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atmosphere

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This commit is contained in:
Evert Prants 2022-12-11 13:41:30 +02:00
parent 0af957094b
commit afe89c4c79
Signed by: evert
GPG Key ID: 1688DA83D222D0B5
7 changed files with 285 additions and 59 deletions
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67
src/atmosphere.ts Normal file
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@ -0,0 +1,67 @@
import {
BackSide,
DirectionalLight,
Mesh,
Object3D,
ShaderMaterial,
SphereGeometry,
} from 'three';
import { plainText as vertexShader } from './shaders/atmosphere.vert';
import { plainText as fragmentShader } from './shaders/atmosphere.frag';
export class Atmosphere extends Object3D {
public Rayleigh = 0.0025;
public Mie = 0.0005;
public Exposure = 15.0;
public Scale = 1;
public ScaleDepth = 0.25;
public G = -0.95;
public Wavelength = [0.65, 0.57, 0.475];
public geom?: SphereGeometry;
public mesh?: Mesh;
public shader = new ShaderMaterial({
vertexShader,
fragmentShader,
side: BackSide,
transparent: true,
});
constructor(public innerRadius: number, public outerRadius: number) {
super();
this.Scale = 1 / (this.outerRadius - this.innerRadius);
this.setUniforms(this.shader);
this.initialize();
}
setUniforms(shader: ShaderMaterial) {
shader.uniforms.invWavelength = {
value: [
1 / Math.pow(this.Wavelength[0], 4),
1 / Math.pow(this.Wavelength[1], 4),
1 / Math.pow(this.Wavelength[2], 4),
],
};
shader.uniforms.outerRadius = { value: this.outerRadius };
shader.uniforms.innerRadius = { value: this.innerRadius };
shader.uniforms.Kr = { value: this.Rayleigh };
shader.uniforms.Km = { value: this.Mie };
shader.uniforms.ESun = { value: this.Exposure };
shader.uniforms.scale = { value: this.Scale };
shader.uniforms.scaleDepth = { value: this.ScaleDepth };
shader.uniforms.g = { value: this.G };
}
setLight(light: DirectionalLight) {
this.shader.uniforms.lightDirection = {
value: light.position.clone().normalize(),
};
}
initialize() {
this.geom = new SphereGeometry(this.outerRadius, 128, 128);
this.mesh = new Mesh(this.geom, this.shader);
this.add(this.mesh);
}
}

61
src/globe.ts
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@ -2,20 +2,20 @@ import {
SphereGeometry,
Texture,
Mesh,
MeshPhongMaterial,
Object3D,
TextureLoader,
Color,
DirectionalLight,
Shader,
ShaderMaterial,
} from 'three';
import { plainText as vertexShader } from './shaders/earth.vert';
import { plainText as fragmentShader } from './shaders/earth.frag';
import { Atmosphere } from './atmosphere';
export class Globe extends Object3D {
private sphere = new SphereGeometry(1, 32, 32);
private sphere = new SphereGeometry(1, 128, 128);
private atmosphere = new Atmosphere(1, 1.05);
private earthMaterial?: ShaderMaterial;
public earthMesh?: Mesh;
private loader = new TextureLoader();
@ -53,60 +53,11 @@ export class Globe extends Object3D {
},
});
// this.earthMaterial = new MeshPhongMaterial();
// this.earthMaterial.onBeforeCompile = (shader) => {
// let fragment = shader.fragmentShader;
// let vertex = shader.vertexShader;
// vertex = injectBefore(
// vertex,
// 'void main() {',
// `uniform vec3 lightDirection;\nvarying vec3 surfaceToLight;\n`
// );
// vertex = injectBefore(
// vertex,
// '#include <logdepthbuf_vertex>',
// 'surfaceToLight = mat3(modelViewMatrix) * lightDirection;\n'
// );
// fragment = injectBefore(
// fragment,
// 'void main() {',
// `varying vec3 surfaceToLight;\nuniform sampler2D nightmap;\n`
// );
// fragment = replaceWith(fragment, '#include <map_fragment>', '');
// fragment = injectBefore(
// fragment,
// '#include <lights_phong_fragment>',
// `
// vec4 sampledDiffuseColor = texture2D(map, vUv);
// vec4 sampledDiffuseColorNight = texture2D(nightmap, vUv);
// diffuseColor *= sampledDiffuseColor;
// `
// );
// fragment = injectBefore(
// fragment,
// '#include <output_fragment>',
// `float cosineAngleSunToNormal = dot(geometryNormal, surfaceToLight);
// cosineAngleSunToNormal = clamp( cosineAngleSunToNormal * 1.0, -1.0, 1.0);
// float mixAmount = cosineAngleSunToNormal * 0.5 + 0.5;
// outgoingLight = mix(sampledDiffuseColorNight.xyz, outgoingLight, mixAmount);
// `
// );
// console.log(fragment);
// shader.uniforms.nightmap = { value: textures[1] };
// shader.uniforms.lightDirection = {
// value: light.position.clone(),
// };
// shader.fragmentShader = fragment;
// shader.vertexShader = vertex;
// };
// this.earthMaterial.map = textures[0];
// this.earthMaterial.normalMap = textures[3];
// this.earthMaterial.specularMap = textures[4];
// this.earthMaterial.specular = new Color('grey');
this.atmosphere.setUniforms(this.earthMaterial);
this.atmosphere.setLight(light);
this.earthMesh = new Mesh(this.sphere, this.earthMaterial);
this.add(this.earthMesh);
this.add(this.atmosphere);
}
public tick() {}

