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Commit 8b4ab814 authored by Alec Mouri's avatar Alec Mouri
Browse files

Only scale SDR luminance by content max luminance for tonemapping 

If color conversion is SDR->SDR, then scale luminance only by the
display luminance.

The use-case is for applying a color transform, which was defined to
occcur in linear space. Since uniform generation for tonemapping is (for
now) dataspace-agnostic, this means that scaling by the content
luminance should not be used since a tone-mapping operator may override
the one that is provided by applications.

Bug: 200310159
Test: builds, boots
Test: librenderengine_test
Change-Id: I2cc5860b6df064664c5e462674df20b589eae291
parent 465b2967

libs/renderengine/skia/filters/LinearEffect.cpp

+23 −8
Original line number Diff line number Diff line
@@ -114,7 +114,8 @@ static void generateXYZTransforms(SkString& shader) { 
}



// Conversion from relative light to absolute light (maps from [0, 1] to [0, maxNits])

static void generateLuminanceScalesForOOTF(ui::Dataspace inputDataspace, SkString& shader) {

static void generateLuminanceScalesForOOTF(ui::Dataspace inputDataspace,

                                           ui::Dataspace outputDataspace, SkString& shader) {

    switch (inputDataspace & HAL_DATASPACE_TRANSFER_MASK) {

        case HAL_DATASPACE_TRANSFER_ST2084:

            shader.append(R"(
@@ -131,12 +132,26 @@ static void generateLuminanceScalesForOOTF(ui::Dataspace inputDataspace, SkStrin 
                )");

            break;

        default:

            switch (outputDataspace & HAL_DATASPACE_TRANSFER_MASK) {

                case HAL_DATASPACE_TRANSFER_ST2084:

                case HAL_DATASPACE_TRANSFER_HLG:

                    // SDR -> HDR tonemap

                    shader.append(R"(

                            float3 ScaleLuminance(float3 xyz) {

                                return xyz * in_libtonemap_inputMaxLuminance;

                            }

                        )");

                    break;

                default:

                    // Input and output are both SDR, so no tone-mapping is expected so

                    // no-op the luminance normalization.

                    shader.append(R"(

                                float3 ScaleLuminance(float3 xyz) {

                                    return xyz * in_libtonemap_displayMaxLuminance;

                                }

                            )");

                    break;

            }

    }

}
@@ -174,7 +189,7 @@ static void generateOOTF(ui::Dataspace inputDataspace, ui::Dataspace outputDatas 
                                                          toAidlDataspace(outputDataspace))

                          .c_str());



    generateLuminanceScalesForOOTF(inputDataspace, shader);

    generateLuminanceScalesForOOTF(inputDataspace, outputDataspace, shader);

    generateLuminanceNormalizationForOOTF(outputDataspace, shader);



    shader.append(R"(