City Rendering, PolyLines, Uncategorized

OSM Renderer – Polylines part 2

Rendering Polylines In part 1 I learned how to identify polylines and came up with a simple visual representation by drawing the polylines using the OpenGL "GL_LINES" primitive. This led to a network of lines representing the centres of roads/rivers/railway lines etc. Extracting the data To allow us to render the roads with some proper "width"… Continue reading OSM Renderer – Polylines part 2

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PolyLines

OSM Renderer – Polylines part 1

Line Based Objects As you may have read in previous posts - a lot of the objects in open street map are represented as polygons, however, many other objects are represented as polylines. A polyline is simply a collection of points which together represent straight line segments. When chained together these line segments work together to… Continue reading OSM Renderer – Polylines part 1

City Rendering

Open Street Map video – Now in HD!

I decided the previous video could do with some improvements! This version now has a small route programmed for the camera to get rid of the jerky movement from the previous video. This video is also HD - in 1080p @ 48 fps as opposed to the previous 480p video. This video also introduces the rendering of… Continue reading Open Street Map video – Now in HD!

Building Heights, City Rendering

Building Heights!

We have heights! To improve the realism of the building/city rendering the next step I took was to parse the building heights from the Open Street map objects. The height tag is described on the OSM Wiki here. The main points are as following:  the "height" tag of the way returns the maximum height of the… Continue reading Building Heights!

City Rendering, Lighting

Calculating normals + lighting

Lighting Basics The next step I took to improve the rendering was to add in lighting. Until now I had just gave everything a normal of "up". This meant that every surface of the building had the same brightness as the normal represents the direction the surface is facing. Basic is lighting is done by… Continue reading Calculating normals + lighting

City Rendering

Rendering Rooftops – Triangulating polygons

Now that we have the walls complete, I thought it would be a good time to move onto rendering the rooftops! Instead of having to triangulate the polygons myself, I looked online to find a triangular to do it for me. I stumbled across an old flipcode article that had a triangular in it. I simply… Continue reading Rendering Rooftops – Triangulating polygons

City Rendering

Rendering solid walls

Progressing Forwards At the end of the previous post I had processed the Openstreet map data - created polygon data for each building and then drawn these buildings using the GL_LINE primitives to give us a wireframe outline for the building as shown below: To take this to the next stage - the next task was to draw… Continue reading Rendering solid walls