2
src/main.ts
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@ -22,7 +22,7 @@ const control = new OrbitControls(main.camera, main.canvas);
function tick() {
requestAnimationFrame(tick);
control.update();
globe.rotateY(Math.PI * 0.0005);
// globe.rotateY(Math.PI * 0.0005);
main.render();
globe.tick();
}

28
src/shaders/atmosphere.frag Normal file
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@ -0,0 +1,28 @@
#include <common>
uniform vec3 lightDirection;
uniform float g;
varying vec3 v3Direction;
varying vec3 c0;
varying vec3 c1;
// Calculates the Mie phase function
float getMiePhase(float fCos, float fCos2, float g, float g2){
return 1.5 * ((1.0 - g2) / (2.0 + g2)) * (1.0 + fCos2) / pow(1.0 + g2 - 2.0 * g * fCos, 1.5);
}
// Calculates the Rayleigh phase function
float getRayleighPhase(float fCos2) {
// return 0.75 + 0.75 * fCos2;
return 0.75 * (2.0 + 0.5 * fCos2);
}
void main (void) {
float fCos = dot(lightDirection, v3Direction) / length(v3Direction);
float fCos2 = fCos * fCos;
vec3 color = getRayleighPhase(fCos2) * c0 +
getMiePhase(fCos, fCos2, g, pow(g, 2.0)) * c1;
gl_FragColor = vec4(color, 1.0);
gl_FragColor.a = gl_FragColor.b;
}

