[{"id":39759,"web_url":"https://patchwork.libcamera.org/comment/39759/","msgid":"<73ffa103-4246-4fb2-9fce-cf18e863999c@nxsw.ie>","date":"2026-07-20T10:56:21","subject":"Re: [RFC PATCH v8 6/6] libcamera: software_isp: debayer_egl: Add LSC\n\tsupport","submitter":{"id":226,"url":"https://patchwork.libcamera.org/api/people/226/","name":"Bryan O'Donoghue","email":"bod.linux@nxsw.ie"},"content":"On 16/07/2026 23:25, Milan Zamazal wrote:\n> From: Xander Pronk \n> \n> Add support for passing the LSC table from debayerParams to the shaders.\n> \n> The LSC table values are floats, we must add `type' parameter to\n> createTexture2D to support this. Moreover, we use 16-bit internal\n> format for the values, primarily because this works for me, unlike\n> 32-bit floats.\n> \n> When LSC is disabled by the runtime control, we provide a constant 1.0\n> correction table, i.e. a no-op table. This is preferred to having a\n> runtime flag, to not disturb GPU computation with runtime switches,\n> assuming that disabling LSC in runtime is not a common use case.\n> \n> Co-developed-by: Rick ten Wolde \n> Signed-off-by: Rick ten Wolde \n> Signed-off-by: Xander Pronk \n> Signed-off-by: Milan Zamazal \n> ---\n> include/libcamera/internal/egl.h | 6 +++-\n> .../internal/software_isp/debayer_params.h | 2 ++\n> src/ipa/simple/algorithms/lsc.cpp | 11 ++++---\n> src/libcamera/egl.cpp | 10 +++++--\n> src/libcamera/software_isp/debayer.cpp | 5 ++++\n> src/libcamera/software_isp/debayer_egl.cpp | 29 +++++++++++++++++--\n> src/libcamera/software_isp/debayer_egl.h | 6 ++++\n> 7 files changed, 60 insertions(+), 9 deletions(-)\n> \n> diff --git a/include/libcamera/internal/egl.h b/include/libcamera/internal/egl.h\n> index 030c813a5..37da2b18a 100644\n> --- a/include/libcamera/internal/egl.h\n> +++ b/include/libcamera/internal/egl.h\n> @@ -107,7 +107,11 @@ public:\n> \n> \tint createInputDMABufTexture2D(eGLImage &eglImage, int fd);\n> \tint createOutputDMABufTexture2D(eGLImage &eglImage, int fd);\n> -\tvoid createTexture2D(eGLImage &eglImage, void *data, GLint filter);\n> +\tvoid createTexture2D(eGLImage &eglImage,\n> +\t\t\t GLint internalFormat,\n> +\t\t\t GLenum type,\n> +\t\t\t const void *data,\n> +\t\t\t GLint filter);\n> \n> \tvoid pushEnv(std::vector &shaderEnv, const char *str);\n> \tvoid makeCurrent();\n> diff --git a/include/libcamera/internal/software_isp/debayer_params.h b/include/libcamera/internal/software_isp/debayer_params.h\n> index e3e01bc04..76825e6c8 100644\n> --- a/include/libcamera/internal/software_isp/debayer_params.h\n> +++ b/include/libcamera/internal/software_isp/debayer_params.h\n> @@ -29,6 +29,8 @@ struct DebayerParams {\n> \n> \tstatic constexpr unsigned int kLscGridSize = 16;\n> \tstatic constexpr unsigned int kLscValuesPerCell = 3;\n> +\tstatic constexpr unsigned int kLscBytesPerCell =\n> +\t\tkLscValuesPerCell * sizeof(float);\n> \tusing LscLookupTable =\n> \t\tstd::array;\n> \tLscLookupTable lscLut{};\n> diff --git a/src/ipa/simple/algorithms/lsc.cpp b/src/ipa/simple/algorithms/lsc.cpp\n> index c531937c7..51c5b63d5 100644\n> --- a/src/ipa/simple/algorithms/lsc.cpp\n> +++ b/src/ipa/simple/algorithms/lsc.cpp\n> @@ -46,13 +46,16 @@ void Lsc::prepare([[maybe_unused]] IPAContext &context,\n> \t\t IPAFrameContext &frameContext,\n> \t\t DebayerParams *params)\n> {\n> -\tparams->lscEnabled = frameContext.lsc.enabled;\n> -\n> \tunsigned int ct = frameContext.awb.colourTemperature;\n> \tconstexpr unsigned int minTemperatureChange = 100;\n> \n> -\tif (!frameContext.lsc.enabled ||\n> -\t utils::abs_diff(ct, lastAppliedCt_) < minTemperatureChange)\n> +\tif (!frameContext.lsc.enabled) {\n> +\t\tparams->lscLut.fill(1.0);\n> +\t\tlastAppliedCt_ = 0;\n> +\t\treturn;\n> +\t}\n> +\n> +\tif (utils::abs_diff(ct, lastAppliedCt_) < minTemperatureChange)\n> \t\treturn;\n> \n> \tconst lsc::Components &set = lscAlgo_.interpolateComponents(ct);\n> diff --git a/src/libcamera/egl.cpp b/src/libcamera/egl.cpp\n> index aeac5d313..c2a158ce7 100644\n> --- a/src/libcamera/egl.cpp\n> +++ b/src/libcamera/egl.cpp\n> @@ -241,6 +241,8 @@ int eGL::createOutputDMABufTexture2D(eGLImage &eglImage, int fd)\n> /**\n> * \\brief Create a 2D texture from a memory buffer\n> * \\param[in,out] eglImage EGL image to associate with the texture\n> + * \\param[in] internalFormat OpenGL internal storage format (e.g., GL_RGB8, GL_RGBA8)\n> + * \\param[in] type OpenGL pixel data type (e.g., GL_UNSIGNED_BYTE, GL_FLOAT)\n> * \\param[in] data Pointer to pixel data, or nullptr for uninitialised texture\n> * \\param[in] filter GL texture filter setting\n> *\n> @@ -249,7 +251,11 @@ int eGL::createOutputDMABufTexture2D(eGLImage &eglImage, int fd)\n> * is useful for uploading static data like lookup tables or uniform color\n> * matrices to the GPU.