{"id":25319,"url":"https://patchwork.libcamera.org/api/patches/25319/?format=json","web_url":"https://patchwork.libcamera.org/patch/25319/","project":{"id":1,"url":"https://patchwork.libcamera.org/api/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":"<20251202134544.662446-11-bryan.odonoghue@linaro.org>","date":"2025-12-02T13:45:30","name":"[v6,10/24] libcamera: shaders: Add support for contrast","commit_ref":null,"pull_url":null,"state":"superseded","archived":false,"hash":"53faf1395ca3fc81730e83eb84452a869de30776","submitter":{"id":175,"url":"https://patchwork.libcamera.org/api/people/175/?format=json","name":"Bryan O'Donoghue","email":"bryan.odonoghue@linaro.org"},"delegate":null,"mbox":"https://patchwork.libcamera.org/patch/25319/mbox/","series":[{"id":5631,"url":"https://patchwork.libcamera.org/api/series/5631/?format=json","web_url":"https://patchwork.libcamera.org/project/libcamera/list/?series=5631","date":"2025-12-02T13:45:20","name":"Add GLES 2.0 GPUISP to libcamera","version":6,"mbox":"https://patchwork.libcamera.org/series/5631/mbox/"}],"comments":"https://patchwork.libcamera.org/api/patches/25319/comments/","check":"pending","checks":"https://patchwork.libcamera.org/api/patches/25319/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 D7895C32EF\n\tfor ;\n\tTue, 2 Dec 2025 13:46:14 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 005C960D17;\n\tTue, 2 Dec 2025 14:46:13 +0100 (CET)","from mail-wm1-x331.google.com (mail-wm1-x331.google.com\n\t[IPv6:2a00:1450:4864:20::331])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 9795A60D1A\n\tfor ;\n\tTue, 2 Dec 2025 14:46:07 +0100 (CET)","by mail-wm1-x331.google.com with SMTP id\n\t5b1f17b1804b1-4779d47be12so44926835e9.2\n\tfor ;\n\tTue, 02 Dec 2025 05:46:07 -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\t5b1f17b1804b1-47926f0ec69sm19383375e9.1.2025.12.02.05.46.05\n\t(version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256);\n\tTue, 02 Dec 2025 05:46:05 -0800 (PST)"],"Authentication-Results":"lancelot.ideasonboard.com; dkim=pass (2048-bit key;\n\tunprotected) header.d=linaro.org header.i=@linaro.org\n\theader.b=\"cx1rFdu3\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed;\n\td=linaro.org; s=google; t=1764683166; x=1765287966;\n\tdarn=lists.libcamera.org; \n\th=content-transfer-encoding:mime-version:references:in-reply-to\n\t:message-id:date:subject:cc:to:from:from:to:cc:subject:date\n\t:message-id:reply-to;\n\tbh=C/sV5SonuYN3A35MLfu7GzsniU0bzqMrcJSwifQ1Hik=;\n\tb=cx1rFdu3zr+rQDeRvuCQRCpd9PQrDwhkYY12hpOPpI5FYd7gCoZDT2Hr5T1+m0Ik/p\n\tA/lRp2bKNevHDjzXI0+SOholmNzck3YnjlYOXhHDLSzveKe9zlWq/ajp+oQtnGe5Bl7G\n\trFsgRbEw5YoNdgY8GFIV/5rqSgq6b3bnGMB8nlAMMY8S6TYKnSwHQJFpouePascGW+XQ\n\tlZb4XdEu2mb1e5gtxv4oXdpD478PX315hLjrZrxoTIruBYOdlQe8RVM7cbNuUpO4ub9V\n\tmwlSkUUxVAzRoD4kLy9ENSndIRRB1hv5OzGgBjdOR88Uga6O7BwdgDHRuv8cmrzTrVKj\n\tPWMg==","X-Google-DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed;\n\td=1e100.net; s=20230601; t=1764683166; x=1765287966;\n\th=content-transfer-encoding:mime-version:references:in-reply-to\n\t:message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from\n\t:to:cc:subject:date:message-id:reply-to;\n\tbh=C/sV5SonuYN3A35MLfu7GzsniU0bzqMrcJSwifQ1Hik=;\n\tb=pSQzomaen7i8gDfaNxvLPBDnnuNSGgFfKelNuHECxhvbhH+fbj0CaYznCvLm+8pRP4\n\tqRVDSu5hDFndUWMVbhhJy7kcw9gotjf/i6SEa1UXzxiKcq3+7I5Ue//OmUygcfF/BSNK\n\t1/AB+2tHM248swqW1uexKhCJUgkEVGlKmClU3qzd0ReHHc0rjG/nWpzgGPWpYkFwVP0z\n\tkQ0IhvhSrGA6ZVijO5XesqB8f08KAK1Aj0GPWMt2gM9vNsyEFbt+bexvkTuPxtNz4/fu\n\tpBFWhfHMVNyuwhq/c+iL2WuujxlcBnjc4UY7wFDTiRfXF096QKgCFAsyuk48+rmXcGKk\n\tSsFQ==","X-Gm-Message-State":"AOJu0YxMcMGJMd21sbCOp0N+UvpCrC1z8XOc66gDOt83irdWushEFWZi\n\tWZco44GCuWmza+yiMbXvZBt8V3fGe7AB/S6UNbX3fKcUu3ucbeYne/MBbsbVF2WNfIK6zRSGVhQ\n\tuW4xa","X-Gm-Gg":"ASbGncvwm43dB0l+kTp7WdPynYWOvwNxeN9M/XeponXyN0p3KoMQQVWjoRg8/eoDVmz\n\t2WLB3TH8KgT4lc6GJFb5dYBnrU/emTLBr073I+yxu5ETL9GqcsbmichZpEmakaYhlbsOmL6ZL5A\n\tT+EBtPBcsBe/fsICUANCFyLWmqtOlzw0TgHW2VyavjsdcKHLhYaC4dX8zQrhJqBLG9MHHplJ5XM\n\tTGQz0qi6vDMizeRy/81hd4nm9Ms7ert6IhlJfrOk5/nwKzkNBnYezm1BaleapF4uM5J95poJPGT\n\twK2V3XzWGgu0nkC+6QTEeZg0zYNokOf7QJaEFsI93guJxxcw8Qu7t+C7+BxoY69BS/CG5cY3hHo\n\taRmxNnVOIJ2cU5gFx8pO9tRNHrahOLfyj6JfaIivPZ/yDCUVZWqDTvTC39cvyiahxjQewR/5PjR\n\tbTDY8bB+zfCKqhK+Vef1SAaPydGk+tzv1OAIayIyLAdavGSApJnqdxArwLy7u8fwONLa0=","X-Google-Smtp-Source":"AGHT+IFofNvOacnLduLBPdUDH62M9if1OU5eoHP6UlGVwUjxgqWnAot+k6CNhiXEtjbAoaJJ0QrLFw==","X-Received":"by 2002:a05:600c:5494:b0:477:93f7:bbc5 with SMTP id\n\t5b1f17b1804b1-477c0184c3amr404258905e9.10.1764683166581; \n\tTue, 02 Dec 2025 05:46:06 -0800 (PST)","From":"Bryan O'Donoghue ","To":"libcamera-devel@lists.libcamera.org","Cc":"pavel@ucw.cz, Bryan O'Donoghue ,\n\tMilan Zamazal ","Subject":"[PATCH v6 10/24] libcamera: shaders: Add support for contrast","Date":"Tue, 2 Dec 2025 13:45:30 +0000","Message-ID":"<20251202134544.662446-11-bryan.odonoghue@linaro.org>","X-Mailer":"git-send-email 2.52.0","In-Reply-To":"<20251202134544.662446-1-bryan.odonoghue@linaro.org>","References":"<20251202134544.662446-1-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 | 19 +++++++++++++++++++\n src/libcamera/shaders/bayer_unpacked.frag | 19 +++++++++++++++++++\n 2 files changed, 38 insertions(+)","diff":"diff --git a/src/libcamera/shaders/bayer_1x_packed.frag b/src/libcamera/shaders/bayer_1x_packed.frag\nindex 77d9fbfa7..2fc9952e2 100644\n--- a/src/libcamera/shaders/bayer_1x_packed.frag\n+++ b/src/libcamera/shaders/bayer_1x_packed.frag\n@@ -68,6 +68,19 @@ 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 normalise, float contrast_in)\n+{\n+\t// Convert 0..2 contrast to 0..infinity; avoid actual infinity at tan(pi/2)\n+\tfloat contrastExp = tan(clamp(contrast_in * 0.78539816339744830962, 0.0, 1.5707963267948966 - 0.00001));\n+\n+\t// Apply simple S-curve\n+\tif (normalise < 0.5)\n+\t\treturn 0.5 * pow(normalise / 0.5, contrastExp);\n+\telse\n+\t\treturn 1.0 - 0.5 * pow((1.0 - normalise) / 0.5, contrastExp);\n+}\n \n void main(void)\n {\n@@ -261,6 +274,12 @@ 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/* Contrast */\n+\trgb = clamp(rgb, 0.0, 1.0);\n+\trgb.r = apply_contrast(rgb.r, contrast);\n+\trgb.g = apply_contrast(rgb.g, contrast);\n+\trgb.b = apply_contrast(rgb.b, contrast);\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..caa0ba15d 100644\n--- a/src/libcamera/shaders/bayer_unpacked.frag\n+++ b/src/libcamera/shaders/bayer_unpacked.frag\n@@ -27,6 +27,19 @@ 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 normalise, float contrast_in)\n+{\n+ // Convert 0..2 contrast to 0..infinity; avoid actual infinity at tan(pi/2)\n+ float contrastExp = tan(clamp(contrast_in * 0.78539816339744830962, 0.0, 1.5707963267948966 - 0.00001));\n+\n+ // Apply simple S-curve\n+ if (normalise < 0.5)\n+ return 0.5 * pow(normalise / 0.5, contrastExp);\n+ else\n+ return 1.0 - 0.5 * pow((1.0 - normalise) / 0.5, contrastExp);\n+}\n \n void main(void) {\n vec3 rgb;\n@@ -156,6 +169,12 @@ 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+ /* Contrast */\n+ rgb = clamp(rgb, 0.0, 1.0);\n+ rgb.r = apply_contrast(rgb.r, contrast);\n+ rgb.g = apply_contrast(rgb.g, contrast);\n+ rgb.b = apply_contrast(rgb.b, contrast);\n+\n /* Apply gamma after colour correction */\n rgb = pow(rgb, vec3(gamma));\n \n","prefixes":["v6","10/24"]}