96
src/shaders/atmosphere.vert Normal file
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@ -0,0 +1,96 @@
#include <common>
uniform vec3 lightDirection; // The direction vector to the light source
uniform vec3 invWavelength; // 1 / pow(wavelength, 4) for the red, green, and blue channels
uniform float outerRadius; // The outer (atmosphere) radius
uniform float innerRadius; // The inner (planetary) radius
uniform float ESun; // Sun exposure
uniform float Km; // Mie coefficient
uniform float Kr; // Rayleigh coefficient
uniform float scale; // 1 / (outerRadius - innerRadius)
uniform float scaleDepth; // The scale depth (i.e. the altitude at which the atmosphere's average density is found)
const int nSamples = 2;
const float fSamples = 1.0;
varying vec3 v3Direction;
varying vec3 c0;
varying vec3 c1;
float dscale(float fCos) {
float x = 1.0 - fCos;
return scaleDepth * exp(-0.00287 + x * (0.459 + x * (3.83 + x * (-6.80 + x * 5.25))));
}
float calculateNearScatter(vec3 v3CameraPosition, vec3 v3Ray, float fCameraHeight, float fOuterRadius) {
float B = 2.0 * dot(v3CameraPosition, v3Ray);
float C = pow(fCameraHeight, 2.0) - pow(fOuterRadius, 2.0);
float fDet = max(0.0, B * B - 4.0 * C);
return 0.5 * (-B - sqrt(fDet));
}
void main(void) {
vec3 mvPosition = (modelMatrix * vec4(position, 1.0)).xyz;
// Initialize variables
float cameraHeight = length(vec3(0.0, 0.0, 0.0) - cameraPosition);
float KmESun = Km * ESun;
float KrESun = Kr * ESun;
float Kr4PI = Kr * 4.0 * PI;
float Km4PI = Km * 4.0 * PI;
float scaleOverScaleDepth = scale / scaleDepth;
// Get the ray from the camera to the vertex and its length (which is the far point of the ray passing through the atmosphere)
vec3 v3Ray = mvPosition - cameraPosition;
float fFar = length(v3Ray);
v3Ray /= fFar;
vec3 v3Start;
float fStartAngle;
float fStartDepth;
float fStartOffset;
if (cameraHeight > outerRadius) {
// Sky from space
// Calculate the closest intersection of the ray with the outer atmosphere (which is the near point of the ray passing through the atmosphere)
float fNear = calculateNearScatter(cameraPosition, v3Ray, cameraHeight, outerRadius);
// Calculate the ray's starting position, then calculate its scattering offset
v3Start = cameraPosition + v3Ray * fNear;
fFar -= fNear;
fStartAngle = dot(v3Ray, v3Start) / outerRadius;
fStartDepth = exp(-1.0 / scaleDepth);
fStartOffset = fStartDepth * dscale(fStartAngle);
} else {
// Sky from within the atmosphere
v3Start = cameraPosition;
fStartDepth = exp(scaleOverScaleDepth * (innerRadius - cameraHeight));
fStartAngle = dot(v3Ray, v3Start) / length(v3Start);
fStartOffset = fStartDepth * dscale(fStartAngle);
}
// Initialize the scattering loop variables
float fSampleLength = fFar / fSamples;
float scaledLength = fSampleLength * scale;
vec3 v3SampleRay = v3Ray * fSampleLength;
vec3 v3SamplePoint = v3Start + v3SampleRay * 0.5;
// Now loop through the sample rays
vec3 v3FrontColor = vec3(0.0, 0.0, 0.0);
for(int i=0; i<nSamples; i++)
{
float fHeight = length(v3SamplePoint);
float fDepth = exp(scaleOverScaleDepth * (innerRadius - fHeight));
float fLightAngle = dot(lightDirection, v3SamplePoint) / fHeight;
float fCameraAngle = dot(v3Ray, v3SamplePoint) / fHeight;
float fScatter = (fStartOffset + fDepth * (dscale(fLightAngle) - dscale(fCameraAngle)));
vec3 v3Attenuate = exp(-fScatter * (invWavelength * Kr4PI + Km4PI));
v3FrontColor += v3Attenuate * (fDepth * scaledLength);
v3SamplePoint += v3SampleRay;
}
// Finally, scale the Mie and Rayleigh colors and set up the varying variables for the pixel shader
gl_Position = projectionMatrix * viewMatrix * modelMatrix * vec4(position, 1);
c0 = v3FrontColor * (invWavelength * KrESun);
c1 = v3FrontColor * KmESun;
v3Direction = cameraPosition - mvPosition;
}

7
src/shaders/earth.frag
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@ -19,6 +19,9 @@ uniform sampler2D specularMap;
#include <normal_pars_fragment>
#include <normalmap_pars_fragment>
varying vec3 c0;
varying vec3 c1;
void main() {
vec4 sampledDiffuseColor = texture2D(texture0, vUv);
vec4 sampledDiffuseColorNight = texture2D(texture1, vUv);
@ -37,10 +40,10 @@ void main() {
vec4 texelSpecular = texture2D(specularMap, vUv);
float specularStrength = texelSpecular.r;
vec3 outgoingLight = mix(sampledDiffuseColorNight.xyz, sampledDiffuseColor.xyz, mixAmount);
vec3 outgoingLight = mix(sampledDiffuseColorNight.xyz, c0 + sampledDiffuseColor.xyz * c1, mixAmount);
float specularAmount = max(0.0, specularAngle);
specularAmount = pow(specularAmount, 32.0 * shininess) * specularStrength;
gl_FragColor = vec4( outgoingLight + specular * specularAmount, 1.0 );
gl_FragColor = vec4( (outgoingLight + specular * specularAmount), 1.0 );
}