\n> */\n> -void eGL::createTexture2D(eGLImage &eglImage, void *data, GLint filter)\n> +void eGL::createTexture2D(eGLImage &eglImage,\n> +\t\t\t GLint internalFormat,\n> +\t\t\t GLenum type,\n> +\t\t\t const void *data,\n> +\t\t\t GLint filter)\n> {\n> \tASSERT(tid_ == Thread::currentId());\n> \n> @@ -257,7 +263,7 @@ void eGL::createTexture2D(eGLImage &eglImage, void *data, GLint filter)\n> \tglBindTexture(GL_TEXTURE_2D, eglImage.texture_);\n> \n> \t// Generate texture, bind, associate image to texture, configure, unbind\n> -\tglTexImage2D(GL_TEXTURE_2D, 0, eglImage.format_, eglImage.width_, eglImage.height_, 0, eglImage.format_, GL_UNSIGNED_BYTE, data);\n> +\tglTexImage2D(GL_TEXTURE_2D, 0, internalFormat, eglImage.width_, eglImage.height_, 0, eglImage.format_, type, data);\n> \n> \t// Nearest filtering\n> \tglTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, filter);\n> diff --git a/src/libcamera/software_isp/debayer.cpp b/src/libcamera/software_isp/debayer.cpp\n> index 5ae9f032f..70c0e3336 100644\n> --- a/src/libcamera/software_isp/debayer.cpp\n> +++ b/src/libcamera/software_isp/debayer.cpp\n> @@ -53,6 +53,11 @@ namespace libcamera {\n> * \\brief Number of pixel values per each of the lens shading grid areas\n> */\n> \n> +/**\n> + * \\var DebayerParams::kLscBytesPerCell\n> + * \\brief Number of bytes per each of the lens shading grid areas\n> + */\n> +\n> /**\n> * \\typedef DebayerParams::LscLookupTable\n> * \\brief Lookup table for lens shading correction\n> diff --git a/src/libcamera/software_isp/debayer_egl.cpp b/src/libcamera/software_isp/debayer_egl.cpp\n> index 562e9fc7a..0fdf0e6e8 100644\n> --- a/src/libcamera/software_isp/debayer_egl.cpp\n> +++ b/src/libcamera/software_isp/debayer_egl.cpp\n> @@ -128,6 +128,8 @@ int DebayerEGL::getShaderVariableLocations(void)\n> \ttextureUniformBayerFirstRed_ = glGetUniformLocation(programId_, \"tex_bayer_first_red\");\n> \ttextureUniformProjMatrix_ = glGetUniformLocation(programId_, \"proj_matrix\");\n> \n> +\ttextureUniformLsc_ = glGetUniformLocation(programId_, \"lsc_tex\");\n> +\n> \tLOG(Debayer, Debug) << \"vertexIn \" << attributeVertex_ << \" textureIn \" << attributeTexture_\n> \t\t\t << \" tex_y \" << textureUniformBayerDataIn_\n> \t\t\t << \" awb \" << awbUniformDataIn_\n> @@ -139,7 +141,8 @@ int DebayerEGL::getShaderVariableLocations(void)\n> \t\t\t << \" tex_size \" << textureUniformSize_\n> \t\t\t << \" stride_factor \" << textureUniformStrideFactor_\n> \t\t\t << \" tex_bayer_first_red \" << textureUniformBayerFirstRed_\n> -\t\t\t << \" proj_matrix \" << textureUniformProjMatrix_;\n> +\t\t\t << \" proj_matrix \" << textureUniformProjMatrix_\n> +\t\t\t << \" tex_lsc \" << textureUniformLsc_;\n> \treturn 0;\n> }\n> \n> @@ -156,6 +159,9 @@ int DebayerEGL::initBayerShaders(PixelFormat inputFormat, PixelFormat outputForm\n> \t/* Specify GL_OES_EGL_image_external */\n> \tegl_.pushEnv(shaderEnv, \"#extension GL_OES_EGL_image_external: enable\");\n> \n> +\tif (lscEnabled_)\n> +\t\tegl_.pushEnv(shaderEnv, \"#define APPLY_LSC\");\n> +\n> \t/*\n> \t * Tell shaders how to re-order output taking account of how the pixels\n> \t * are actually stored by EGL.\n> @@ -348,6 +354,18 @@ int DebayerEGL::configure(const StreamConfiguration &inputCfg,\n> \t */\n> \tstats_->setWindow(Rectangle(window_.size()));\n> \n> +\tif (lscEnabled_) {\n> +\t\tconstexpr unsigned int gridSize = DebayerParams::kLscGridSize;\n> +\t\tconst unsigned int stride = gridSize * DebayerParams::kLscBytesPerCell;\n> +\t\teglImageLscLookup_ =\n> +\t\t\tstd::make_unique(GL_RGB,\n> +\t\t\t\t\t\t gridSize,\n> +\t\t\t\t\t\t gridSize,\n> +\t\t\t\t\t\t stride,\n> +\t\t\t\t\t\t GL_TEXTURE2,\n> +\t\t\t\t\t\t 2);\n> +\t}\n> +\n> \treturn 0;\n> }\n> \n> @@ -483,6 +501,12 @@ void DebayerEGL::setShaderVariableValues(const DebayerParams ¶ms)\n> \tglUniformMatrix3fv(ccmUniformDataIn_, 1, GL_TRUE, params.combinedMatrix.data().data());\n> \tLOG(Debayer, Debug) << \" ccmUniformDataIn_ \" << ccmUniformDataIn_ << \" data \" << params.combinedMatrix;\n> \n> +\tif (lscEnabled_) {\n> +\t\tegl_.createTexture2D(*eglImageLscLookup_, GL_RGB16F, GL_FLOAT,\n> +\t\t\t\t params.lscLut.data(), GL_LINEAR);\n\nAs we are discussing in the multi-pass thread, GL_RGB16F is dependent on \nthe optional GL_EXT_color_buffer_half_float\n\nhttps://registry.khronos.org/OpenGL/extensions/EXT/EXT_color_buffer_half_float.txt\n\nI think it should be pretty easy to disjunct on that as a flag in the \nbase class - a flag I plan to add for SSBO stats but also perfectly \nhappy for you to add.\n\nHalf float linear filtering requires OES_texture_half_float_linear\n\nglGetString(GL_EXTENSIONS) | grep OES_texture_half_float_linear | \ndebayer_egl{ bool _has_OES_texture_half_float_linear;} or whatever\n\nif (_has_OES_texture_half_float_linear)\n\tGL_RGB16F;\n\nCould we repreent the LSC data as uint8 natively ? I mean without \nstoring it all as float and then converting to uint8 on each LSC \napplication cycle ?