Merge "Add libtonemap library"
diff --git a/libs/renderengine/Android.bp b/libs/renderengine/Android.bp
index a62d2b9..ecfaef8 100644
--- a/libs/renderengine/Android.bp
+++ b/libs/renderengine/Android.bp
@@ -40,6 +40,10 @@
"libui",
"libutils",
],
+
+ static_libs: [
+ "libtonemap",
+ ],
local_include_dirs: ["include"],
export_include_dirs: ["include"],
}
@@ -97,7 +101,7 @@
"skia/filters/GaussianBlurFilter.cpp",
"skia/filters/KawaseBlurFilter.cpp",
"skia/filters/LinearEffect.cpp",
- "skia/filters/StretchShaderFactory.cpp"
+ "skia/filters/StretchShaderFactory.cpp",
],
}
diff --git a/libs/renderengine/benchmark/Android.bp b/libs/renderengine/benchmark/Android.bp
index 5968399..baa5054 100644
--- a/libs/renderengine/benchmark/Android.bp
+++ b/libs/renderengine/benchmark/Android.bp
@@ -23,7 +23,10 @@
cc_benchmark {
name: "librenderengine_bench",
- defaults: ["skia_deps", "surfaceflinger_defaults"],
+ defaults: [
+ "skia_deps",
+ "surfaceflinger_defaults",
+ ],
srcs: [
"main.cpp",
"Codec.cpp",
@@ -32,6 +35,7 @@
],
static_libs: [
"librenderengine",
+ "libtonemap",
],
cflags: [
"-DLOG_TAG=\"RenderEngineBench\"",
@@ -50,5 +54,5 @@
"libutils",
],
- data: [ "resources/*"],
+ data: ["resources/*"],
}
diff --git a/libs/renderengine/skia/filters/LinearEffect.cpp b/libs/renderengine/skia/filters/LinearEffect.cpp
index 73dadef..53136e4 100644
--- a/libs/renderengine/skia/filters/LinearEffect.cpp
+++ b/libs/renderengine/skia/filters/LinearEffect.cpp
@@ -19,6 +19,7 @@
#define ATRACE_TAG ATRACE_TAG_GRAPHICS
#include <SkString.h>
+#include <tonemap/tonemap.h>
#include <utils/Trace.h>
#include <optional>
@@ -32,6 +33,11 @@
namespace renderengine {
namespace skia {
+static aidl::android::hardware::graphics::common::Dataspace toAidlDataspace(
+ ui::Dataspace dataspace) {
+ return static_cast<aidl::android::hardware::graphics::common::Dataspace>(dataspace);
+}
+
static void generateEOTF(ui::Dataspace dataspace, SkString& shader) {
switch (dataspace & HAL_DATASPACE_TRANSFER_MASK) {
case HAL_DATASPACE_TRANSFER_ST2084:
@@ -127,159 +133,13 @@
default:
shader.append(R"(
float3 ScaleLuminance(float3 xyz) {
- return xyz * in_inputMaxLuminance;
+ return xyz * in_libtonemap_inputMaxLuminance;
}
)");
break;
}
}
-static void generateToneMapInterpolation(ui::Dataspace inputDataspace,
- ui::Dataspace outputDataspace, SkString& shader) {
- switch (inputDataspace & HAL_DATASPACE_TRANSFER_MASK) {
- case HAL_DATASPACE_TRANSFER_ST2084:
- case HAL_DATASPACE_TRANSFER_HLG:
- switch (outputDataspace & HAL_DATASPACE_TRANSFER_MASK) {
- case HAL_DATASPACE_TRANSFER_ST2084:
- shader.append(R"(
- float3 ToneMap(float3 xyz) {
- return xyz;
- }
- )");
- break;
- case HAL_DATASPACE_TRANSFER_HLG:
- // PQ has a wider luminance range (10,000 nits vs. 1,000 nits) than HLG, so
- // we'll clamp the luminance range in case we're mapping from PQ input to HLG
- // output.
- shader.append(R"(
- float3 ToneMap(float3 xyz) {
- return clamp(xyz, 0.0, 1000.0);
- }
- )");
- break;
- default:
- // Here we're mapping from HDR to SDR content, so interpolate using a Hermitian
- // polynomial onto the smaller luminance range.
