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Allow sampling data from neighboring pixels

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This commit is contained in:
Andreas Hocevar
2021-08-14 23:05:19 +02:00
parent 324148c606
commit 7acd5338c9
8 changed files with 250 additions and 21 deletions
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1
src/ol/layer.js
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@@ -13,3 +13,4 @@ export {default as Vector} from './layer/Vector.js';
export {default as VectorImage} from './layer/VectorImage.js';
export {default as VectorTile} from './layer/VectorTile.js';
export {default as WebGLPoints} from './layer/WebGLPoints.js';
export {default as WebGLTile} from './layer/WebGLTile.js';

4
src/ol/layer/WebGLTile.js
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@@ -215,6 +215,10 @@ function parseStyle(style, bandCount) {
varying vec2 v_textureCoord;
uniform float ${Uniforms.TRANSITION_ALPHA};
uniform float ${Uniforms.TEXTURE_PIXEL_WIDTH};
uniform float ${Uniforms.TEXTURE_PIXEL_HEIGHT};
uniform float ${Uniforms.RESOLUTION};
uniform float ${Uniforms.ZOOM};
${uniformDeclarations.join('\n')}

52
src/ol/renderer/webgl/TileLayer.js
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@@ -35,6 +35,10 @@ export const Uniforms = {
TILE_TRANSFORM: 'u_tileTransform',
TRANSITION_ALPHA: 'u_transitionAlpha',
DEPTH: 'u_depth',
TEXTURE_PIXEL_WIDTH: 'u_texturePixelWidth',
TEXTURE_PIXEL_HEIGHT: 'u_texturePixelHeight',
RESOLUTION: 'u_resolution',
ZOOM: 'u_zoom',
};
export const Attributes = {
@@ -75,6 +79,23 @@ function addTileTextureToLookup(tileTexturesByZ, tileTexture, z) {
tileTexturesByZ[z].push(tileTexture);
}
/**
*
* @param {import("../../PluggableMap.js").FrameState} frameState Frame state.
* @return {import("../../extent.js").Extent} Extent.
*/
function getRenderExtent(frameState) {
const layerState = frameState.layerStatesArray[frameState.layerIndex];
let extent = frameState.extent;
if (layerState.extent) {
extent = getIntersection(
extent,
fromUserExtent(layerState.extent, frameState.viewState.projection)
);
}
return extent;
}
/**
* @typedef {Object} Options
* @property {string} vertexShader Vertex shader source.
@@ -183,6 +204,9 @@ class WebGLTileLayerRenderer extends WebGLLayerRenderer {
* @return {boolean} Layer is ready to be rendered.
*/
prepareFrame(frameState) {
if (isEmpty(getRenderExtent(frameState))) {
return false;
}
const source = this.getLayer().getSource();
if (!source) {
return false;
@@ -198,20 +222,9 @@ class WebGLTileLayerRenderer extends WebGLLayerRenderer {
renderFrame(frameState) {
this.preRender(frameState);
const layerState = frameState.layerStatesArray[frameState.layerIndex];
const viewState = frameState.viewState;
let extent = frameState.extent;
if (layerState.extent) {
extent = getIntersection(
extent,
fromUserExtent(layerState.extent, viewState.projection)
);
}
if (isEmpty(extent)) {
return;
}
const layerState = frameState.layerStatesArray[frameState.layerIndex];
const extent = getRenderExtent(frameState);
const tileLayer = this.getLayer();
const tileSource = tileLayer.getSource();
const tileGrid = tileSource.getTileGridForProjection(viewState.projection);
@@ -421,6 +434,19 @@ class WebGLTileLayerRenderer extends WebGLLayerRenderer {
this.helper.setUniformFloatValue(Uniforms.TRANSITION_ALPHA, alpha);
this.helper.setUniformFloatValue(Uniforms.DEPTH, depth);
this.helper.setUniformFloatValue(
Uniforms.TEXTURE_PIXEL_WIDTH,
tileSize[0]
);
this.helper.setUniformFloatValue(
Uniforms.TEXTURE_PIXEL_HEIGHT,
tileSize[1]
);
this.helper.setUniformFloatValue(
Uniforms.RESOLUTION,
viewState.resolution
);
this.helper.setUniformFloatValue(Uniforms.ZOOM, viewState.zoom);
this.helper.drawElements(0, this.indices_.getSize());
}

2
src/ol/source.js
View File

@@ -5,6 +5,8 @@
export {default as BingMaps} from './source/BingMaps.js';
export {default as CartoDB} from './source/CartoDB.js';
export {default as Cluster} from './source/Cluster.js';
export {default as DataTile} from './source/DataTile.js';
export {default as GeoTIFF} from './source/GeoTIFF.js';
export {default as IIIF} from './source/IIIF.js';
export {default as Image} from './source/Image.js';
export {default as ImageArcGISRest} from './source/ImageArcGISRest.js';

