libcamera: software_isp: blacklevel: Make black level available in debayer params

Populate black level gain in blacklevel::prepare(). A copy is made of the gain
value in the DebayerParams structure.

Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Milan Zamazal <mzamazal@redhat.com>
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

include/libcamera/internal/software_isp/debayer_params.h

@@ -14,6 +14,7 @@
 #include <stdint.h>
 
 #include "libcamera/internal/matrix.h"
+#include "libcamera/internal/vector.h"
 
 namespace libcamera {
 
@@ -56,6 +57,7 @@ struct DebayerParams {
 	 * Per frame corrections as calculated by the IPA
 	 */
 	Matrix<float, 3, 3> ccm;
+	RGB<float> blackLevel;
 };
 
 } /* namespace libcamera */

src/ipa/simple/algorithms/blc.cpp

@@ -47,6 +47,15 @@ int BlackLevel::configure(IPAContext &context,
 	return 0;
 }
 
+void BlackLevel::prepare(IPAContext &context,
+			 [[maybe_unused]] const uint32_t frame,
+			 [[maybe_unused]] IPAFrameContext &frameContext,
+			 DebayerParams *params)
+{
+	/* Latch the blacklevel gain so GPUISP can apply. */
+	params->blackLevel = RGB<float>(context.activeState.blc.level / 255.0f);
+}
+
 void BlackLevel::process(IPAContext &context,
 			 [[maybe_unused]] const uint32_t frame,
 			 IPAFrameContext &frameContext,

src/ipa/simple/algorithms/blc.h

@@ -24,6 +24,10 @@ public:
 
 	int init(IPAContext &context, const YamlObject &tuningData) override;
 	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,
 		     const SwIspStats *stats,

src/libcamera/software_isp/debayer.cpp

@@ -105,6 +105,11 @@ namespace libcamera {
  * \brief Per frame colour correction matrix for GPUISP
  */
 
+/**
+ * \var DebayerParams::blackLevel
+ * \brief Blacklevel gains for the GPUISP
+ */
+
 /**
  * \class Debayer
  * \brief Base debayering class