- shader.append(R"(
- float3 ToneMap(float3 xyz) {
- float maxInLumi = in_inputMaxLuminance;
- float maxOutLumi = in_displayMaxLuminance;
-
- float nits = xyz.y;
-
- // if the max input luminance is less than what we can output then
- // no tone mapping is needed as all color values will be in range.
- if (maxInLumi <= maxOutLumi) {
- return xyz;
- } else {
-
- // three control points
- const float x0 = 10.0;
- const float y0 = 17.0;
- float x1 = maxOutLumi * 0.75;
- float y1 = x1;
- float x2 = x1 + (maxInLumi - x1) / 2.0;
- float y2 = y1 + (maxOutLumi - y1) * 0.75;
-
- // horizontal distances between the last three control points
- float h12 = x2 - x1;
- float h23 = maxInLumi - x2;
- // tangents at the last three control points
- float m1 = (y2 - y1) / h12;
- float m3 = (maxOutLumi - y2) / h23;
- float m2 = (m1 + m3) / 2.0;
-
- if (nits < x0) {
- // scale [0.0, x0] to [0.0, y0] linearly
- float slope = y0 / x0;
- return xyz * slope;
- } else if (nits < x1) {
- // scale [x0, x1] to [y0, y1] linearly
- float slope = (y1 - y0) / (x1 - x0);
- nits = y0 + (nits - x0) * slope;
- } else if (nits < x2) {
- // scale [x1, x2] to [y1, y2] using Hermite interp
- float t = (nits - x1) / h12;
- nits = (y1 * (1.0 + 2.0 * t) + h12 * m1 * t) * (1.0 - t) * (1.0 - t) +
- (y2 * (3.0 - 2.0 * t) + h12 * m2 * (t - 1.0)) * t * t;
- } else {
- // scale [x2, maxInLumi] to [y2, maxOutLumi] using Hermite interp
- float t = (nits - x2) / h23;
- nits = (y2 * (1.0 + 2.0 * t) + h23 * m2 * t) * (1.0 - t) * (1.0 - t) +
- (maxOutLumi * (3.0 - 2.0 * t) + h23 * m3 * (t - 1.0)) * t * t;
- }
- }
-
- // color.y is greater than x0 and is thus non-zero
- return xyz * (nits / xyz.y);
- }
- )");
- break;
- }
- break;
- default:
- switch (outputDataspace & HAL_DATASPACE_TRANSFER_MASK) {
- case HAL_DATASPACE_TRANSFER_ST2084:
- case HAL_DATASPACE_TRANSFER_HLG:
- // Map from SDR onto an HDR output buffer
- // Here we use a polynomial curve to map from [0, displayMaxLuminance] onto
- // [0, maxOutLumi] which is hard-coded to be 3000 nits.
- shader.append(R"(
- float3 ToneMap(float3 xyz) {
- const float maxOutLumi = 3000.0;
-
- const float x0 = 5.0;
- const float y0 = 2.5;
- float x1 = in_displayMaxLuminance * 0.7;
- float y1 = maxOutLumi * 0.15;
- float x2 = in_displayMaxLuminance * 0.9;
- float y2 = maxOutLumi * 0.45;
- float x3 = in_displayMaxLuminance;
- float y3 = maxOutLumi;
-
- float c1 = y1 / 3.0;
- float c2 = y2 / 2.0;
- float c3 = y3 / 1.5;
-
- float nits = xyz.y;
-
- if (nits <= x0) {
- // scale [0.0, x0] to [0.0, y0] linearly
- float slope = y0 / x0;
- return xyz * slope;
- } else if (nits <= x1) {
- // scale [x0, x1] to [y0, y1] using a curve
- float t = (nits - x0) / (x1 - x0);
- nits = (1.0 - t) * (1.0 - t) * y0 + 2.0 * (1.0 - t) * t * c1 + t * t * y1;
- } else if (nits <= x2) {
- // scale [x1, x2] to [y1, y2] using a curve
- float t = (nits - x1) / (x2 - x1);
- nits = (1.0 - t) * (1.0 - t) * y1 + 2.0 * (1.0 - t) * t * c2 + t * t * y2;
- } else {
- // scale [x2, x3] to [y2, y3] using a curve
- float t = (nits - x2) / (x3 - x2);
- nits = (1.0 - t) * (1.0 - t) * y2 + 2.0 * (1.0 - t) * t * c3 + t * t * y3;
- }
-
- // xyz.y is greater than x0 and is thus non-zero
- return xyz * (nits / xyz.y);
- }
- )");
- break;
- default:
- // For completeness, this is tone-mapping from SDR to SDR, where this is just a
- // no-op.
