ol
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OpenLayers mapping library
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JavaScript
/**
* Classes and utilities for generating shaders from literal style objects
* @module ol/webgl/ShaderBuilder
*/
import { expressionToGlsl, getStringNumberEquivalent, ValueTypes } from '../style/expressions.js';
/**
* @typedef {Object} VaryingDescription
* @property {string} name Varying name, as will be declared in the header.
* @property {string} type Varying type, either `float`, `vec2`, `vec4`...
* @property {string} expression Expression which will be assigned to the varying in the vertex shader, and
* passed on to the fragment shader.
*/
/**
* @classdesc
* This class implements a classic builder pattern for generating many different types of shaders.
* Methods can be chained, e. g.:
*
* ```js
* const shader = new ShaderBuilder()
* .addVarying('v_width', 'float', 'a_width')
* .addUniform('u_time')
* .setColorExpression('...')
* .setSizeExpression('...')
* .outputSymbolFragmentShader();
* ```
*/
var ShaderBuilder = /** @class */ (function () {
function ShaderBuilder() {
/**
* Uniforms; these will be declared in the header (should include the type).
* @type {Array<string>}
* @private
*/
this.uniforms = [];
/**
* Attributes; these will be declared in the header (should include the type).
* @type {Array<string>}
* @private
*/
this.attributes = [];
/**
* Varyings with a name, a type and an expression.
* @type {Array<VaryingDescription>}
* @private
*/
this.varyings = [];
/**
* @type {string}
* @private
*/
this.sizeExpression = 'vec2(1.0)';
/**
* @type {string}
* @private
*/
this.rotationExpression = '0.0';
/**
* @type {string}
* @private
*/
this.offsetExpression = 'vec2(0.0)';
/**
* @type {string}
* @private
*/
this.colorExpression = 'vec4(1.0)';
/**
* @type {string}
* @private
*/
this.texCoordExpression = 'vec4(0.0, 0.0, 1.0, 1.0)';
/**
* @type {string}
* @private
*/
this.discardExpression = 'false';
/**
* @type {boolean}
* @private
*/
this.rotateWithView = false;
}
/**
* Adds a uniform accessible in both fragment and vertex shaders.
* The given name should include a type, such as `sampler2D u_texture`.
* @param {string} name Uniform name
* @return {ShaderBuilder} the builder object
*/
ShaderBuilder.prototype.addUniform = function (name) {
this.uniforms.push(name);
return this;
};
/**
* Adds an attribute accessible in the vertex shader, read from the geometry buffer.
* The given name should include a type, such as `vec2 a_position`.
* @param {string} name Attribute name
* @return {ShaderBuilder} the builder object
*/
ShaderBuilder.prototype.addAttribute = function (name) {
this.attributes.push(name);
return this;
};
/**
* Adds a varying defined in the vertex shader and accessible from the fragment shader.
* The type and expression of the varying have to be specified separately.
* @param {string} name Varying name
* @param {'float'|'vec2'|'vec3'|'vec4'} type Type
* @param {string} expression Expression used to assign a value to the varying.
* @return {ShaderBuilder} the builder object
*/
ShaderBuilder.prototype.addVarying = function (name, type, expression) {
this.varyings.push({
name: name,
type: type,
expression: expression
});
return this;
};
/**
* Sets an expression to compute the size of the shape.
* This expression can use all the uniforms and attributes available
* in the vertex shader, and should evaluate to a `vec2` value.
* @param {string} expression Size expression
* @return {ShaderBuilder} the builder object
*/
ShaderBuilder.prototype.setSizeExpression = function (expression) {
this.sizeExpression = expression;
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
*/
ShaderBuilder.prototype.setRotationExpression = function (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
* in the vertex shader, and should evaluate to a `vec2` value.
* Note: will only be used for point geometry shaders.
* @param {string} expression Offset expression
* @return {ShaderBuilder} the builder object
*/
ShaderBuilder.prototype.setSymbolOffsetExpression = function (expression) {
this.offsetExpression = expression;
return this;
};
/**
* Sets an expression to compute the color of the shape.
* This expression can use all the uniforms, varyings and attributes available
* in the fragment shader, and should evaluate to a `vec4` value.
* @param {string} expression Color expression
* @return {ShaderBuilder} the builder object
*/
ShaderBuilder.prototype.setColorExpression = function (expression) {
this.colorExpression = expression;
return this;
};
/**
* Sets an expression to compute the texture coordinates of the vertices.
* This expression can use all the uniforms and attributes available
* in the vertex shader, and should evaluate to a `vec4` value.
