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{ "id": 22256, "url": "https://patchwork.libcamera.org/api/patches/22256/?format=api", "web_url": "https://patchwork.libcamera.org/patch/22256/", "project": { "id": 1, "url": "https://patchwork.libcamera.org/api/projects/1/?format=api", "name": "libcamera", "link_name": "libcamera", "list_id": "libcamera_core", "list_email": "libcamera-devel@lists.libcamera.org", "web_url": "", "scm_url": "", "webscm_url": "" }, "msgid": "<20241209100415.168483-1-pobrn@protonmail.com>", "date": "2024-12-09T10:04:17", "name": "[v2] libcamera: libipa: camera_sensor_helper: Use `variant` instead of `union`", "commit_ref": null, "pull_url": null, "state": "accepted", "archived": false, "hash": "8b762970e8521dd37814ec0643b072e8039632fd", "submitter": { "id": 133, "url": "https://patchwork.libcamera.org/api/people/133/?format=api", "name": "Pőcze Barnabás", "email": "pobrn@protonmail.com" }, "delegate": null, "mbox": "https://patchwork.libcamera.org/patch/22256/mbox/", "series": [ { "id": 4864, "url": "https://patchwork.libcamera.org/api/series/4864/?format=api", "web_url": "https://patchwork.libcamera.org/project/libcamera/list/?series=4864", "date": "2024-12-09T10:04:17", "name": "[v2] libcamera: libipa: camera_sensor_helper: Use `variant` instead of `union`", "version": 2, "mbox": "https://patchwork.libcamera.org/series/4864/mbox/" } ], "comments": "https://patchwork.libcamera.org/api/patches/22256/comments/", "check": "pending", "checks": "https://patchwork.libcamera.org/api/patches/22256/checks/", "tags": {}, "headers": { "Return-Path": "<libcamera-devel-bounces@lists.libcamera.org>", "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 03D4ABE080\n\tfor <parsemail@patchwork.libcamera.org>;\n\tMon, 9 Dec 2024 10:04:28 +0000 (UTC)", "from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id B80E667E47;\n\tMon, 9 Dec 2024 11:04:27 +0100 (CET)", "from mail-40134.protonmail.ch (mail-40134.protonmail.ch\n\t[185.70.40.134])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 6272267E47\n\tfor <libcamera-devel@lists.libcamera.org>;\n\tMon, 9 Dec 2024 11:04:26 +0100 (CET)" ], "Authentication-Results": "lancelot.ideasonboard.com;\n\tdkim=fail reason=\"signature verification failed\" (2048-bit key;\n\tunprotected) header.d=protonmail.com header.i=@protonmail.com\n\theader.b=\"GKaqSqgg\"; dkim-atps=neutral", "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/relaxed; d=protonmail.com;\n\ts=protonmail3; t=1733738665; x=1733997865;\n\tbh=ClaKNuOUzvodq7W7BrK9BfBAcQTL6sBAmdfLTw/VXXo=;\n\th=Date:To:From:Cc:Subject:Message-ID:Feedback-ID:From:To:Cc:Date:\n\tSubject:Reply-To:Feedback-ID:Message-ID:BIMI-Selector:\n\tList-Unsubscribe:List-Unsubscribe-Post;\n\tb=GKaqSqggOtyOVcy6M/uOeb9QoWFv9G7a29cAyq70OI0tvi9dQ4O0Lzcr1EwxDX9I6\n\t9V1+oBKFdNQaV2mGpMKMdrOmXtnB/fx0sRu4mjDStYy4+ErjYKPHadgBrbCx7JktoE\n\tfAobBVzEFn9MQXk5YitA3Y1fIFduTT3kRlcbJXSMLT5hUmvJ5jZlIdrXCp8FYQwRFT\n\tuEcG64zj9/DSWHbufQV+0/u9+sJtlM0LuS/NhcpVzifKupj4QRfphhtr1pm3KHXV4T\n\tS9hno3AL9mt86SBaMokIvS4hU8nHsvUZIujtFGtPDilqGdxcUKwnZfF0HXFcM1FvrW\n\tATqmQTrd+RNOA==", "Date": "Mon, 09 Dec 2024 10:04:17 +0000", "To": "libcamera-devel@lists.libcamera.org", "From": "=?utf-8?q?Barnab=C3=A1s_P=C5=91cze?