- shader.append(R"(
- float3 ToneMap(float3 xyz) {
- return xyz;
- }
- )");
- break;
- }
- break;
- }
-}
-
// Normalizes from absolute light back to relative light (maps from [0, maxNits] back to [0, 1])
static void generateLuminanceNormalizationForOOTF(ui::Dataspace outputDataspace, SkString& shader) {
switch (outputDataspace & HAL_DATASPACE_TRANSFER_MASK) {
@@ -300,7 +160,7 @@
default:
shader.append(R"(
float3 NormalizeLuminance(float3 xyz) {
- return xyz / in_displayMaxLuminance;
+ return xyz / in_libtonemap_displayMaxLuminance;
}
)");
break;
@@ -309,19 +169,22 @@
static void generateOOTF(ui::Dataspace inputDataspace, ui::Dataspace outputDataspace,
SkString& shader) {
- // Input uniforms
- shader.append(R"(
- uniform float in_displayMaxLuminance;
- uniform float in_inputMaxLuminance;
- )");
+ shader.append(tonemap::getToneMapper()
+ ->generateTonemapGainShaderSkSL(toAidlDataspace(inputDataspace),
+ toAidlDataspace(outputDataspace))
+ .c_str());
generateLuminanceScalesForOOTF(inputDataspace, shader);
- generateToneMapInterpolation(inputDataspace, outputDataspace, shader);
generateLuminanceNormalizationForOOTF(outputDataspace, shader);
shader.append(R"(
- float3 OOTF(float3 xyz) {
- return NormalizeLuminance(ToneMap(ScaleLuminance(xyz)));
+ float3 OOTF(float3 linearRGB, float3 xyz) {
+ float3 scaledLinearRGB = ScaleLuminance(linearRGB);
+ float3 scaledXYZ = ScaleLuminance(xyz);
+
+ float gain = libtonemap_LookupTonemapGain(scaledLinearRGB, scaledXYZ);
+
+ return NormalizeLuminance(scaledXYZ * gain);
}
)");
}
@@ -399,7 +262,9 @@
)");
}
shader.append(R"(
- c.rgb = OETF(ToRGB(OOTF(ToXYZ(EOTF(c.rgb)))));
+ float3 linearRGB = EOTF(c.rgb);
+ float3 xyz = ToXYZ(linearRGB);
+ c.rgb = OETF(ToRGB(OOTF(linearRGB, xyz)));
)");
if (undoPremultipliedAlpha) {
shader.append(R"(
@@ -465,11 +330,20 @@
colorTransform * mat4(outputColorSpace.getXYZtoRGB());
}
- effectBuilder.uniform("in_displayMaxLuminance") = maxDisplayLuminance;
- // If the input luminance is unknown, use display luminance (aka, no-op any luminance changes)
- // This will be the case for eg screenshots in addition to uncalibrated displays
- effectBuilder.uniform("in_inputMaxLuminance") =
- maxLuminance > 0 ? maxLuminance : maxDisplayLuminance;
+ tonemap::Metadata metadata{.displayMaxLuminance = maxDisplayLuminance,
+ // If the input luminance is unknown, use display luminance (aka,
+ // no-op any luminance changes)
+ // This will be the case for eg screenshots in addition to
+ // uncalibrated displays
+ .contentMaxLuminance =
+ maxLuminance > 0 ? maxLuminance : maxDisplayLuminance};
+
+ const auto uniforms = tonemap::getToneMapper()->generateShaderSkSLUniforms(metadata);
+
+ for (const auto& uniform : uniforms) {
+ effectBuilder.uniform(uniform.name.c_str()).set(uniform.value.data(), uniform.value.size());
+ }
+
return effectBuilder.makeShader(nullptr, false);
}
diff --git a/libs/renderengine/tests/Android.bp b/libs/renderengine/tests/Android.bp
index d0e19dd..52b6c8f 100644
--- a/libs/renderengine/tests/Android.bp
+++ b/libs/renderengine/tests/Android.bp
@@ -23,7 +23,10 @@
cc_test {
name: "librenderengine_test",
- defaults: ["skia_deps", "surfaceflinger_defaults"],
+ defaults: [
+ "skia_deps",
+ "surfaceflinger_defaults",
+ ],
test_suites: ["device-tests"],
srcs: [
"RenderEngineTest.cpp",
@@ -36,6 +39,7 @@
"libgmock",
"librenderengine",
"librenderengine_mocks",
+ "libtonemap",
],
shared_libs: [
