From patchwork Mon Jul 20 09:59:48 2026 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Milan Zamazal X-Patchwork-Id: 27381 Return-Path: X-Original-To: parsemail@patchwork.libcamera.org Delivered-To: parsemail@patchwork.libcamera.org Received: from lancelot.ideasonboard.com (lancelot.ideasonboard.com [92.243.16.209]) by patchwork.libcamera.org (Postfix) with ESMTPS id BB16DBF415 for ; Mon, 20 Jul 2026 10:00:18 +0000 (UTC) Received: from lancelot.ideasonboard.com (localhost [IPv6:::1]) by lancelot.ideasonboard.com (Postfix) with ESMTP id 7451D66149; Mon, 20 Jul 2026 12:00:18 +0200 (CEST) Authentication-Results: lancelot.ideasonboard.com; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.b="AIazvqDK"; dkim-atps=neutral Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lancelot.ideasonboard.com (Postfix) with ESMTPS id 501766612C for ; Mon, 20 Jul 2026 12:00:17 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1784541616; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=QRuJ5/9KcNuHCpobXEKvlUmLimeiVOhqvPLI+TvS71g=; b=AIazvqDKYxWQiKCF8SVQY6hCrct56h358UF5pOcn1D0qn2uA0Pdy2c11EOfp6HWfg+0XPA eG2R5PfwDIBrplyisT/V5+cIRkAuaBvYTWoW5/znn0RlQJ0WjKOHi5meRn028CMN+m3gxQ Flmxjqj5mJSxCxdz48HhwD61UcEL640= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-470-ipOzHVvgPCWFJqESmww7eg-1; Mon, 20 Jul 2026 06:00:14 -0400 X-MC-Unique: ipOzHVvgPCWFJqESmww7eg-1 X-Mimecast-MFC-AGG-ID: ipOzHVvgPCWFJqESmww7eg_1784541613 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 1CCDD1944AAF; Mon, 20 Jul 2026 10:00:13 +0000 (UTC) Received: from mzamazal-thinkpadp1gen7.tpbc.com (unknown [10.44.33.73]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id E2E8530002D6; Mon, 20 Jul 2026 10:00:09 +0000 (UTC) From: Milan Zamazal To: libcamera-devel@lists.libcamera.org Cc: Xander Pronk , Bryan O'Donoghue , Hans de Goede , Laurent Pinchart , Rick ten Wolde , Milan Zamazal Subject: [RFC PATCH v9 4/6] libcamera: shaders: Add LSC support Date: Mon, 20 Jul 2026 11:59:48 +0200 Message-ID: <20260720095951.49979-5-mzamazal@redhat.com> In-Reply-To: <20260720095951.49979-1-mzamazal@redhat.com> References: <20260720095951.49979-1-mzamazal@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: GvXGfsUaj7Nz1G31GcNI7VElMOSWZqYbNUJ-h26F8ow_1784541613 X-Mimecast-Originator: redhat.com content-type: text/plain; charset="US-ASCII"; x-default=true X-BeenThere: libcamera-devel@lists.libcamera.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: libcamera-devel-bounces@lists.libcamera.org Sender: "libcamera-devel" From: Xander Pronk Lens shading correction should be applied after black level subtraction (in order to make the computations with meaningful values) and before white balance (especially before white balance stats are computed). Note that lens shading correction depends on temperature, which is computed from the preceding, rather than current, frame (this is due to how white balance is currently computed). The shaders are compiled on initialisation, while lens shading correction can be enabled or disabled dynamically, using the corresponding control. The whole correction in the shader is wrapped by a conditional macro to be able to disable it and all the related overheads if Lsc algorithm is not enabled at all. If Lsc algorithm is enabled, the correction is always applied, whether the given control is enabled or not. If it is not, 1.0 multipliers are expected to be provided. This is because lens shading correction is supposed to be rarely switched off using the runtime control when Lsc algorithm is enabled, e.g. only for demoing or debugging purposes. We prefer accepting the performance penalty of applying a no-op correction in such cases rather than disturbing GPU computation in the regular flow by introducing a runtime `if'. Co-developed-by: Rick ten Wolde Signed-off-by: Rick ten Wolde Signed-off-by: Xander Pronk Signed-off-by: Milan Zamazal --- src/libcamera/shaders/bayer_1x_packed.frag | 8 ++++++++ src/libcamera/shaders/bayer_unpacked.frag | 8 ++++++++ 2 files changed, 16 insertions(+) diff --git a/src/libcamera/shaders/bayer_1x_packed.frag b/src/libcamera/shaders/bayer_1x_packed.frag index 0b641a5f3..e1c6fad4c 100644 --- a/src/libcamera/shaders/bayer_1x_packed.frag +++ b/src/libcamera/shaders/bayer_1x_packed.frag @@ -71,6 +71,10 @@ uniform vec3 blacklevel; uniform float gamma; uniform float contrastExp; +#if defined(APPLY_LSC) +uniform sampler2D lsc_tex; +#endif + float apply_contrast(float value) { // Apply simple S-curve @@ -232,6 +236,10 @@ void main(void) */ rgb = (rgb - blacklevel) / (1.0 - blacklevel); +#if defined(APPLY_LSC) + rgb = rgb * texture2D(lsc_tex, textureOut).rgb; +#endif + /* Apply AWB gains, and saturate each channel at sensor range */ rgb = clamp(rgb * awb, vec3(0.0), vec3(1.0)); diff --git a/src/libcamera/shaders/bayer_unpacked.frag b/src/libcamera/shaders/bayer_unpacked.frag index 10c5e941b..5b870fb2c 100644 --- a/src/libcamera/shaders/bayer_unpacked.frag +++ b/src/libcamera/shaders/bayer_unpacked.frag @@ -30,6 +30,10 @@ uniform vec3 blacklevel; uniform float gamma; uniform float contrastExp; +#if defined(APPLY_LSC) +uniform sampler2D lsc_tex; +#endif + float apply_contrast(float value) { // Apply simple S-curve @@ -135,6 +139,10 @@ void main(void) { */ rgb = (rgb - blacklevel) / (1.0 - blacklevel); +#if defined(APPLY_LSC) + rgb = rgb * texture2D(lsc_tex, center.xy).rgb; +#endif + /* Apply AWB gains, and saturate each channel at sensor range */ rgb = clamp(rgb * awb, vec3(0.0), vec3(1.0));