= <pobrn@protonmail.com>", "Cc": "Laurent Pinchart <laurent.pinchart@ideasonboard.com>", "Subject": "[PATCH v2] libcamera: libipa: camera_sensor_helper: Use `variant`\n\tinstead of `union`", "Message-ID": "<20241209100415.168483-1-pobrn@protonmail.com>", "Feedback-ID": "20568564:user:proton", "X-Pm-Message-ID": "fb9fbd54a3bcbe1c1c3aa9f4f1bc5dde82520edc", "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": "<libcamera-devel.lists.libcamera.org>", "List-Unsubscribe": "<https://lists.libcamera.org/options/libcamera-devel>,\n\t<mailto:libcamera-devel-request@lists.libcamera.org?subject=unsubscribe>", "List-Archive": "<https://lists.libcamera.org/pipermail/libcamera-devel/>", "List-Post": "<mailto:libcamera-devel@lists.libcamera.org>", "List-Help": "<mailto:libcamera-devel-request@lists.libcamera.org?subject=help>", "List-Subscribe": "<https://lists.libcamera.org/listinfo/libcamera-devel>,\n\t<mailto:libcamera-devel-request@lists.libcamera.org?subject=subscribe>", "Errors-To": "libcamera-devel-bounces@lists.libcamera.org", "Sender": "\"libcamera-devel\" <libcamera-devel-bounces@lists.libcamera.org>" }, "content": "Use an `std::variant` to store the analogue gain instead of a bare union + tag.\n\nSigned-off-by: Barnabás Pőcze <pobrn@protonmail.com>\nReviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>\n---\nChanges in v2:\n * fix code style issues\n\n---\n src/ipa/libipa/camera_sensor_helper.cpp | 194 ++++++++----------------\n src/ipa/libipa/camera_sensor_helper.h | 18 +--\n 2 files changed, 66 insertions(+), 146 deletions(-)\n\n--\n2.47.1", "diff": "diff --git a/src/ipa/libipa/camera_sensor_helper.cpp b/src/ipa/libipa/camera_sensor_helper.cpp\nindex a76e5e75..7c66cd57 100644\n--- a/src/ipa/libipa/camera_sensor_helper.cpp\n+++ b/src/ipa/libipa/camera_sensor_helper.cpp\n@@ -87,21 +87,16 @@ namespace ipa {\n */\n uint32_t CameraSensorHelper::gainCode(double gain) const\n {\n-\tconst AnalogueGainConstants &k = gainConstants_;\n+\tif (auto *l = std::get_if<AnalogueGainLinear>(&gain_)) {\n+\t\tASSERT(l->m0 == 0 || l->m1 == 0);\n\n-\tswitch (gainType_) {\n-\tcase AnalogueGainLinear:\n-\t\tASSERT(k.linear.m0 == 0 || k.linear.m1 == 0);\n+\t\treturn (l->c0 - l->c1 * gain) /\n+\t\t (l->m1 * gain - l->m0);\n+\t} else if (auto *e = std::get_if<AnalogueGainExp>(&gain_)) {\n+\t\tASSERT(e->a != 0 && e->m != 0);\n\n-\t\treturn (k.linear.c0 - k.linear.c1 * gain) /\n-\t\t (k.linear.m1 * gain - k.linear.m0);\n-\n-\tcase AnalogueGainExponential:\n-\t\tASSERT(k.exp.a != 0 && k.exp.m != 0);\n-\n-\t\treturn std::log2(gain / k.exp.a) / k.exp.m;\n-\n-\tdefault:\n+\t\treturn std::log2(gain / e->a) / e->m;\n+\t} else {\n \t\tASSERT(false);\n \t\treturn 0;\n \t}\n@@ -119,38 +114,26 @@ uint32_t CameraSensorHelper::gainCode(double gain) const\n */\n double CameraSensorHelper::gain(uint32_t gainCode) const\n {\n-\tconst AnalogueGainConstants &k = gainConstants_;\n \tdouble gain = static_cast<double>(gainCode);\n\n-\tswitch (gainType_) {\n-\tcase AnalogueGainLinear:\n-\t\tASSERT(k.linear.m0 == 0 || k.linear.m1 == 0);\n-\n-\t\treturn (k.linear.m0 * gain + k.linear.c0) /\n-\t\t (k.linear.m1 * gain + k.linear.c1);\n+\tif (auto *l = std::get_if<AnalogueGainLinear>(&gain_)) {\n+\t\tASSERT(l->m0 == 0 || l->m1 == 0);\n\n-\tcase AnalogueGainExponential:\n-\t\tASSERT(k.exp.a != 0 && k.exp.m != 0);\n+\t\treturn (l->m0 * gain + l->c0) /\n+\t\t (l->m1 * gain + l->c1);\n+\t} else if (auto *e = std::get_if<AnalogueGainExp>(&gain_)) {\n+\t\tASSERT(e->a != 0 && e->m != 0);\n\n-\t\treturn k.exp.a * std::exp2(k.exp.m * gain);\n-\n-\tdefault:\n+\t\treturn e->a * std::exp2(e->m * gain);\n+\t} else {\n \t\tASSERT(false);\n \t\treturn 0.0;\n \t}\n }\n\n /**\n- * \\enum CameraSensorHelper::AnalogueGainType\n- * \\brief The gain calculation modes as defined by the MIPI CCS\n- *\n- * Describes the image sensor analogue gain capabilities.\n- * Two modes are possible, depending on the sensor: Linear and Exponential.\n- */\n-\n-/**\n- * \\var CameraSensorHelper::AnalogueGainLinear\n- * \\brief Gain is computed using linear gain estimation\n+ * \\struct CameraSensorHelper::AnalogueGainLinear\n+ * \\brief Analogue gain constants for the linear gain model\n *\n * The relationship between the integer gain parameter and the resulting gain\n * multiplier is given by the following equation:\n@@ -165,11 +148,27 @@ double CameraSensorHelper::gain(uint32_t gainCode) const\n * The full Gain equation therefore reduces to either:\n *\n * \\f$gain=\\frac{c0}{m1x+c1}\\f$ or \\f$\\frac{m0x+c0}{c1}\\f$\n+ *\n+ * \\var CameraSensorHelper::AnalogueGainLinear::m0\n+ * \\brief Constant used in the linear gain coding/decoding\n+ *\n+ * \\note Either m0 or m1 shall be zero.\n+ *\n+ * \\var CameraSensorHelper::AnalogueGainLinear::c0\n+ * \\brief Constant used in the linear gain coding/decoding\n+ *\n+ * \\var CameraSensorHelper::AnalogueGainLinear::m1\n+ * \\brief Constant used in the linear gain coding/decoding\n+ *\n+ * \\note Either m0 or m1 shall be zero.\n+ *\n+ * \\var CameraSensorHelper::AnalogueGainLinear::c1\n+ * \\brief Constant used in the linear gain coding/decoding\n */\n\n /**\n- * \\var CameraSensorHelper::AnalogueGainExponential\n- * \\brief Gain is expressed using an exponential model\n+ * \\struct CameraSensorHelper::AnalogueGainExp\n+ * \\brief Analogue gain constants for the exponential gain model\n *\n * The relationship between the integer gain parameter and the resulting gain\n * multiplier is given by the following equation:\n@@ -185,54 +184,14 @@ double CameraSensorHelper::gain(uint32_t gainCode) const\n *\n * When the gain is expressed in dB, 'a' is equal to 1 and 'm' to\n * \\f$log_{2}{10^{\\frac{1}{20}}}\\f$.