191 lines
6.7 KiB
JavaScript
191 lines
6.7 KiB
JavaScript
const viewer = new Cesium.Viewer('cesiumContainer')
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let xMin = 115.894604,
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yMin = 39.516896,
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xMax = 117.431959,
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yMax = 40.630521
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let rect = new Cesium.Rectangle(
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Cesium.Math.toRadians(xMin),
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Cesium.Math.toRadians(yMin),
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Cesium.Math.toRadians(xMax),
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Cesium.Math.toRadians(yMax)
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)
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const rectangle = new Cesium.RectangleGeometry({
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rectangle: rect,
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height: 10000.0,
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})
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const geometry = Cesium.RectangleGeometry.createGeometry(rectangle)
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viewer.scene.primitives.add(
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new Cesium.Primitive({
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asynchronous: false,
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geometryInstances: new Cesium.GeometryInstance({
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geometry: geometry,
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}),
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appearance: new Cesium.MaterialAppearance({
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material: new Cesium.Material({
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fabric: {
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uniforms: {
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image: './texture.png',
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},
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},
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}),
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fragmentShaderSource: `
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in vec3 v_positionEC;//顶点 相机（眼睛）坐标系
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in vec3 v_normalEC;//顶点法线 相机（眼睛）坐标系
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in vec2 v_st;//纹理坐标 uv
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/**
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This tab contains all the necessary noise functions required to model a cloud shape.
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*/
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// Hash by David_Hoskins
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#define UI0 1597334673U
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#define UI1 3812015801U
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#define UI2 uvec2(UI0, UI1)
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#define UI3 uvec3(UI0, UI1, 2798796415U)
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#define UIF (1.0 / float(0xffffffffU))
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vec3 hash33(vec3 p)
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{
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uvec3 q = uvec3(ivec3(p)) * UI3;
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q = (q.x ^ q.y ^ q.z)*UI3;
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return -1. + 2. * vec3(q) * UIF;
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}
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float remap(float x, float a, float b, float c, float d)
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{
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return (((x - a) / (b - a)) * (d - c)) + c;
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}
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// Gradient noise by iq (modified to be tileable)
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float gradientNoise(vec3 x, float freq)
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{
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// grid
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vec3 p = floor(x);
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vec3 w = fract(x);
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// quintic interpolant
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vec3 u = w * w * w * (w * (w * 6. - 15.) + 10.);
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// gradients
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vec3 ga = hash33(mod(p + vec3(0., 0., 0.), freq));
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vec3 gb = hash33(mod(p + vec3(1., 0., 0.), freq));
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vec3 gc = hash33(mod(p + vec3(0., 1., 0.), freq));
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vec3 gd = hash33(mod(p + vec3(1., 1., 0.), freq));
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vec3 ge = hash33(mod(p + vec3(0., 0., 1.), freq));
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vec3 gf = hash33(mod(p + vec3(1., 0., 1.), freq));
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vec3 gg = hash33(mod(p + vec3(0., 1., 1.), freq));
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vec3 gh = hash33(mod(p + vec3(1., 1., 1.), freq));
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// projections
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float va = dot(ga, w - vec3(0., 0., 0.));
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float vb = dot(gb, w - vec3(1., 0., 0.));
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float vc = dot(gc, w - vec3(0., 1., 0.));
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float vd = dot(gd, w - vec3(1., 1., 0.));
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float ve = dot(ge, w - vec3(0., 0., 1.));
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float vf = dot(gf, w - vec3(1., 0., 1.));
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float vg = dot(gg, w - vec3(0., 1., 1.));
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float vh = dot(gh, w - vec3(1., 1., 1.));
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// interpolation
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return va +
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u.x * (vb - va) +
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u.y * (vc - va) +
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u.z * (ve - va) +
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u.x * u.y * (va - vb - vc + vd) +
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u.y * u.z * (va - vc - ve + vg) +
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u.z * u.x * (va - vb - ve + vf) +
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u.x * u.y * u.z * (-va + vb + vc - vd + ve - vf - vg + vh);
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}
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// Tileable 3D worley noise
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float worleyNoise(vec3 uv, float freq)
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{
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vec3 id = floor(uv);
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vec3 p = fract(uv);
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float minDist = 10000.;
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for (float x = -1.; x <= 1.; ++x)
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{
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for(float y = -1.; y <= 1.; ++y)
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{
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for(float z = -1.; z <= 1.; ++z)
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{
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vec3 offset = vec3(x, y, z);
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vec3 h = hash33(mod(id + offset, vec3(freq))) * .5 + .5;
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h += offset;
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vec3 d = p - h;
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minDist = min(minDist, dot(d, d));
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}
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}
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}
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// inverted worley noise
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return 1. - minDist;
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}
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// Fbm for Perlin noise based on iq's blog
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float perlinfbm(vec3 p, float freq, int octaves)
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{
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float G = exp2(-.85);
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float amp = 1.;
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float noise = 0.;
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for (int i = 0; i < octaves; ++i)
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{
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noise += amp * gradientNoise(p * freq, freq);
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freq *= 2.;
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amp *= G;
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}
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return noise;
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}
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// Tileable Worley fbm inspired by Andrew Schneider's Real-Time Volumetric Cloudscapes
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// chapter in GPU Pro 7.
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float worleyFbm(vec3 p, float freq)
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{
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return worleyNoise(p*freq, freq) * .625 +
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worleyNoise(p*freq*2., freq*2.) * .25 +
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worleyNoise(p*freq*4., freq*4.) * .125;
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}
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void main( )
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{
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vec2 uv = v_st;
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float iTime=czm_frameNumber/100.;
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uv -= .02 * iTime;
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vec2 m = vec2(0.5);
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vec4 col = vec4(0.);
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float slices = 128.; // number of layers of the 3d texture
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float freq = 4.;
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float pfbm= mix(1., perlinfbm(vec3(uv, floor(m.y*slices)/slices), 4., 7), .5);
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pfbm = abs(pfbm * 2. - 1.); // billowy perlin noise
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col.g += worleyFbm(vec3(uv, floor(m.y*slices)/slices), freq);
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col.b += worleyFbm(vec3(uv, floor(m.y*slices)/slices), freq*2.);
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col.a += worleyFbm(vec3(uv, floor(m.y*slices)/slices), freq*4.);
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col.r += remap(pfbm, 0., 1., col.g, 1.); // perlin-worley
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float perlinWorley = col.r;
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// worley fbms with different frequencies
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vec3 worley = col.yzw;
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float wfbm = worley.x * .625 +
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worley.y * .125 +
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worley.z * .25;
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// cloud shape modeled after the GPU Pro 7 chapter
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float cloud = remap(perlinWorley, wfbm - 1., 1., 0., 1.);
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cloud = remap(cloud, .65, 1., 0., 1.); // fake cloud coverage
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vec3 col_ = vec3(0.);
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col_ += cloud;
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out_FragColor = vec4(col_,col.r); }`,
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}),
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})
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)
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