* @param {string} expression Texture coordinate expression
* @return {ShaderBuilder} the builder object
*/
ShaderBuilder.prototype.setTextureCoordinateExpression = function (expression) {
this.texCoordExpression = expression;
return this;
};
/**
* Sets an expression to determine whether a fragment (pixel) should be discarded,
* i.e. not drawn at all.
* This expression can use all the uniforms, varyings and attributes available
* in the fragment shader, and should evaluate to a `bool` value (it will be
* used in an `if` statement)
* @param {string} expression Fragment discard expression
* @return {ShaderBuilder} the builder object
*/
ShaderBuilder.prototype.setFragmentDiscardExpression = function (expression) {
this.discardExpression = expression;
return this;
};
/**
* Sets whether the symbols should rotate with the view or stay aligned with the map.
* Note: will only be used for point geometry shaders.
* @param {boolean} rotateWithView Rotate with view
* @return {ShaderBuilder} the builder object
*/
ShaderBuilder.prototype.setSymbolRotateWithView = function (rotateWithView) {
this.rotateWithView = rotateWithView;
return this;
};
/**
* @returns {string} Previously set size expression
*/
ShaderBuilder.prototype.getSizeExpression = function () {
return this.sizeExpression;
};
/**
* @returns {string} Previously set symbol offset expression
*/
ShaderBuilder.prototype.getOffsetExpression = function () {
return this.offsetExpression;
};
/**
* @returns {string} Previously set color expression
*/
ShaderBuilder.prototype.getColorExpression = function () {
return this.colorExpression;
};
/**
* @returns {string} Previously set texture coordinate expression
*/
ShaderBuilder.prototype.getTextureCoordinateExpression = function () {
return this.texCoordExpression;
};
/**
* @returns {string} Previously set fragment discard expression
*/
ShaderBuilder.prototype.getFragmentDiscardExpression = function () {
return this.discardExpression;
};
/**
* Generates a symbol vertex shader from the builder parameters,
* intended to be used on point geometries.
*
* Three uniforms are hardcoded in all shaders: `u_projectionMatrix`, `u_offsetScaleMatrix`,
* `u_offsetRotateMatrix`, `u_time`.
*
* The following attributes are hardcoded and expected to be present in the vertex buffers:
* `vec2 a_position`, `float a_index` (being the index of the vertex in the quad, 0 to 3).
*
* The following varyings are hardcoded and gives the coordinate of the pixel both in the quad and on the texture:
* `vec2 v_quadCoord`, `vec2 v_texCoord`
*
* @param {boolean} [forHitDetection] If true, the shader will be modified to include hit detection variables
* (namely, hit color with encoded feature id).
* @returns {string} The full shader as a string.
*/
ShaderBuilder.prototype.getSymbolVertexShader = function (forHitDetection) {
var offsetMatrix = this.rotateWithView ?
'u_offsetScaleMatrix * u_offsetRotateMatrix' :
'u_offsetScaleMatrix';
var attributes = this.attributes;
var varyings = this.varyings;
if (forHitDetection) {
attributes = attributes.concat('vec4 a_hitColor');
varyings = varyings.concat({
name: 'v_hitColor',
type: 'vec4',
expression: 'a_hitColor'
});
}
return "precision mediump float;\nuniform mat4 u_projectionMatrix;\nuniform mat4 u_offsetScaleMatrix;\nuniform mat4 u_offsetRotateMatrix;\nuniform float u_time;\nuniform float u_zoom;\nuniform float u_resolution;\n" + this.uniforms.map(function (uniform) {
return 'uniform ' + uniform + ';';
}).join('\n') + "\nattribute vec2 a_position;\nattribute float a_index;\n" + attributes.map(function (attribute) {
return 'attribute ' + attribute + ';';
}).join('\n') + "\nvarying vec2 v_texCoord;\nvarying vec2 v_quadCoord;\n" + varyings.map(function (varying) {
return 'varying ' + varying.type + ' ' + varying.name + ';';