\n- */\n-\n-/**\n- * \\struct CameraSensorHelper::AnalogueGainLinearConstants\n- * \\brief Analogue gain constants for the linear gain model\n *\n- * \\var CameraSensorHelper::AnalogueGainLinearConstants::m0\n- * \\brief Constant used in the linear gain coding/decoding\n- *\n- * \\note Either m0 or m1 shall be zero.\n- *\n- * \\var CameraSensorHelper::AnalogueGainLinearConstants::c0\n- * \\brief Constant used in the linear gain coding/decoding\n- *\n- * \\var CameraSensorHelper::AnalogueGainLinearConstants::m1\n- * \\brief Constant used in the linear gain coding/decoding\n- *\n- * \\note Either m0 or m1 shall be zero.\n- *\n- * \\var CameraSensorHelper::AnalogueGainLinearConstants::c1\n- * \\brief Constant used in the linear gain coding/decoding\n- */\n-\n-/**\n- * \\struct CameraSensorHelper::AnalogueGainExpConstants\n- * \\brief Analogue gain constants for the exponential gain model\n- *\n- * \\var CameraSensorHelper::AnalogueGainExpConstants::a\n+ * \\var CameraSensorHelper::AnalogueGainExp::a\n * \\brief Constant used in the exponential gain coding/decoding\n *\n- * \\var CameraSensorHelper::AnalogueGainExpConstants::m\n+ * \\var CameraSensorHelper::AnalogueGainExp::m\n * \\brief Constant used in the exponential gain coding/decoding\n */\n\n-/**\n- * \\struct CameraSensorHelper::AnalogueGainConstants\n- * \\brief Analogue gain model constants\n- *\n- * This union stores the constants used to calculate the analogue gain. The\n- * CameraSensorHelper::gainType_ variable selects which union member is valid.\n- *\n- * \\var CameraSensorHelper::AnalogueGainConstants::linear\n- * \\brief Constants for the linear gain model\n- *\n- * \\var CameraSensorHelper::AnalogueGainConstants::exp\n- * \\brief Constants for the exponential gain model\n- */\n-\n /**\n * \\var CameraSensorHelper::blackLevel_\n * \\brief The black level of the sensor\n@@ -240,12 +199,7 @@ double CameraSensorHelper::gain(uint32_t gainCode) const\n */\n\n /**\n- * \\var CameraSensorHelper::gainType_\n- * \\brief The analogue gain model type\n- */\n-\n-/**\n- * \\var CameraSensorHelper::gainConstants_\n+ * \\var CameraSensorHelper::gain_\n * \\brief The analogue gain parameters used for calculation\n *\n * The analogue gain is calculated through a formula, and its parameters are\n@@ -526,8 +480,7 @@ public:\n \t{\n \t\t/* From datasheet: 64 at 10bits. */\n \t\tblackLevel_ = 4096;\n-\t\tgainType_ = AnalogueGainLinear;\n-\t\tgainConstants_.linear = { 100, 0, 0, 1024 };\n+\t\tgain_ = AnalogueGainLinear{ 100, 0, 0, 1024 };\n \t}\n };\n REGISTER_CAMERA_SENSOR_HELPER(\"gc05a2\", CameraSensorHelperGc05a2)\n@@ -539,8 +492,7 @@ public:\n \t{\n \t\t/* From datasheet: 64 at 10bits. */\n \t\tblackLevel_ = 4096;\n-\t\tgainType_ = AnalogueGainLinear;\n-\t\tgainConstants_.linear = { 100, 0, 0, 1024 };\n+\t\tgain_ = AnalogueGainLinear{ 