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Webgl / implement support for custom attributes in webgl buffers

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Only numerical attributes can be pushed in webgl buffers.
This commit is contained in:
Olivier Guyot
2019-05-14 14:17:55 +02:00
parent 27e520add4
commit c6d214b585
2 changed files with 50 additions and 7 deletions
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31
src/ol/renderer/webgl/Layer.js
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@@ -76,7 +76,8 @@ class WebGLLayerRenderer extends LayerRenderer {
* @param {import("../../format/GeoJSON").GeoJSONFeature} geojsonFeature Feature in geojson format, coordinates
* expressed in EPSG:4326.
* @param {Array<string>} [opt_attributes] Custom attributes. An array of properties which will be read from the
* feature and pushed in the buffer in the given order.
* feature and pushed in the buffer in the given order. Note: attributes can only be numerical! Any other type or
* NaN will result in `0` being pushed in the buffer.
*/
export function pushFeatureInBuffer(vertexBuffer, indexBuffer, geojsonFeature, opt_attributes) {
if (!geojsonFeature.geometry) {
@@ -89,6 +90,8 @@ export function pushFeatureInBuffer(vertexBuffer, indexBuffer, geojsonFeature, o
}
}
const tmpArray_ = [];
/**
* Pushes a quad (two triangles) based on a point geometry
* @param vertexBuffer
@@ -116,12 +119,26 @@ function pushPointGeomInBuffer_(vertexBuffer, indexBuffer, geojsonFeature, opt_a
const alpha = color[3];
const baseIndex = vertexBuffer.getArray().length / stride;
vertexBuffer.getArray().push(
x, y, -size / 2, -size / 2, u0, v0, opacity, rotateWithView, red, green, blue, alpha,
x, y, +size / 2, -size / 2, u1, v0, opacity, rotateWithView, red, green, blue, alpha,
x, y, +size / 2, +size / 2, u1, v1, opacity, rotateWithView, red, green, blue, alpha,
x, y, -size / 2, +size / 2, u0, v1, opacity, rotateWithView, red, green, blue, alpha
);
// read custom numerical attributes on the feature
const customAttributeValues = tmpArray_;
customAttributeValues.length = opt_attributes ? opt_attributes.length : 0;
for (let i = 0; i < customAttributeValues.length; i++) {
customAttributeValues[i] = parseFloat(geojsonFeature.properties[opt_attributes[i]]) || 0;
}
// push vertices for each of the four quad corners (first standard then custom attributes)
vertexBuffer.getArray().push(x, y, -size / 2, -size / 2, u0, v0, opacity, rotateWithView, red, green, blue, alpha);
Array.prototype.push.apply(vertexBuffer.getArray(), customAttributeValues);
vertexBuffer.getArray().push(x, y, +size / 2, -size / 2, u1, v0, opacity, rotateWithView, red, green, blue, alpha);
Array.prototype.push.apply(vertexBuffer.getArray(), customAttributeValues);
vertexBuffer.getArray().push(x, y, +size / 2, +size / 2, u1, v1, opacity, rotateWithView, red, green, blue, alpha);
Array.prototype.push.apply(vertexBuffer.getArray(), customAttributeValues);
vertexBuffer.getArray().push(x, y, -size / 2, +size / 2, u0, v1, opacity, rotateWithView, red, green, blue, alpha);
Array.prototype.push.apply(vertexBuffer.getArray(), customAttributeValues);
indexBuffer.getArray().push(
baseIndex, baseIndex + 1, baseIndex + 3,
baseIndex + 1, baseIndex + 2, baseIndex + 3