\n\n> +\t\tglUniform1i(textureUniformLsc_, eglImageLscLookup_->texture_unit_uniform_id_);\n> +\t}\n> +\n> \t/*\n> \t * 0 = Red, 1 = Green, 2 = Blue\n> \t */\n> @@ -530,7 +554,8 @@ int DebayerEGL::debayerGPU(FrameBuffer *input, FrameBuffer *output, const Debaye\n> \t\t\tLOG(Debayer, Error) << \"mmap-ing buffer(s) failed\";\n> \t\t\treturn -ENODEV;\n> \t\t}\n> -\t\tegl_.createTexture2D(*eglImageBayerIn_, inMapped->value().planes()[0].data(), GL_NEAREST);\n> +\t\tegl_.createTexture2D(*eglImageBayerIn_, glFormat_, GL_UNSIGNED_BYTE,\n> +\t\t\t\t inMapped->value().planes()[0].data(), GL_NEAREST);\n> \t}\n> \n> \t/* Generate the output render framebuffer as render to texture */\n> diff --git a/src/libcamera/software_isp/debayer_egl.h b/src/libcamera/software_isp/debayer_egl.h\n> index 82ed1305d..f3913d564 100644\n> --- a/src/libcamera/software_isp/debayer_egl.h\n> +++ b/src/libcamera/software_isp/debayer_egl.h\n> @@ -78,7 +78,10 @@ private:\n> \tstd::unique_ptr eglImageBayerIn_;\n> \tstd::unique_ptr eglImageBayerOut_;\n> \n> +\t/* LSC lookup table */\n> +\tstd::unique_ptr eglImageLscLookup_;\n> \tbool lscEnabled_;\n> +\n> \t/* Shader parameters */\n> \tfloat firstRed_x_;\n> \tfloat firstRed_y_;\n> @@ -95,6 +98,9 @@ private:\n> \t/* Per-frame AWB gains */\n> \tGLint awbUniformDataIn_;\n> \n> +\t/* Lens shading correction */\n> +\tGLint textureUniformLsc_;\n> +\n> \t/* Represent per-frame CCM as a uniform vector of floats 3 x 3 */\n> \tGLint ccmUniformDataIn_;\n> \n> --\n> 2.55.0\n>","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 9151ABF415\n\tfor ;\n\tMon, 20 Jul 2026 10:56:33 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 7E75266151;\n\tMon, 20 Jul 2026 12:56:32 +0200 (CEST)","from mail-10625.protonmail.ch (mail-10625.protonmail.ch\n\t[79.135.106.25])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 20A9066122\n\tfor ;\n\tMon, 20 Jul 2026 12:56:31 +0200 (CEST)"],"Authentication-Results":"lancelot.ideasonboard.com; dkim=pass (2048-bit key;\n\tunprotected) header.d=nxsw.ie header.i=@nxsw.ie header.b=\"k9ONQ+3m\";\n\tdkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed; d=nxsw.ie;\n\ts=protonmail; t=1784544987; x=1784804187;\n\tbh=SJtYhEDbbPp7HLuzyzQIGrUb7PtoTD09cYcep/OrdjA=;\n\th=Date:To:From:Cc:Subject:Message-ID:In-Reply-To:References:\n\tFeedback-ID:From:To:Cc:Date:Subject:Reply-To:Feedback-ID:\n\tMessage-ID:BIMI-Selector;\n\tb=k9ONQ+3m+JAeqfbhAdkzK5uHEU6uXRztRIutkd7wmcSs01H/XbaTLLtuPauKAvX/V\n\t/58Vb/0dxBifCk/KDg7ZSZsbm3q4if9JCERc7xpxBkYRiwSNyCHrld8gYkhD2ELOHy\n\toBGtn/ZRVN73qNxdXCFf80CxK1yjzFN86I6CXnU9DK7sjCLtM4dHj5DeytloxMgBn0\n\tQ/9U6Ndz+3Se3tx+5jmENB7kUAB1L/9JSRIrjQ8lwWX3VAK89GqkD1kc40ySmEW40C\n\tKkSY8cE6BVuoYx9gvQ5VvIdKUIFekOngjuyFO9TPQILKEp7HTerfOCAGB1dY9E9+RJ\n\tPaSPaghpZIkLw==","Date":"Mon, 20 Jul 2026 10:56:21 +0000","To":"Milan Zamazal , libcamera-devel@lists.libcamera.org","From":"Bryan O'Donoghue ","Cc":"Xander Pronk ,\n\tHans de Goede ,\n\tLaurent Pinchart ,\n\tRick ten Wolde ","Subject":"Re: [RFC PATCH v8 6/6] libcamera: software_isp: debayer_egl: Add LSC\n\tsupport","Message-ID":"<73ffa103-4246-4fb2-9fce-cf18e863999c@nxsw.ie>","In-Reply-To":"<20260716222515.251464-7-mzamazal@redhat.com>","References":"<20260716222515.251464-1-mzamazal@redhat.com>\n\t<20260716222515.251464-7-mzamazal@redhat.com>","Feedback-ID":"136405006:user:proton","X-Pm-Message-ID":"884c43ae720f33ec99cebab42621a7aba3cfe574","MIME-Version":"1.0","Content-Type":"text/plain; charset=utf-8","Content-Transfer-Encoding":"quoted-printable","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}},{"id":39760,"web_url":"https://patchwork.libcamera.org/comment/39760/","msgid":"<864b0a29-ddd0-4f84-a7ca-da5ea96f6807@nxsw.ie>","date":"2026-07-20T11:07:30","subject":"Re: [RFC PATCH v8 6/6] libcamera: software_isp: debayer_egl: Add LSC\n\tsupport","submitter":{"id":226,"url":"https://patchwork.libcamera.org/api/people/226/","name":"Bryan O'Donoghue","email":"bod.linux@nxsw.ie"},"content":"On 16/07/2026 23:25, Milan Zamazal wrote:\n> @@ -483,6 +501,12 @@ void DebayerEGL::setShaderVariableValues(const DebayerParams ¶ms)\n> \tglUniformMatrix3fv(ccmUniformDataIn_, 1, GL_TRUE, params.combinedMatrix.data().data());\n> \tLOG(Debayer, Debug) << \" ccmUniformDataIn_ \" << ccmUniformDataIn_ << \" data \" << params.combinedMatrix;\n> \n> +\tif (lscEnabled_) {\n> +\t\tegl_.createTexture2D(*eglImageLscLookup_, GL_RGB16F, GL_FLOAT,\n> +\t\t\t\t params.lscLut.data(), GL_LINEAR);\n> +\t\tglUniform1i(textureUniformLsc_, eglImageLscLookup_->texture_unit_uniform_id_);\n> +\t}\n> +\n\nCreate texture should happen in configure() and we should use \negl_.updateTexture2D - if and only if the LSC algorithm has called for \nnew data - else it is sufficient to create and populate the texture and \nthen reuse the texture_id on subsequent passes.