100, 0, 0, 1024 };\n \t}\n };\n REGISTER_CAMERA_SENSOR_HELPER(\"gc08a3\", CameraSensorHelperGc08a3)\n@@ -552,8 +504,7 @@ public:\n \t{\n \t\t/* From datasheet: 64 at 10bits. */\n \t\tblackLevel_ = 4096;\n-\t\tgainType_ = AnalogueGainLinear;\n-\t\tgainConstants_.linear = { 0, 512, -1, 512 };\n+\t\tgain_ = AnalogueGainLinear{ 0, 512, -1, 512 };\n \t}\n };\n REGISTER_CAMERA_SENSOR_HELPER(\"imx214\", CameraSensorHelperImx214)\n@@ -565,8 +516,7 @@ public:\n \t{\n \t\t/* From datasheet: 64 at 10bits. */\n \t\tblackLevel_ = 4096;\n-\t\tgainType_ = AnalogueGainLinear;\n-\t\tgainConstants_.linear = { 0, 256, -1, 256 };\n+\t\tgain_ = AnalogueGainLinear{ 0, 256, -1, 256 };\n \t}\n };\n REGISTER_CAMERA_SENSOR_HELPER(\"imx219\", CameraSensorHelperImx219)\n@@ -578,8 +528,7 @@ public:\n \t{\n \t\t/* From datasheet: 0x40 at 10bits. */\n \t\tblackLevel_ = 4096;\n-\t\tgainType_ = AnalogueGainLinear;\n-\t\tgainConstants_.linear = { 0, 512, -1, 512 };\n+\t\tgain_ = AnalogueGainLinear{ 0, 512, -1, 512 };\n \t}\n };\n REGISTER_CAMERA_SENSOR_HELPER(\"imx258\", CameraSensorHelperImx258)\n@@ -591,8 +540,7 @@ public:\n \t{\n \t\t/* From datasheet: 0x32 at 10bits. */\n \t\tblackLevel_ = 3200;\n-\t\tgainType_ = AnalogueGainLinear;\n-\t\tgainConstants_.linear = { 0, 2048, -1, 2048 };\n+\t\tgain_ = AnalogueGainLinear{ 0, 2048, -1, 2048 };\n \t}\n };\n REGISTER_CAMERA_SENSOR_HELPER(\"imx283\", CameraSensorHelperImx283)\n@@ -604,8 +552,7 @@ public:\n \t{\n \t\t/* From datasheet: 0xf0 at 12bits. */\n \t\tblackLevel_ = 3840;\n-\t\tgainType_ = AnalogueGainExponential;\n-\t\tgainConstants_.exp = { 1.0, expGainDb(0.3) };\n+\t\tgain_ = AnalogueGainExp{ 1.0, expGainDb(0.3) };\n \t}\n };\n REGISTER_CAMERA_SENSOR_HELPER(\"imx290\", CameraSensorHelperImx290)\n@@ -615,8 +562,7 @@ class CameraSensorHelperImx296 : public CameraSensorHelper\n public:\n \tCameraSensorHelperImx296()\n \t{\n-\t\tgainType_ = AnalogueGainExponential;\n-\t\tgainConstants_.exp = { 1.0, expGainDb(0.1) };\n+\t\tgain_ = AnalogueGainExp{ 1.0, expGainDb(0.1) };\n \t}\n };\n REGISTER_CAMERA_SENSOR_HELPER(\"imx296\", CameraSensorHelperImx296)\n@@ -633,8 +579,7 @@ public:\n \t{\n \t\t/* From datasheet: 0x32 at 10bits. */\n \t\tblackLevel_ = 3200;\n-\t\tgainType_ = AnalogueGainExponential;\n-\t\tgainConstants_.exp = { 1.0, expGainDb(0.3) };\n+\t\tgain_ = AnalogueGainExp{ 1.0, expGainDb(0.3) };\n \t}\n };\n REGISTER_CAMERA_SENSOR_HELPER(\"imx335\", CameraSensorHelperImx335)\n@@ -644,8 +589,7 @@ class CameraSensorHelperImx415 : public CameraSensorHelper\n public:\n \tCameraSensorHelperImx415()\n \t{\n-\t\tgainType_ = AnalogueGainExponential;\n-\t\tgainConstants_.exp = { 1.0, expGainDb(0.3) };\n+\t\tgain_ = AnalogueGainExp{ 1.0, expGainDb(0.3) };\n \t}\n };\n REGISTER_CAMERA_SENSOR_HELPER(\"imx415\", CameraSensorHelperImx415)\n@@ -660,8 +604,7 @@ class CameraSensorHelperImx477 : public CameraSensorHelper\n public:\n \tCameraSensorHelperImx477()\n \t{\n-\t\tgainType_ = AnalogueGainLinear;\n-\t\tgainConstants_.linear = { 0, 1024, -1, 1024 };\n+\t\tgain_ = AnalogueGainLinear{ 0, 1024, -1, 1024 };\n \t}\n };\n REGISTER_CAMERA_SENSOR_HELPER(\"imx477\", CameraSensorHelperImx477)\n@@ -675,8 +618,7 @@ public:\n \t\t * The Sensor Manual doesn't appear to document the gain model.