diff --git a/libs/tonemap/Android.bp b/libs/tonemap/Android.bp
new file mode 100644
index 0000000..231a342
--- /dev/null
+++ b/libs/tonemap/Android.bp
@@ -0,0 +1,37 @@
+// Copyright 2021 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package {
+ // See: http://go/android-license-faq
+ // A large-scale-change added 'default_applicable_licenses' to import
+ // all of the 'license_kinds' from "frameworks_native_license"
+ // to get the below license kinds:
+ // SPDX-license-identifier-Apache-2.0
+ default_applicable_licenses: ["frameworks_native_license"],
+}
+
+cc_library_static {
+ name: "libtonemap",
+ vendor_available: true,
+
+ export_include_dirs: ["include"],
+ local_include_dirs: ["include"],
+
+ shared_libs: [
+ "android.hardware.graphics.common-V3-ndk",
+ ],
+ srcs: [
+ "tonemap.cpp",
+ ],
+}
diff --git a/libs/tonemap/OWNERS b/libs/tonemap/OWNERS
new file mode 100644
index 0000000..6d91da3
--- /dev/null
+++ b/libs/tonemap/OWNERS
@@ -0,0 +1,4 @@
+alecmouri@google.com
+jreck@google.com
+sallyqi@google.com
+scroggo@google.com
\ No newline at end of file
diff --git a/libs/tonemap/TEST_MAPPING b/libs/tonemap/TEST_MAPPING
new file mode 100644
index 0000000..00f83ba
--- /dev/null
+++ b/libs/tonemap/TEST_MAPPING
@@ -0,0 +1,10 @@
+{
+ "presubmit": [
+ {
+ "name": "librenderengine_test"
+ },
+ {
+ "name": "libtonemap_test"
+ }
+ ]
+}
diff --git a/libs/tonemap/include/tonemap/tonemap.h b/libs/tonemap/include/tonemap/tonemap.h
new file mode 100644
index 0000000..d350e16
--- /dev/null
+++ b/libs/tonemap/include/tonemap/tonemap.h
@@ -0,0 +1,103 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <aidl/android/hardware/graphics/common/Dataspace.h>
+
+#include <string>
+#include <vector>
+
+namespace android::tonemap {
+
+// Describes a shader uniform
+// The shader uniform is intended to be passed into a SkRuntimeShaderBuilder, i.e.:
+//
+// SkRuntimeShaderBuilder builder;
+// builder.uniform(<uniform name>).set(<uniform value>.data(), <uniform value>.size());
+struct ShaderUniform {
+ // The name of the uniform, used for binding into a shader.
+ // The shader must contain a uniform whose name matches this.
+ std::string name;
+
+ // The value for the uniform, which should be bound to the uniform identified by <name>
+ std::vector<uint8_t> value;
+};
+
+// Describes metadata which may be used for constructing the shader uniforms.
+// This metadata should not be used for manipulating the source code of the shader program directly,
+// as otherwise caching by other system of these shaders may break.
+struct Metadata {
+ float displayMaxLuminance = 0.0;
+ float contentMaxLuminance = 0.0;
+};
+
+class ToneMapper {
+public:
+ virtual ~ToneMapper() {}
+ // Constructs a tonemap shader whose shader language is SkSL
+ //
+ // The returned shader string *must* contain a function with the following signature:
+ // float libtonemap_LookupTonemapGain(vec3 linearRGB, vec3 xyz);
+ //
+ // The arguments are:
+ // * linearRGB is the absolute nits of the RGB pixels in linear space
+ // * xyz is linearRGB converted into XYZ
+ //
+ // libtonemap_LookupTonemapGain() returns a float representing the amount by which to scale the
+ // absolute nits of the pixels. This function may be plugged into any existing SkSL shader, and
+ // is expected to look something like this:
+ //
+ // vec3 rgb = ...;
+ // // apply the EOTF based on the incoming dataspace to convert to linear nits.