\n\nI guess ? LSC doesn't need to be updated for each frame - even if it \ndoes updateTexture2D should be used - as its role in life is to update a \nGPU texture we already have instead of nuking and replacing.\n\n---\nbod","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 1F3A2BE080\n\tfor ;\n\tMon, 20 Jul 2026 11:07:36 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 3B0A567E30;\n\tMon, 20 Jul 2026 13:07:35 +0200 (CEST)","from mail-24421.protonmail.ch (mail-24421.protonmail.ch\n\t[109.224.244.21])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 49E1C66122\n\tfor ;\n\tMon, 20 Jul 2026 13:07:34 +0200 (CEST)"],"Authentication-Results":"lancelot.ideasonboard.com; dkim=pass (2048-bit key;\n\tunprotected) header.d=nxsw.ie header.i=@nxsw.ie header.b=\"elGVCUVY\";\n\tdkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed; d=nxsw.ie;\n\ts=protonmail; t=1784545653; x=1784804853;\n\tbh=vEjLH5LpzSIMgkj6/6BO4ZSnDf1MIroRTUM3IWAmS1A=;\n\th=Date:To:From:Cc:Subject:Message-ID:In-Reply-To:References:\n\tFeedback-ID:From:To:Cc:Date:Subject:Reply-To:Feedback-ID:\n\tMessage-ID:BIMI-Selector;\n\tb=elGVCUVYUQTP/b5JxiFb4L1jU2LQKR83jV6c6KTea0xW/JJo3qzKIWmxXnrMWA1cp\n\tsJw5YH9YPCoz/zlmeJ0ChQ4DFzlBYdzTXIydc1sl9j77wEpnDIbcYQskQczQ/oVmAw\n\tvCnihlQtAXpMbrTC7Z9zodpTcOli/UL0H8snjXBY+k+e4BChwuwT0B2T0FqU3RKHS5\n\tl3FsI9pUFmWRrQlwqTavXU1s6rkw+I6idh6/hL//Nrbsd2cBSfAKe6IJdGiRX85R6t\n\tNVOnojxe9920nAG09zvUPyGL1lE9DLyTJSdxSCDtX2ex7TwxJN/Kiuh1MjDXadatC2\n\tetRHZK9nSmS2A==","Date":"Mon, 20 Jul 2026 11:07:30 +0000","To":"Milan Zamazal , libcamera-devel@lists.libcamera.org","From":"Bryan O'Donoghue ","Cc":"Xander Pronk ,\n\tHans de Goede ,\n\tLaurent Pinchart ,\n\tRick ten Wolde ","Subject":"Re: [RFC PATCH v8 6/6] libcamera: software_isp: debayer_egl: Add LSC\n\tsupport","Message-ID":"<864b0a29-ddd0-4f84-a7ca-da5ea96f6807@nxsw.ie>","In-Reply-To":"<20260716222515.251464-7-mzamazal@redhat.com>","References":"<20260716222515.251464-1-mzamazal@redhat.com>\n\t<20260716222515.251464-7-mzamazal@redhat.com>","Feedback-ID":"136405006:user:proton","X-Pm-Message-ID":"d7e361c79429709b85c7631654b99a65cd712d8f","MIME-Version":"1.0","Content-Type":"text/plain; charset=utf-8","Content-Transfer-Encoding":"quoted-printable","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}},{"id":39765,"web_url":"https://patchwork.libcamera.org/comment/39765/","msgid":"<85h5ltkclx.fsf@mzamazal-thinkpadp1gen7.tpbc.csb>","date":"2026-07-20T13:35:38","subject":"Re: [RFC PATCH v8 6/6] libcamera: software_isp: debayer_egl: Add\n\tLSC support","submitter":{"id":177,"url":"https://patchwork.libcamera.org/api/people/177/","name":"Milan Zamazal","email":"mzamazal@redhat.com"},"content":"Bryan O'Donoghue writes:\n\n> On 16/07/2026 23:25, Milan Zamazal wrote:\n>> From: Xander Pronk \n>> \n>\n>> Add support for passing the LSC table from debayerParams to the shaders.\n>> \n>> The LSC table values are floats, we must add `type' parameter to\n>> createTexture2D to support this. Moreover, we use 16-bit internal\n>> format for the values, primarily because this works for me, unlike\n>> 32-bit floats.\n>> \n>> When LSC is disabled by the runtime control, we provide a constant 1.0\n>> correction table, i.e. a no-op table. This is preferred to having a\n>> runtime flag, to not disturb GPU computation with runtime switches,\n>> assuming that disabling LSC in runtime is not a common use case.\n>> \n>> Co-developed-by: Rick ten Wolde \n>> Signed-off-by: Rick ten Wolde \n>> Signed-off-by: Xander Pronk \n>> Signed-off-by: Milan Zamazal \n>> ---\n>> include/libcamera/internal/egl.h | 6 +++-\n>> .../internal/software_isp/debayer_params.h | 2 ++\n>> src/ipa/simple/algorithms/lsc.cpp | 11 ++++---\n>> src/libcamera/egl.cpp | 10 +++++--\n>> src/libcamera/software_isp/debayer.cpp | 5 ++++\n>> src/libcamera/software_isp/debayer_egl.cpp | 29 +++++++++++++++++--\n>> src/libcamera/software_isp/debayer_egl.h | 6 ++++\n>> 7 files changed, 60 insertions(+), 9 deletions(-)\n>> \n>> diff --git a/include/libcamera/internal/egl.h b/include/libcamera/internal/egl.h\n>> index 030c813a5..37da2b18a 100644\n>> --- a/include/libcamera/internal/egl.h\n>> +++ b/include/libcamera/internal/egl.h\n>> @@ -107,7 +107,11 @@ public:\n>> \n>> \tint createInputDMABufTexture2D(eGLImage &eglImage, int fd);\n>> \tint createOutputDMABufTexture2D(eGLImage &eglImage, int fd);\n>> -\tvoid createTexture2D(eGLImage &eglImage, void *data, GLint filter);\n>> +\tvoid createTexture2D(eGLImage &eglImage,\n>> +\t\t\t GLint internalFormat,\n>> +\t\t\t GLenum type,\n>> +\t\t\t const void *data,\n>> +\t\t\t GLint filter);\n>> \n>> \tvoid pushEnv(std::vector &shaderEnv, const char *str);\n>> \tvoid makeCurrent();\n>> diff --git a/include/libcamera/internal/software_isp/debayer_params.h b/include/libcamera/internal/software_isp/debayer_params.h\n>> index e3e01bc04..76825e6c8 100644\n>> --- a/include/libcamera/internal/software_isp/debayer_params.h\n>> +++ b/include/libcamera/internal/software_isp/debayer_params.h\n>> @@ -29,6 +29,8 @@ struct DebayerParams {\n>> \n>> \tstatic constexpr unsigned int kLscGridSize = 16;\n>> \tstatic constexpr unsigned int kLscValuesPerCell = 3;\n>> +\tstatic constexpr unsigned int kLscBytesPerCell =\n>> +\t\tkLscValuesPerCell * sizeof(float);\n>> \tusing LscLookupTable =\n>> \t\tstd::array;\n>> \tLscLookupTable lscLut{};\n>> diff --git a/src/ipa/simple/algorithms/lsc.cpp b/src/ipa/simple/algorithms/lsc.cpp\n>> index c531937c7..51c5b63d5 100644\n>> --- a/src/ipa/simple/algorithms/lsc.cpp\n>> +++ b/src/ipa/simple/algorithms/lsc.cpp\n>> @@ -46,13 +46,16 @@ void Lsc::prepare([[maybe_unused]] IPAContext &context,\n>> \t\t IPAFrameContext &frameContext,\n>> \t\t DebayerParams *params)\n>> {\n>> -\tparams->lscEnabled = frameContext.lsc.enabled;\n>> -\n>> \tunsigned int ct = frameContext.awb.colourTemperature;\n>> \tconstexpr unsigned int minTemperatureChange = 100;\n>> \n>> -\tif (!frameContext.lsc.enabled ||\n>> -\t utils::abs_diff(ct, lastAppliedCt_) < minTemperatureChange)\n>> +\tif (!frameContext.lsc.enabled) {\n>> +\t\tparams->lscLut.fill(1.0);\n>> +\t\tlastAppliedCt_ = 0;\n>> +\t\treturn;\n>> +\t}\n>> +\n>> +\tif (utils::abs_diff(ct, lastAppliedCt_) < minTemperatureChange)\n>> \t\treturn;\n>> \n>> \tconst lsc::Components &set = lscAlgo_.interpolateComponents(ct);\n>> diff --git a/src/libcamera/egl.cpp b/src/libcamera/egl.cpp\n>> index aeac5d313..c2a158ce7 100644\n>> --- a/src/libcamera/egl.cpp\n>> +++ b/src/libcamera/egl.cpp\n>> @@ -241,6 +241,8 @@ int eGL::createOutputDMABufTexture2D(eGLImage &eglImage, int fd)\n>> /**\n>> * \\brief Create a 2D texture from a memory buffer\n>> * \\param[in,out] eglImage EGL image to associate with the texture\n>> + * \\param[in] internalFormat OpenGL internal storage format (e.g., GL_RGB8, GL_RGBA8)\n>> + * \\param[in] type OpenGL pixel data type (e.g., GL_UNSIGNED_BYTE, GL_FLOAT)\n>> * \\param[in] data Pointer to pixel data, or nullptr for uninitialised texture\n>> * \\param[in] filter GL texture filter setting\n>> *\n>> @@ -249,7 +251,11 @@ int eGL::createOutputDMABufTexture2D(eGLImage &eglImage, int fd)\n>> * is useful for uploading static data like lookup tables or uniform color\n>> * matrices to the GPU.\n>> */\n>> -void eGL::createTexture2D(eGLImage &eglImage, void *data, GLint filter)\n>> +void eGL::createTexture2D(eGLImage &eglImage,\n>> +\t\t\t GLint internalFormat,\n>> +\t\t\t GLenum type,\n>> +\t\t\t const void *data,\n>> +\t\t\t GLint filter)\n>> {\n>> \tASSERT(tid_ == Thread::currentId());\n>> \n>> @@ -257,7 +263,7 @@ void eGL::createTexture2D(eGLImage &eglImage, void *data, GLint filter)\n>> \tglBindTexture(GL_TEXTURE_2D, eglImage.texture_);\n>> \n>> \t// Generate texture, bind, associate image to texture, configure, unbind\n>> -\tglTexImage2D(GL_TEXTURE_2D, 0, eglImage.format_, eglImage.width_, eglImage.height_, 0, eglImage.format_, GL_UNSIGNED_BYTE, data);\n>> +\tglTexImage2D(GL_TEXTURE_2D, 0, internalFormat, eglImage.width_, eglImage.height_, 0, eglImage.format_, type, data);\n>> \n>> \t// Nearest filtering\n>> \tglTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, filter);\n>> diff --git a/src/libcamera/software_isp/debayer.cpp b/src/libcamera/software_isp/debayer.cpp\n>> index 5ae9f032f..70c0e3336 100644\n>> --- a/src/libcamera/software_isp/debayer.cpp\n>> +++ b/src/libcamera/software_isp/debayer.cpp\n>> @@ -53,6 +53,11 @@ namespace libcamera {\n>> * \\brief Number of pixel values per each of the lens shading grid areas\n>> */\n>> \n>> +/**\n>> + * \\var DebayerParams::kLscBytesPerCell\n>> + * \\brief Number of bytes per each of the lens shading grid areas\n>> + */\n>> +\n>> /**\n>> * \\typedef DebayerParams::LscLookupTable\n>> * \\brief Lookup table for lens shading correction\n>> diff --git a/src/libcamera/software_isp/debayer_egl.cpp b/src/libcamera/software_isp/debayer_egl.cpp\n>> index 562e9fc7a..0fdf0e6e8 100644\n>> --- a/src/libcamera/software_isp/debayer_egl.cpp\n>> +++ b/src/libcamera/software_isp/debayer_egl.cpp\n>> @@ -128,6 +128,8 @@ int DebayerEGL::getShaderVariableLocations(void)\n>> \ttextureUniformBayerFirstRed_ = glGetUniformLocation(programId_, \"tex_bayer_first_red\");\n>> \ttextureUniformProjMatrix_ = glGetUniformLocation(programId_, \"proj_matrix\");\n>> \n>> +\ttextureUniformLsc_ = glGetUniformLocation(programId_, \"lsc_tex\");\n>> +\n>> \tLOG(Debayer, Debug) << \"vertexIn \" << attributeVertex_ << \" textureIn \" << attributeTexture_\n>> \t\t\t << \" tex_y \" << textureUniformBayerDataIn_\n>> \t\t\t << \" awb \" << awbUniformDataIn_\n>> @@ -139,7 +141,8 @@ int DebayerEGL::getShaderVariableLocations(void)\n>> \t\t\t << \" tex_size \" << textureUniformSize_\n>> \t\t\t << \" stride_factor \" << textureUniformStrideFactor_\n>> \t\t\t << \" tex_bayer_first_red \" << textureUniformBayerFirstRed_\n>> -\t\t\t << \" proj_matrix \" << textureUniformProjMatrix_;\n>> +\t\t\t << \" proj_matrix \" << textureUniformProjMatrix_\n>> +\t\t\t << \" tex_lsc \" << textureUniformLsc_;\n>> \treturn 0;\n>> }\n>> \n>> @@ -156,6 +159,9 @@ int DebayerEGL::initBayerShaders(PixelFormat inputFormat, PixelFormat outputForm\n>> \t/* Specify GL_OES_EGL_image_external */\n>> \tegl_.pushEnv(shaderEnv, \"#extension GL_OES_EGL_image_external: enable\");\n>> \n>> +\tif (lscEnabled_)\n>> +\t\tegl_.pushEnv(shaderEnv, \"#define APPLY_LSC\");\n>> +\n>> \t/*\n>> \t * Tell shaders how to re-order output taking account of how the pixels\n>> \t * are actually stored by EGL.