[{"id":39463,"web_url":"https://patchwork.libcamera.org/comment/39463/","msgid":"<85wlvljxk8.fsf@mzamazal-thinkpadp1gen7.tpbc.csb>","date":"2026-06-26T12:28:07","subject":"Re: [PATCH v3 6/8] libcamera: egl: Add activateBindTexture","submitter":{"id":177,"url":"https://patchwork.libcamera.org/api/people/177/","name":"Milan Zamazal","email":"mzamazal@redhat.com"},"content":"Bryan O'Donoghue writes:\n\n> When operating from a texture cache on dma-buf inputs we will no longer\n> create new textures nor attach those textures for dma-buf handles we have\n> already encountered.\n>\n> This means we will use the texture id associated with a given texture unit\n> to switch between one texture and another. The pages associated with the\n> texture will have been populated with new data by the CSI2 receiver. All we\n> will do is say to the GPU \"reuse this texture id\" aka zero-copy.\n>\n> However we must also activate and bind that texture for each loop. This\n> cost is small but necessary for zero-copy.\n>\n> Reviewed-by: Robert Mader \n> Signed-off-by: Bryan O'Donoghue \n> ---\n> include/libcamera/internal/egl.h | 1 +\n> src/libcamera/egl.cpp | 24 +++++++++++++++++++-----\n> 2 files changed, 20 insertions(+), 5 deletions(-)\n>\n> diff --git a/include/libcamera/internal/egl.h b/include/libcamera/internal/egl.h\n> index 9b679332c..e4d366abd 100644\n> --- a/include/libcamera/internal/egl.h\n> +++ b/include/libcamera/internal/egl.h\n> @@ -112,6 +112,7 @@ public:\n> \tvoid createOutputTexture2D(eGLImage &eglImage);\n> \n> \tint attachTextureToFBO(eGLImage &eglImage);\n> +\tvoid activateBindTexture(eGLImage &eglImage);\n> \n> \tvoid pushEnv(std::vector &shaderEnv, const char *str);\n> \tvoid makeCurrent();\n> diff --git a/src/libcamera/egl.cpp b/src/libcamera/egl.cpp\n> index 22f46e92a..4eabddcc7 100644\n> --- a/src/libcamera/egl.cpp\n> +++ b/src/libcamera/egl.cpp\n> @@ -138,6 +138,23 @@ int eGL::attachTextureToFBO(eGLImage &eglImage)\n> \treturn ret;\n> }\n> \n> +/**\n> + * \\brief Activate a texture unit and bind a texture to that unit\n> + * \\param[in,out] eglImage EGL image containing data related to unit and texture id\n> + *\n> + * When we create a texture we will bind a texture unit and texture id so\n> + * we can set filters. For the case where a texture already exists thought\n\ns/thought/though/\n\nWith the typo fixed:\n\nReviewed-by: Milan Zamazal \n\n> + * we need to activate and bind an existing texture. This helper function\n> + * facilitates both cases.\n> + *\n> + */\n> +void eGL::activateBindTexture(eGLImage &eglImage)\n> +{\n> +\t// Bind texture unit and texture\n> +\tglActiveTexture(eglImage.texture_unit_);\n> +\tglBindTexture(GL_TEXTURE_2D, eglImage.texture_);\n> +}\n> +\n> /**\n> * \\brief Create a DMA-BUF backed 2D texture\n> * \\param[in,out] eglImage EGL image to associate with the DMA-BUF\n> @@ -197,9 +214,7 @@ int eGL::createDMABufTexture2D(eGLImage &eglImage, int fd, bool output)\n> \t\treturn -ENODEV;\n> \t}\n> \n> -\t// Bind texture unit and texture\n> -\tglActiveTexture(eglImage.texture_unit_);\n> -\tglBindTexture(GL_TEXTURE_2D, eglImage.texture_);\n> +\tactivateBindTexture(eglImage);\n> \n> \t// Generate texture with filter semantics\n> \tglEGLImageTargetTexture2DOES(GL_TEXTURE_2D, image);\n> @@ -270,8 +285,7 @@ void eGL::createTexture2D(eGLImage &eglImage, void *data)\n> {\n> \tASSERT(tid_ == Thread::currentId());\n> \n> -\tglActiveTexture(eglImage.texture_unit_);\n> -\tglBindTexture(GL_TEXTURE_2D, eglImage.texture_);\n> +\tactivateBindTexture(eglImage);\n> \n> \t// Generate texture, bind, associate image to texture, configure, unbind\n> \tglTexImage2D(GL_TEXTURE_2D, 0, eglImage.format_, eglImage.width_, eglImage.height_, 0, eglImage.format_, GL_UNSIGNED_BYTE, data);","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 B5AA0C3264\n\tfor ;\n\tFri, 26 Jun 2026 12:28:15 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id DD07365ED9;\n\tFri, 26 Jun 2026 14:28:14 +0200 (CEST)","from us-smtp-delivery-124.mimecast.com\n\t(us-smtp-delivery-124.mimecast.com [170.10.129.124])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 82BA3658FA\n\tfor ;\n\tFri, 26 Jun 2026 14:28:13 +0200 (CEST)","from mail-wm1-f69.google.com (mail-wm1-f69.google.com\n\t[209.85.128.69]) by relay.mimecast.com with ESMTP with STARTTLS\n\t(version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id\n\tus-mta-265-WsEi3CDtOMCDRCadhqfv-Q-1; Fri, 26 Jun 2026 08:28:10 -0400","by mail-wm1-f69.google.com with SMTP id\n\t5b1f17b1804b1-49244130073so6929515e9.1\n\tfor ;\n\tFri, 26 Jun 2026 05:28:10 -0700 (PDT)","from mzamazal-thinkpadp1gen7.tpbc.csb\n\t(ip-77-48-47-4.net.vodafone.cz. 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