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Webgl points renderer / fix hit detection

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Due to the fact that the points renderer does not know for sure
which attributes will be used for rendering, it is now mandatory
to provide both vertex/fragment shaders for rendering AND hit
detection.

The hit detection shaders should expect having an `a_hitColor`
that they should return to allow matching the feature uid.

This will be all one eventually by shader builders under the hood.
This commit is contained in:
Olivier Guyot
2019-09-25 12:11:06 +02:00
parent 109f9718f9
commit 23c2999cab
4 changed files with 140 additions and 86 deletions
Download Patch File Download Diff File Expand all files Collapse all files

32
examples/icon-sprite-webgl.js
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@@ -79,6 +79,7 @@ class WebglPointsLayer extends VectorLayer {
'varying float v_year;',
'void main(void) {',
// color is interpolated based on year
' float ratio = clamp((v_year - 1950.0) / (2013.0 - 1950.0), 0.0, 1.1);',
' vec3 color = mix(vec3(' + formatColor(oldColor) + '),',
@@ -88,6 +89,37 @@ class WebglPointsLayer extends VectorLayer {
' gl_FragColor.rgb *= gl_FragColor.a;',
'}'
].join(' '),
hitVertexShader: [
'precision mediump float;',
'uniform mat4 u_projectionMatrix;',
'uniform mat4 u_offsetScaleMatrix;',
'uniform mat4 u_offsetRotateMatrix;',
'attribute vec2 a_position;',
'attribute float a_index;',
'attribute vec4 a_hitColor;',
'varying vec4 v_hitColor;',
'void main(void) {',
' mat4 offsetMatrix = u_offsetScaleMatrix;',
' float offsetX = a_index == 0.0 || a_index == 3.0 ? ',
' ' + formatNumber(-size / 2) + ' : ' + formatNumber(size / 2) + ';',
' float offsetY = a_index == 0.0 || a_index == 1.0 ? ',
' ' + formatNumber(-size / 2) + ' : ' + formatNumber(size / 2) + ';',
' vec4 offsets = offsetMatrix * vec4(offsetX, offsetY, 0.0, 0.0);',
' gl_Position = u_projectionMatrix * vec4(a_position, 0.0, 1.0) + offsets;',
' v_hitColor = a_hitColor;',
'}'
].join(' '),
hitFragmentShader: [
'precision mediump float;',
'varying vec4 v_hitColor;',
'void main(void) {',
' gl_FragColor = v_hitColor;',
'}'
].join(' '),
texture: texture // FIXME: this doesn't work yet
});
}