\n \t\t * This has been validated with some empirical testing only.\n \t\t */\n-\t\tgainType_ = AnalogueGainLinear;\n-\t\tgainConstants_.linear = { 1, 0, 0, 128 };\n+\t\tgain_ = AnalogueGainLinear{ 1, 0, 0, 128 };\n \t}\n };\n REGISTER_CAMERA_SENSOR_HELPER(\"ov2685\", CameraSensorHelperOv2685)\n@@ -686,8 +628,7 @@ class CameraSensorHelperOv2740 : public CameraSensorHelper\n public:\n \tCameraSensorHelperOv2740()\n \t{\n-\t\tgainType_ = AnalogueGainLinear;\n-\t\tgainConstants_.linear = { 1, 0, 0, 128 };\n+\t\tgain_ = AnalogueGainLinear{ 1, 0, 0, 128 };\n \t}\n };\n REGISTER_CAMERA_SENSOR_HELPER(\"ov2740\", CameraSensorHelperOv2740)\n@@ -699,8 +640,7 @@ public:\n \t{\n \t\t/* From datasheet: 0x40 at 12bits. */\n \t\tblackLevel_ = 1024;\n-\t\tgainType_ = AnalogueGainLinear;\n-\t\tgainConstants_.linear = { 1, 0, 0, 128 };\n+\t\tgain_ = AnalogueGainLinear{ 1, 0, 0, 128 };\n \t}\n };\n REGISTER_CAMERA_SENSOR_HELPER(\"ov4689\", CameraSensorHelperOv4689)\n@@ -712,8 +652,7 @@ public:\n \t{\n \t\t/* From datasheet: 0x10 at 10bits. */\n \t\tblackLevel_ = 1024;\n-\t\tgainType_ = AnalogueGainLinear;\n-\t\tgainConstants_.linear = { 1, 0, 0, 16 };\n+\t\tgain_ = AnalogueGainLinear{ 1, 0, 0, 16 };\n \t}\n };\n REGISTER_CAMERA_SENSOR_HELPER(\"ov5640\", CameraSensorHelperOv5640)\n@@ -723,8 +662,7 @@ class CameraSensorHelperOv5647 : public CameraSensorHelper\n public:\n \tCameraSensorHelperOv5647()\n \t{\n-\t\tgainType_ = AnalogueGainLinear;\n-\t\tgainConstants_.linear = { 1, 0, 0, 16 };\n+\t\tgain_ = AnalogueGainLinear{ 1, 0, 0, 16 };\n \t}\n };\n REGISTER_CAMERA_SENSOR_HELPER(\"ov5647\", CameraSensorHelperOv5647)\n@@ -734,8 +672,7 @@ class CameraSensorHelperOv5670 : public CameraSensorHelper\n public:\n \tCameraSensorHelperOv5670()\n \t{\n-\t\tgainType_ = AnalogueGainLinear;\n-\t\tgainConstants_.linear = { 1, 0, 0, 128 };\n+\t\tgain_ = AnalogueGainLinear{ 1, 0, 0, 128 };\n \t}\n };\n REGISTER_CAMERA_SENSOR_HELPER(\"ov5670\", CameraSensorHelperOv5670)\n@@ -747,8 +684,7 @@ public:\n \t{\n \t\t/* From Linux kernel driver: 0x40 at 10bits. */\n \t\tblackLevel_ = 4096;\n-\t\tgainType_ = AnalogueGainLinear;\n-\t\tgainConstants_.linear = { 1, 0, 0, 128 };\n+\t\tgain_ = AnalogueGainLinear{ 1, 0, 0, 128 };\n \t}\n };\n REGISTER_CAMERA_SENSOR_HELPER(\"ov5675\", CameraSensorHelperOv5675)\n@@ -758,8 +694,7 @@ class CameraSensorHelperOv5693 : public CameraSensorHelper\n public:\n \tCameraSensorHelperOv5693()\n \t{\n-\t\tgainType_ = AnalogueGainLinear;\n-\t\tgainConstants_.linear = { 1, 0, 0, 16 };\n+\t\tgain_ = AnalogueGainLinear{ 1, 0, 0, 16 };\n \t}\n };\n