Merge "[Lut shader] Fix the issue if using HLG/PQ transfer function." into main (bb68e3d7) · Commits · e / os / android_frameworks_native

libs/renderengine/skia/filters/LutShader.cpp

+23 −8

Original line number	Diff line number	Diff line
		@@ -39,10 +39,13 @@ static const SkString kShader = SkString(R"(
		uniform int key;
		uniform int dimension;
		uniform vec3 luminanceCoefficients; // for CIE_Y
		// for hlg/pq transfer function, we need normalize it to [0.0, 1.0]
		// we use `normalizeScalar` to do so
		uniform float normalizeScalar;

		vec4 main(vec2 xy) {
		float4 rgba = image.eval(xy);
		float3 linear = toLinearSrgb(rgba.rgb);
		float3 linear = toLinearSrgb(rgba.rgb) * normalizeScalar;
		if (dimension == 1) {
		// RGB
		if (key == 0) {
		@@ -52,19 +55,19 @@ static const SkString kShader = SkString(R"(
		float gainR = lut.eval(vec2(indexR, 0.0) + 0.5).r;
		float gainG = lut.eval(vec2(indexG, 0.0) + 0.5).r;
		float gainB = lut.eval(vec2(indexB, 0.0) + 0.5).r;
		return float4(linear.r * gainR, linear.g * gainG, linear.b * gainB, rgba.a);
		linear = float3(linear.r * gainR, linear.g * gainG, linear.b * gainB);
		// MAX_RGB
		} else if (key == 1) {
		float maxRGB = max(linear.r, max(linear.g, linear.b));
		float index = maxRGB * float(size - 1);
		float gain = lut.eval(vec2(index, 0.0) + 0.5).r;
		return float4(linear * gain, rgba.a);
		linear = linear * gain;
		// CIE_Y
		} else if (key == 2) {
		float y = dot(linear, luminanceCoefficients) / 3.0;
		float index = y * float(size - 1);
		float gain = lut.eval(vec2(index, 0.0) + 0.5).r;
		return float4(linear * gain, rgba.a);
		linear = linear * gain;
		}
		} else if (dimension == 3) {
		if (key == 0) {
		@@ -110,12 +113,10 @@ static const SkString kShader = SkString(R"(
		float3 c0 = mix(c00, c10, linear.g);
		float3 c1 = mix(c01, c11, linear.g);

		float3 val = mix(c0, c1, linear.b);

		return float4(val, rgba.a);
		linear = mix(c0, c1, linear.b);
		}
		}
		return rgba;
		return float4(linear, rgba.a);
		})");

		// same as shader::toColorSpace function
		@@ -197,9 +198,22 @@ sk_sp<SkShader> LutShader::generateLutShader(sk_sp<SkShader> input,
		? SkSamplingOptions(SkFilterMode::kLinear)
		: SkSamplingOptions());

		float normalizeScalar = 1.0;
		switch (srcDataspace & HAL_DATASPACE_TRANSFER_MASK) {
		case HAL_DATASPACE_TRANSFER_HLG:
		normalizeScalar = 0.203;
		break;
		case HAL_DATASPACE_TRANSFER_ST2084:
		normalizeScalar = 0.0203;
		break;
		default:
		normalizeScalar = 1.0;
		}
		const int uSize = static_cast<int>(size);
		const int uKey = static_cast<int>(samplingKey);
		const int uDimension = static_cast<int>(dimension);
		const float uNormalizeScalar = static_cast<float>(normalizeScalar);

		if (static_cast<LutProperties::SamplingKey>(samplingKey) == LutProperties::SamplingKey::CIE_Y) {
		// Use predefined colorspaces of input dataspace so that we can get D65 illuminant
		mat3 toXYZMatrix(toColorSpace(srcDataspace).getRGBtoXYZ());
		@@ -211,6 +225,7 @@ sk_sp<SkShader> LutShader::generateLutShader(sk_sp<SkShader> input,
		mBuilder->uniform("size") = uSize;
		mBuilder->uniform("key") = uKey;
		mBuilder->uniform("dimension") = uDimension;
		mBuilder->uniform("normalizeScalar") = uNormalizeScalar;
		return mBuilder->makeShader();
		}