proj4 implementation for glsl
implemented projections:
- aea
- geocent
- gnom
- tmerc
var regl = require('regl')()
var camera = require('regl-camera')(regl, { distance: 10 })
var glsl = require('glslify')
var proj = require('glsl-proj4')
var p = proj('+proj=aea +lat_1=16 +lat_2=24 +lat_0=19 +lon_0=-157 +x_0=0 +y_0=0'
+ '+ellps=GRS80 +datum=NAD83 +units=m +no_defs')
var mesh = require('./hawaii.json')
var draw = regl({
frag: `
precision mediump float;
void main () {
gl_FragColor = vec4(0.5,0.5,0.5,1);
}
`,
vert: glsl`
precision mediump float;
#pragma glslify: forward = require('../aea/forward')
#pragma glslify: proj_t = require('../aea/t')
uniform proj_t proj;
attribute vec2 position;
void main () {
vec3 p = forward(proj, position);
gl_Position = vec4(p*1e-6,1);
}
`,
attributes: {
position: mesh.positions
},
uniforms: p.members('proj'),
elements: mesh.cells
})
regl.clear({ color: [1,1,1,1], depth: true })
draw()
var proj = require('glsl-proj4')
Create a proj instance p
from a proj4 string str
.
Return an object that maps member keys under the prefix name
to values. You
can pass this object as a struct uniform
String name of the projection.
#pragma glslify: aea_t = require('glsl-proj4/aea/t')
#pragma glslify: aea_forward = require('glsl-proj4/aea/forward')
#pragma glslify: aea_inverse = require('glsl-proj4/aea/inverse')
#pragma glslify: geocent_t = require('glsl-proj4/geocent/t')
#pragma glslify: geocent_forward = require('glsl-proj4/geocent/forward')
#pragma glslify: geocent_inverse = require('glsl-proj4/geocent/inverse')
#pragma glslify: gnom_t = require('glsl-proj4/gnom/t')
#pragma glslify: gnom_forward = require('glsl-proj4/gnom/forward')
#pragma glslify: gnom_inverse = require('glsl-proj4/gnom/inverse')
#pragma glslify: tmerc_t = require('glsl-proj4/tmerc/t')
#pragma glslify: tmerc_forward = require('glsl-proj4/tmerc/forward')
#pragma glslify: tmerc_inverse = require('glsl-proj4/tmerc/inverse')
Forward project pt
using the parameters from t
.
Forward project pt
using the parameters from t
with an altitude of 0.
Inverse project pt
using the parameters from t
.
Inverse project pt
using the parameters from t
and an altitude of 0.
npm install glsl-proj4
BSD