{"id":25583,"url":"https://patchwork.libcamera.org/api/1.1/patches/25583/?format=json","web_url":"https://patchwork.libcamera.org/patch/25583/","project":{"id":1,"url":"https://patchwork.libcamera.org/api/1.1/projects/1/?format=json","name":"libcamera","link_name":"libcamera","list_id":"libcamera_core","list_email":"libcamera-devel@lists.libcamera.org","web_url":"","scm_url":"","webscm_url":""},"msgid":"<20251217100138.82525-11-bryan.odonoghue@linaro.org>","date":"2025-12-17T10:01:22","name":"[v9,10/26] libcamera: shaders: Add support for contrast","commit_ref":null,"pull_url":null,"state":"superseded","archived":false,"hash":"d6ede263ceeb9481d7f326b36781ecb2b49b871d","submitter":{"id":175,"url":"https://patchwork.libcamera.org/api/1.1/people/175/?format=json","name":"Bryan O'Donoghue","email":"bryan.odonoghue@linaro.org"},"delegate":null,"mbox":"https://patchwork.libcamera.org/patch/25583/mbox/","series":[{"id":5669,"url":"https://patchwork.libcamera.org/api/1.1/series/5669/?format=json","web_url":"https://patchwork.libcamera.org/project/libcamera/list/?series=5669","date":"2025-12-17T10:01:12","name":"Add GLES 2.0 GPUISP to libcamera","version":9,"mbox":"https://patchwork.libcamera.org/series/5669/mbox/"}],"comments":"https://patchwork.libcamera.org/api/patches/25583/comments/","check":"pending","checks":"https://patchwork.libcamera.org/api/patches/25583/checks/","tags":{},"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 0F404C3257\n\tfor ;\n\tWed, 17 Dec 2025 10:02:08 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 7D75D61EF2;\n\tWed, 17 Dec 2025 11:02:07 +0100 (CET)","from mail-wm1-x329.google.com (mail-wm1-x329.google.com\n\t[IPv6:2a00:1450:4864:20::329])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id DA77961A62\n\tfor ;\n\tWed, 17 Dec 2025 11:01:54 +0100 (CET)","by mail-wm1-x329.google.com with SMTP id\n\t5b1f17b1804b1-4779cc419b2so55738595e9.3\n\tfor ;\n\tWed, 17 Dec 2025 02:01:54 -0800 (PST)","from inspiron14p-linux.ht.home (188-141-3-146.dynamic.upc.ie.\n\t[188.141.3.146]) by smtp.gmail.com with ESMTPSA id\n\t5b1f17b1804b1-47bdc1583fbsm32292585e9.0.2025.12.17.02.01.52\n\t(version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256);\n\tWed, 17 Dec 2025 02:01:53 -0800 (PST)"],"Authentication-Results":"lancelot.ideasonboard.com; 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\n\tWed, 17 Dec 2025 02:01:54 -0800 (PST)","From":"Bryan O'Donoghue ","To":"libcamera-devel@lists.libcamera.org","Cc":"pavel@ucw.cz, Bryan O'Donoghue ,\n\tMilan Zamazal ","Subject":"[PATCH v9 10/26] libcamera: shaders: Add support for contrast","Date":"Wed, 17 Dec 2025 10:01:22 +0000","Message-ID":"<20251217100138.82525-11-bryan.odonoghue@linaro.org>","X-Mailer":"git-send-email 2.52.0","In-Reply-To":"<20251217100138.82525-1-bryan.odonoghue@linaro.org>","References":"<20251217100138.82525-1-bryan.odonoghue@linaro.org>","MIME-Version":"1.0","Content-Transfer-Encoding":"8bit","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "},"content":"Apply contrast after black-level and CCM operations.