REGISTER_CAMERA_SENSOR_HELPER(\"ov5693\", CameraSensorHelperOv5693)\n@@ -769,8 +704,7 @@ class CameraSensorHelperOv64a40 : public CameraSensorHelper\n public:\n \tCameraSensorHelperOv64a40()\n \t{\n-\t\tgainType_ = AnalogueGainLinear;\n-\t\tgainConstants_.linear = { 1, 0, 0, 128 };\n+\t\tgain_ = AnalogueGainLinear{ 1, 0, 0, 128 };\n \t}\n };\n REGISTER_CAMERA_SENSOR_HELPER(\"ov64a40\", CameraSensorHelperOv64a40)\n@@ -780,15 +714,13 @@ class CameraSensorHelperOv8858 : public CameraSensorHelper\n public:\n \tCameraSensorHelperOv8858()\n \t{\n-\t\tgainType_ = AnalogueGainLinear;\n-\n \t\t/*\n \t\t * \\todo Validate the selected 1/128 step value as it differs\n \t\t * from what the sensor manual describes.\n \t\t *\n \t\t * See: https://patchwork.linuxtv.org/project/linux-media/patch/20221106171129.166892-2-nicholas@rothemail.net/#142267\n \t\t */\n-\t\tgainConstants_.linear = { 1, 0, 0, 128 };\n+\t\tgain_ = AnalogueGainLinear{ 1, 0, 0, 128 };\n \t}\n };\n REGISTER_CAMERA_SENSOR_HELPER(\"ov8858\", CameraSensorHelperOv8858)\n@@ -798,8 +730,7 @@ class CameraSensorHelperOv8865 : public CameraSensorHelper\n public:\n \tCameraSensorHelperOv8865()\n \t{\n-\t\tgainType_ = AnalogueGainLinear;\n-\t\tgainConstants_.linear = { 1, 0, 0, 128 };\n+\t\tgain_ = AnalogueGainLinear{ 1, 0, 0, 128 };\n \t}\n };\n REGISTER_CAMERA_SENSOR_HELPER(\"ov8865\", CameraSensorHelperOv8865)\n@@ -809,8 +740,7 @@ class CameraSensorHelperOv13858 : public CameraSensorHelper\n public:\n \tCameraSensorHelperOv13858()\n \t{\n-\t\tgainType_ = AnalogueGainLinear;\n-\t\tgainConstants_.linear = { 1, 0, 0, 128 };\n+\t\tgain_ = AnalogueGainLinear{ 1, 0, 0, 128 };\n \t}\n };\n REGISTER_CAMERA_SENSOR_HELPER(\"ov13858\", CameraSensorHelperOv13858)\ndiff --git a/src/ipa/libipa/camera_sensor_helper.h b/src/ipa/libipa/camera_sensor_helper.h\nindex 75868205..a9300a64 100644\n--- a/src/ipa/libipa/camera_sensor_helper.h\n+++ b/src/ipa/libipa/camera_sensor_helper.h\n@@ -11,6 +11,7 @@\n #include <optional>\n #include <stdint.h>\n #include <string>\n+#include <variant>\n #include <vector>\n\n #include <libcamera/base/class.h>\n@@ -30,31 +31,20 @@ public:\n \tvirtual double gain(uint32_t gainCode) const;\n\n protected:\n-\tenum AnalogueGainType {\n-\t\tAnalogueGainLinear,\n-\t\tAnalogueGainExponential,\n-\t};\n-\n-\tstruct AnalogueGainLinearConstants {\n+\tstruct AnalogueGainLinear {\n \t\tint16_t m0;\n \t\tint16_t c0;\n \t\tint16_t m1;\n \t\tint16_t c1;\n \t};\n\n-\tstruct AnalogueGainExpConstants {\n+\tstruct AnalogueGainExp {\n \t\tdouble a;\n \t\tdouble m;\n \t};\n\n-\tunion AnalogueGainConstants {\n-\t\tAnalogueGainLinearConstants linear;\n-\t\tAnalogueGainExpConstants exp;\n-\t};\n-\n \tstd::optional<int16_t> blackLevel_;\n-\tAnalogueGainType gainType_;\n-\tAnalogueGainConstants gainConstants_;\n+\tstd::variant<std::monostate, AnalogueGainLinear, AnalogueGainExp> gain_;\n\n private:\n \tLIBCAMERA_DISABLE_COPY_AND_MOVE(CameraSensorHelper)\n", "prefixes": [ "v2" ] }