}).join('\n') + "\nvoid main(void) {\n mat4 offsetMatrix = " + offsetMatrix + ";\n vec2 halfSize = " + this.sizeExpression + " * 0.5;\n vec2 offset = " + this.offsetExpression + ";\n float angle = " + this.rotationExpression + ";\n float offsetX;\n float offsetY;\n if (a_index == 0.0) {\n offsetX = (offset.x - halfSize.x) * cos(angle) + (offset.y - halfSize.y) * sin(angle);\n offsetY = (offset.y - halfSize.y) * cos(angle) - (offset.x - halfSize.x) * sin(angle);\n } else if (a_index == 1.0) {\n offsetX = (offset.x + halfSize.x) * cos(angle) + (offset.y - halfSize.y) * sin(angle);\n offsetY = (offset.y - halfSize.y) * cos(angle) - (offset.x + halfSize.x) * sin(angle);\n } else if (a_index == 2.0) {\n offsetX = (offset.x + halfSize.x) * cos(angle) + (offset.y + halfSize.y) * sin(angle);\n offsetY = (offset.y + halfSize.y) * cos(angle) - (offset.x + halfSize.x) * sin(angle);\n } else {\n offsetX = (offset.x - halfSize.x) * cos(angle) + (offset.y + halfSize.y) * sin(angle);\n offsetY = (offset.y + halfSize.y) * cos(angle) - (offset.x - halfSize.x) * sin(angle);\n }\n vec4 offsets = offsetMatrix * vec4(offsetX, offsetY, 0.0, 0.0);\n gl_Position = u_projectionMatrix * vec4(a_position, 0.0, 1.0) + offsets;\n vec4 texCoord = " + this.texCoordExpression + ";\n float u = a_index == 0.0 || a_index == 3.0 ? texCoord.s : texCoord.p;\n float v = a_index == 2.0 || a_index == 3.0 ? texCoord.t : texCoord.q;\n v_texCoord = vec2(u, v);\n u = a_index == 0.0 || a_index == 3.0 ? 0.0 : 1.0;\n v = a_index == 2.0 || a_index == 3.0 ? 0.0 : 1.0;\n v_quadCoord = vec2(u, v);\n" + varyings.map(function (varying) {
return ' ' + varying.name + ' = ' + varying.expression + ';';
}).join('\n') + "\n}";
};
/**
* Generates a symbol fragment shader from the builder parameters,
* intended to be used on point geometries.
*
* Expects the following varyings to be transmitted by the vertex shader:
* `vec2 v_quadCoord`, `vec2 v_texCoord`
*
* @param {boolean} [forHitDetection] If true, the shader will be modified to include hit detection variables
* (namely, hit color with encoded feature id).
* @returns {string} The full shader as a string.
*/
ShaderBuilder.prototype.getSymbolFragmentShader = function (forHitDetection) {
var hitDetectionBypass = forHitDetection ?
' if (gl_FragColor.a < 0.1) { discard; } gl_FragColor = v_hitColor;' : '';
var varyings = this.varyings;
if (forHitDetection) {
varyings = varyings.concat({
name: 'v_hitColor',
type: 'vec4',
expression: 'a_hitColor'
});
}
return "precision mediump float;\nuniform float u_time;\nuniform float u_zoom;\nuniform float u_resolution;\n" + this.uniforms.map(function (uniform) {
return 'uniform ' + uniform + ';';
}).join('\n') + "\nvarying vec2 v_texCoord;\nvarying vec2 v_quadCoord;\n" + varyings.map(function (varying) {
return 'varying ' + varying.type + ' ' + varying.name + ';';
}).join('\n') + "\nvoid main(void) {\n if (" + this.discardExpression + ") { discard; }\n gl_FragColor = " + this.colorExpression + ";\n gl_FragColor.rgb *= gl_FragColor.a;\n" + hitDetectionBypass + "\n}";
};
return ShaderBuilder;
}());
export { ShaderBuilder };
/**
* @typedef {Object} StyleParseResult
* @property {ShaderBuilder} builder Shader builder pre-configured according to a given style
* @property {Object.<string,import("./Helper").UniformValue>} uniforms Uniform definitions.
* @property {Array<import("../renderer/webgl/PointsLayer").CustomAttribute>} attributes Attribute descriptions.
*/
/**
* Parses a {@link import("../style/LiteralStyle").LiteralStyle} object and returns a {@link ShaderBuilder}
* object that has been configured according to the given style, as well as `attributes` and `uniforms`
* arrays to be fed to the `WebGLPointsRenderer` class.
*
* Also returns `uniforms` and `attributes` properties as expected by the
* {@link module:ol/renderer/webgl/PointsLayer~WebGLPointsLayerRenderer}.
*
* @param {import("../style/LiteralStyle").LiteralStyle} style Literal style.
* @returns {StyleParseResult} Result containing shader params, attributes and uniforms.
