From patchwork Thu Oct 22 09:40:46 2026 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Milan Zamazal X-Patchwork-Id: 28554 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 38641C3261 for ; Thu, 22 Oct 2026 09:41:34 +0000 (UTC) Received: from lancelot.ideasonboard.com (localhost [IPv6:::1]) by lancelot.ideasonboard.com (Postfix) with ESMTP id C591B68F78; Thu, 22 Oct 2026 11:41:33 +0200 (CEST) Authentication-Results: lancelot.ideasonboard.com; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.b="cVrsBVWR"; 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 8D2E768F5E for ; Thu, 22 Oct 2026 11:41:30 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1792662089; 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=CM8FHC7s6yx6pU4x75EC1tOcxwQsxNTgnSiGYjluz5o=; b=cVrsBVWRF+1hHvU6ZG/35TteSrnMCdny46Hq7WpKXZfAq9qBmpU8WHXD6+e86rYGbRsv2S 8+7H9pNFPgOQo+HixbGzdJACxW4Ms4FXHbaxORQbPsN3EOARaaKx07e0M0bUtCiWOyoMY8 gv+EOnozUInUMBM8qvPYxYBMq5P6s1U= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-643-jlMnygmROhusIF0Ga9bRCw-1; Thu, 22 Oct 2026 09:41:28 +0000 X-MC-Unique: jlMnygmROhusIF0Ga9bRCw-1 X-Mimecast-MFC-AGG-ID: jlMnygmROhusIF0Ga9bRCw_1792662087 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-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 69117180058A; Thu, 22 Oct 2026 09:41:26 +0000 (UTC) Received: from mzamazal-thinkpadp1gen7.redhat.corp (headnet04.pony-001.prod.iad2.dc.redhat.com [10.2.32.116]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 825541800642; Thu, 22 Oct 2026 09:41:24 +0000 (UTC) From: Milan Zamazal To: libcamera-devel@lists.libcamera.org Cc: Xander Pronk , Kieran Bingham , Rick ten Wolde , Milan Zamazal , Bryan O'Donoghue , =?utf-8?q?Barnab=C3=A1s_P=C5=91cze?= Subject: [PATCH v16 4/6] libcamera: shaders: Add LSC support Date: Thu, 22 Oct 2026 11:40:46 +0200 Message-ID: <20261022094048.20277-5-mzamazal@redhat.com> In-Reply-To: <20261022094048.20277-1-mzamazal@redhat.com> References: <20261022094048.20277-1-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: zpXCodhTqZ2LhhUSUJE9xb3LSU_g_ndTtxj9ZBZ7hVk_1792662087 X-Mimecast-Originator: redhat.com 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'. lsc_tex texture contains 8-bit UQ<2, 6> quantized data as provided by the IPA algorithm. It is converted to float in the shader by multiplying it by 4.0. Co-developed-by: Rick ten Wolde Signed-off-by: Rick ten Wolde Signed-off-by: Xander Pronk Signed-off-by: Milan Zamazal Reviewed-by: Bryan O'Donoghue Tested-by: Barnabás Pőcze --- src/libcamera/shaders/bayer_1x_packed.frag | 12 ++++++++++++ src/libcamera/shaders/bayer_unpacked.frag | 9 +++++++++ 2 files changed, 21 insertions(+) diff --git a/src/libcamera/shaders/bayer_1x_packed.frag b/src/libcamera/shaders/bayer_1x_packed.frag index 0b641a5f3..e61334070 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 +236,14 @@ void main(void) */ rgb = (rgb - blacklevel) / (1.0 - blacklevel); +#if defined(APPLY_LSC) + /* Multiple by 4.0 for UQ<2, 6> -> float conversion: + * texture2D(...) = original_float * 2^6 (quantization) * 1/2^8 (texture byte to float) + * => original_float = texture2D(...) / 2^6 * 2^8 = texture2D(...) * 2^2 + */ + rgb = rgb * (texture2D(lsc_tex, textureOut).rgb * 4.0); +#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..be2f89dd0 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 +139,11 @@ void main(void) { */ rgb = (rgb - blacklevel) / (1.0 - blacklevel); +#if defined(APPLY_LSC) + /* Multiple by 4.0 for UQ<2, 6> -> float conversion */ + rgb = rgb * (texture2D(lsc_tex, center.xy).rgb * 4.0); +#endif + /* Apply AWB gains, and saturate each channel at sensor range */ rgb = clamp(rgb * awb, vec3(0.0), vec3(1.0));