95
src/ol/renderer/webgl/PointsLayer.js
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@@ -18,74 +18,6 @@ import {create as createWebGLWorker} from '../../worker/webgl.js';
import {getUid} from '../../util.js';
import WebGLRenderTarget from '../../webgl/RenderTarget.js';
const VERTEX_SHADER = `
precision mediump float;
attribute vec2 a_position;
attribute vec2 a_texCoord;
attribute float a_rotateWithView;
attribute vec2 a_offsets;
attribute float a_opacity;
attribute vec4 a_color;
uniform mat4 u_projectionMatrix;
uniform mat4 u_offsetScaleMatrix;
uniform mat4 u_offsetRotateMatrix;
varying vec2 v_texCoord;
varying float v_opacity;
varying vec4 v_color;
void main(void) {
mat4 offsetMatrix = u_offsetScaleMatrix;
if (a_rotateWithView == 1.0) {
offsetMatrix = u_offsetScaleMatrix * u_offsetRotateMatrix;
}
vec4 offsets = offsetMatrix * vec4(a_offsets, 0.0, 0.0);
gl_Position = u_projectionMatrix * vec4(a_position, 0.0, 1.0) + offsets;
v_texCoord = a_texCoord;
v_opacity = a_opacity;
v_color = a_color;
}`;
const FRAGMENT_SHADER = `
precision mediump float;
uniform sampler2D u_texture;
varying vec2 v_texCoord;
varying float v_opacity;
varying vec4 v_color;
void main(void) {
if (v_opacity == 0.0) {
discard;
}
vec4 textureColor = texture2D(u_texture, v_texCoord);
gl_FragColor = v_color * textureColor;
gl_FragColor.a *= v_opacity;
gl_FragColor.rgb *= gl_FragColor.a;
}`;
const HIT_FRAGMENT_SHADER = `
precision mediump float;
uniform sampler2D u_texture;
varying vec2 v_texCoord;
varying float v_opacity;
varying vec4 v_color;
void main(void) {
if (v_opacity == 0.0) {
discard;
}
vec4 textureColor = texture2D(u_texture, v_texCoord);
if (textureColor.a < 0.1) {
discard;
}
gl_FragColor = v_color;
}`;
/**
* @typedef {Object} CustomAttribute A description of a custom attribute to be passed on to the GPU, with a value different
* for each feature.
@@ -101,8 +33,10 @@ const HIT_FRAGMENT_SHADER = `
* * In the vertex shader as an `attribute` by prefixing it with `a_`
* * In the fragment shader as a `varying` by prefixing it with `v_`
* Please note that these can only be numerical values.
* @property {string} [vertexShader] Vertex shader source
* @property {string} [fragmentShader] Fragment shader source
* @property {string} vertexShader Vertex shader source, mandatory.
* @property {string} fragmentShader Fragment shader source, mandatory.
* @property {string} [hitVertexShader] Vertex shader source for hit detection rendering.
* @property {string} [hitFragmentShader] Fragment shader source for hit detection rendering.
* @property {Object.<string,import("../../webgl/Helper").UniformValue>} [uniforms] Uniform definitions for the post process steps
* Please note that `u_texture` is reserved for the main texture slot.
* @property {Array<import("./Layer").PostProcessesOptions>} [postProcesses] Post-processes definitions
@@ -204,11 +138,9 @@ class WebGLPointsLayerRenderer extends WebGLLayerRenderer {
/**
* @param {import("../../layer/Vector.js").default} vectorLayer Vector layer.
* @param {Options=} [opt_options] Options.
* @param {Options=} options Options.
*/
constructor(vectorLayer, opt_options) {
const options = opt_options || {};
constructor(vectorLayer, options) {
const uniforms = options.uniforms || {};
uniforms.u_texture = getBlankImageData();
const projectionMatrixTransform = createTransform();
@@ -226,12 +158,12 @@ class WebGLPointsLayerRenderer extends WebGLLayerRenderer {
this.indicesBuffer_ = new WebGLArrayBuffer(ELEMENT_ARRAY_BUFFER, DYNAMIC_DRAW);
this.program_ = this.helper.getProgram(
options.fragmentShader || FRAGMENT_SHADER,
options.vertexShader || VERTEX_SHADER
options.fragmentShader,
options.vertexShader
);
this.hitProgram_ = this.helper.getProgram(
HIT_FRAGMENT_SHADER,
VERTEX_SHADER
options.hitFragmentShader,
options.hitVertexShader
);
const customAttributes = options.attributes ?
@@ -271,7 +203,7 @@ class WebGLPointsLayerRenderer extends WebGLLayerRenderer {
size: 1,
type: AttributeType.FLOAT
}, {
name: 'a_color',
name: 'a_hitColor',
size: 4,
type: AttributeType.FLOAT
}, {
@@ -429,6 +361,11 @@ class WebGLPointsLayerRenderer extends WebGLLayerRenderer {
this.helper.makeProjectionTransform(frameState, projectionTransform);
const features = vectorSource.getFeatures();
// here we anticipate the amount of render instructions that we well generate
// this can be done since we know that for normal render we only have x, y as base instructions,
// and x, y, r, g, b, a and featureUid for hit render instructions
// and we also know the amount of custom attributes to append to these
const totalInstructionsCount = (2 + this.customAttributes.length) * features.length;
if (!this.renderInstructions_ || this.renderInstructions_.length !== totalInstructionsCount) {
this.renderInstructions_ = new Float32Array(totalInstructionsCount);

2
src/ol/worker/webgl.js
View File

@@ -14,7 +14,7 @@ const worker = self;
worker.onmessage = event => {
const received = event.data;
if (received.type === WebGLWorkerMessageType.GENERATE_BUFFERS) {
// This is specific to point features
// This is specific to point features (x, y, index)
const baseVertexAttrsCount = 3;
const baseInstructionsCount = 2;

