From patchwork Tue Sep 10 23:46:49 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Laurent Pinchart X-Patchwork-Id: 21227 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 75272C3259 for ; Tue, 10 Sep 2024 23:47:31 +0000 (UTC) Received: from lancelot.ideasonboard.com (localhost [IPv6:::1]) by lancelot.ideasonboard.com (Postfix) with ESMTP id CF0D863501; Wed, 11 Sep 2024 01:47:30 +0200 (CEST) Authentication-Results: lancelot.ideasonboard.com; dkim=pass (1024-bit key; unprotected) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="FrmEDzEd"; dkim-atps=neutral Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647]) by lancelot.ideasonboard.com (Postfix) with ESMTPS id 547F6634FD for ; Wed, 11 Sep 2024 01:47:26 +0200 (CEST) Received: from pendragon.ideasonboard.com (213-229-8-243.static.upcbusiness.at [213.229.8.243]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 36EDB11D6; Wed, 11 Sep 2024 01:46:09 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1726011969; bh=g48epqajRJ9hCS8P7kBtlFSX96b9dh8PpIeMSWb2c2o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FrmEDzEdzfIcZPstYUz4Xhc99D5JyXXjiBqTO78xFOzRwoWeHXjaS7cXVaGjs/LQs c1sLioQorBSfaCi/+2LYChns+6r0wf3/cCfkeVqXC/COQgDinn6v7lm9+0SHGhfdAg Mx6KmYjxn6g6mrLm6fUly9F+WRn5an3zK2iDc/Go= From: Laurent Pinchart To: libcamera-devel@lists.libcamera.org Cc: Neal Gompa Subject: [PATCH 3/3] qcam: viewfinder_gl: Render image centered in letterbox Date: Wed, 11 Sep 2024 02:46:49 +0300 Message-ID: <20240910234649.28591-4-laurent.pinchart@ideasonboard.com> X-Mailer: git-send-email 2.44.2 In-Reply-To: <20240910234649.28591-1-laurent.pinchart@ideasonboard.com> References: <20240910234649.28591-1-laurent.pinchart@ideasonboard.com> MIME-Version: 1.0 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" Mimic the letterbox behaviour of the Qt viewfinder by rendering the image centered. This is done by adding a projection matrix to the vertex shader to scale the rendered rectangle. Another option would have been to keep using glViewport() (which would have needed to be moved to paintGL(), as Qt resets the viewport to span the full widget before calling). Hidpi displays would then need special handling of the device pixel ratio, which is done automatically by Qt when it sets the default viewport. Using a projection matrix avoids this complication. Signed-off-by: Laurent Pinchart --- src/apps/qcam/assets/shader/bayer_8.vert | 4 ++- src/apps/qcam/assets/shader/identity.vert | 3 ++- src/apps/qcam/viewfinder_gl.cpp | 31 +++++++++++++++-------- src/apps/qcam/viewfinder_gl.h | 2 +- 4 files changed, 26 insertions(+), 14 deletions(-) diff --git a/src/apps/qcam/assets/shader/bayer_8.vert b/src/apps/qcam/assets/shader/bayer_8.vert index 3695a5e910c9..fb5109eee3f5 100644 --- a/src/apps/qcam/assets/shader/bayer_8.vert +++ b/src/apps/qcam/assets/shader/bayer_8.vert @@ -19,6 +19,8 @@ Copyright (C) 2021, Linaro attribute vec4 vertexIn; attribute vec2 textureIn; +uniform mat4 proj_matrix; + uniform vec2 tex_size; /* The texture size in pixels */ uniform vec2 tex_step; @@ -47,5 +49,5 @@ void main(void) { yCoord = center.y + vec4(-2.0 * tex_step.y, -tex_step.y, tex_step.y, 2.0 * tex_step.y); - gl_Position = vertexIn; + gl_Position = proj_matrix * vertexIn; } diff --git a/src/apps/qcam/assets/shader/identity.vert b/src/apps/qcam/assets/shader/identity.vert index 12c41377cfe7..907e8741fae7 100644 --- a/src/apps/qcam/assets/shader/identity.vert +++ b/src/apps/qcam/assets/shader/identity.vert @@ -9,10 +9,11 @@ attribute vec4 vertexIn; attribute vec2 textureIn; varying vec2 textureOut; +uniform mat4 proj_matrix; uniform float stride_factor; void main(void) { - gl_Position = vertexIn; + gl_Position = proj_matrix * vertexIn; textureOut = vec2(textureIn.x * stride_factor, textureIn.y); } diff --git a/src/apps/qcam/viewfinder_gl.cpp b/src/apps/qcam/viewfinder_gl.cpp index b2096faf859f..f31956ff0504 100644 --- a/src/apps/qcam/viewfinder_gl.cpp +++ b/src/apps/qcam/viewfinder_gl.cpp @@ -12,6 +12,7 @@ #include #include #include +#include #include #include @@ -464,6 +465,7 @@ bool ViewFinderGL::createFragmentShader() vertexBuffer_.release(); + projMatrixUniform_ = shaderProgram_.uniformLocation("proj_matrix"); textureUniformY_ = shaderProgram_.uniformLocation("tex_y"); textureUniformU_ = shaderProgram_.uniformLocation("tex_u"); textureUniformV_ = shaderProgram_.uniformLocation("tex_v"); @@ -509,7 +511,7 @@ void ViewFinderGL::initializeGL() glEnable(GL_TEXTURE_2D); glDisable(GL_DEPTH_TEST); - static const GLfloat coordinates[2][4][2]{ + const GLfloat coordinates[2][4][2]{ { /* Vertex coordinates */ { -1.0f, -1.0f }, @@ -801,6 +803,17 @@ void ViewFinderGL::doRender() shaderProgram_.setUniformValue(textureUniformStrideFactor_, static_cast(size_.width() - 1) / (stridePixels - 1)); + + /* + * Place the viewfinder in the centre of the widget, preserving the + * aspect ratio of the image. + */ + QMatrix4x4 projMatrix; + QSizeF scaledSize = size_.scaled(size(), Qt::KeepAspectRatio); + projMatrix.scale(scaledSize.width() / size().width(), + scaledSize.height() / size().height()); + + shaderProgram_.setUniformValue(projMatrixUniform_, projMatrix); } void ViewFinderGL::paintGL() @@ -818,18 +831,14 @@ void ViewFinderGL::paintGL() close(); } - if (image_) { - glClearColor(0.0f, 0.0f, 0.0f, 1.0f); - glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); + if (!image_) + return; - doRender(); - glDrawArrays(GL_TRIANGLE_FAN, 0, 4); - } -} + glClearColor(0.0f, 0.0f, 0.0f, 1.0f); + glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); -void ViewFinderGL::resizeGL(int w, int h) -{ - glViewport(0, 0, w, h); + doRender(); + glDrawArrays(GL_TRIANGLE_FAN, 0, 4); } QSize ViewFinderGL::sizeHint() const diff --git a/src/apps/qcam/viewfinder_gl.h b/src/apps/qcam/viewfinder_gl.h index 23744b411c86..23c657bcfae2 100644 --- a/src/apps/qcam/viewfinder_gl.h +++ b/src/apps/qcam/viewfinder_gl.h @@ -51,7 +51,6 @@ Q_SIGNALS: protected: void initializeGL() override; void paintGL() override; - void resizeGL(int w, int h) override; QSize sizeHint() const override; private: @@ -88,6 +87,7 @@ private: /* Common texture parameters */ GLuint textureMinMagFilters_; + GLuint projMatrixUniform_; /* YUV texture parameters */ GLuint textureUniformU_;