glsl-proj4-texture
pre-calculate proj4 coordinate transformations as a texture
example
generate proj4 texture data:
var ptex =var tex =processstdout
in your vertex shader using glslify:
precision highp float;# ptex = require('glsl-proj4-texture')attribute vec2 position;uniform sampler2D coordmap;uniform float size;void
usage
usage: glsl-proj4-texture
Write a binary coordinate texture to stdout.
--size texture width and height in pixels. default: 128
--src proj4 source string
--dst proj4 destination string
-w --west default: -180
-s --south default: -90
-e --east default: +180
-n --north default: +90
js api
var ptex =
var data = ptex(opts)
Return a Float32Array texture from:
- opts.size - texture
[width,height]
. default:[128,128]
- opts.src - proj4 source string
- opts.dst - proj4 destination string
- opts.bounds -
[west,south,east,north]
in degrees. default:[-180,-90,180,90]
glsl api
# ptex = require('glsl-proj4-texture')
vec3 pt = ptex(sampler2D texture, vec4 bbox, vec2 lonlat)
Return a vec3 pt
from the texture lookup on a texture created with a bbox
mapping lonlat
in degrees to screen coordinates in pt
.
install
npm install glsl-proj4-texture
license
BSD