[{"id":37197,"web_url":"https://patchwork.libcamera.org/comment/37197/","msgid":"<85wm331ptk.fsf@mzamazal-thinkpadp1gen7.tpbc.csb>","date":"2025-12-03T16:40:39","subject":"Re: [PATCH v6 08/24] libcamera: shaders: Add support for black\n\tlevel compensation","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> Add the ability to apply a int blacklevel gain against the demosaiced data\n> prior to application of colour correction data.\n>\n> We calculate the index into the RGB black-level table so that we can apply\n> the black level when we sample the input prior to the demosiac operation.\n\ns/demosiac/demosaic/\n\n>\n> Don't do this when using the lookup tables as the black level is\n> already calculated in those.\n\nThe two paragraphs are confusing, they probably try to say that the\nblack level should be subtracted only in GPU ISP?\n\nWith the commit message improved:\n\nReviewed-by: Milan Zamazal \n\n> Signed-off-by: Bryan O'Donoghue \n> ---\n> src/libcamera/shaders/bayer_1x_packed.frag | 3 +++\n> src/libcamera/shaders/bayer_unpacked.frag | 3 +++\n> 2 files changed, 6 insertions(+)\n>\n> diff --git a/src/libcamera/shaders/bayer_1x_packed.frag b/src/libcamera/shaders/bayer_1x_packed.frag\n> index db8c2a0b3..7036fe278 100644\n> --- a/src/libcamera/shaders/bayer_1x_packed.frag\n> +++ b/src/libcamera/shaders/bayer_1x_packed.frag\n> @@ -66,6 +66,7 @@ uniform vec2 tex_bayer_first_red;\n> \n> uniform sampler2D tex_y;\n> uniform mat3 ccm;\n> +uniform vec3 blacklevel;\n>\n> void main(void)\n> {\n> @@ -213,6 +214,8 @@ void main(void)\n> \t\t\tvec3(patterns.y, C, patterns.x) :\n> \t\t\tvec3(patterns.wz, C));\n> \n> +\trgb = rgb - blacklevel;\n> +\n> \t/*\n> \t * CCM is a 3x3 in the format\n> \t *\n> diff --git a/src/libcamera/shaders/bayer_unpacked.frag b/src/libcamera/shaders/bayer_unpacked.frag\n> index 06d80f3dd..f0d8cd1e2 100644\n> --- a/src/libcamera/shaders/bayer_unpacked.frag\n> +++ b/src/libcamera/shaders/bayer_unpacked.frag\n> @@ -25,6 +25,7 @@ varying vec4 center;\n> varying vec4 yCoord;\n> varying vec4 xCoord;\n> uniform mat3 ccm;\n> +uniform vec3 blacklevel;\n> \n> void main(void) {\n> vec3 rgb;\n> @@ -108,6 +109,8 @@ void main(void) {\n> vec3(PATTERN.w, C, PATTERN.z) :\n> vec3(PATTERN.yx, C));\n> \n> + rgb = rgb - blacklevel;\n> +\n> /*\n> * CCM is a 3x3 in the format\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 3509DC3257\n\tfor ;\n\tWed, 3 Dec 2025 16:40:47 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 8486660F74;\n\tWed, 3 Dec 2025 17:40:46 +0100 (CET)","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 180C8609D8\n\tfor ;\n\tWed, 3 Dec 2025 17:40:44 +0100 (CET)","from mail-wr1-f70.google.com (mail-wr1-f70.google.com\n\t[209.85.221.70]) by relay.mimecast.com with ESMTP with STARTTLS\n\t(version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id\n\tus-mta-175-U1H4J9jNMLiwnXGIZZRJfw-1; Wed, 03 Dec 2025 11:40:42 -0500","by mail-wr1-f70.google.com with SMTP id\n\tffacd0b85a97d-42e29783a15so855187f8f.1\n\tfor ;\n\tWed, 03 Dec 2025 08:40:42 -0800 (PST)","from mzamazal-thinkpadp1gen7.tpbc.csb\n\t(ip-77-48-47-2.net.vodafone.cz. 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