Fit texture coordinates to rectangle/trapezoid geometry

[lilleyse]

It would be useful to support stretching a texture along a rectangle/trapezoid geometry, or perhaps even support explicit texture coordinates. The effect would look like the second image:

@rumicuna created a demo for testing this:

https://cesiumjs.org/Cesium/Apps/Sandcastle/index.html?src=Hello%20World.html&label=Showcases&gist=079b7bbc6c2c16bdaf23c57fe0a7f2c4

[hpinkos]

We also need this to support KML latLonQuads

[pjcozzi]

We have done this in some of our other projects; see http://help.agi.com/AGIComponentsJava/html/BlogTrapezoidalTextureProjectionWithOpenGL.htm

[hpinkos]

I took the very first steps of this in https://github.com/AnalyticalGraphicsInc/cesium/tree/trapezoid but this requires GroundPrimitive to support other appearances than just PerInstanceColorAppearance

[pjcozzi]

Specifically, this requires texturing ground primitive. @bagnell has most of the work done in this branch: https://github.com/AnalyticalGraphicsInc/cesium/compare/ground-primitive-tex-coords

[hpinkos]

This came up again on the forum: https://groups.google.com/d/msg/cesium-dev/x3sYLgIr8Mc/wH2tdn_hCwAJ

[lilleyse]

Came up on the forum again: https://groups.google.com/forum/?hl=en#!topic/cesium-dev/zYikVZcfRMo

[lilleyse]

Talked about this offline with @likangning93. This will require specific changes to GroundPrimitive.

Some early thoughts:

There may be a uv -> uv mapping that could accomplish this, you'd probably need to start by mapping the corners of the trapezoid into the ground primitive uv space. Perhaps you could pass the 4 corners in groundPrimitiveUvSpace as uniforms or constants in the shader, then do a barycentric operation using the fragment's groundPrimitiveUvSpace coordinate.

It might be possible to do a proof-of-concept using a custom shader material.

[hpinkos]

@likangning93 @lilleyse read http://help.agi.com/AGIComponentsJava/html/BlogTrapezoidalTextureProjectionWithOpenGL.htm if you haven't already

[tmshv]

Hi guys! Any progress with this issue? Or maybe someone has a samples of code at least?

[wq8806]

Any progress with this issue?

[jony89]

4 years later. Please - Any progress with this issue?

[rumicuna]

I updated the sandcastle demo to reproduce it with the latest Cesium (link below). On the bright side, there has been an awesome improvement since I posted this, the video is now overlaid on the 3D terrain! Nice! Having this capability would mean we would be able to ovelay live drone video on the terrain (that is not directly pointing down and is not north up).

https://sandcastle.cesium.com/index.html#c=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

[ggetz]

Reported on the forum in https://community.cesium.com/t/how-to-project-textures-correctly/20592.

[ysp]

Hi! Any progress with this issue?

[ggetz]

@ysp There hasn't been any activity on this item recently.

If you'd like to add more information about your use case, that may help us prioritize. If you are interesting in contributing, please let us know and we'd be happy to discuss implementation or review a PR. Thanks!

[Zuzon]

updated sandcastle demo: https://sandcastle.cesium.com/index.html#c=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