[v2,09/12] ipa: rkisp1: goc: Re-work to use GammaAlgorithm class

27069 diff mbox series

Re-work the RkISP1 Gamma Out Correction algorithm to use the new
GammaAlgorithm class from libipa, which allows us to share an
implementation with the other IPAs.

Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Daniel Scally <dan.scally@ideasonboard.com>
---
Changes in v2:

        - Fixed includes
	- Dropped the comment explaining how gamma correction is
	  implemented - it's on libipa gamma now
	- Dropped unused variable kDefaultGamma
---
 src/ipa/rkisp1/algorithms/goc.cpp | 63 +++++++++++----------------------------
 src/ipa/rkisp1/algorithms/goc.h   |  7 ++++-
 src/ipa/rkisp1/ipa_context.h      | 10 ++-----
 3 files changed, 26 insertions(+), 54 deletions(-)

Hi Dan

On Fri, Jun 26, 2026 at 02:05:56PM +0100, Daniel Scally wrote:
> Re-work the RkISP1 Gamma Out Correction algorithm to use the new
> GammaAlgorithm class from libipa, which allows us to share an
> implementation with the other IPAs.
>
> Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
> Signed-off-by: Daniel Scally <dan.scally@ideasonboard.com>

Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>

Thanks
  j

> ---
> Changes in v2:
>
>         - Fixed includes
> 	- Dropped the comment explaining how gamma correction is
> 	  implemented - it's on libipa gamma now
> 	- Dropped unused variable kDefaultGamma
> ---
>  src/ipa/rkisp1/algorithms/goc.cpp | 63 +++++++++++----------------------------
>  src/ipa/rkisp1/algorithms/goc.h   |  7 ++++-
>  src/ipa/rkisp1/ipa_context.h      | 10 ++-----
>  3 files changed, 26 insertions(+), 54 deletions(-)
>
> diff --git a/src/ipa/rkisp1/algorithms/goc.cpp b/src/ipa/rkisp1/algorithms/goc.cpp
> index e8f64bf3d5e028c2013d37b7ef9fe90b737fad5f..e3bea4bbef186dde28fdd5a3aa14b7662a9ffe69 100644
> --- a/src/ipa/rkisp1/algorithms/goc.cpp
> +++ b/src/ipa/rkisp1/algorithms/goc.cpp
> @@ -6,10 +6,11 @@
>   */
>  #include "goc.h"
>
> +#include <array>
>  #include <cmath>
>
>  #include <libcamera/base/log.h>
> -#include <libcamera/base/utils.h>
> +#include <libcamera/base/span.h>
>
>  #include <libcamera/control_ids.h>
>
> @@ -29,21 +30,13 @@ namespace ipa::rkisp1::algorithms {
>   * \class GammaOutCorrection
>   * \brief RkISP1 Gamma out correction
>   *
> - * This algorithm implements the gamma out curve for the RkISP1. It defaults to
> - * a gamma value of 2.2.
> - *
> - * As gamma is internally represented as a piecewise linear function with only
> - * 17 knots, the difference between gamma=2.2 and sRGB gamma is minimal.
> - * Therefore sRGB gamma was not implemented as special case.
> - *
> - * Useful links:
> - * - https://www.cambridgeincolour.com/tutorials/gamma-correction.htm
> - * - https://en.wikipedia.org/wiki/SRGB
> + * This algorithm implements the gamma out curve for the RkISP1 using the
> + * libipa GammaAlgorithm class.
>   */
>
>  LOG_DEFINE_CATEGORY(RkISP1Gamma)
>
> -const float kDefaultGamma = 2.2f;
> +static constexpr unsigned int kNumLutSegments = RKISP1_CIF_ISP_GAMMA_OUT_MAX_SAMPLES_V10 - 1;
>
>  /**
>   * \copydoc libcamera::ipa::Algorithm::init
> @@ -57,10 +50,12 @@ int GammaOutCorrection::init(IPAContext &context, const ValueNode &tuningData)
>  		return -EINVAL;
>  	}
>
> -	defaultGamma_ = tuningData["gamma"].get<double>(kDefaultGamma);
> -	context.ctrlMap[&controls::Gamma] = ControlInfo(0.1f, 10.0f, defaultGamma_);
> +	std::array<unsigned int, kNumLutSegments> segments = {
> +		 64,  64,  64,  64, 128, 128, 128, 128,
> +		256, 256, 256, 512, 512, 512, 512, 512
> +	};
>
> -	return 0;
> +	return gammaAlgo_.init(context.ctrlMap, tuningData, segments);
>  }
>
>  /**
> @@ -69,7 +64,7 @@ int GammaOutCorrection::init(IPAContext &context, const ValueNode &tuningData)
>  int GammaOutCorrection::configure(IPAContext &context,
>  				  [[maybe_unused]] const IPACameraSensorInfo &configInfo)
