#WEBGL TESSELLATION TRIANGLE TWIST HOW TO#
#WEBGL TESSELLATION TRIANGLE TWIST UPDATE#
#WEBGL TESSELLATION TRIANGLE TWIST FULL#
#WEBGL TESSELLATION TRIANGLE TWIST CODE#

I’m the coauthor, with Dave Shreiner, of the textbook Interactive Computer Graphics, which is now in its seventh edition.

Here are some of my observations, many of which echo some of Eric’s on previous blog posts, and many that relate to the present state of MOOCs.įirst, something about me and my course. The experience was interesting, at times exasperating, ultimately rewarding and a lot of work. Having taken Eric’s excellent three.js course with Udacity, I was interested in doing a very different course. Note that the width parameter is a pure number, and the tessellate Polyline()method does not make any assumption with regard to the units being used from now on, we will assume that width is in pixels, but a better option would be using points or some other screen-space length unit.Įach graphic becomes a promise in the this.promises array each promise resolves to an object that contains the resulting mesh as well as the attribute and symbol objects of the original graphic, effectively binding together the mesh and all the information that may determine its appearance on screen.Recently I finished teaching a Coursera MOOC entitled Interactive Computer Graphics with WebGL. For instance a width attribute of the graphics can be passed as the width parameter of tessellate Polyline() method.

#WEBGL TESSELLATION TRIANGLE TWIST CODE#

In the following code snippets we focus on the polyline case, but the other cases are analogous.Īttributes from the graphic can be used to drive the values of the other parameters of the tessellate*()method of choice. The geometry type determines which tessellate*() method is called to create the mesh.

#WEBGL TESSELLATION TRIANGLE TWIST UPDATE#

When done, all the meshes are saved to the meshes member variable and the entire layer view is marked as dirty by setting needs Update to true, meaning the collection of meshes has changed but they have not been uploaded to the GPU for rendering.Įach graphic is converted to a mesh by a call to process Graphic(). In the attach() method of the custom layer view a listener is set up that will fire for any change to the graphic collection when a change is detected all the graphics are reprocessed using the custom method this.process Graphic() each call to this.process Graphic() creates a promise that resolves when the mesh for that graphic has been created. Every time that the graphics change, the layerview will reprocess all the graphics and recreate all the meshes.

The custom layer is a subclass of GraphicsLayer. The update Positions() method in the original sample has been modified to convert the geometry of any graphic into triangle meshes these meshes have special per-vertex attributes that the shader program uses to render any geometry type. These helpers methods allow the developer to create triangle meshes for any geometry type, including polylines and polygons. This sample instead uses the new tessellate*() methods implemented by BaseLayerViewGL2D. It is similar to the Custom WebGL layer view sample, which triangulates points into quads. This description assumes familiarity with WebGL and custom WebGL layer views.

#WEBGL TESSELLATION TRIANGLE TWIST FULL#

It can be used as the starting point for complex visualizations where the developer has full control of the rendering process.

#WEBGL TESSELLATION TRIANGLE TWIST HOW TO#

This sample demonstrates how to render graphics using a custom WebGL layer view.

This sample targets expert developers familiar with WebGL and hardware-accelerated rendering.

This sample shows experimental functionality, please read the documentation carefully before using it in a product.

Webgl tessellation triangle twist