\n>> @@ -348,6 +354,18 @@ int DebayerEGL::configure(const StreamConfiguration &inputCfg,\n>> \t */\n>> \tstats_->setWindow(Rectangle(window_.size()));\n>> \n>> +\tif (lscEnabled_) {\n>> +\t\tconstexpr unsigned int gridSize = DebayerParams::kLscGridSize;\n>> +\t\tconst unsigned int stride = gridSize * DebayerParams::kLscBytesPerCell;\n>> +\t\teglImageLscLookup_ =\n>> +\t\t\tstd::make_unique(GL_RGB,\n>> +\t\t\t\t\t\t gridSize,\n>> +\t\t\t\t\t\t gridSize,\n>> +\t\t\t\t\t\t stride,\n>> +\t\t\t\t\t\t GL_TEXTURE2,\n>> +\t\t\t\t\t\t 2);\n>> +\t}\n>> +\n>> \treturn 0;\n>> }\n>> \n>> @@ -483,6 +501,12 @@ void DebayerEGL::setShaderVariableValues(const DebayerParams ¶ms)\n>> \tglUniformMatrix3fv(ccmUniformDataIn_, 1, GL_TRUE, params.combinedMatrix.data().data());\n>> \tLOG(Debayer, Debug) << \" ccmUniformDataIn_ \" << ccmUniformDataIn_ << \" data \" << params.combinedMatrix;\n>> \n>> +\tif (lscEnabled_) {\n>> +\t\tegl_.createTexture2D(*eglImageLscLookup_, GL_RGB16F, GL_FLOAT,\n>> +\t\t\t\t params.lscLut.data(), GL_LINEAR);\n>\n> As we are discussing in the multi-pass thread, GL_RGB16F is dependent on \n> the optional GL_EXT_color_buffer_half_float\n>\n> https://registry.khronos.org/OpenGL/extensions/EXT/EXT_color_buffer_half_float.txt\n>\n> I think it should be pretty easy to disjunct on that as a flag in the \n> base class - a flag I plan to add for SSBO stats but also perfectly \n> happy for you to add.\n>\n> Half float linear filtering requires OES_texture_half_float_linear\n>\n> glGetString(GL_EXTENSIONS) | grep OES_texture_half_float_linear | \n> debayer_egl{ bool _has_OES_texture_half_float_linear;} or whatever\n>\n> if (_has_OES_texture_half_float_linear)\n> \tGL_RGB16F;\n>\n> Could we repreent the LSC data as uint8 natively ? I mean without \n> storing it all as float and then converting to uint8 on each LSC \n> application cycle ?\n\nWe could. `float' would be a nice and clear interface. But I'd prefer\nnot to deal with conditional support, especially if we had to handle the\nunsupported case some way. Since we opt for UQ<2,6> with libipa in the\nalgorithm part, we can pass that to debayering. It may become a\nlimitation in the future, but for now, why not, it's not that difficult\nto change once/if needed.\n\n>> +\t\tglUniform1i(textureUniformLsc_, eglImageLscLookup_->texture_unit_uniform_id_);\n>> +\t}\n>> +\n>> \t/*\n>> \t * 0 = Red, 1 = Green, 2 = Blue\n>> \t */\n>> @@ -530,7 +554,8 @@ int DebayerEGL::debayerGPU(FrameBuffer *input, FrameBuffer *output, const Debaye\n>> \t\t\tLOG(Debayer, Error) << \"mmap-ing buffer(s) failed\";\n>> \t\t\treturn -ENODEV;\n>> \t\t}\n>> -\t\tegl_.createTexture2D(*eglImageBayerIn_, inMapped->value().planes()[0].data(), GL_NEAREST);\n>> +\t\tegl_.createTexture2D(*eglImageBayerIn_, glFormat_, GL_UNSIGNED_BYTE,\n>> +\t\t\t\t inMapped->value().planes()[0].data(), GL_NEAREST);\n>> \t}\n>> \n>> \t/* Generate the output render framebuffer as render to texture */\n>> diff --git a/src/libcamera/software_isp/debayer_egl.h b/src/libcamera/software_isp/debayer_egl.h\n>> index 82ed1305d..f3913d564 100644\n>> --- a/src/libcamera/software_isp/debayer_egl.h\n>> +++ b/src/libcamera/software_isp/debayer_egl.h\n>> @@ -78,7 +78,10 @@ private:\n>> \tstd::unique_ptr eglImageBayerIn_;\n>> \tstd::unique_ptr eglImageBayerOut_;\n>> \n>> +\t/* LSC lookup table */\n>> +\tstd::unique_ptr eglImageLscLookup_;\n>> \tbool lscEnabled_;\n>> +\n>> \t/* Shader parameters */\n>> \tfloat firstRed_x_;\n>> \tfloat firstRed_y_;\n>> @@ -95,6 +98,9 @@ private:\n>> \t/* Per-frame AWB gains */\n>> \tGLint awbUniformDataIn_;\n>> \n>> +\t/* Lens shading correction */\n>> +\tGLint textureUniformLsc_;\n>> +\n>> \t/* Represent per-frame CCM as a uniform vector of floats 3 x 3 */\n>> \tGLint ccmUniformDataIn_;\n>> \n>> --\n>> 2.55.0\n>>","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id F276AC328C\n\tfor ;\n\tMon, 20 Jul 2026 13:35:48 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 1D96567E42;\n\tMon, 20 Jul 2026 15:35:48 +0200 (CEST)","from us-smtp-delivery-124.mimecast.com\n\t(us-smtp-delivery-124.mimecast.com [170.10.129.124])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 101C066177\n\tfor ;\n\tMon, 20 Jul 2026 15:35:46 +0200 (CEST)","from mail-lf1-f72.google.com (mail-lf1-f72.google.com\n\t[209.85.167.72]) by relay.mimecast.com with ESMTP with STARTTLS\n\t(version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id\n\tus-mta-623-3NgnAAzkOTedEzmXiwhEEg-1; Mon, 20 Jul 2026 09:35:43 -0400","by mail-lf1-f72.google.com with SMTP id\n\t2adb3069b0e04-5aeb49bb645so4172033e87.0\n\tfor ;\n\tMon, 20 Jul 2026 06:35:42 -0700 (PDT)","from mzamazal-thinkpadp1gen7.tpbc.csb\n\t(ip-77-48-47-4.net.vodafone.cz. 