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Webgl points / read only one pixel for feature hit detection

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Also implements `hasFeatureAtCoordinate`.

`hitTolerance` is not supported for now.
This commit is contained in:
Olivier Guyot
2019-06-06 11:38:59 +02:00
parent e852294938
commit 28b99767f8
4 changed files with 83 additions and 9 deletions
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16
src/ol/renderer/webgl/PointsLayer.js
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@@ -377,6 +377,7 @@ class WebGLPointsLayerRenderer extends WebGLLayerRenderer {
}
this.renderHitDetection(frameState);
this.hitRenderTarget_.clearCachedData();
return canvas;
}
@@ -533,17 +534,14 @@ class WebGLPointsLayerRenderer extends WebGLLayerRenderer {
* @inheritDoc
*/
forEachFeatureAtCoordinate(coordinate, frameState, hitTolerance, callback, declutteredFeatures) {
const pixel = applyTransform(frameState.coordinateToPixelTransform, coordinate.slice(0, 2));
const width = frameState.size[0];
const height = frameState.size[1];
const pixel = applyTransform(frameState.coordinateToPixelTransform, coordinate.slice());
const data = this.hitRenderTarget_.read();
const index = Math.floor(pixel[0]) + (height - Math.floor(pixel[1])) * width;
const data = this.hitRenderTarget_.readPixel(pixel[0], pixel[1]);
const color = [
data[index * 4] / 255,
data[index * 4 + 1] / 255,
data[index * 4 + 2] / 255,
data[index * 4 + 3] / 255
data[0] / 255,
data[1] / 255,
data[2] / 255,
data[3] / 255
];
const uid = colorDecodeId(color).toString();