>  {
> -	context.activeState.goc.gamma = defaultGamma_;
> +	gammaAlgo_.configure(context.activeState.gamma);
>  	return 0;
>  }
>
> @@ -80,17 +75,8 @@ void GammaOutCorrection::queueRequest(IPAContext &context, const uint32_t frame,
>  				      IPAFrameContext &frameContext,
>  				      const ControlList &controls)
>  {
> -	if (frame == 0)
> -		frameContext.goc.update = true;
> -
> -	const auto &gamma = controls.get(controls::Gamma);
> -	if (gamma) {
> -		context.activeState.goc.gamma = *gamma;
> -		frameContext.goc.update = true;
> -		LOG(RkISP1Gamma, Debug) << "Set gamma to " << *gamma;
> -	}
> -
> -	frameContext.goc.gamma = context.activeState.goc.gamma;
> +	gammaAlgo_.queueRequest(context.activeState.gamma, frame,
> +				frameContext.gamma, controls);
>  }
>
>  /**
> @@ -104,29 +90,14 @@ void GammaOutCorrection::prepare(IPAContext &context,
>  	ASSERT(context.hw.numGammaOutSamples ==
>  	       RKISP1_CIF_ISP_GAMMA_OUT_MAX_SAMPLES_V10);
>
> -	if (!frameContext.goc.update)
> +	if (!frameContext.gamma.update)
>  		return;
>
> -	/*
> -	 * The logarithmic segments as specified in the reference.
> -	 * Plus an additional 0 to make the loop easier
> -	 */
> -	static constexpr std::array<unsigned int, RKISP1_CIF_ISP_GAMMA_OUT_MAX_SAMPLES_V10> segments = {
> -		64, 64, 64, 64, 128, 128, 128, 128, 256,
> -		256, 256, 512, 512, 512, 512, 512, 0
> -	};
> -
>  	auto config = params->block<BlockType::Goc>();
>  	config.setEnabled(true);
>
> -	__u16 *gamma_y = config->gamma_y;
> -
> -	unsigned x = 0;
> -	for (const auto [i, size] : utils::enumerate(segments)) {
> -		gamma_y[i] = std::pow(x / 4096.0, 1.0 / frameContext.goc.gamma) * 1023.0;
> -		x += size;
> -	}
> -
> +	Span<uint16_t> lut{ config->gamma_y };
> +	gammaAlgo_.prepare(frameContext.gamma, lut);
>  	config->mode = RKISP1_CIF_ISP_GOC_MODE_LOGARITHMIC;
>  }
>
> @@ -139,7 +110,7 @@ void GammaOutCorrection::process([[maybe_unused]] IPAContext &context,
>  				 [[maybe_unused]] const rkisp1_stat_buffer *stats,
>  				 ControlList &metadata)
>  {
> -	metadata.set(controls::Gamma, frameContext.goc.gamma);
> +	gammaAlgo_.process(frameContext.gamma, metadata);
>  }
>
>  REGISTER_IPA_ALGORITHM(GammaOutCorrection, "GammaOutCorrection")
> diff --git a/src/ipa/rkisp1/algorithms/goc.h b/src/ipa/rkisp1/algorithms/goc.h
> index bd79fe19cc86b8aefa2603e98e9d7130b44105d9..767d707b2758a89db286ab62d8f20d7a01912a2a 100644
> --- a/src/ipa/rkisp1/algorithms/goc.h
> +++ b/src/ipa/rkisp1/algorithms/goc.h
> @@ -9,6 +9,11 @@
>
>  #include "algorithm.h"
>
> +#include <linux/rkisp1-config.h>
> +
> +#include <libipa/fixedpoint.h>
> +#include <libipa/gamma.h>
> +
>  namespace libcamera {
>
>  namespace ipa::rkisp1::algorithms {
> @@ -35,7 +40,7 @@ public:
>  		     ControlList &metadata) override;
>
>  private:
> -	float defaultGamma_;
> +	GammaAlgorithm<RKISP1_CIF_ISP_GAMMA_OUT_MAX_SAMPLES_V10, UQ<0, 10>> gammaAlgo_;
>  };
>
>  } /* namespace ipa::rkisp1::algorithms */
> diff --git a/src/ipa/rkisp1/ipa_context.h b/src/ipa/rkisp1/ipa_context.h
> index 7b4346c54ed2b8850ed147b0ce2b8a20155b80cf..8011c353c4eaade85d0a0007b44de8af7beaa9d6 100644
> --- a/src/ipa/rkisp1/ipa_context.h
> +++ b/src/ipa/rkisp1/ipa_context.h
> @@ -30,6 +30,7 @@
>  #include "libipa/ccm.h"
>  #include "libipa/fc_queue.h"
>  #include "libipa/fixedpoint.h"
> +#include "libipa/gamma.h"
>  #include "libipa/lsc.h"
>
>  namespace libcamera {
> @@ -127,9 +128,7 @@ struct IPAActiveState {
>  		uint8_t sharpness;
>  	} filter;
>
> -	struct {
> -		double gamma;
> -	} goc;
> +	ipa::gamma::ActiveState gamma;
>
>  	struct {
>  		double lux;
> @@ -194,10 +193,7 @@ struct IPAFrameContext : public FrameContext {
>  		bool update;
>  	} filter;
>
> -	struct {
> -		double gamma;
> -		bool update;
> -	} goc;
> +	ipa::gamma::FrameContext gamma;
>
>  	struct {
>  		uint32_t exposure;
>
> --
> 2.43.0
>