Vertexwahn
https://vertexwahn.de/
Recent content on VertexwahnHugo -- gohugo.ioen-usJulian AmannSun, 06 Jun 2021 00:05:52 +0200Bazel: Bazelizing Qt5 & Qt6
https://vertexwahn.de/2021/06/06/bazelizeqt/
Sun, 06 Jun 2021 00:05:52 +0200https://vertexwahn.de/2021/06/06/bazelizeqt/Why Qt? Qt is the defacto standard for cross-platform UI interfaces using C++. Of course, someone can argue that it is heavy to deploy, carries around a lot of legacy stuff, etc. Nevertheless, I would recommend using it even when your only use case is to open up only a blank window where you do all the rendering yourself since the framework has more than 20 years of experience in opening blank windows on many different platforms.Ray Tracing 101: Ray Triangle Intersection
https://vertexwahn.de/2021/05/29/raytriangleintersection/
Sat, 29 May 2021 00:05:52 +0200https://vertexwahn.de/2021/05/29/raytriangleintersection/Möller, Trumbore triangle intersection Tomas Möller and Ben Trumbore wrote a tiny paper with the title “Fast, Minimum Storage Ray/Triangle Intersection”. It describes an algorithm that can compute the intersection of a ray with a triangle. The paper was published in 1997. It contains one sentence that should draw your attention to this paper: “…, we believe it is the fastest ray/triangle intersection routine for triangles …”. I call the paper tiny because it consists only of 7 pages.Okapi Renderer
https://vertexwahn.de/page/okapi/
Thu, 13 May 2021 08:31:36 +0200https://vertexwahn.de/page/okapi/Okapi Renderer is an renderer developed by me.
Gallery Scene rendered with Okapi Renderer (BMW 315 DA2 scene provided by Maciej Ptaszyński):
Download Alpha 1.0.2 (will be released soon) Okapi Renderer Alpha 1.0.1 for Windows
Notes This is a very earily Alpha version.
Changes Minor tweaks to UI Alpha 1.0.1 (06.06.2021) Okapi Renderer Alpha 1.0.1 for Windows
Video Notes This is a very earily Alpha version.Bazel: Handling external dependencies in OpenEXR
https://vertexwahn.de/2021/04/02/externaldependenciesbazelopenexr/
Fri, 02 Apr 2021 00:05:58 +0200https://vertexwahn.de/2021/04/02/externaldependenciesbazelopenexr/I spend some time in adding support for Bazel to OpenEXR. OpenEXR v3.0.1 comes now with support for Bazel. OpenEXR has a dependencies to zlib and to Imath. If you want to build OpenEXR you also need to build some state of zlib and Imath.
If you do not have a monorepo you have always the dilemma of how to combining different repositories. A focus of Bazel is to have reproducible builds.Bazel: Offical support for OpenEXR
https://vertexwahn.de/2021/03/14/officialbazelsupportopenexr/
Sun, 14 Mar 2021 00:05:52 +0200https://vertexwahn.de/2021/03/14/officialbazelsupportopenexr/I wrote a blog post about Bazelizing OpenEXR already. In the meanwhile, my pull request was accepted. OpenEXR has official support for Bazel now.
Here is an example that shows how to OpenEXR with Bazel (in case you want to give Bazel a try download it and follow the install instructions):
Create a WORKSPACE.bazel file:
# SPDX-License-Identifier: BSD-3-Clause # Copyright Contributors to the OpenEXR Project. load("@bazel_tools//tools/build_defs/repo:git.bzl", "git_repository") git_repository( name = "openexr", # branch = "master", commit = "28fa44d5c24dbed3f05c38b81d75ae08d72c0cf9", remote = "https://github.Ray Tracing 101: Image sampling and reconstruction
https://vertexwahn.de/2021/02/28/imagereconstruction/
Sun, 28 Feb 2021 00:05:53 +0200https://vertexwahn.de/2021/02/28/imagereconstruction/Pixel positions Integer coordinates can be used to address different positions on a discrete pixel image grid. Usually, the top left pixel has the coorinates $(0,0)$ and the bottom right one $(width-1,height-1)$. This is space is called the raster space. This was already described in an earlier blog post.
When sampling an image plane we use floating-point coordinates. One important question is how to convert from discrete coordinates to continuous ones and vice versa.Bazel: Bazelizing OpenEXR
https://vertexwahn.de/2021/01/24/bazelizeopenexr/
Sun, 24 Jan 2021 00:05:52 +0200https://vertexwahn.de/2021/01/24/bazelizeopenexr/Introduction bazelizing, bazelization, to bazelize, bazelized: The act of converting some existing software artifact to be easily consumed by the Bazel build tool
OpenEXR is a library to store high-dynamic-range (HDR) image files. Usually, the extension .exr is chosen for such files. For instance, an HRD image can store 32-Bits per color channel instead of only 8-Bits. For viewing HDR images you need either an HDR screen or proper tone mapping on an LDR screen.Bazel: Bazelizing Embree 3.12.1
https://vertexwahn.de/2021/01/12/bazelizingembree3.12.1/
Tue, 12 Jan 2021 00:05:52 +0200https://vertexwahn.de/2021/01/12/bazelizingembree3.12.1/Introduction bazelizing, bazelization, to bazelize, bazelized: The act of converting some existing software artifact to be easily consumed by the Bazel build tool
Embree is middleware for ray tracing that computes intersections points between rays and different shape types. The source code of Embree is under the Apache 2.0 license and hosted on GitHub. Embree targets CPU ray tracing and contains special code to make use of SSE, AVX, AVX2, and AVX-512 instructions if the target CPU supports it.Ray Tracing 101: Shooting rays
https://vertexwahn.de/2021/01/03/shootingrays/
Sun, 03 Jan 2021 00:05:53 +0200https://vertexwahn.de/2021/01/03/shootingrays/How do we shoot a rays into our scene given a perspective matrix?
