From 424744cc4d9ef8daa624ed6a3687cb9ebf4c9b7e Mon Sep 17 00:00:00 2001
From: Jaesung Chung <jaesung@google.com>
Date: Thu, 9 Nov 2017 12:51:32 +0900
Subject: [PATCH] Use RGB24 format instead of BGR32

BGR32 mode is in RPi3's camera has a RB color swapping issue. This CL
makes to use stable RGB24 mode instead to avoid the problem without
causing any quality regression.

Bug: 69075512
Test: RB color swapping problem is gone on preview, recording and stil.
Exempt-From-Owner-Approval: HAL is owned by Things team.
Change-Id: I109363c0f68cec45f92e739a978f554e70032151
---
 modules/camera/3_4/README.md         |  5 +----
 modules/camera/3_4/stream_format.cpp |  6 +++---
 modules/camera/3_4/v4l2_gralloc.cpp  | 14 ++++++++++++++
 3 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/modules/camera/3_4/README.md b/modules/camera/3_4/README.md
index 73d0c13b..30f36d7d 100644
--- a/modules/camera/3_4/README.md
+++ b/modules/camera/3_4/README.md
@@ -28,7 +28,7 @@ to load the V4L2 HAL instead of a default Camera HAL.
 Devices and cameras wishing to use this HAL must meet
 the following requirements:
 
-* The camera must support BGR32, YUV420, and JPEG formats.
+* The camera must support RGB24, YUV420, and JPEG formats.
 * The gralloc and other graphics modules used by the device must use
 `HAL_PIXEL_FORMAT_RGBA_8888` as the `HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED`
 
@@ -146,6 +146,3 @@ is underfeatured compared to the ideal/what is possible.
 
 * A variety of features are unimplemented: High speed capture,
 flash torch mode, hotplugging/unplugging.
-* The HAL uses BGR for RGBA. Again, the HAL was designed for the Raspberry Pi
-camera, which doesn't support RGB, but RGB is a common default format for
-graphics stacks.
diff --git a/modules/camera/3_4/stream_format.cpp b/modules/camera/3_4/stream_format.cpp
index c85c26be..70900abb 100644
--- a/modules/camera/3_4/stream_format.cpp
+++ b/modules/camera/3_4/stream_format.cpp
@@ -57,7 +57,7 @@ FormatCategory StreamFormat::Category() const {
     case V4L2_PIX_FMT_JPEG:
       return kFormatCategoryStalling;
     case V4L2_PIX_FMT_YUV420:  // Fall through.
-    case V4L2_PIX_FMT_BGR32:
+    case V4L2_PIX_FMT_RGB24:
       return kFormatCategoryNonStalling;
     default:
       // Note: currently no supported RAW formats.
@@ -87,7 +87,7 @@ int StreamFormat::V4L2ToHalPixelFormat(uint32_t v4l2_pixel_format) {
     case V4L2_PIX_FMT_YUV420:
       hal_pixel_format = HAL_PIXEL_FORMAT_YCbCr_420_888;
       break;
-    case V4L2_PIX_FMT_BGR32:
+    case V4L2_PIX_FMT_RGB24:
       hal_pixel_format = HAL_PIXEL_FORMAT_RGBA_8888;
       break;
     default:
@@ -106,7 +106,7 @@ uint32_t StreamFormat::HalToV4L2PixelFormat(int hal_pixel_format) {
     case HAL_PIXEL_FORMAT_RGBA_8888:
       // Should be RGB32, but RPi doesn't support that.
       // For now we accept that the colors will be off.
-      v4l2_pixel_format = V4L2_PIX_FMT_BGR32;
+      v4l2_pixel_format = V4L2_PIX_FMT_RGB24;
       break;
     case HAL_PIXEL_FORMAT_YCbCr_420_888:
       v4l2_pixel_format = V4L2_PIX_FMT_YUV420;
diff --git a/modules/camera/3_4/v4l2_gralloc.cpp b/modules/camera/3_4/v4l2_gralloc.cpp
index 7da3c4e2..2fcef355 100644
--- a/modules/camera/3_4/v4l2_gralloc.cpp
+++ b/modules/camera/3_4/v4l2_gralloc.cpp
@@ -146,6 +146,7 @@ int V4L2Gralloc::lock(const camera3_stream_buffer_t* camera_buffer,
         return ret;
       }
       break;
+    case V4L2_PIX_FMT_RGB24:  // Fall-through.
     case V4L2_PIX_FMT_BGR32:  // Fall-through.
     case V4L2_PIX_FMT_RGB32:
       // RGB formats have nice agreed upon representation. Unless using android
@@ -204,6 +205,19 @@ int V4L2Gralloc::unlock(const v4l2_buffer* device_buffer) {
   const camera3_stream_buffer_t* camera_buffer = buffer_data->camera_buffer;
   const buffer_handle_t buffer = *camera_buffer->buffer;
 
+  if (StreamFormat::HalToV4L2PixelFormat(camera_buffer->stream->format) == V4L2_PIX_FMT_RGB24) {
+    // Convert RGB24 to RGB32.
+    size_t rgb_size = camera_buffer->stream->width * camera_buffer->stream->height;
+    uint8_t* tail_rgb24 = (uint8_t*)data + 3 * rgb_size - 1;
+    uint8_t* tail_rgb32 = (uint8_t*)data + 4 * rgb_size - 1;
+    for (int i = 0; i < rgb_size; i++) {
+      *(tail_rgb32--) = 0xff;
+      *(tail_rgb32--) = *(tail_rgb24--);
+      *(tail_rgb32--) = *(tail_rgb24--);
+      *(tail_rgb32--) = *(tail_rgb24--);
+    }
+  }
+
   // Check for transform.
   if (buffer_data->transform_dest) {
     HAL_LOGV("Transforming V4L2 YUV to gralloc YUV.");