Supply extra brightness parameters to RenderEngine

A future CL will update the HLG->SDR tonemapping algorithm to consider
current display brightness, as recommended by BT2100.

In preparation for this:
* Fix an issue where maxLuminance was using the current display
brightness if supplied from DisplayManager instead of the max luminance
* Add currentDisplayBrightnessNits to the RenderEngine interface to
support the current brightness
* Plumb current display brightness all the way to libtonemap, where
nothing uses it (yet)

Bug: 206035964
Test: libcompositionengine_test

Change-Id: I3e9f0fdb23fbb08c50e4733e5a16bcd20948d750

1 files changed, 2 insertions, 0 deletions

diff --git a/libs/shaders/shaders.cpp b/libs/shaders/shaders.cpp
index 6019c4ac28..4d88d5d417 100644
--- a/libs/shaders/shaders.cpp
+++ b/libs/shaders/shaders.cpp
@@ -463,6 +463,7 @@ std::vector<uint8_t> buildUniformValue(T value) {
 std::vector<tonemap::ShaderUniform> buildLinearEffectUniforms(const LinearEffect& linearEffect,
                                                               const mat4& colorTransform,
                                                               float maxDisplayLuminance,
+                                                              float currentDisplayLuminanceNits,
                                                               float maxLuminance) {
     std::vector<tonemap::ShaderUniform> uniforms;
     if (linearEffect.inputDataspace == linearEffect.outputDataspace) {
@@ -480,6 +481,7 @@ std::vector<tonemap::ShaderUniform> buildLinearEffectUniforms(const LinearEffect
     }
 
     tonemap::Metadata metadata{.displayMaxLuminance = maxDisplayLuminance,
+                               .currentDisplayLuminanceNits = currentDisplayLuminanceNits,
                                // 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