[RFC,v9,6/6] libcamera: software_isp: debayer_egl: Add LSC support
diff mbox series

Message ID 20260720095951.49979-7-mzamazal@redhat.com
State New
Headers show
Series
  • LSC for SoftISP simple pipeline
Related show

Commit Message

Milan Zamazal July 20, 2026, 9:59 a.m. UTC 
From: Xander Pronk <xander.c.pronk@gmail.com>

Add support for passing the LSC table from debayerParams to the shaders.

The LSC table values are floats, we must add `type' parameter to
createTexture2D to support this.  Moreover, we use 16-bit internal
format for the values, primarily because this works for me, unlike
32-bit floats.

When LSC is disabled by the runtime control, we provide a constant 1.0
correction table, i.e. a no-op table.  This is preferred to having a
runtime flag, to not disturb GPU computation with runtime switches,
assuming that disabling LSC in runtime is not a common use case.

Co-developed-by: Rick ten Wolde <rick_libcamera@wolde.info>
Signed-off-by: Rick ten Wolde <rick_libcamera@wolde.info>
Signed-off-by: Xander Pronk <xander.c.pronk@gmail.com>
Signed-off-by: Milan Zamazal <mzamazal@redhat.com>
---
 include/libcamera/internal/egl.h              |  6 +++-
 .../internal/software_isp/debayer_params.h    |  2 ++
 src/ipa/simple/algorithms/lsc.cpp             | 11 ++++---
 src/libcamera/egl.cpp                         | 12 +++++--
 src/libcamera/software_isp/debayer.cpp        |  5 +++
 src/libcamera/software_isp/debayer_egl.cpp    | 32 +++++++++++++++++--
 src/libcamera/software_isp/debayer_egl.h      |  6 ++++
 7 files changed, 64 insertions(+), 10 deletions(-)

Patch
diff mbox series 

diff --git a/include/libcamera/internal/egl.h b/include/libcamera/internal/egl.h
index 9edc28ea4..441599a1d 100644
--- a/include/libcamera/internal/egl.h
+++ b/include/libcamera/internal/egl.h
@@ -107,7 +107,11 @@  public:
 
 	int createInputDMABufTexture2D(eGLImage &eglImage, int fd);
 	int createOutputDMABufTexture2D(eGLImage &eglImage, int fd);
-	void createTexture2D(eGLImage &eglImage, void *data, GLint filter);
+	void createTexture2D(eGLImage &eglImage,
+			     GLint internalFormat,
+			     GLenum type,
+			     const void *data,
+			     GLint filter);
 	void updateTexture2D(eGLImage &eglImage, void *data);
 	void createOutputTexture2D(eGLImage &eglImage);
 
diff --git a/include/libcamera/internal/software_isp/debayer_params.h b/include/libcamera/internal/software_isp/debayer_params.h
index e3e01bc04..76825e6c8 100644
--- a/include/libcamera/internal/software_isp/debayer_params.h
+++ b/include/libcamera/internal/software_isp/debayer_params.h
@@ -29,6 +29,8 @@  struct DebayerParams {
 
 	static constexpr unsigned int kLscGridSize = 16;
 	static constexpr unsigned int kLscValuesPerCell = 3;
+	static constexpr unsigned int kLscBytesPerCell =
+		kLscValuesPerCell * sizeof(float);
 	using LscLookupTable =
 		std::array<float, kLscGridSize * kLscGridSize * kLscValuesPerCell>;
 	LscLookupTable lscLut{};
diff --git a/src/ipa/simple/algorithms/lsc.cpp b/src/ipa/simple/algorithms/lsc.cpp
index c531937c7..51c5b63d5 100644
--- a/src/ipa/simple/algorithms/lsc.cpp
+++ b/src/ipa/simple/algorithms/lsc.cpp
@@ -46,13 +46,16 @@  void Lsc::prepare([[maybe_unused]] IPAContext &context,
 		  IPAFrameContext &frameContext,
 		  DebayerParams *params)
 {
-	params->lscEnabled = frameContext.lsc.enabled;
-
 	unsigned int ct = frameContext.awb.colourTemperature;
 	constexpr unsigned int minTemperatureChange = 100;
 