76
src/ol/style/expressions.js
View File

@@ -3,6 +3,7 @@
* @module ol/style/expressions
*/
import {Uniforms} from '../renderer/webgl/TileLayer.js';
import {asArray, isStringColor} from '../color.js';
/**
@@ -12,12 +13,13 @@ import {asArray, isStringColor} from '../color.js';
* The following operators can be used:
*
* * Reading operators:
* * `['band', bandIndex]` fetches a pixel value from band `bandIndex` of the source's data. The first
* `bandIndex` of the source data is `1`. Fetched values are in the 0..1 range.
* {@link import("../source/TileImage.js").default} sources have 4 bands: red, green, blue and alpha.
* {@link import("../source/DataTile.js").default} sources can have any number of bands, depending on
* the underlying data source and
* {@link import("../source/GeoTIFF.js").Options configuration}.
* * `['band', bandIndex, xOffset, yOffset]` For tile layers only. Fetches pixel values from band
* `bandIndex` of the source's data. The first `bandIndex` of the source data is `1`. Fetched values
* are in the 0..1 range. {@link import("../source/TileImage.js").default} sources have 4 bands: red,
* green, blue and alpha. {@link import("../source/DataTile.js").default} sources can have any number
* of bands, depending on the underlying data source and
* {@link import("../source/GeoTIFF.js").Options configuration}. `xOffset` and `yOffset` are optional
* and allow specifying pixel offsets for x and y. This is used for sampling data from neighboring pixels.
* * `['get', 'attributeName']` fetches a feature attribute (it will be prefixed by `a_` in the shader)
* Note: those will be taken from the attributes provided to the renderer
* * `['resolution']` returns the current resolution
@@ -34,6 +36,9 @@ import {asArray, isStringColor} from '../color.js';
* * `['%', value1, value2]` returns the result of `value1 % value2` (modulo)
* * `['^', value1, value2]` returns the value of `value1` raised to the `value2` power
* * `['abs', value1]` returns the absolute value of `value1`
* * `['sin', value1]` returns the sine of `value1`
* * `['cos', value1]` returns the cosine of `value1`
* * `['atan', value1, value2]` returns `atan2(value1, value2)`. If `value2` is not provided, returns `atan(value1)`
*
* * Transform operators:
* * `['case', condition1, output1, ...conditionN, outputN, fallback]` selects the first output whose corresponding
@@ -416,7 +421,8 @@ Operators['band'] = {
return ValueTypes.NUMBER;
},
toGlsl: function (context, args) {
assertArgsCount(args, 1);
assertArgsMinCount(args, 1);
assertArgsMaxCount(args, 3);
const band = args[0];
if (typeof band !== 'number') {
throw new Error('Band index must be a number');
@@ -428,7 +434,22 @@ Operators['band'] = {
// LUMINANCE_ALPHA - band 1 assigned to rgb and band 2 assigned to alpha
bandIndex = 3;
}
return `color${colorIndex}[${bandIndex}]`;
if (args.length === 1) {
return `color${colorIndex}[${bandIndex}]`;
} else {
const xOffset = args[1];
const yOffset = args[2] || 0;
assertNumber(xOffset);
assertNumber(yOffset);
const uniformName = Uniforms.TILE_TEXTURE_PREFIX + colorIndex;
return `texture2D(${uniformName}, v_textureCoord + vec2(${expressionToGlsl(
context,
xOffset
)} / ${Uniforms.TEXTURE_PIXEL_WIDTH}, ${expressionToGlsl(
context,
yOffset
)} / ${Uniforms.TEXTURE_PIXEL_HEIGHT}))[${bandIndex}]`;
}
},
};
@@ -570,6 +591,45 @@ Operators['abs'] = {
},
};
Operators['sin'] = {
getReturnType: function (args) {
return ValueTypes.NUMBER;
},
toGlsl: function (context, args) {
assertArgsCount(args, 1);
assertNumbers(args);
return `sin(${expressionToGlsl(context, args[0])})`;
},
};
Operators['cos'] = {
getReturnType: function (args) {
return ValueTypes.NUMBER;
},
toGlsl: function (context, args) {
assertArgsCount(args, 1);
assertNumbers(args);
return `cos(${expressionToGlsl(context, args[0])})`;
},
};
Operators['atan'] = {
getReturnType: function (args) {
return ValueTypes.NUMBER;
},
toGlsl: function (context, args) {
assertArgsMinCount(args, 1);
assertArgsMaxCount(args, 2);
assertNumbers(args);
return args.length === 2
? `atan(${expressionToGlsl(context, args[0])}, ${expressionToGlsl(
context,
args[1]
)})`
: `atan(${expressionToGlsl(context, args[0])})`;
},
};
Operators['>'] = {
getReturnType: function (args) {
return ValueTypes.BOOLEAN;