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Webgl / add support for a rotation parameter in LiteralStyle

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The ShaderBuilder can now take a rotation expression.
This commit is contained in:
Olivier Guyot
2019-12-20 17:14:06 +01:00
parent 6f000e3155
commit 6c46eb1dd0
3 changed files with 159 additions and 15 deletions
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1
src/ol/style/LiteralStyle.js
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@@ -35,6 +35,7 @@ export const SymbolType = {
* @property {string} [src] Path to the image to be used for the symbol. Only required with `symbolType: 'image'`.
* @property {import("../color.js").Color|Array<ExpressionValue>|string} [color='#FFFFFF'] Color used for the representation (either fill, line or symbol).
* @property {ExpressionValue} [opacity=1] Opacity.
* @property {ExpressionValue} [rotation=0] Symbol rotation in radians.
* @property {Array<ExpressionValue, ExpressionValue>} [offset] Offset on X and Y axis for symbols. If not specified, the symbol will be centered.
* @property {Array<ExpressionValue, ExpressionValue, ExpressionValue, ExpressionValue>} [textureCoord] Texture coordinates. If not specified, the whole texture will be used (range for 0 to 1 on both axes).
* @property {boolean} [rotateWithView=false] Specify whether the symbol must rotate with the view or stay upwards.

41
src/ol/webgl/ShaderBuilder.js
View File

@@ -56,6 +56,12 @@ export class ShaderBuilder {
*/
this.sizeExpression = 'vec2(1.0)';
/**
* @type {string}
* @private
*/
this.rotationExpression = '0.0';
/**
* @type {string}
* @private
@@ -138,6 +144,18 @@ export class ShaderBuilder {
return this;
}
/**
* Sets an expression to compute the rotation of the shape.
* This expression can use all the uniforms and attributes available
* in the vertex shader, and should evaluate to a `float` value in radians.
* @param {string} expression Size expression
* @return {ShaderBuilder} the builder object
*/
setRotationExpression(expression) {
this.rotationExpression = expression;
return this;
}
/**
* Sets an expression to compute the offset of the symbol from the point center.
* This expression can use all the uniforms and attributes available
@@ -291,10 +309,24 @@ ${varyings.map(function(varying) {
}).join('\n')}
void main(void) {
mat4 offsetMatrix = ${offsetMatrix};
vec2 size = ${this.sizeExpression};
vec2 halfSize = ${this.sizeExpression} * 0.5;
vec2 offset = ${this.offsetExpression};
float offsetX = a_index == 0.0 || a_index == 3.0 ? offset.x - size.x / 2.0 : offset.x + size.x / 2.0;
float offsetY = a_index == 0.0 || a_index == 1.0 ? offset.y - size.y / 2.0 : offset.y + size.y / 2.0;
float angle = ${this.rotationExpression};
float offsetX;
float offsetY;
if (a_index == 0.0) {
offsetX = (offset.x - halfSize.x) * cos(angle) + (offset.y - halfSize.y) * sin(angle);
offsetY = (offset.y - halfSize.y) * cos(angle) - (offset.x - halfSize.x) * sin(angle);
} else if (a_index == 1.0) {
offsetX = (offset.x + halfSize.x) * cos(angle) + (offset.y - halfSize.y) * sin(angle);
offsetY = (offset.y - halfSize.y) * cos(angle) - (offset.x + halfSize.x) * sin(angle);
} else if (a_index == 2.0) {
offsetX = (offset.x + halfSize.x) * cos(angle) + (offset.y + halfSize.y) * sin(angle);
offsetY = (offset.y + halfSize.y) * cos(angle) - (offset.x + halfSize.x) * sin(angle);
} else {
offsetX = (offset.x - halfSize.x) * cos(angle) + (offset.y + halfSize.y) * sin(angle);
offsetY = (offset.y + halfSize.y) * cos(angle) - (offset.x - halfSize.x) * sin(angle);
}
vec4 offsets = offsetMatrix * vec4(offsetX, offsetY, 0.0, 0.0);
gl_Position = u_projectionMatrix * vec4(a_position, 0.0, 1.0) + offsets;
vec4 texCoord = ${this.texCoordExpression};
@@ -381,6 +413,7 @@ export function parseLiteralStyle(style) {
const texCoord = symbStyle.textureCoord || [0, 0, 1, 1];
const offset = symbStyle.offset || [0, 0];
const opacity = symbStyle.opacity !== undefined ? symbStyle.opacity : 1;
const rotation = symbStyle.rotation !== undefined ? symbStyle.rotation : 0;
/**
* @type {import("../style/expressions.js").ParsingContext}
@@ -406,6 +439,7 @@ export function parseLiteralStyle(style) {
};
const parsedColor = expressionToGlsl(fragContext, color, ValueTypes.COLOR);
const parsedOpacity = expressionToGlsl(fragContext, opacity, ValueTypes.NUMBER);
const parsedRotation = expressionToGlsl(fragContext, rotation, ValueTypes.NUMBER);
let opacityFilter = '1.0';
const visibleSize = `vec2(${expressionToGlsl(fragContext, size, ValueTypes.NUMBER_ARRAY | ValueTypes.NUMBER)}).x`;
@@ -427,6 +461,7 @@ export function parseLiteralStyle(style) {
const builder = new ShaderBuilder()
.setSizeExpression(`vec2(${parsedSize})`)
.setRotationExpression(parsedRotation)
.setSymbolOffsetExpression(parsedOffset)
.setTextureCoordinateExpression(parsedTexCoord)
.setSymbolRotateWithView(!!symbStyle.rotateWithView)