import {WebGLUtils} from 'gisplay-es6-webpack/src/Gisplay/Helpers/WebglUtils.js'

public class | source

WebGLUtils

Class with static methods that will help with WebGL related stuff(Matrices, web mercator projection and shaders). Always remeber WebGL is column major when reading the matrix code.

See:

http://ptgmedia.pearsoncmg.com/images/chap3_9780321902924/elementLinks/03fig27.jpg

Static Method Summary

Static Public Methods
public static	createAndCompileShader(type: string, source_code: string, webgl: _webgl): WebGLShader Creates and compiles a shader.
public static	createWebGLProgram(webgl: {gl: WebGLRenderingContext, program: WebGLProgram}): void Initializes: 1)WebGLProgram, 2) Generates shadders, 3) Attaches shaders to the program, 4) links program, 5) uses program.
public static	finalMatrix(scale: number, width: number, height: number, offsetX: number, offsetY: number): Float32Array This is the result matrix from the multiplication of M1M2M3
public static	generateShadersSourceCode(): {vertexCode: string, fragmentCode: string} Creates shaders(Vertex + Fragment) source code.
public static	webMercatorProjection(longitudeCenter: number, latitudeCenter: number, zoom: number, tileSize: number, width: number, height: number): {scale: number, offsetX: number, offsetY: number} Calculates the scale and offset(X and Y) for the Web Mercator projection.

Static Public Methods

public static createAndCompileShader(type: string, source_code: string, webgl: _webgl): WebGLShader source

Creates and compiles a shader.

Params:

Name	Type	Attribute	Description
type	string		Type of shader. Options are: VERTEX_SHADER or FRAGMENT_SHADER;
source_code	string		The shader source code.
webgl	_webgl		Webgl object used by the Map class.

Return:

WebGLShader

The shader(vertex of fragment).

public static createWebGLProgram(webgl: {gl: WebGLRenderingContext, program: WebGLProgram}): void source

Initializes: 1)WebGLProgram, 2) Generates shadders, 3) Attaches shaders to the program, 4) links program, 5) uses program.

Params:

Name	Type	Attribute	Description
webgl	{gl: WebGLRenderingContext, program: WebGLProgram}

Return:

void

public static finalMatrix(scale: number, width: number, height: number, offsetX: number, offsetY: number): Float32Array source

This is the result matrix from the multiplication of M1M2M3

Params:

Name	Type	Attribute	Description
scale	number		The scale calculated with WebMercator projection.
width	number		The width of the canvas.
height	number		The height of the canvas.
offsetX	number		The offsetX calculated with WebMercator projection.
offsetY	number		The offsetY calculated with WebMercator projection.

Return:

Float32Array

The resulting matrix (M1M2M3) in a single matrix to send to WebGL in order to calculate the resulting position.

See:

Rui's thesis

public static generateShadersSourceCode(): {vertexCode: string, fragmentCode: string} source

Creates shaders(Vertex + Fragment) source code.

Return:

{vertexCode: string, fragmentCode: string}

The code for the vertex and fragment shaders.

public static webMercatorProjection(longitudeCenter: number, latitudeCenter: number, zoom: number, tileSize: number, width: number, height: number): {scale: number, offsetX: number, offsetY: number} source

Calculates the scale and offset(X and Y) for the Web Mercator projection.

Params:

Name	Type	Attribute	Description
longitudeCenter	number		Longitude of the given position.
latitudeCenter	number		Latitude of the given position.
zoom	number		Current zoom level of the background map.
tileSize	number		The size of each tile in the background map. Usually is 256. If different should be given in the API options.
width	number		Width of the current canvas.
height	number		Height of the current canvas.

Return:

{scale: number, offsetX: number, offsetY: number}

Returns the scale, offsetX and offsetY of the point given using the Web Mercator projection.