From patchwork Thu Jul 16 22:25:11 2026 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Milan Zamazal X-Patchwork-Id: 27372 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 E8DC1C3304 for ; Thu, 16 Jul 2026 22:25:49 +0000 (UTC) Received: from lancelot.ideasonboard.com (localhost [IPv6:::1]) by lancelot.ideasonboard.com (Postfix) with ESMTP id 8485767E3F; Fri, 17 Jul 2026 00:25:49 +0200 (CEST) Authentication-Results: lancelot.ideasonboard.com; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.b="IPyp4c2u"; dkim-atps=neutral Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lancelot.ideasonboard.com (Postfix) with ESMTPS id DBAE467E2B for ; Fri, 17 Jul 2026 00:25:47 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1784240746; 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=IPyp4c2uyPZPG1m0F7pcRxmztziOY/L6jiJxMr6gJu9ghPIjM/uqUbHDR3ZMZchzj9WFMA s7bF5suja7Cpuc+0sqse3phTv1/cbHKSECWg/zxJvh+sJpjYmzC2WZ7j0y5ge05lyECKu8 zNoopeS6iKYk0Fq2+08tBzaNW5AFFw4= Received: from mx-prod-mc-01.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-619-gS26_IaAObS2aGVbZYguAg-1; Thu, 16 Jul 2026 18:25:41 -0400 X-MC-Unique: gS26_IaAObS2aGVbZYguAg-1 X-Mimecast-MFC-AGG-ID: gS26_IaAObS2aGVbZYguAg_1784240740 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (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-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id D6AE21956044; Thu, 16 Jul 2026 22:25:39 +0000 (UTC) Received: from mzamazal-thinkpadp1gen7.tpbc.com (unknown [10.44.32.11]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id BD4F11800361; Thu, 16 Jul 2026 22:25:36 +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 v8 4/6] libcamera: shaders: Add LSC support Date: Fri, 17 Jul 2026 00:25:11 +0200 Message-ID: <20260716222515.251464-5-mzamazal@redhat.com> In-Reply-To: <20260716222515.251464-1-mzamazal@redhat.com> References: <20260716222515.251464-1-mzamazal@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: Dtc8kYfyInlLCpUF27_BWaIwZ8Si_sKcIzgNPqRagSY_1784240740 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));