Assume that our virtual film plane is $800$ by $600$ pixel in size. This means that raster coordinates range from $[0,800] \times [0,600]$. The positive x-axis goes form left to right and the positive y-axis goes from top to bottom. The top left corner has the raster coordinates $(0,0)$ and the right bottom has the raster coordinates $(800,600)$.Ray tracing 101: Perspective projection
https://vertexwahn.de/2020/12/27/perspectiveprojection/
Sun, 27 Dec 2020 00:05:52 +0200https://vertexwahn.de/2020/12/27/perspectiveprojection/Perspective projection To get the gist of perspective projection consider the following image:
Given the Point $P(p_x, p_y, p_z)$ what is are the coordinates of the projected point $P’(p’_x,p’_y,p’_z)$?
$$ p'_x = d \frac{p_x}{p_z} $$ $$ p'_y = d \frac{p_y}{p_z} $$ $$ p'_z = d $$ If $d = 1$ then the problem simplifies to just dividing by the z-coordinate. And this is what the whole magic about perspective projection is all about.Ray Tracing 101: How does a look-at transform work?
https://vertexwahn.de/2020/12/21/lookat/
Mon, 21 Dec 2020 00:05:52 +0200https://vertexwahn.de/2020/12/21/lookat/Ray Tracing 101: How does a look at transform work? The matrix that transforms world space coordinates to view space is called the view matrix. A look at matrix is a view matrix that is constructed from an eye point, a look at direction or target point and an up vector.
If you take a look at the source code of pbrt-v3 and figure out how a camera spans a ray you will recognize that the ray is first described in camera space, which means that the start of a ray is always at the point (0,0,0).Ray tracing 101: Matrices and Coordinate Systems
https://vertexwahn.de/2020/12/20/coordinatesystemsandmatrices/
Sun, 20 Dec 2020 00:05:52 +0200https://vertexwahn.de/2020/12/20/coordinatesystemsandmatrices/Row-major vs. column-major matrices There are row-major and column-major matrices.
A translation matrix defined in column-major fashion looks like this:
$$ T(t_x,t_y,t_z) = \begin{pmatrix} 1 & 0 & 0 & t_x \\ 0 & 1 & 0 & t_y \\ 0 & 0 & 1 & t_z \\ 0 & 0 & 0 & 1 \end{pmatrix} $$ A translation matrix defined in row-major fashion looks like this:
$$ T(t_x,t_y,t_z) = \begin{pmatrix} 1 & 0 & 0 & 0 \\ 0 & 1 & 0 & 0 \\ 0 & 0 & 1 & 0 \\ t_x & t_y & t_z & 1 \end{pmatrix} $$ I stick here to column-major matrices.Ray tracing 101: Refraction of Light
https://vertexwahn.de/2020/12/19/refraction/
Sat, 19 Dec 2020 00:05:52 +0200https://vertexwahn.de/2020/12/19/refraction/I think a good way to get started with ray tracing is to begin with refraction. This is a basic operation that happens in almost every ray tracer. Refraction happens when a light ray hits another medium as shown in the following image:
Of course, this is just a simplified model of how light travels through space and how light is modeled, but this is fine enough to render some pleasant pictures.Open Source
https://vertexwahn.de/page/open_source/
Wed, 01 Jan 2020 08:31:36 +0200https://vertexwahn.de/page/open_source/Some examples of my past work
Minior contributions Bazel & Bazelization of libraries bazel_rules_qt (Commits) Bazel (Commits) Embree Imath (Commits) oneTBB (Commits) OpenEXR (Commits) rules_boost (Commits) rules_qt6
Major contributions Here you will find some projects to which I did major contributions.
FlatlandRT FlatlandRT is a 2D ray tracer visualization tool.
https://github.com/Vertexwahn/FlatlandRT
Open Infra Platform https://github.com/tumcms/Open-Infra-Platform
BlueFramework BlueFramework is divided into different parts e.g. Core, ImageProcessing, Rasterizer, and Engine.Publications
https://vertexwahn.de/page/publications/
Tue, 04 Jul 2017 08:43:54 +0200https://vertexwahn.de/page/publications/Please check my Google Scholar profile for my publications.
Here you will find only a not complete and not up to date list of some selected papers:
An Approach to Describe Arbitrary Transition Curves in an IFC Based Alignment Product Data Model Julian Amann¹, Matthias Flurl¹, Javier R. Jubierre¹, André Borrmann¹ , In: Proc. of the 2014 International Conference on Computing in Civil and Building Engineering, ISBN 978-0-7844-1361-6, Orlando, USA, 2014Imprint
https://vertexwahn.de/page/imprint/
Tue, 04 Jul 2017 08:31:36 +0200https://vertexwahn.de/page/imprint/Imprint according to german law Dr. rer. nat. Julian Amann
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E-Mail: dev@vertexwahn.de
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84030 Ergolding
E-Mail: dev@vertexwahn.de
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