[3D] Add support for data defined properties of points #57929
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This will be used by `QgsPoint3DSymbol` in the next commit.
`QgsInstancedPoint3DSymbolHandler` uses OpenGL instancing in order to draw multiple times the same entity at different locations with the same shape. In practice, this means that only two Qt3D entities are created: - one for the points which are not selected - one for the selected points Indeed, the selected points do not have the same color as the normal ones. If there isn't any selected point, only one entity is created. When a point can have a data defined radius, this logic needs to be updated. The idea is to group the points which have the same radius. This logic is handled by the `PointData` class and the `==` operator. If two different have the same state (selected or normal) and the same radius, they are grouped together in the same `PointData` instance and their respective positions are stored in `positions`. This means that if there are 3 different radii, at most 6 different entities are created: 1. Entity1: (normal, radius1) 2. Entity2: (selected, radius1) 3. Entity3: (normal, radius2) 4. Entity4: (selected, radius2) 5. Entity5: (normal, radius3) 6. Entity6: (selected, radius3) If there is only one radius, the previous case still applies.
This will be used by `QgsPoint3DSymbol` in the next commit.
This will be used by `QgsPoint3DSymbol` in the next commit.
This will be used by `QgsPoint3DSymbol` in the next commit.
This will be used by `QgsPoint3DSymbol` in the next commit.
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| BottomRadius SIP_MONKEYPATCH_COMPAT_NAME( PropertyHeight ), //!< Bottom Radius | ||
| MinorRadius SIP_MONKEYPATCH_COMPAT_NAME( PropertySize ), //!< Minor Radius | ||
| TopRadius SIP_MONKEYPATCH_COMPAT_NAME( PropertyHeight ), //!< Top Radius | ||
| Size SIP_MONKEYPATCH_COMPAT_NAME( PropertySize ), //!< Size |
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Size is not a reserved word?
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I'm wondering how well this approach scales. Eg if you had a point layer with thousands of points , and each has there own distinct height, we'll end up with a LOT of entities. Have you tested to see what the usable limits are? I suspect we would need some way to abort creating new entities early if we approach the usable limit... |
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The QGIS project highly values your contribution and would love to see this work merged! Unfortunately this PR has not had any activity in the last 14 days and is being automatically marked as "stale". If you think this pull request should be merged, please check
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I have the same concerns as Nyall - this approach will likely not perform well when used with slightly larger datasets, with many thousands of draw commands required. The correct solution here is to add data-defined properties to vertex buffers and handle sizing in the vertex shader code... |
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The QGIS project highly values your contribution and would love to see this work merged! Unfortunately this PR has not had any activity in the last 14 days and is being automatically marked as "stale". If you think this pull request should be merged, please check
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Description
This PR introduces support for data defined properties (radius, length...). This needs some changes in
QgsInstancedPoint3DSymbolHandler. Inded, it uses OpenGL instancing in order to draw multiple times the same entity at different locations with the same shape. In practice, this means that only 2 Qt3D entities arecreated:
Indeed, the selected points do not have the same color as the normal ones. If there isn't any selected point, only one entity is created.
When a point can have a data defined shapes, this logic needs to be updated. The idea is to group the points which have the same shape. This logic is handled by the
PointDataclass and the==operator. If two different have the same state (selected or normal) and the same shape, they are grouped together in the samePointDatainstance and their respective positions are stored in
positions. With that logic, the following entities are created:...
If there is only one shape, the previous case still applies.
Example