[Lut HAL] documentation update.
Bug: 329472100
Test: builds
Change-Id: Ie5ea02123e2ac73ca959cce9d31ffc58d5eca36d
diff --git a/graphics/composer/aidl/android/hardware/graphics/composer3/Luts.aidl b/graphics/composer/aidl/android/hardware/graphics/composer3/Luts.aidl
index 592ac50..393354e 100644
--- a/graphics/composer/aidl/android/hardware/graphics/composer3/Luts.aidl
+++ b/graphics/composer/aidl/android/hardware/graphics/composer3/Luts.aidl
@@ -40,15 +40,16 @@
* For data precision, 32-bit float is used to specify a Lut by both the HWC and
* the platform.
*
- * For unflattening/flattening 3D Lut(s), the algorithm below should be observed
- * by both the HWC and the platform.
* Assuming that we have a 3D array `ORIGINAL[WIDTH, HEIGHT, DEPTH]`, we would turn it into
* `FLAT[WIDTH * HEIGHT * DEPTH]` by
*
* `FLAT[z + DEPTH * (y + HEIGHT * x)] = ORIGINAL[x, y, z]`
*
- * Noted that 1D Lut(s) should be gain curve ones
- * and 3D Lut(s) should be pure color lookup ones.
+ * Note that 1D Lut(s) should be gain curve ones and 3D Lut(s) should be pure color lookup
+ * ones. For 3D Luts buffer,the values of the lut buffer should be normalized, ranging from 0.0
+ * to 1.0, inclusively and the data is organized in the order of R, G, B channels.
+ * For 1D Luts, the lut's values should be also normalized for fixed point pixel formats,
+ * and we now ignore floating point pixel formats + extended range buffers.
*/
@nullable ParcelFileDescriptor pfd;