83
src/shaders/earth.vert
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@ -6,6 +6,35 @@ varying vec3 vEyeNormal;
#include <common>
#include <normal_pars_vertex>
uniform vec3 light;
uniform vec3 invWavelength; // 1 / pow(wavelength, 4) for the red, green, and blue channels
uniform float outerRadius; // The outer (atmosphere) radius
uniform float innerRadius; // The inner (planetary) radius
uniform float ESun; // Sun exposure
uniform float Km; // Mie coefficient
uniform float Kr; // Rayleigh coefficient
uniform float scale; // 1 / (outerRadius - innerRadius)
uniform float scaleDepth; // The scale depth (i.e. the altitude at which the atmosphere's average density is found)
const int nSamples = 2;
const float fSamples = 1.0;
varying vec3 v3Direction;
varying vec3 c0;
varying vec3 c1;
float dscale(float fCos) {
float x = 1.0 - fCos;
return scaleDepth * exp(-0.00287 + x * (0.459 + x * (3.83 + x * (-6.80 + x * 5.25))));
}
float calculateNearScatter(vec3 v3CameraPosition, vec3 v3Ray, float fCameraHeight, float fOuterRadius) {
float B = 2.0 * dot(v3CameraPosition, v3Ray);
float C = pow(fCameraHeight, 2.0) - pow(fOuterRadius, 2.0);
float fDet = max(0.0, B * B - 4.0 * C);
return 0.5 * (-B - sqrt(fDet));
}
void main() {
#include <beginnormal_vertex>
#include <defaultnormal_vertex>
@ -13,8 +42,60 @@ void main() {
#include <begin_vertex>
#include <project_vertex>
vViewPosition = - mvPosition.xyz;
vLightDirection = (viewMatrix * vec4(light, 0.)).xyz;
vec3 modelPosition = (modelMatrix * vec4(position, 1.0)).xyz;
float cameraHeight = length(vec3(0.0, 0.0, 0.0) - cameraPosition);
float KmESun = Km * ESun;
float KrESun = Kr * ESun;
float Kr4PI = Kr * 4.0 * PI;
float Km4PI = Km * 4.0 * PI;
float scaleOverScaleDepth = scale / scaleDepth;
// Get the ray from the camera to the vertex and its length (which is the far point of the ray passing through the atmosphere)
vec3 v3Ray = modelPosition - cameraPosition;
float fFar = length(v3Ray);
v3Ray /= fFar;
// Calculate the closest intersection of the ray with the outer atmosphere (which is the near point of the ray passing through the atmosphere)
float fNear = calculateNearScatter(cameraPosition, v3Ray, cameraHeight, outerRadius);
// Calculate the ray's starting position, then calculate its scattering offset
vec3 v3Start = cameraPosition + v3Ray * fNear;
fFar -= fNear;
float fDepth = exp((innerRadius - outerRadius) / scaleDepth);
float fCameraAngle = dot(-v3Ray, modelPosition) / length(modelPosition);
float fLightAngle = dot(normalize(light), modelPosition) / length(modelPosition);
float fCameraScale = dscale(fCameraAngle);
float fLightScale = dscale(fLightAngle);
float fCameraOffset = fDepth*fCameraScale;
float fTemp = (fLightScale + fCameraScale);
// Initialize the scattering loop variables
float fSampleLength = fFar / fSamples;
float fScaledLength = fSampleLength * scale;
vec3 v3SampleRay = v3Ray * fSampleLength;
vec3 v3SamplePoint = v3Start + v3SampleRay * 0.5;
// Now loop through the sample rays
vec3 v3FrontColor = vec3(0.0, 0.0, 0.0);
vec3 v3Attenuate;
for(int i=0; i<nSamples; i++)
{
float fHeight = length(v3SamplePoint);
float fDepth = exp(scaleOverScaleDepth * (innerRadius - fHeight));
float fScatter = fDepth*fTemp - fCameraOffset;
v3Attenuate = exp(-fScatter * (invWavelength * Kr4PI + Km4PI));
v3FrontColor += v3Attenuate * (fDepth * fScaledLength);
v3SamplePoint += v3SampleRay;
}
// Calculate the attenuation factor for the ground
c0 = v3Attenuate;
c1 = v3FrontColor * (invWavelength * KrESun + KmESun);
vViewPosition = - mvPosition.xyz;
vec4 viewPos = modelViewMatrix * vec4(position, 1.0);
vEyeNormal = (modelViewMatrix * vec4(normal, 0.)).xyz;