-	if (!frameContext.lsc.enabled ||
-	    utils::abs_diff(ct, lastAppliedCt_) < minTemperatureChange)
+	if (!frameContext.lsc.enabled) {
+		params->lscLut.fill(1.0);
+		lastAppliedCt_ = 0;
+		return;
+	}
+
+	if (utils::abs_diff(ct, lastAppliedCt_) < minTemperatureChange)
 		return;
 
 	const lsc::Components<uint8_t> &set = lscAlgo_.interpolateComponents(ct);
diff --git a/src/libcamera/egl.cpp b/src/libcamera/egl.cpp
index 53390f370..1e876e51f 100644
--- a/src/libcamera/egl.cpp
+++ b/src/libcamera/egl.cpp
@@ -274,6 +274,8 @@  int eGL::createOutputDMABufTexture2D(eGLImage &eglImage, int fd)
 /**
  * \brief Create a 2D texture from a memory buffer
  * \param[in,out] eglImage EGL image to associate with the texture
+ * \param[in] internalFormat OpenGL internal storage format (e.g., GL_RGB8, GL_RGBA8)
+ * \param[in] type OpenGL pixel data type (e.g., GL_UNSIGNED_BYTE, GL_FLOAT)
  * \param[in] data Pointer to pixel data, or nullptr for uninitialised texture
  * \param[in] filter GL texture filter setting
  *
@@ -282,14 +284,18 @@  int eGL::createOutputDMABufTexture2D(eGLImage &eglImage, int fd)
  * is useful for uploading static data like lookup tables or uniform color
  * matrices to the GPU.
  */
-void eGL::createTexture2D(eGLImage &eglImage, void *data, GLint filter)
+void eGL::createTexture2D(eGLImage &eglImage,
+			  GLint internalFormat,
+			  GLenum type,
+			  const void *data,
+			  GLint filter)
 {
 	ASSERT(tid_ == Thread::currentId());
 
 	activateBindTexture(eglImage);
 
 	// Generate texture, bind, associate image to texture, configure, unbind
-	glTexImage2D(GL_TEXTURE_2D, 0, eglImage.format_, eglImage.width_, eglImage.height_, 0, eglImage.format_, GL_UNSIGNED_BYTE, data);
+	glTexImage2D(GL_TEXTURE_2D, 0, internalFormat, eglImage.width_, eglImage.height_, 0, eglImage.format_, type, data);
 
 	// Nearest filtering
 	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, filter);
@@ -370,7 +376,7 @@  void eGL::updateTexture2D(eGLImage &eglImage, void *data)
  */
 void eGL::createOutputTexture2D(eGLImage &eglImage)
 {
-	createTexture2D(eglImage, NULL, GL_NEAREST);
+	createTexture2D(eglImage, eglImage.format_, GL_UNSIGNED_BYTE, NULL, GL_NEAREST);
 	attachTextureToFBO(eglImage);
 }
 
diff --git a/src/libcamera/software_isp/debayer.cpp b/src/libcamera/software_isp/debayer.cpp
index 5ae9f032f..70c0e3336 100644
--- a/src/libcamera/software_isp/debayer.cpp
+++ b/src/libcamera/software_isp/debayer.cpp
@@ -53,6 +53,11 @@  namespace libcamera {
  * \brief Number of pixel values per each of the lens shading grid areas
  */
 
+/**
+ * \var DebayerParams::kLscBytesPerCell
+ * \brief Number of bytes per each of the lens shading grid areas
+ */
+
 /**
  * \typedef DebayerParams::LscLookupTable
  * \brief Lookup table for lens shading correction
diff --git a/src/libcamera/software_isp/debayer_egl.cpp b/src/libcamera/software_isp/debayer_egl.cpp
index 7cb0ee6ff..98ba5b24b 100644
--- a/src/libcamera/software_isp/debayer_egl.cpp
+++ b/src/libcamera/software_isp/debayer_egl.cpp
@@ -128,6 +128,8 @@  int DebayerEGL::getShaderVariableLocations(void)
 	textureUniformBayerFirstRed_ = glGetUniformLocation(programId_, "tex_bayer_first_red");
 	textureUniformProjMatrix_ = glGetUniformLocation(programId_, "proj_matrix");
 
