[PATCH v4 3/6] ipa: simple: Report the ColourGains in metadata

[Milan Zamazal]

From: Kieran Bingham <kieran.bingham at ideasonboard.com>

Provide the determined colour gains back into the metadata
to add to completed requests.

Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
Signed-off-by: Milan Zamazal <mzamazal at redhat.com>
---
 src/ipa/simple/algorithms/awb.cpp | 23 +++++++++++++++++++++--
 src/ipa/simple/algorithms/awb.h   |  6 +++++-
 src/ipa/simple/ipa_context.h      |  4 ++++
 3 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/src/ipa/simple/algorithms/awb.cpp b/src/ipa/simple/algorithms/awb.cpp
index 195de41d..3b4146f1 100644
--- a/src/ipa/simple/algorithms/awb.cpp
+++ b/src/ipa/simple/algorithms/awb.cpp
@@ -14,6 +14,8 @@
 
 #include "simple/ipa_context.h"
 
+#include "control_ids.h"
+
 namespace libcamera {
 
 LOG_DEFINE_CATEGORY(IPASoftAwb)
@@ -29,15 +31,32 @@ int Awb::configure(IPAContext &context,
 	return 0;
 }
 
+void Awb::prepare(IPAContext &context,
+		  [[maybe_unused]] const uint32_t frame,
+		  IPAFrameContext &frameContext,
+		  [[maybe_unused]] DebayerParams *params)
+{
+	auto &gains = context.activeState.gains;
+	frameContext.gains.red = gains.red;
+	frameContext.gains.blue = gains.blue;
+}
+
 void Awb::process(IPAContext &context,
 		  [[maybe_unused]] const uint32_t frame,
-		  [[maybe_unused]] IPAFrameContext &frameContext,
+		  IPAFrameContext &frameContext,
 		  const SwIspStats *stats,
-		  [[maybe_unused]] ControlList &metadata)
+		  ControlList &metadata)
 {
 	const SwIspStats::Histogram &histogram = stats->yHistogram;
 	const uint8_t blackLevel = context.activeState.blc.level;
 
+	const float maxGain = 1024.0;
+	const float mdGains[] = {
+		static_cast<float>(frameContext.gains.red / maxGain),
+		static_cast<float>(frameContext.gains.blue / maxGain)
+	};
+	metadata.set(controls::ColourGains, mdGains);
+
 	/*
 	 * Black level must be subtracted to get the correct AWB ratios, they
 	 * would be off if they were computed from the whole brightness range
diff --git a/src/ipa/simple/algorithms/awb.h b/src/ipa/simple/algorithms/awb.h
index db1496cd..ad993f39 100644
--- a/src/ipa/simple/algorithms/awb.h
+++ b/src/ipa/simple/algorithms/awb.h
@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 /*
- * Copyright (C) 2024, Red Hat Inc.
+ * Copyright (C) 2024-2025 Red Hat Inc.
  *
  * Auto white balance
  */
@@ -20,6 +20,10 @@ public:
 	~Awb() = default;
 
 	int configure(IPAContext &context, const IPAConfigInfo &configInfo) override;
+	void prepare(IPAContext &context,
+		     const uint32_t frame,
+		     IPAFrameContext &frameContext,
+		     DebayerParams *params) override;
 	void process(IPAContext &context,
 		     const uint32_t frame,
 		     IPAFrameContext &frameContext,
diff --git a/src/ipa/simple/ipa_context.h b/src/ipa/simple/ipa_context.h
index 4af51306..99cb6284 100644
--- a/src/ipa/simple/ipa_context.h
+++ b/src/ipa/simple/ipa_context.h
@@ -58,6 +58,10 @@ struct IPAFrameContext : public FrameContext {
 		int32_t exposure;
 		double gain;
 	} sensor;
+	struct {
+		double red;
+		double blue;
+	} gains;
 };
 
 struct IPAContext {
-- 
2.48.1