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\n\tMon, 20 Jul 2026 06:35:40 -0700 (PDT)","by 2002:a05:6512:641a:b0:5b0:eda:de1d with SMTP id\n\t2adb3069b0e04-5b28f874113mr2677389e87.18.1784554540309; \n\tMon, 20 Jul 2026 06:35:40 -0700 (PDT)"],"From":"Milan Zamazal ","To":"Bryan O'Donoghue ","Cc":"libcamera-devel@lists.libcamera.org, Xander Pronk\n\t, Hans de Goede\n\t, Laurent Pinchart\n\t, Rick ten Wolde\n\t","Subject":"Re: [RFC PATCH v8 6/6] libcamera: software_isp: debayer_egl: Add\n\tLSC support","In-Reply-To":"<73ffa103-4246-4fb2-9fce-cf18e863999c@nxsw.ie> (Bryan\n\tO'Donoghue's message of \"Mon, 20 Jul 2026 10:56:21 +0000\")","References":"<20260716222515.251464-1-mzamazal@redhat.com>\n\t<20260716222515.251464-7-mzamazal@redhat.com>\n\t<73ffa103-4246-4fb2-9fce-cf18e863999c@nxsw.ie>","Date":"Mon, 20 Jul 2026 15:35:38 +0200","Message-ID":"<85h5ltkclx.fsf@mzamazal-thinkpadp1gen7.tpbc.csb>","User-Agent":"Gnus/5.13 (Gnus v5.13)","MIME-Version":"1.0","X-Mimecast-Spam-Score":"0","X-Mimecast-MFC-PROC-ID":"1wVnwzwq2yoS67HnaX1RPowE6x1rQznp0AWgRsOX9qg_1784554541","X-Mimecast-Originator":"redhat.com","Content-Type":"text/plain","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}},{"id":39766,"web_url":"https://patchwork.libcamera.org/comment/39766/","msgid":"<85cxwhkchn.fsf@mzamazal-thinkpadp1gen7.tpbc.csb>","date":"2026-07-20T13:38:12","subject":"Re: [RFC PATCH v8 6/6] libcamera: software_isp: debayer_egl: Add\n\tLSC support","submitter":{"id":177,"url":"https://patchwork.libcamera.org/api/people/177/","name":"Milan Zamazal","email":"mzamazal@redhat.com"},"content":"Bryan O'Donoghue writes:\n\n> On 16/07/2026 23:25, Milan Zamazal wrote:\n>> @@ -483,6 +501,12 @@ void DebayerEGL::setShaderVariableValues(const DebayerParams ¶ms)\n>> \tglUniformMatrix3fv(ccmUniformDataIn_, 1, GL_TRUE, params.combinedMatrix.data().data());\n>> \tLOG(Debayer, Debug) << \" ccmUniformDataIn_ \" << ccmUniformDataIn_ << \" data \" << params.combinedMatrix;\n>> \n>> +\tif (lscEnabled_) {\n>> +\t\tegl_.createTexture2D(*eglImageLscLookup_, GL_RGB16F, GL_FLOAT,\n>> +\t\t\t\t params.lscLut.data(), GL_LINEAR);\n>> +\t\tglUniform1i(textureUniformLsc_, eglImageLscLookup_->texture_unit_uniform_id_);\n>> +\t}\n>> +\n>\n> Create texture should happen in configure() and we should use \n> egl_.updateTexture2D - if and only if the LSC algorithm has called for \n> new data - else it is sufficient to create and populate the texture and \n> then reuse the texture_id on subsequent passes.\n>\n> I guess ? LSC doesn't need to be updated for each frame - even if it \n> does updateTexture2D should be used - as its role in life is to update a \n> GPU texture we already have instead of nuking and replacing.\n\nOK, we have it now so let's use it. I'll do something about it in v10.","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 9C7EFC328C\n\tfor ;\n\tMon, 20 Jul 2026 13:38:21 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id D759A67E42;\n\tMon, 20 Jul 2026 15:38:20 +0200 (CEST)","from us-smtp-delivery-124.mimecast.com\n\t(us-smtp-delivery-124.mimecast.com [170.10.129.124])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 73F1B66177\n\tfor ;\n\tMon, 20 Jul 2026 15:38:18 +0200 (CEST)","from mail-ed1-f71.google.com (mail-ed1-f71.google.com\n\t[209.85.208.71]) by relay.mimecast.com with ESMTP with STARTTLS\n\t(version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id\n\tus-mta-527-szwcDcL3OUikBsj_-CDGHQ-1; Mon, 20 Jul 2026 09:38:15 -0400","by mail-ed1-f71.google.com with SMTP id\n\t4fb4d7f45d1cf-69841da1946so8085127a12.2\n\tfor ;\n\tMon, 20 Jul 2026 06:38:15 -0700 (PDT)","from mzamazal-thinkpadp1gen7.tpbc.csb\n\t(ip-77-48-47-4.net.vodafone.cz. 