributes.samples = 0;
-  attributes.sample_buffers = 0;
   attributes.bind_generates_resource = false;
   attributes.color_space = gpu::COLOR_SPACE_SRGB;
 

content/renderer/render_thread_impl.cc

@@ -338,11 +338,6 @@ scoped_refptr<viz::ContextProviderCommandBuffer> CreateOffscreenContext(
   // This is for an offscreen context, so the default framebuffer doesn't need
   // alpha, depth, stencil, antialiasing.
   gpu::ContextCreationAttribs attributes;
-  attributes.alpha_size = -1;
-  attributes.depth_size = 0;
-  attributes.stencil_size = 0;
-  attributes.samples = 0;
-  attributes.sample_buffers = 0;
   attributes.bind_generates_resource = false;
   attributes.lose_context_when_out_of_memory = true;
   attributes.enable_gles2_interface = support_gles2_interface;

content/renderer/renderer_blink_platform_impl.cc

@@ -665,11 +665,6 @@ RendererBlinkPlatformImpl::CreateOffscreenGraphicsContext3DProvider(
   Collect3DContextInformation(gl_info, gpu_channel_host->gpu_info());
 
   gpu::ContextCreationAttribs attributes;
-  attributes.alpha_size = -1;
-  attributes.depth_size = 0;
-  attributes.stencil_size = 0;
-  attributes.samples = 0;
-  attributes.sample_buffers = 0;
   attributes.bind_generates_resource = false;
   attributes.enable_raster_interface = web_attributes.enable_raster_interface;
   attributes.enable_oop_rasterization =

gpu/command_buffer/common/capabilities.h

@@ -90,7 +90,6 @@ struct GPU_EXPORT Capabilities {
   int max_viewport_height = 0;
   int num_compressed_texture_formats = 0;
   int num_shader_binary_formats = 0;
-  int num_stencil_bits = 0;  // For the default framebuffer.
   int bind_generates_resource_chromium = 0;
 
   int max_3d_texture_size = 0;

gpu/command_buffer/common/context_creation_attribs.h

@@ -7,6 +7,7 @@
 
 #include <stdint.h>
 
+#include "build/build_config.h"
 #include "gpu/gpu_export.h"
 #include "ui/gfx/geometry/size.h"
 #include "ui/gl/gpu_preference.h"
@@ -48,19 +49,14 @@ struct GPU_EXPORT ContextCreationAttribs {
   gl::GpuPreference gpu_preference = gl::GpuPreference::kLowPower;
   // -1 if invalid or unspecified.
   int32_t alpha_size = -1;
+#if BUILDFLAG(IS_ANDROID)
   int32_t blue_size = -1;
   int32_t green_size = -1;
   int32_t red_size = -1;
-  int32_t depth_size = -1;
-  int32_t stencil_size = -1;
-  int32_t samples = -1;
-  int32_t sample_buffers = -1;
-  bool buffer_preserved = true;
+#endif
   bool bind_generates_resource = true;
   bool fail_if_major_perf_caveat = false;
   bool lose_context_when_out_of_memory = false;
-  bool should_use_native_gmb_for_backbuffer = false;
-  bool single_buffer = false;
   bool enable_gles2_interface = true;
   bool enable_grcontext = false;
   bool enable_raster_interface = false;

gpu/command_buffer/service/gles2_cmd_decoder.cc

@@ -3606,16 +3606,7 @@ gpu::ContextResult GLES2DecoderImpl::Initialize(
   }
   CHECK_GL_ERROR();
 
-  should_use_native_gmb_for_backbuffer_ =
-      attrib_helper.should_use_native_gmb_for_backbuffer;
-
-#if !BUILDFLAG(IS_OZONE)
-  if (should_use_native_gmb_for_backbuffer_) {
-    LOG(ERROR) << "ContextResult::kFatalFailure: "
-                  "native gmb format not supported";
-    return gpu::ContextResult::kFatalFailure;
-  }
-#endif
+  should_use_native_gmb_for_backbuffer_ = false;
 