+	textureUniformLsc_ = glGetUniformLocation(programId_, "lsc_tex");
+
 	LOG(Debayer, Debug) << "vertexIn " << attributeVertex_ << " textureIn " << attributeTexture_
 			    << " tex_y " << textureUniformBayerDataIn_
 			    << " awb " << awbUniformDataIn_
@@ -139,7 +141,8 @@  int DebayerEGL::getShaderVariableLocations(void)
 			    << " tex_size " << textureUniformSize_
 			    << " stride_factor " << textureUniformStrideFactor_
 			    << " tex_bayer_first_red " << textureUniformBayerFirstRed_
-			    << " proj_matrix " << textureUniformProjMatrix_;
+			    << " proj_matrix " << textureUniformProjMatrix_
+			    << " tex_lsc " << textureUniformLsc_;
 	return 0;
 }
 
@@ -156,6 +159,9 @@  int DebayerEGL::initBayerShaders(PixelFormat inputFormat, PixelFormat outputForm
 	/* Specify GL_OES_EGL_image_external */
 	egl_.pushEnv(shaderEnv, "#extension GL_OES_EGL_image_external: enable");
 
+	if (lscEnabled_)
+		egl_.pushEnv(shaderEnv, "#define APPLY_LSC");
+
 	/*
 	 * Tell shaders how to re-order output taking account of how the pixels
 	 * are actually stored by EGL.
@@ -351,6 +357,18 @@  int DebayerEGL::configure(const StreamConfiguration &inputCfg,
 	inputBufferCount_ = inputCfg.bufferCount;
 	outputBufferCount_ = outputCfg.bufferCount;
 
+	if (lscEnabled_) {
+		constexpr unsigned int gridSize = DebayerParams::kLscGridSize;
+		const unsigned int stride = gridSize * DebayerParams::kLscBytesPerCell;
+		eglImageLscLookup_ =
+			std::make_unique<eGLImage>(GL_RGB,
+						   gridSize,
+						   gridSize,
+						   stride,
+						   GL_TEXTURE2,
+						   2);
+	}
+
 	return 0;
 }
 
@@ -486,6 +504,12 @@  void DebayerEGL::setShaderVariableValues(eGLImage &eglImageIn, const DebayerPara
 	glUniformMatrix3fv(ccmUniformDataIn_, 1, GL_TRUE, params.combinedMatrix.data().data());
 	LOG(Debayer, Debug) << " ccmUniformDataIn_ " << ccmUniformDataIn_ << " data " << params.combinedMatrix;
 
+	if (lscEnabled_) {
+		egl_.createTexture2D(*eglImageLscLookup_, GL_RGB16F, GL_FLOAT,
+				     params.lscLut.data(), GL_LINEAR);
+		glUniform1i(textureUniformLsc_, eglImageLscLookup_->texture_unit_uniform_id_);
+	}
+
 	/*
 	 * 0 = Red, 1 = Green, 2 = Blue
 	 */
@@ -552,7 +576,11 @@  eGLImage *DebayerEGL::getCachedInputFrameBuffer(FrameBuffer *input, std::optiona
 		return nullptr;
 	}
 	if (cache_miss)
-		egl_.createTexture2D(*eglImageIn, inMapped->value().planes()[0].data(), GL_NEAREST);
+		egl_.createTexture2D(*eglImageIn,
+				     eglImageIn->format_,
+				     GL_UNSIGNED_BYTE,
+				     inMapped->value().planes()[0].data(),
+				     GL_NEAREST);
 	else
 		egl_.updateTexture2D(*eglImageIn, inMapped->value().planes()[0].data());
 
diff --git a/src/libcamera/software_isp/debayer_egl.h b/src/libcamera/software_isp/debayer_egl.h
index 26b009da4..f12c0aef3 100644
--- a/src/libcamera/software_isp/debayer_egl.h
+++ b/src/libcamera/software_isp/debayer_egl.h
@@ -84,7 +84,10 @@  private:
 	unsigned int inputBufferCount_;
 	unsigned int outputBufferCount_;
 
+	/* LSC lookup table */
+	std::unique_ptr<eGLImage> eglImageLscLookup_;
 	bool lscEnabled_;
+
 	/* Shader parameters */
 	float firstRed_x_;
 	float firstRed_y_;
@@ -101,6 +104,9 @@  private:
 	/* Per-frame AWB gains */
 	GLint awbUniformDataIn_;
 
+	/* Lens shading correction */
+	GLint textureUniformLsc_;
+
 	/* Represent per-frame CCM as a uniform vector of floats 3 x 3 */
 	GLint ccmUniformDataIn_;