+ // vec3 linearRGB = applyEOTF(rgb);
+ // // apply a RGB->XYZ matrix float3
+ // vec3 xyz = toXYZ(linearRGB);
+ // // Scale the luminance based on the content standard
+ // vec3 absoluteRGB = ScaleLuminance(linearRGB);
+ // vec3 absoluteXYZ = ScaleLuminance(xyz);
+ // float gain = libtonemap_LookupTonemapGain(absoluteRGB, absoluteXYZ);
+ // // Normalize the luminance back down to a [0, 1] range
+ // xyz = NormalizeLuminance(absoluteXYZ * gain);
+ // // apply a XYZ->RGB matrix and apply the output OETf.
+ // vec3 finalColor = applyOETF(ToRGB(xyz));
+ // ...
+ //
+ // Helper methods in this shader should be prefixed with "libtonemap_". Accordingly, libraries
+ // which consume this shader must *not* contain any methods prefixed with "libtonemap_" to
+ // guarantee that there are no conflicts in name resolution.
+ virtual std::string generateTonemapGainShaderSkSL(
+ aidl::android::hardware::graphics::common::Dataspace sourceDataspace,
+ aidl::android::hardware::graphics::common::Dataspace destinationDataspace) = 0;
+
+ // Constructs uniform descriptions that correspond to those that are generated for the tonemap
+ // shader. Uniforms must be prefixed with "in_libtonemap_". Libraries which consume this shader
+ // must not bind any new uniforms that begin with this prefix.
+ //
+ // Downstream shaders may assume the existence of the uniform in_libtonemap_displayMaxLuminance
+ // and in_libtonemap_inputMaxLuminance, in order to assist with scaling and normalizing
+ // luminance as described in the documentation for generateTonemapGainShaderSkSL(). That is,
+ // shaders plugging in a tone-mapping shader returned by generateTonemapGainShaderSkSL() may
+ // assume that there are predefined floats in_libtonemap_displayMaxLuminance and
+ // in_libtonemap_inputMaxLuminance inside of the body of the tone-mapping shader.
+ virtual std::vector<ShaderUniform> generateShaderSkSLUniforms(const Metadata& metadata) = 0;
+};
+
+// Retrieves a tonemapper instance.
+// This instance is globally constructed.
+ToneMapper* getToneMapper();
+
+} // namespace android::tonemap
\ No newline at end of file
diff --git a/libs/tonemap/tests/Android.bp b/libs/tonemap/tests/Android.bp
new file mode 100644
index 0000000..e58d519
--- /dev/null
+++ b/libs/tonemap/tests/Android.bp
@@ -0,0 +1,38 @@
+// Copyright 2021 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package {
+ // See: http://go/android-license-faq
+ // A large-scale-change added 'default_applicable_licenses' to import
+ // all of the 'license_kinds' from "frameworks_native_license"
+ // to get the below license kinds:
+ // SPDX-license-identifier-Apache-2.0
+ default_applicable_licenses: ["frameworks_native_license"],
+}
+
+cc_test {
+ name: "libtonemap_test",
+ test_suites: ["device-tests"],
+ srcs: [
+ "tonemap_test.cpp",
+ ],
+ shared_libs: [
+ "android.hardware.graphics.common-V3-ndk",
+ ],
+ static_libs: [
+ "libgmock",
+ "libgtest",
+ "libtonemap",
+ ],
+}
diff --git a/libs/tonemap/tests/tonemap_test.cpp b/libs/tonemap/tests/tonemap_test.cpp
new file mode 100644
index 0000000..7a7958f
--- /dev/null
+++ b/libs/tonemap/tests/tonemap_test.cpp
@@ -0,0 +1,76 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+#include <tonemap/tonemap.h>
+#include <cmath>
+
+namespace android {
+
+using testing::HasSubstr;
+
+struct TonemapTest : public ::testing::Test {};
+
+TEST_F(TonemapTest, generateShaderSkSLUniforms_containsDefaultUniforms) {
+ static const constexpr float kDisplayMaxLuminance = 1.f;
+ static const constexpr float kContentMaxLuminance = 2.f;
+ tonemap::Metadata metadata{.displayMaxLuminance = kDisplayMaxLuminance,
+ .contentMaxLuminance = kContentMaxLuminance};
+ const auto uniforms = tonemap::getToneMapper()->generateShaderSkSLUniforms(metadata);
+
+ ASSERT_EQ(1, std::count_if(uniforms.cbegin(), uniforms.cend(), [](const auto& data) {
+ return data.name == "in_libtonemap_displayMaxLuminance";
+ }));
+ ASSERT_EQ(1, std::count_if(uniforms.cbegin(), uniforms.cend(), [](const auto& data) {
+ return data.name == "in_libtonemap_inputMaxLuminance";
+ }));
+
+ // Smoke check that metadata values are "real", specifically that they're non-zero and actually
+ // numbers. This is to help avoid shaders using these uniforms from dividing by zero or other
+ // catastrophic errors.