   // In theory |needs_emulation| needs to be true on Desktop GL 4.1 or lower.
   // However, we set it to true everywhere, not to trust drivers to handle
@@ -3738,20 +3729,12 @@ gpu::ContextResult GLES2DecoderImpl::Initialize(
   GLint alpha_bits = 0;
 
   if (offscreen) {
+#if BUILDFLAG(IS_ANDROID)
     offscreen_buffer_should_have_alpha_ = attrib_helper.alpha_size > 0;
-
-    if (attrib_helper.samples > 0 && attrib_helper.sample_buffers > 0 &&
-        features().chromium_framebuffer_multisample) {
-      // Per ext_framebuffer_multisample spec, need max bound on sample count.
-      // max_sample_count must be initialized to a sane value.  If
-      // glGetIntegerv() throws a GL error, it leaves its argument unchanged.
-      GLint max_sample_count = 0;
-      api()->glGetIntegervFn(GL_MAX_SAMPLES_EXT, &max_sample_count);
-      offscreen_target_samples_ = std::min(attrib_helper.samples,
-                                           max_sample_count);
-    } else {
-      offscreen_target_samples_ = 0;
-    }
+#else
+    offscreen_buffer_should_have_alpha_ = false;
+#endif
+    offscreen_target_samples_ = 0;
 
     if (gl_version_info().is_es) {
       const bool rgb8_supported = features().oes_rgb8_rgba8;
@@ -3776,18 +3759,9 @@ gpu::ContextResult GLES2DecoderImpl::Initialize(
           feature_info_->feature_flags().packed_depth24_stencil8;
       VLOG(1) << "GL_OES_packed_depth_stencil "
               << (depth24_stencil8_supported ? "" : "not ") << "supported.";
-      if ((attrib_helper.depth_size > 0 || attrib_helper.stencil_size > 0) &&
-          depth24_stencil8_supported) {
-        offscreen_target_depth_format_ = GL_DEPTH24_STENCIL8;
-        offscreen_target_stencil_format_ = 0;
-      } else {
-        // It may be the case that this depth/stencil combination is not
-        // supported, but this will be checked later by CheckFramebufferStatus.
-        offscreen_target_depth_format_ = attrib_helper.depth_size > 0 ?
-            GL_DEPTH_COMPONENT16 : 0;
-        offscreen_target_stencil_format_ = attrib_helper.stencil_size > 0 ?
-            GL_STENCIL_INDEX8 : 0;
-      }
+
+      offscreen_target_depth_format_ = 0;
+      offscreen_target_stencil_format_ = 0;
     } else {
       offscreen_target_color_format_ =
           offscreen_buffer_should_have_alpha_ ||
@@ -3803,16 +3777,8 @@ gpu::ContextResult GLES2DecoderImpl::Initialize(
       VLOG(1) << "GL_EXT_packed_depth_stencil "
               << (depth24_stencil8_supported ? "" : "not ") << "supported.";
 
-      if ((attrib_helper.depth_size > 0 || attrib_helper.stencil_size > 0) &&
-          depth24_stencil8_supported) {
-        offscreen_target_depth_format_ = GL_DEPTH24_STENCIL8;
-        offscreen_target_stencil_format_ = 0;
-      } else {
-        offscreen_target_depth_format_ = attrib_helper.depth_size > 0 ?
-            GL_DEPTH_COMPONENT : 0;
-        offscreen_target_stencil_format_ = attrib_helper.stencil_size > 0 ?
-            GL_STENCIL_INDEX : 0;
-      }
+      offscreen_target_depth_format_ = 0;
+      offscreen_target_stencil_format_ = 0;
     }
 
     offscreen_saved_color_format_ = offscreen_buffer_should_have_alpha_ ||
@@ -3874,7 +3840,7 @@ gpu::ContextResult GLES2DecoderImpl::Initialize(
       back_buffer_has_stencil_ = stencil_bits > 0;
       num_stencil_bits_ = stencil_bits;
     } else {
-      num_stencil_bits_ = attrib_helper.stencil_size;
+      num_stencil_bits_ = 0;
     }
 
     state_.viewport_width = surface->GetSize().width();
@@ -3959,14 +3925,12 @@ gpu::ContextResult GLES2DecoderImpl::Initialize(
         std::make_unique<BackRenderbuffer>(this);
     offscreen_target_stencil_render_buffer_->Create();
 
