Merge "Add remaining tone mapping support in Skia-RenderEngine"
diff --git a/libs/renderengine/skia/filters/LinearEffect.cpp b/libs/renderengine/skia/filters/LinearEffect.cpp
index 376abdf..b628b3e 100644
--- a/libs/renderengine/skia/filters/LinearEffect.cpp
+++ b/libs/renderengine/skia/filters/LinearEffect.cpp
@@ -22,6 +22,7 @@
#include "log/log.h"
#include "math/mat4.h"
+#include "system/graphics-base-v1.0.h"
#include "ui/ColorSpace.h"
namespace android {
@@ -46,6 +47,30 @@
}
)");
break;
+ case HAL_DATASPACE_TRANSFER_HLG:
+ shader.append(R"(
+ float EOTF_channel(float channel) {
+ const float a = 0.17883277;
+ const float b = 0.28466892;
+ const float c = 0.55991073;
+ return channel <= 0.5 ? channel * channel / 3.0 :
+ (exp((channel - c) / a) + b) / 12.0;
+ }
+
+ float3 EOTF(float3 color) {
+ return float3(EOTF_channel(color.r), EOTF_channel(color.g),
+ EOTF_channel(color.b));
+ }
+ )");
+ break;
+ case HAL_DATASPACE_TRANSFER_LINEAR:
+ shader.append(R"(
+ float3 EOTF(float3 color) {
+ return color;
+ }
+ )");
+ break;
+ case HAL_DATASPACE_TRANSFER_SRGB:
default:
shader.append(R"(
@@ -79,13 +104,8 @@
)");
}
-static void generateOOTF(ui::Dataspace inputDataspace, ui::Dataspace outputDataspace,
- SkString& shader) {
- shader.append(R"(
- uniform float in_displayMaxLuminance;
- uniform float in_inputMaxLuminance;
- uniform float in_maxContentLuminance;
- )");
+// Conversion from relative light to absolute light (maps from [0, 1] to [0, maxNits])
+static void generateLuminanceScalesForOOTF(ui::Dataspace inputDataspace, SkString& shader) {
switch (inputDataspace & HAL_DATASPACE_TRANSFER_MASK) {
case HAL_DATASPACE_TRANSFER_ST2084:
shader.append(R"(
@@ -93,9 +113,50 @@
return xyz * 10000.0;
}
)");
+ break;
+ case HAL_DATASPACE_TRANSFER_HLG:
+ shader.append(R"(
+ float3 ScaleLuminance(float3 xyz) {
+ return xyz * 1000.0 * pow(xyz.y, 0.2);
+ }
+ )");
+ break;
+ default:
+ shader.append(R"(
+ float3 ScaleLuminance(float3 xyz) {
+ return xyz * in_displayMaxLuminance;
+ }
+ )");
+ 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;
@@ -155,18 +216,70 @@
}
break;
default:
- shader.append(R"(
- float3 ScaleLuminance(float3 xyz) {
- return xyz * in_displayMaxLuminance;
- }
+ 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;
- float3 ToneMap(float3 xyz) {
- return xyz;
- }
- )");
+ 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) {
case HAL_DATASPACE_TRANSFER_ST2084:
shader.append(R"(
@@ -175,6 +288,13 @@
}
)");
break;
+ case HAL_DATASPACE_TRANSFER_HLG:
+ shader.append(R"(
+ float3 NormalizeLuminance(float3 xyz) {
+ return xyz / 1000.0 * pow(xyz.y / 1000.0, -0.2 / 1.2);
+ }
+ )");
+ break;
default:
shader.append(R"(
float3 NormalizeLuminance(float3 xyz) {
@@ -183,6 +303,19 @@
)");
break;
}
+}
+
+static void generateOOTF(ui::Dataspace inputDataspace, ui::Dataspace outputDataspace,
+ SkString& shader) {
+ // Input uniforms
+ shader.append(R"(
+ uniform float in_displayMaxLuminance;
+ uniform float in_inputMaxLuminance;
+ )");
+
+ generateLuminanceScalesForOOTF(inputDataspace, shader);
+ generateToneMapInterpolation(inputDataspace, outputDataspace, shader);
+ generateLuminanceNormalizationForOOTF(outputDataspace, shader);
shader.append(R"(
float3 OOTF(float3 xyz) {
@@ -209,6 +342,30 @@
}
)");
break;
+ case HAL_DATASPACE_TRANSFER_HLG:
+ shader.append(R"(
+ float OETF_channel(float channel) {
+ const float a = 0.17883277;
+ const float b = 0.28466892;
+ const float c = 0.55991073;
+ return channel <= 1.0 / 12.0 ? sqrt(3.0 * channel) :
+ a * log(12.0 * channel - b) + c;
+ }
+
+ float3 OETF(float3 linear) {
+ return float3(OETF_channel(linear.r), OETF_channel(linear.g),
+ OETF_channel(linear.b));
+ }
+ )");
+ break;
+ case HAL_DATASPACE_TRANSFER_LINEAR:
+ shader.append(R"(
+ float3 OETF(float3 linear) {
+ return linear;
+ }
+ )");
+ break;
+ case HAL_DATASPACE_TRANSFER_SRGB:
default:
shader.append(R"(
float OETF_sRGB(float linear) {