97
test/spec/ol/renderer/webgl/pointslayer.test.js
View File

@@ -7,7 +7,6 @@ import {get as getProjection} from '../../../../../src/ol/proj.js';
import ViewHint from '../../../../../src/ol/ViewHint.js';
import {WebGLWorkerMessageType} from '../../../../../src/ol/renderer/webgl/Layer.js';
import {compose as composeTransform, create as createTransform} from '../../../../../src/ol/transform.js';
import {getSymbolVertexShader} from '../../../../../src/ol/webgl/ShaderBuilder.js';
const baseFrameState = {
viewHints: [],
@@ -22,6 +21,54 @@ const baseFrameState = {
pixelRatio: 1
};
const simpleVertexShader = `
precision mediump float;
uniform mat4 u_projectionMatrix;
uniform mat4 u_offsetScaleMatrix;
attribute vec2 a_position;
attribute float a_index;
void main(void) {
mat4 offsetMatrix = u_offsetScaleMatrix;
float offsetX = a_index == 0.0 || a_index == 3.0 ? -2.0 : 2.0;
float offsetY = a_index == 0.0 || a_index == 1.0 ? -2.0 : 2.0;
vec4 offsets = offsetMatrix * vec4(offsetX, offsetY, 0.0, 0.0);
gl_Position = u_projectionMatrix * vec4(a_position, 0.0, 1.0) + offsets;
}`;
const simpleFragmentShader = `
precision mediump float;
void main(void) {
gl_FragColor = vec4(1.0, 1.0, 1.0, 1.0);
}`;
// these shaders support hit detection
// they have a built-in size value of 4
const hitVertexShader = `
precision mediump float;
uniform mat4 u_projectionMatrix;
uniform mat4 u_offsetScaleMatrix;
attribute vec2 a_position;
attribute float a_index;
attribute vec4 a_hitColor;
varying vec4 v_hitColor;
void main(void) {
mat4 offsetMatrix = u_offsetScaleMatrix;
float offsetX = a_index == 0.0 || a_index == 3.0 ? -2.0 : 2.0;
float offsetY = a_index == 0.0 || a_index == 1.0 ? -2.0 : 2.0;
vec4 offsets = offsetMatrix * vec4(offsetX, offsetY, 0.0, 0.0);
gl_Position = u_projectionMatrix * vec4(a_position, 0.0, 1.0) + offsets;
v_hitColor = a_hitColor;
}`;
const hitFragmentShader = `
precision mediump float;
varying vec4 v_hitColor;
void main(void) {
gl_FragColor = v_hitColor;
}`;
describe('ol.renderer.webgl.PointsLayer', function() {
describe('constructor', function() {
@@ -43,7 +90,10 @@ describe('ol.renderer.webgl.PointsLayer', function() {
const layer = new VectorLayer({
source: new VectorSource()
});
const renderer = new WebGLPointsLayerRenderer(layer);
const renderer = new WebGLPointsLayerRenderer(layer, {
vertexShader: simpleVertexShader,
fragmentShader: simpleFragmentShader
});
expect(renderer).to.be.a(WebGLPointsLayerRenderer);
});
@@ -56,7 +106,10 @@ describe('ol.renderer.webgl.PointsLayer', function() {
layer = new VectorLayer({
source: new VectorSource()
});
renderer = new WebGLPointsLayerRenderer(layer);
renderer = new WebGLPointsLayerRenderer(layer, {
vertexShader: simpleVertexShader,
fragmentShader: simpleFragmentShader
});
frameState = Object.assign({
size: [2, 2],
extent: [-100, -100, 100, 100]
@@ -95,6 +148,35 @@ describe('ol.renderer.webgl.PointsLayer', function() {
});
});
it('fills up the hit render buffer with 2 triangles per point', function(done) {
layer.getSource().addFeature(new Feature({
geometry: new Point([10, 20])
}));
layer.getSource().addFeature(new Feature({
geometry: new Point([30, 40])
}));
renderer.prepareFrame(frameState);
const attributePerVertex = 8;
renderer.worker_.addEventListener('message', function(event) {
if (event.data.type !== WebGLWorkerMessageType.GENERATE_BUFFERS) {
return;
}
if (!renderer.hitVerticesBuffer_.getArray()) {
return;
}
expect(renderer.hitVerticesBuffer_.getArray().length).to.eql(2 * 4 * attributePerVertex);
expect(renderer.indicesBuffer_.getArray().length).to.eql(2 * 6);
expect(renderer.hitVerticesBuffer_.getArray()[0]).to.eql(10);
expect(renderer.hitVerticesBuffer_.getArray()[1]).to.eql(20);
expect(renderer.hitVerticesBuffer_.getArray()[4 * attributePerVertex + 0]).to.eql(30);
expect(renderer.hitVerticesBuffer_.getArray()[4 * attributePerVertex + 1]).to.eql(40);
done();
});
});
it('clears the buffers when the features are gone', function(done) {
const source = layer.getSource();
source.addFeature(new Feature({
@@ -163,9 +245,10 @@ describe('ol.renderer.webgl.PointsLayer', function() {
})
});
renderer = new WebGLPointsLayerRenderer(layer, {
vertexShader: getSymbolVertexShader({
size: 4
})
vertexShader: simpleVertexShader,
fragmentShader: simpleFragmentShader,
hitVertexShader: hitVertexShader,
hitFragmentShader: hitFragmentShader
});
});
@@ -261,6 +344,8 @@ describe('ol.renderer.webgl.PointsLayer', function() {
source: new VectorSource()
});
const renderer = new WebGLPointsLayerRenderer(layer, {
vertexShader: simpleVertexShader,
fragmentShader: simpleFragmentShader
});
const spyHelper = sinon.spy(renderer.helper, 'disposeInternal');