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Jonah Williams
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[Impeller] Use a device buffer for SkBitmap allocation, use Linear texture on Metal backend. (#41374)
This reduces the cost of uploading the glyph atlas, as we can exploit metal's capabilies to create a texture from a device buffer and share the underlying memory with a linear texture. This also means that subsequent updates don't require uploads or copies either. From scrolling through wonderous, this shaves off about 0.2 ms (0.6 ms -> 0.4 ms) of fresh atlas construction.
1 parent ff92235 commit fddd5ad

14 files changed

Lines changed: 275 additions & 85 deletions

‎impeller/renderer/backend/metal/context_mtl.mm‎

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@@ -55,6 +55,7 @@ static bool DeviceSupportsComputeSubgroups(id<MTLDevice> device) {
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.SetSupportsBufferToTextureBlits(true)
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.SetSupportsTextureToTextureBlits(true)
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.SetSupportsDecalTileMode(true)
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.SetSupportsSharedDeviceBufferTextureMemory(true)
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.SetSupportsFramebufferFetch(DeviceSupportsFramebufferFetch(device))
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.SetDefaultColorFormat(color_format)
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.SetDefaultStencilFormat(PixelFormat::kS8UInt)

‎impeller/renderer/backend/vulkan/capabilities_vk.cc‎

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@@ -348,10 +348,16 @@ bool CapabilitiesVK::SupportsReadFromOnscreenTexture() const {
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return false;
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}
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// |Capabilities|
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bool CapabilitiesVK::SupportsDecalTileMode() const {
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return true;
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}
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// |Capabilities|
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bool CapabilitiesVK::SupportsSharedDeviceBufferTextureMemory() const {
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return false;
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}
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// |Capabilities|
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PixelFormat CapabilitiesVK::GetDefaultColorFormat() const {
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return color_format_;

‎impeller/renderer/backend/vulkan/capabilities_vk.h‎

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@@ -79,6 +79,9 @@ class CapabilitiesVK final : public Capabilities,
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// |Capabilities|
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bool SupportsDecalTileMode() const override;
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// |Capabilities|
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bool SupportsSharedDeviceBufferTextureMemory() const override;
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// |Capabilities|
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PixelFormat GetDefaultColorFormat() const override;
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‎impeller/renderer/capabilities.cc‎

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@@ -66,6 +66,11 @@ class StandardCapabilities final : public Capabilities {
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return supports_decal_tile_mode_;
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}
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// |Capabilities|
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bool SupportsSharedDeviceBufferTextureMemory() const override {
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return supports_shared_device_buffer_texture_memory_;
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}
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// |Capabilities|
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PixelFormat GetDefaultColorFormat() const override {
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return default_color_format_;
@@ -88,6 +93,7 @@ class StandardCapabilities final : public Capabilities {
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bool supports_read_from_onscreen_texture,
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bool supports_read_from_resolve,
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bool supports_decal_tile_mode,
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bool supports_shared_device_buffer_texture_memory,
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PixelFormat default_color_format,
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PixelFormat default_stencil_format)
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: has_threading_restrictions_(has_threading_restrictions),
@@ -102,6 +108,8 @@ class StandardCapabilities final : public Capabilities {
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supports_read_from_onscreen_texture),
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supports_read_from_resolve_(supports_read_from_resolve),
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supports_decal_tile_mode_(supports_decal_tile_mode),
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supports_shared_device_buffer_texture_memory_(
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supports_shared_device_buffer_texture_memory),
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default_color_format_(default_color_format),
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default_stencil_format_(default_stencil_format) {}
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@@ -118,6 +126,7 @@ class StandardCapabilities final : public Capabilities {
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bool supports_read_from_onscreen_texture_ = false;
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bool supports_read_from_resolve_ = false;
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bool supports_decal_tile_mode_ = false;
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bool supports_shared_device_buffer_texture_memory_ = false;
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PixelFormat default_color_format_ = PixelFormat::kUnknown;
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PixelFormat default_stencil_format_ = PixelFormat::kUnknown;
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@@ -202,6 +211,12 @@ CapabilitiesBuilder& CapabilitiesBuilder::SetSupportsDecalTileMode(bool value) {
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return *this;
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}
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CapabilitiesBuilder&
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CapabilitiesBuilder::SetSupportsSharedDeviceBufferTextureMemory(bool value) {
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supports_shared_device_buffer_texture_memory_ = value;
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return *this;
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}
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std::unique_ptr<Capabilities> CapabilitiesBuilder::Build() {
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return std::unique_ptr<StandardCapabilities>(new StandardCapabilities( //
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has_threading_restrictions_, //
@@ -215,6 +230,7 @@ std::unique_ptr<Capabilities> CapabilitiesBuilder::Build() {
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supports_read_from_onscreen_texture_, //
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supports_read_from_resolve_, //
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supports_decal_tile_mode_, //
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supports_shared_device_buffer_texture_memory_, //
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*default_color_format_, //
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*default_stencil_format_ //
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));

‎impeller/renderer/capabilities.h‎

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@@ -37,6 +37,8 @@ class Capabilities {
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virtual bool SupportsDecalTileMode() const = 0;
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virtual bool SupportsSharedDeviceBufferTextureMemory() const = 0;
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virtual PixelFormat GetDefaultColorFormat() const = 0;
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virtual PixelFormat GetDefaultStencilFormat() const = 0;
@@ -79,6 +81,8 @@ class CapabilitiesBuilder {
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CapabilitiesBuilder& SetSupportsDecalTileMode(bool value);
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CapabilitiesBuilder& SetSupportsSharedDeviceBufferTextureMemory(bool value);
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std::unique_ptr<Capabilities> Build();
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private:
@@ -93,6 +97,7 @@ class CapabilitiesBuilder {
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bool supports_read_from_onscreen_texture_ = false;
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bool supports_read_from_resolve_ = false;
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bool supports_decal_tile_mode_ = false;
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bool supports_shared_device_buffer_texture_memory_ = false;
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std::optional<PixelFormat> default_color_format_ = std::nullopt;
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std::optional<PixelFormat> default_stencil_format_ = std::nullopt;
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‎impeller/renderer/capabilities_unittests.cc‎

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@@ -29,6 +29,7 @@ CAPABILITY_TEST(SupportsComputeSubgroups, false);
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CAPABILITY_TEST(SupportsReadFromOnscreenTexture, false);
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CAPABILITY_TEST(SupportsReadFromResolve, false);
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CAPABILITY_TEST(SupportsDecalTileMode, false);
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CAPABILITY_TEST(SupportsSharedDeviceBufferTextureMemory, false);
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} // namespace testing
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} // namespace impeller

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