+ const auto& displayLum = std::find_if(uniforms.cbegin(), uniforms.cend(), [](const auto& data) {
+ return data.name == "in_libtonemap_displayMaxLuminance";
+ })->value;
+
+ float displayLumFloat = 0.f;
+ std::memcpy(&displayLumFloat, displayLum.data(), displayLum.size());
+ EXPECT_FALSE(std::isnan(displayLumFloat));
+ EXPECT_GT(displayLumFloat, 0);
+
+ const auto& contentLum = std::find_if(uniforms.cbegin(), uniforms.cend(), [](const auto& data) {
+ return data.name == "in_libtonemap_inputMaxLuminance";
+ })->value;
+
+ float contentLumFloat = 0.f;
+ std::memcpy(&contentLumFloat, contentLum.data(), contentLum.size());
+ EXPECT_FALSE(std::isnan(contentLumFloat));
+ EXPECT_GT(contentLumFloat, 0);
+}
+
+TEST_F(TonemapTest, generateTonemapGainShaderSkSL_containsEntryPoint) {
+ const auto shader =
+ tonemap::getToneMapper()
+ ->generateTonemapGainShaderSkSL(aidl::android::hardware::graphics::common::
+ Dataspace::BT2020_ITU_PQ,
+ aidl::android::hardware::graphics::common::
+ Dataspace::DISPLAY_P3);
+
+ // Other tests such as librenderengine_test will plug in the shader to check compilation.
+ EXPECT_THAT(shader, HasSubstr("float libtonemap_LookupTonemapGain(vec3 linearRGB, vec3 xyz)"));
+}
+
+} // namespace android
diff --git a/libs/tonemap/tonemap.cpp b/libs/tonemap/tonemap.cpp
new file mode 100644
index 0000000..350bca4
--- /dev/null
+++ b/libs/tonemap/tonemap.cpp
@@ -0,0 +1,256 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <tonemap/tonemap.h>
+
+#include <cstdint>
+#include <mutex>
+#include <type_traits>
+
+namespace android::tonemap {
+
+namespace {
+
+// Flag containing the variant of tone map algorithm to use.
+enum class ToneMapAlgorithm {
+ AndroidO, // Default algorithm in place since Android O,
+};
+
+static const constexpr auto kToneMapAlgorithm = ToneMapAlgorithm::AndroidO;
+
+static const constexpr auto kTransferMask =
+ static_cast<int32_t>(aidl::android::hardware::graphics::common::Dataspace::TRANSFER_MASK);
+static const constexpr auto kTransferST2084 =
+ static_cast<int32_t>(aidl::android::hardware::graphics::common::Dataspace::TRANSFER_ST2084);
+static const constexpr auto kTransferHLG =
+ static_cast<int32_t>(aidl::android::hardware::graphics::common::Dataspace::TRANSFER_HLG);
+
+template <typename T, std::enable_if_t<std::is_trivially_copyable<T>::value, bool> = true>
+std::vector<uint8_t> buildUniformValue(T value) {
+ std::vector<uint8_t> result;
+ result.resize(sizeof(value));
+ std::memcpy(result.data(), &value, sizeof(value));
+ return result;
+}
+
+class ToneMapperO : public ToneMapper {
+public:
+ std::string generateTonemapGainShaderSkSL(
+ aidl::android::hardware::graphics::common::Dataspace sourceDataspace,
+ aidl::android::hardware::graphics::common::Dataspace destinationDataspace) override {
+ const int32_t sourceDataspaceInt = static_cast<int32_t>(sourceDataspace);
+ const int32_t destinationDataspaceInt = static_cast<int32_t>(destinationDataspace);
+
+ std::string program;
+ // Define required uniforms
+ program.append(R"(
+ uniform float in_libtonemap_displayMaxLuminance;
+ uniform float in_libtonemap_inputMaxLuminance;
+ )");
+ switch (sourceDataspaceInt & kTransferMask) {
+ case kTransferST2084:
+ case kTransferHLG:
+ switch (destinationDataspaceInt & kTransferMask) {
+ case kTransferST2084:
+ program.append(R"(
+ float libtonemap_ToneMapTargetNits(vec3 xyz) {
+ return xyz.y;
+ }
+ )");
+ break;
+ case kTransferHLG:
+ // PQ has a wider luminance range (10,000 nits vs. 1,000 nits) than HLG, so
+ // we'll clamp the luminance range in case we're mapping from PQ input to
+ // HLG output.