-    if (!attrib_helper.single_buffer) {
-      // Create the saved offscreen texture. The target frame buffer is copied
-      // here when SwapBuffers is called.
-      offscreen_saved_frame_buffer_ = std::make_unique<BackFramebuffer>(this);
-      offscreen_saved_frame_buffer_->Create();
-      offscreen_saved_color_texture_ = std::make_unique<BackTexture>(this);
-      offscreen_saved_color_texture_->Create();
-    }
+    // Create the saved offscreen texture. The target frame buffer is copied
+    // here when SwapBuffers is called.
+    offscreen_saved_frame_buffer_ = std::make_unique<BackFramebuffer>(this);
+    offscreen_saved_frame_buffer_->Create();
+    offscreen_saved_color_texture_ = std::make_unique<BackTexture>(this);
+    offscreen_saved_color_texture_->Create();
 
     // Allocate the render buffers at their initial size and check the status
     // of the frame buffers is okay.
@@ -3976,25 +3940,24 @@ gpu::ContextResult GLES2DecoderImpl::Initialize(
                     "Could not allocate offscreen buffer storage.";
       return gpu::ContextResult::kFatalFailure;
     }
-    if (!attrib_helper.single_buffer) {
-      // Allocate the offscreen saved color texture.
-      DCHECK(offscreen_saved_color_format_);
-      // Use 64x64 instead of 1x1 to handle minimum framebuffer size
-      // requirement on some platforms: b/151774454
-      offscreen_saved_color_texture_->AllocateStorage(
-          gfx::Size(64, 64), offscreen_saved_color_format_, true);
 
-      offscreen_saved_frame_buffer_->AttachRenderTexture(
-          offscreen_saved_color_texture_.get());
-      if (offscreen_saved_frame_buffer_->CheckStatus() !=
-          GL_FRAMEBUFFER_COMPLETE) {
-        bool was_lost = CheckResetStatus();
-        LOG(ERROR) << (was_lost ? "ContextResult::kTransientFailure: "
-                                : "ContextResult::kFatalFailure: ")
-                   << "Offscreen saved FBO was incomplete.";
-        return was_lost ? gpu::ContextResult::kTransientFailure
-                        : gpu::ContextResult::kFatalFailure;
-      }
+    // Allocate the offscreen saved color texture.
+    DCHECK(offscreen_saved_color_format_);
+    // Use 64x64 instead of 1x1 to handle minimum framebuffer size
+    // requirement on some platforms: b/151774454
+    offscreen_saved_color_texture_->AllocateStorage(
+        gfx::Size(64, 64), offscreen_saved_color_format_, true);
+
+    offscreen_saved_frame_buffer_->AttachRenderTexture(
+        offscreen_saved_color_texture_.get());
+    if (offscreen_saved_frame_buffer_->CheckStatus() !=
+        GL_FRAMEBUFFER_COMPLETE) {
+      bool was_lost = CheckResetStatus();
+      LOG(ERROR) << (was_lost ? "ContextResult::kTransientFailure: "
+                              : "ContextResult::kFatalFailure: ")
+                 << "Offscreen saved FBO was incomplete.";
+      return was_lost ? gpu::ContextResult::kTransientFailure
+                      : gpu::ContextResult::kFatalFailure;
     }
   }
 
@@ -4189,8 +4152,6 @@ Capabilities GLES2DecoderImpl::GetCapabilities() {
     caps.max_samples = ComputeMaxSamples();
   }
 
