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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
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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
});
}