+ program.append(R"(
+ float libtonemap_ToneMapTargetNits(vec3 xyz) {
+ return clamp(xyz.y, 0.0, 1000.0);
+ }
+ )");
+ break;
+ default:
+ // Here we're mapping from HDR to SDR content, so interpolate using a
+ // Hermitian polynomial onto the smaller luminance range.
+ program.append(R"(
+ float libtonemap_ToneMapTargetNits(vec3 xyz) {
+ float maxInLumi = in_libtonemap_inputMaxLuminance;
+ float maxOutLumi = in_libtonemap_displayMaxLuminance;
+
+ float nits = xyz.y;
+
+ // if the max input luminance is less than what we can
+ // output then no tone mapping is needed as all color
+ // values will be in range.
+ if (maxInLumi <= maxOutLumi) {
+ return xyz.y;
+ } else {
+
+ // three control points
+ const float x0 = 10.0;
+ const float y0 = 17.0;
+ float x1 = maxOutLumi * 0.75;
+ float y1 = x1;
+ float x2 = x1 + (maxInLumi - x1) / 2.0;
+ float y2 = y1 + (maxOutLumi - y1) * 0.75;
+
+ // horizontal distances between the last three
+ // control points
+ float h12 = x2 - x1;
+ float h23 = maxInLumi - x2;
+ // tangents at the last three control points
+ float m1 = (y2 - y1) / h12;
+ float m3 = (maxOutLumi - y2) / h23;
+ float m2 = (m1 + m3) / 2.0;
+
+ if (nits < x0) {
+ // scale [0.0, x0] to [0.0, y0] linearly
+ float slope = y0 / x0;
+ return nits * slope;
+ } else if (nits < x1) {
+ // scale [x0, x1] to [y0, y1] linearly
+ float slope = (y1 - y0) / (x1 - x0);
+ nits = y0 + (nits - x0) * slope;
+ } else if (nits < x2) {
+ // scale [x1, x2] to [y1, y2] using Hermite interp
+ float t = (nits - x1) / h12;
+ nits = (y1 * (1.0 + 2.0 * t) + h12 * m1 * t) *
+ (1.0 - t) * (1.0 - t) +
+ (y2 * (3.0 - 2.0 * t) +
+ h12 * m2 * (t - 1.0)) * t * t;
+ } else {
+ // scale [x2, maxInLumi] to [y2, maxOutLumi] using
+ // Hermite interp
+ float t = (nits - x2) / h23;
+ nits = (y2 * (1.0 + 2.0 * t) + h23 * m2 * t) *
+ (1.0 - t) * (1.0 - t) + (maxOutLumi *
+ (3.0 - 2.0 * t) + h23 * m3 *
+ (t - 1.0)) * t * t;
+ }
+ }
+
+ return nits;
+ }
+ )");
+ break;
+ }
+ break;
+ default:
+ switch (destinationDataspaceInt & kTransferMask) {
+ case kTransferST2084:
+ case kTransferHLG:
+ // Map from SDR onto an HDR output buffer
+ // Here we use a polynomial curve to map from [0, displayMaxLuminance] onto
+ // [0, maxOutLumi] which is hard-coded to be 3000 nits.