-  caps.num_stencil_bits = num_stencil_bits_;
-
   caps.egl_image_external =
       feature_info_->feature_flags().oes_egl_image_external;
   caps.egl_image_external_essl3 =

gpu/command_buffer/service/gles2_cmd_decoder_passthrough.cc

@@ -1245,18 +1245,12 @@ gpu::ContextResult GLES2DecoderPassthroughImpl::Initialize(
       std::min(max_2d_texture_size, max_renderbuffer_size_);
 
   if (offscreen_) {
-    const bool multisampled_framebuffers_supported =
-        feature_info_->feature_flags().chromium_framebuffer_multisample;
-    if (attrib_helper.samples > 0 && attrib_helper.sample_buffers > 0 &&
-        multisampled_framebuffers_supported && !attrib_helper.single_buffer) {
-      GLint max_sample_count = 0;
-      api()->glGetIntegervFn(GL_MAX_SAMPLES_EXT, &max_sample_count);
-      emulated_default_framebuffer_format_.samples =
-          std::min(attrib_helper.samples, max_sample_count);
-    }
-
     const bool rgb8_supported = feature_info_->feature_flags().oes_rgb8_rgba8;
+#if BUILDFLAG(IS_ANDROID)
     const bool alpha_channel_requested = attrib_helper.alpha_size > 0;
+#else
+    const bool alpha_channel_requested = false;
+#endif
     // The only available default render buffer formats in GLES2 have very
     // little precision.  Don't enable multisampling unless 8-bit render
     // buffer formats are available--instead fall back to 8-bit textures.
@@ -1273,25 +1267,6 @@ gpu::ContextResult GLES2DecoderPassthroughImpl::Initialize(
         emulated_default_framebuffer_format_.color_texture_internal_format;
     emulated_default_framebuffer_format_.color_texture_type = GL_UNSIGNED_BYTE;
 
-    const bool depth24_stencil8_supported =
-        feature_info_->feature_flags().packed_depth24_stencil8;
-    if ((attrib_helper.depth_size > 0 || attrib_helper.stencil_size > 0) &&
-        depth24_stencil8_supported) {
-      emulated_default_framebuffer_format_.depth_stencil_internal_format =
-          GL_DEPTH24_STENCIL8;
-    } else {
-      // It may be the case that this depth/stencil combination is not
-      // supported, but this will be checked later by CheckFramebufferStatus.
-      if (attrib_helper.depth_size > 0) {
-        emulated_default_framebuffer_format_.depth_internal_format =
-            GL_DEPTH_COMPONENT16;
-      }
-      if (attrib_helper.stencil_size > 0) {
-        emulated_default_framebuffer_format_.stencil_internal_format =
-            GL_STENCIL_INDEX8;
-      }
-    }
-
     CheckErrorCallbackState();
     emulated_back_buffer_ = std::make_unique<EmulatedDefaultFramebuffer>(this);
     // If we're an offscreen surface with zero width and/or height, set to a

gpu/command_buffer/tests/fuzzer_main.cc

@@ -231,15 +231,13 @@ class BitIterator {
 struct Config {
   size_t MakeFromBits(const uint8_t* bits, size_t size) {
     BitIterator it(bits, size);
+#if BUILDFLAG(IS_ANDROID)
     attrib_helper.red_size = 8;
     attrib_helper.green_size = 8;
     attrib_helper.blue_size = 8;
     attrib_helper.alpha_size = it.GetBit() ? 8 : 0;
-    attrib_helper.depth_size = it.GetBit() ? 24 : 0;
-    attrib_helper.stencil_size = it.GetBit() ? 8 : 0;
-    attrib_helper.buffer_preserved = it.GetBit();
+#endif
     attrib_helper.bind_generates_resource = it.GetBit();
-    attrib_helper.single_buffer = it.GetBit();
     [[maybe_unused]] bool es3 = it.GetBit();
 #if defined(GPU_FUZZER_USE_RASTER_DECODER)
     attrib_helper.context_type = CONTEXT_TYPE_OPENGLES2;

gpu/gles2_conform_support/egl/context.cc

@@ -287,7 +287,6 @@ bool Context::CreateService(gl::GLSurface* gl_surface) {
   CHECK_EQ(stencil_size, 0);
 
   gpu::ContextCreationAttribs helper;
-  helper.buffer_preserved = false;
   helper.bind_generates_resource = kBindGeneratesResources;
   helper.fail_if_major_perf_caveat = false;
   helper.lose_context_when_out_of_memory = kLoseContextWhenOutOfMemory;