*/
export function parseLiteralStyle(style) {
var symbStyle = style.symbol;
var size = symbStyle.size !== undefined ? symbStyle.size : 1;
var color = symbStyle.color || 'white';
var texCoord = symbStyle.textureCoord || [0, 0, 1, 1];
var offset = symbStyle.offset || [0, 0];
var opacity = symbStyle.opacity !== undefined ? symbStyle.opacity : 1;
var rotation = symbStyle.rotation !== undefined ? symbStyle.rotation : 0;
/**
* @type {import("../style/expressions.js").ParsingContext}
*/
var vertContext = {
inFragmentShader: false,
variables: [],
attributes: [],
stringLiteralsMap: {}
};
var parsedSize = expressionToGlsl(vertContext, size, ValueTypes.NUMBER_ARRAY | ValueTypes.NUMBER);
var parsedOffset = expressionToGlsl(vertContext, offset, ValueTypes.NUMBER_ARRAY);
var parsedTexCoord = expressionToGlsl(vertContext, texCoord, ValueTypes.NUMBER_ARRAY);
var parsedRotation = expressionToGlsl(vertContext, rotation, ValueTypes.NUMBER);
/**
* @type {import("../style/expressions.js").ParsingContext}
*/
var fragContext = {
inFragmentShader: true,
variables: vertContext.variables,
attributes: [],
stringLiteralsMap: vertContext.stringLiteralsMap
};
var parsedColor = expressionToGlsl(fragContext, color, ValueTypes.COLOR);
var parsedOpacity = expressionToGlsl(fragContext, opacity, ValueTypes.NUMBER);
var opacityFilter = '1.0';
var visibleSize = "vec2(" + expressionToGlsl(fragContext, size, ValueTypes.NUMBER_ARRAY | ValueTypes.NUMBER) + ").x";
switch (symbStyle.symbolType) {
case 'square': break;
case 'image': break;
// taken from https://thebookofshaders.com/07/
case 'circle':
opacityFilter = "(1.0-smoothstep(1.-4./" + visibleSize + ",1.,dot(v_quadCoord-.5,v_quadCoord-.5)*4.))";
break;
case 'triangle':
var st = '(v_quadCoord*2.-1.)';
var a = "(atan(" + st + ".x," + st + ".y))";
opacityFilter = "(1.0-smoothstep(.5-3./" + visibleSize + ",.5,cos(floor(.5+" + a + "/2.094395102)*2.094395102-" + a + ")*length(" + st + ")))";
break;
default: throw new Error('Unexpected symbol type: ' + symbStyle.symbolType);
}
var builder = new ShaderBuilder()
.setSizeExpression("vec2(" + parsedSize + ")")
.setRotationExpression(parsedRotation)
.setSymbolOffsetExpression(parsedOffset)
.setTextureCoordinateExpression(parsedTexCoord)
.setSymbolRotateWithView(!!symbStyle.rotateWithView)
.setColorExpression("vec4(" + parsedColor + ".rgb, " + parsedColor + ".a * " + parsedOpacity + " * " + opacityFilter + ")");
if (style.filter) {
var parsedFilter = expressionToGlsl(fragContext, style.filter, ValueTypes.BOOLEAN);
builder.setFragmentDiscardExpression("!" + parsedFilter);
}
/** @type {Object.<string,import("../webgl/Helper").UniformValue>} */
var uniforms = {};
// define one uniform per variable
fragContext.variables.forEach(function (varName) {
builder.addUniform("float u_" + varName);
uniforms["u_" + varName] = function () {
if (!style.variables || style.variables[varName] === undefined) {
throw new Error("The following variable is missing from the style: " + varName);
}
var value = style.variables[varName];
if (typeof value === 'string') {
value = getStringNumberEquivalent(vertContext, value);
}
return value !== undefined ? value : -9999999; // to avoid matching with the first string literal
};
});
if (symbStyle.symbolType === 'image' && symbStyle.src) {
var texture = new Image();
texture.src = symbStyle.src;
builder.addUniform('sampler2D u_texture')
.setColorExpression(builder.getColorExpression() +
' * texture2D(u_texture, v_texCoord)');
uniforms['u_texture'] = texture;
}
// for each feature attribute used in the fragment shader, define a varying that will be used to pass data
// from the vertex to the fragment shader, as well as an attribute in the vertex shader (if not already present)
fragContext.attributes.forEach(function (attrName) {
if (vertContext.attributes.indexOf(attrName) === -1) {
vertContext.attributes.push(attrName);
}
builder.addVarying("v_" + attrName, 'float', "a_" + attrName);
});
// for each feature attribute used in the vertex shader, define an attribute in the vertex shader.
vertContext.attributes.forEach(function (attrName) {
builder.addAttribute("float a_" + attrName);
});
return {
builder: builder,
attributes: vertContext.attributes.map(function (attributeName) {
return {
name: attributeName,
callback: function (feature, props) {
var value = props[attributeName];
if (typeof value === 'string') {
value = getStringNumberEquivalent(vertContext, value);
}
return value !== undefined ? value : -9999999; // to avoid matching with the first string literal
}
};
}),
uniforms: uniforms
};
}
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