+ program.append(R"(
+ float libtonemap_ToneMapTargetNits(vec3 xyz) {
+ const float maxOutLumi = 3000.0;
+
+ const float x0 = 5.0;
+ const float y0 = 2.5;
+ float x1 = in_libtonemap_displayMaxLuminance * 0.7;
+ float y1 = maxOutLumi * 0.15;
+ float x2 = in_libtonemap_displayMaxLuminance * 0.9;
+ float y2 = maxOutLumi * 0.45;
+ float x3 = in_libtonemap_displayMaxLuminance;
+ float y3 = maxOutLumi;
+
+ float c1 = y1 / 3.0;
+ float c2 = y2 / 2.0;
+ float c3 = y3 / 1.5;
+
+ float nits = xyz.y;
+
+ if (nits <= x0) {
+ // scale [0.0, x0] to [0.0, y0] linearly
+ float slope = y0 / x0;
+ return nits * slope;
+ } else if (nits <= x1) {
+ // scale [x0, x1] to [y0, y1] using a curve
+ float t = (nits - x0) / (x1 - x0);
+ nits = (1.0 - t) * (1.0 - t) * y0 +
+ 2.0 * (1.0 - t) * t * c1 + t * t * y1;
+ } else if (nits <= x2) {
+ // scale [x1, x2] to [y1, y2] using a curve
+ float t = (nits - x1) / (x2 - x1);
+ nits = (1.0 - t) * (1.0 - t) * y1 +
+ 2.0 * (1.0 - t) * t * c2 + t * t * y2;
+ } else {
+ // scale [x2, x3] to [y2, y3] using a curve
+ float t = (nits - x2) / (x3 - x2);
+ nits = (1.0 - t) * (1.0 - t) * y2 +
+ 2.0 * (1.0 - t) * t * c3 + t * t * y3;
+ }
+
+ return nits;
+ }
+ )");
+ break;
+ default:
+ // For completeness, this is tone-mapping from SDR to SDR, where this is
+ // just a no-op.
+ program.append(R"(
+ float libtonemap_ToneMapTargetNits(vec3 xyz) {
+ return xyz.y;
+ }
+ )");
+ break;
+ }
+ break;
+ }
+
+ program.append(R"(
+ float libtonemap_LookupTonemapGain(vec3 linearRGB, vec3 xyz) {
+ if (xyz.y <= 0.0) {
+ return 1.0;
+ }
+ return libtonemap_ToneMapTargetNits(xyz) / xyz.y;
+ }
+ )");
+ return program;
+ }
+
+ std::vector<ShaderUniform> generateShaderSkSLUniforms(const Metadata& metadata) override {
+ std::vector<ShaderUniform> uniforms;
+
+ uniforms.reserve(2);
+
+ uniforms.push_back({.name = "in_libtonemap_displayMaxLuminance",
+ .value = buildUniformValue<float>(metadata.displayMaxLuminance)});
+ uniforms.push_back({.name = "in_libtonemap_inputMaxLuminance",
+ .value = buildUniformValue<float>(metadata.contentMaxLuminance)});
+
+ return uniforms;
+ }
+};
+
+} // namespace
+
+ToneMapper* getToneMapper() {
+ static std::once_flag sOnce;
+ static std::unique_ptr<ToneMapper> sToneMapper;
+
+ std::call_once(sOnce, [&] {
+ switch (kToneMapAlgorithm) {
+ case ToneMapAlgorithm::AndroidO:
+ sToneMapper = std::unique_ptr<ToneMapper>(new ToneMapperO());
+ break;
+ }
+ });
+
+ return sToneMapper.get();
+}
+
+} // namespace android::tonemap
\ No newline at end of file
diff --git a/services/surfaceflinger/Android.bp b/services/surfaceflinger/Android.bp
index 56b8374..6691575 100644
--- a/services/surfaceflinger/Android.bp
+++ b/services/surfaceflinger/Android.bp
@@ -79,6 +79,7 @@
"libperfetto_client_experimental",
"librenderengine",
"libserviceutils",
+ "libtonemap",
"libtrace_proto",
"libaidlcommonsupport",
],
diff --git a/services/surfaceflinger/CompositionEngine/Android.bp b/services/surfaceflinger/CompositionEngine/Android.bp
index 83b4a25..aefc014 100644
--- a/services/surfaceflinger/CompositionEngine/Android.bp
+++ b/services/surfaceflinger/CompositionEngine/Android.bp
@@ -38,6 +38,7 @@
static_libs: [
"libmath",
"librenderengine",
+ "libtonemap",
"libtrace_proto",
"libaidlcommonsupport",
],
diff --git a/services/surfaceflinger/tests/unittests/Android.bp b/services/surfaceflinger/tests/unittests/Android.bp
index f152ced..1ac5680 100644
--- a/services/surfaceflinger/tests/unittests/Android.bp
+++ b/services/surfaceflinger/tests/unittests/Android.bp
@@ -142,6 +142,7 @@
"libtimestats",
"libtimestats_atoms_proto",
"libtimestats_proto",
+ "libtonemap",
"libtrace_proto",
"perfetto_trace_protos",
],