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\n\tMon, 20 Jul 2026 06:38:14 -0700 (PDT)","by 2002:a17:906:478b:b0:c16:75cc:33a9 with SMTP id\n\ta640c23a62f3a-c16b4754f9dmr665391866b.20.1784554694295; \n\tMon, 20 Jul 2026 06:38:14 -0700 (PDT)"],"From":"Milan Zamazal ","To":"Bryan O'Donoghue ","Cc":"libcamera-devel@lists.libcamera.org, Xander Pronk\n\t, Hans de Goede\n\t, Laurent Pinchart\n\t, Rick ten Wolde\n\t","Subject":"Re: [RFC PATCH v8 6/6] libcamera: software_isp: debayer_egl: Add\n\tLSC support","In-Reply-To":"<864b0a29-ddd0-4f84-a7ca-da5ea96f6807@nxsw.ie> (Bryan\n\tO'Donoghue's message of \"Mon, 20 Jul 2026 11:07:30 +0000\")","References":"<20260716222515.251464-1-mzamazal@redhat.com>\n\t<20260716222515.251464-7-mzamazal@redhat.com>\n\t<864b0a29-ddd0-4f84-a7ca-da5ea96f6807@nxsw.ie>","Date":"Mon, 20 Jul 2026 15:38:12 +0200","Message-ID":"<85cxwhkchn.fsf@mzamazal-thinkpadp1gen7.tpbc.csb>","User-Agent":"Gnus/5.13 (Gnus v5.13)","MIME-Version":"1.0","X-Mimecast-Spam-Score":"0","X-Mimecast-MFC-PROC-ID":"0DJRbKHI1rWNVjgLR3rLbwEfYKHcwe7g7hdzsTuPyGc_1784554695","X-Mimecast-Originator":"redhat.com","Content-Type":"text/plain","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}},{"id":39771,"web_url":"https://patchwork.libcamera.org/comment/39771/","msgid":"","date":"2026-07-20T19:47:56","subject":"Re: [RFC PATCH v8 6/6] libcamera: software_isp: debayer_egl: Add LSC\n\tsupport","submitter":{"id":226,"url":"https://patchwork.libcamera.org/api/people/226/","name":"Bryan O'Donoghue","email":"bod.linux@nxsw.ie"},"content":"On 20/07/2026 14:35, Milan Zamazal wrote:\n>>> @@ -483,6 +501,12 @@ void DebayerEGL::setShaderVariableValues(const DebayerParams ¶ms)\n>>> \tglUniformMatrix3fv(ccmUniformDataIn_, 1, GL_TRUE, params.combinedMatrix.data().data());\n>>> \tLOG(Debayer, Debug) << \" ccmUniformDataIn_ \" << ccmUniformDataIn_ << \" data \" << params.combinedMatrix;\n>>>\n>>> +\tif (lscEnabled_) {\n>>> +\t\tegl_.createTexture2D(*eglImageLscLookup_, GL_RGB16F, GL_FLOAT,\n>>> +\t\t\t\t params.lscLut.data(), GL_LINEAR);\n>> As we are discussing in the multi-pass thread, GL_RGB16F is dependent on\n>> the optional GL_EXT_color_buffer_half_float\n>>\n>> https://registry.khronos.org/OpenGL/extensions/EXT/ \n>> EXT_color_buffer_half_float.txt\n>>\n>> I think it should be pretty easy to disjunct on that as a flag in the\n>> base class - a flag I plan to add for SSBO stats but also perfectly\n>> happy for you to add.\n>>\n>> Half float linear filtering requires OES_texture_half_float_linear\n>>\n>> glGetString(GL_EXTENSIONS) | grep OES_texture_half_float_linear |\n>> debayer_egl{ bool _has_OES_texture_half_float_linear;} or whatever\n>>\n>> if (_has_OES_texture_half_float_linear)\n>> \tGL_RGB16F;\n>>\n>> Could we repreent the LSC data as uint8 natively ? I mean without\n>> storing it all as float and then converting to uint8 on each LSC\n>> application cycle ?\n> We could. `float' would be a nice and clear interface. But I'd prefer\n> not to deal with conditional support, especially if we had to handle the\n> unsupported case some way. Since we opt for UQ<2,6> with libipa in the\n> algorithm part, we can pass that to debayering. It may become a\n> limitation in the future, but for now, why not, it's not that difficult\n> to change once/if needed.\n\nRight so that would fit into eight bits as a regular \nGL_RGB/GL_UNSIGNED_BYTE.\n\nSo long as you do the normalisation in the shader, that should work.\n\n---\nbod","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 9BAC7BE080\n\tfor ;\n\tMon, 20 Jul 2026 19:48:04 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 0D2CB67E64;\n\tMon, 20 Jul 2026 21:48:03 +0200 (CEST)","from mail-4323.protonmail.ch (mail-4323.protonmail.ch\n\t[185.70.43.23])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id DE4E667E44\n\tfor ;\n\tMon, 20 Jul 2026 21:48:00 +0200 (CEST)"],"Authentication-Results":"lancelot.ideasonboard.com; dkim=pass (2048-bit key;\n\tunprotected) header.d=nxsw.ie header.i=@nxsw.ie header.b=\"Nidmi1aU\";\n\tdkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed; d=nxsw.ie;\n\ts=protonmail; t=1784576879; x=1784836079;\n\tbh=mZZYYdagbD1wdznILJAMbJ662JccUMcX8SZmeQs+0fw=;\n\th=Date:To:From:Cc:Subject:Message-ID:In-Reply-To:References:\n\tFeedback-ID:From:To:Cc:Date:Subject:Reply-To:Feedback-ID:\n\tMessage-ID:BIMI-Selector;\n\tb=Nidmi1aUGjsNkt0/OhaCh/VD7chzh8YghzOVLZmfuzLlDffT70qY/kWzBydDteD9X\n\tygMH8iXbtTSCtPCX0LsK0PEPtelaKxIjFPS8osVa5RCitQnJ+7sU8rzW/shqUD4/sn\n\tK2SM6wqwCwbBKIiZHzhFqQWEzF+OK4pqoaWIsW/NAMR0VkLR/IGTRvCmZjIoN5pf8G\n\tNFnr1VeRkF2NoYdBT72UkBTZFO49jKs+pMLPQZmdd7euFXg3KB41vabj1bBKNkMAim\n\tZLJYu7ZKAjmOCL8S+DzUUjNWRK8gkmanEnvVwFqonc53+dmapGfdUKcsYDFubnjAMr\n\tjUy3qCnRx2lgg==","Date":"Mon, 20 Jul 2026 19:47:56 +0000","To":"Milan Zamazal ","From":"Bryan O'Donoghue ","Cc":"libcamera-devel@lists.libcamera.org,\n\tXander Pronk ,\n\tHans de Goede ,\n\tLaurent Pinchart ,\n\tRick ten Wolde ","Subject":"Re: [RFC PATCH v8 6/6] libcamera: software_isp: debayer_egl: Add LSC\n\tsupport","Message-ID":"","In-Reply-To":"<85h5ltkclx.fsf@mzamazal-thinkpadp1gen7.tpbc.csb>","References":"<20260716222515.251464-1-mzamazal@redhat.com>\n\t<20260716222515.251464-7-mzamazal@redhat.com>\n\t<73ffa103-4246-4fb2-9fce-cf18e863999c@nxsw.ie>\n\t<85h5ltkclx.fsf@mzamazal-thinkpadp1gen7.tpbc.csb>","Feedback-ID":"136405006:user:proton","X-Pm-Message-ID":"06dd9ff5c8424d235030b15ecfa685d6e7a3c065","MIME-Version":"1.0","Content-Type":"text/plain; charset=utf-8","Content-Transfer-Encoding":"quoted-printable","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}}]