\n\nSuggested-by: Milan Zamazal \nSigned-off-by: Bryan O'Donoghue \n---\n src/libcamera/shaders/bayer_1x_packed.frag | 21 +++++++++++++++++++++\n src/libcamera/shaders/bayer_unpacked.frag | 21 +++++++++++++++++++++\n 2 files changed, 42 insertions(+)","diff":"diff --git a/src/libcamera/shaders/bayer_1x_packed.frag b/src/libcamera/shaders/bayer_1x_packed.frag\nindex 77d9fbfa7..0b730070e 100644\n--- a/src/libcamera/shaders/bayer_1x_packed.frag\n+++ b/src/libcamera/shaders/bayer_1x_packed.frag\n@@ -68,6 +68,16 @@ uniform sampler2D tex_y;\n uniform mat3 ccm;\n uniform vec3 blacklevel;\n uniform float gamma;\n+uniform float contrast;\n+\n+float apply_contrast(float value, float contrastExp)\n+{\n+\t// Apply simple S-curve\n+\tif (value < 0.5)\n+\t\treturn 0.5 * pow(value / 0.5, contrastExp);\n+\telse\n+\t\treturn 1.0 - 0.5 * pow((1.0 - value) / 0.5, contrastExp);\n+}\n \n void main(void)\n {\n@@ -261,6 +271,17 @@ void main(void)\n \trgb.g = (rin * ccm[1][0]) + (gin * ccm[1][1]) + (bin * ccm[1][2]);\n \trgb.b = (rin * ccm[2][0]) + (gin * ccm[2][1]) + (bin * ccm[2][2]);\n \n+\t/*\n+\t * Contrast\n+\t * contrastExp 0..2 contrast to 0..infinity; avoid actual infinity at tan(pi/2)\n+\t */\n+\tfloat contrastExp = tan(clamp(contrast * 0.78539816339744830962, 0.0, 1.5707963267948966 - 0.00001));\n+\n+\trgb = clamp(rgb, 0.0, 1.0);\n+\trgb.r = apply_contrast(rgb.r, contrastExp);\n+\trgb.g = apply_contrast(rgb.g, contrastExp);\n+\trgb.b = apply_contrast(rgb.b, contrastExp);\n+\n \t/* Apply gamma after colour correction */\n \trgb = pow(rgb, vec3(gamma));\n \ndiff --git a/src/libcamera/shaders/bayer_unpacked.frag b/src/libcamera/shaders/bayer_unpacked.frag\nindex aba11a87f..114e32058 100644\n--- a/src/libcamera/shaders/bayer_unpacked.frag\n+++ b/src/libcamera/shaders/bayer_unpacked.frag\n@@ -27,6 +27,16 @@ varying vec4 xCoord;\n uniform mat3 ccm;\n uniform vec3 blacklevel;\n uniform float gamma;\n+uniform float contrast;\n+\n+float apply_contrast(float value, float contrastExp)\n+{\n+ // Apply simple S-curve\n+ if (value < 0.5)\n+ return 0.5 * pow(value / 0.5, contrastExp);\n+ else\n+ return 1.0 - 0.5 * pow((1.0 - value) / 0.5, contrastExp);\n+}\n \n void main(void) {\n vec3 rgb;\n@@ -156,6 +166,17 @@ void main(void) {\n rgb.g = (rin * ccm[1][0]) + (gin * ccm[1][1]) + (bin * ccm[1][2]);\n rgb.b = (rin * ccm[2][0]) + (gin * ccm[2][1]) + (bin * ccm[2][2]);\n \n+ /*\n+ * Contrast\n+ * Convert 0..2 contrast to 0..infinity; avoid actual infinity at tan(pi/2)\n+ */\n+ float contrastExp = tan(clamp(contrast * 0.78539816339744830962, 0.0, 1.5707963267948966 - 0.00001));\n+\n+ rgb = clamp(rgb, 0.0, 1.0);\n+ rgb.r = apply_contrast(rgb.r, contrastExp);\n+ rgb.g = apply_contrast(rgb.g, contrastExp);\n+ rgb.b = apply_contrast(rgb.b, contrastExp);\n+\n /* Apply gamma after colour correction */\n rgb = pow(rgb, vec3(gamma));\n \n","prefixes":["v9","10/26"]}