incomplete ground and space shading

assets/shaders/planet.fs

@@ -0,0 +1,15 @@
+precision mediump float;
+
+uniform float g;
+uniform float g2;
+
+uniform sampler2D texture0;
+
+varying vec3 c0;
+varying vec3 c1;
+varying vec2 vUV;
+
+void main (void) {
+	vec3 diffuse = texture2D(texture0, vUV).xyz;
+	gl_FragColor = vec4(c1, 1.0) + vec4(diffuse * c0, 1.0);
+}

assets/shaders/planet.vs

@@ -0,0 +1,91 @@
+precision mediump float;
+
+attribute vec3 aVertexPosition;
+attribute vec3 aNormal;
+attribute vec2 aTexCoords;
+
+uniform vec3 v3CameraPosition;	// The camera position
+uniform vec3 v3LightPosition;	// The direction vector to the light source
+uniform vec3 v3InvWavelength;	// 1 / pow(wavelength, 4) for the red, green, and blue channels
+uniform float fCameraHeight;	// The camera's current height
+uniform float fCameraHeight2;	// fCameraHeight^2
+uniform float fOuterRadius;		// The outer (atmosphere) radius
+uniform float fOuterRadius2;	// fOuterRadius^2
+uniform float fInnerRadius;		// The inner (planetary) radius
+uniform float fInnerRadius2;	// fInnerRadius^2
+uniform float fKrESun;			// Kr * ESun
+uniform float fKmESun;			// Km * ESun
+uniform float fKr4PI;			// Kr * 4 * PI
+uniform float fKm4PI;			// Km * 4 * PI
+uniform float fScale;			// 1 / (fOuterRadius - fInnerRadius)
+uniform float fScaleDepth;		// The scale depth (i.e. the altitude at which the atmosphere's average density is found)
+uniform float fScaleOverScaleDepth;	// fScale / fScaleDepth
+
+const int nSamples = 3;
+const float fSamples = 3.0;
+
+varying vec3 c0;
+varying vec3 c1;
+varying vec3 vNormal;
+varying vec2 vUV;
+
+uniform mat4 uModelMatrix;
+uniform mat4 uViewMatrix;
+uniform mat4 uProjectionMatrix;
+
+float scale(float fCos) {
+	float x = 1.0 - fCos;
+	return fScaleDepth * exp(-0.00287 + x*(0.459 + x*(3.83 + x*(-6.80 + x*5.25))));
+}
+
+void main(void) {
+	// 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 = aVertexPosition - v3CameraPosition;
+	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 B = 2.0 * dot(v3CameraPosition, v3Ray);
+	float C = fCameraHeight2 - fOuterRadius2;
+	float fDet = max(0.0, B*B - 4.0 * C);
+	float fNear = 0.5 * (-B - sqrt(fDet));
+
+	// Calculate the ray's starting position, then calculate its scattering offset
+	vec3 v3Start = v3CameraPosition + v3Ray * fNear;
+	fFar -= fNear;
+	float fDepth = exp((fInnerRadius - fOuterRadius) / fScaleDepth);
+	float fCameraAngle = dot(-v3Ray, aVertexPosition) / length(aVertexPosition);
+	float fLightAngle = dot(v3LightPosition, aVertexPosition) / length(aVertexPosition);
+
+	float fCameraScale = scale(fCameraAngle);
+	float fLightScale = scale(fLightAngle);
+	float fCameraOffset = fDepth*fCameraScale;
+	float fTemp = (fLightScale + fCameraScale);
+
+	// Initialize the scattering loop variables
+	float fSampleLength = fFar / fSamples;
+	float fScaledLength = fSampleLength * fScale;
+	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(fScaleOverScaleDepth * (fInnerRadius - fHeight));
+		float fScatter = fDepth*fTemp - fCameraOffset;
+		v3Attenuate = exp(-fScatter * (v3InvWavelength * fKr4PI + fKm4PI));
+		v3FrontColor += v3Attenuate * (fDepth * fScaledLength);
+		v3SamplePoint += v3SampleRay;
+	}
+
+	// Calculate the attenuation factor for the ground
+	c0 = v3Attenuate;
+	c1 = v3FrontColor * (v3InvWavelength * fKrESun + fKmESun);
+
+	gl_Position = uProjectionMatrix * uViewMatrix * uModelMatrix * vec4(aVertexPosition,1);
+	vUV = aTexCoords;
+	vNormal = aNormal;
+}

src/engine/components/planet/atmosphere.js

@@ -10,18 +10,15 @@ class Atmosphere extends MeshInstance {
     this.innerRadius = innerRadius
     this.wavelength = wavelength
 
-    this.Kr = 0.0025
-    this.Km = 0.0020
+    this.Kr = 0.0020
+    this.Km = 0.0010
     this.ESun = 20.0
     this.g = -0.950
     this.scaleDepth = 0.25
     this.mieScaleDepth = 0.1
   }
 
-  draw (gl, shader, camera, sun, sky) {
-    // Set model transform matrix uniform
-    gl.uniformMatrix4fv(shader.getUniformLocation(gl, 'uModelMatrix'), false, this.transform)
-
+  setUniforms (gl, shader, camera, sun) {
     const camHeight = vec3.length(subv3(camera.pos, this.pos))
     const invWavelength = [1 / Math.pow(this.wavelength[0], 4), 1 / Math.pow(this.wavelength[1], 4), 1 / Math.pow(this.wavelength[2], 4)]
     gl.uniform3fv(shader.getUniformLocation(gl, 'v3CameraPosition'), camera.pos)
@@ -42,6 +39,12 @@ class Atmosphere extends MeshInstance {
     gl.uniform1f(shader.getUniformLocation(gl, 'fScaleOverScaleDepth'), 1 / (this.outerRadius - this.innerRadius) / this.scaleDepth)
     gl.uniform1f(shader.getUniformLocation(gl, 'g'), this.g)
     gl.uniform1f(shader.getUniformLocation(gl, 'g2'), this.g * this.g)
+  }
+
+  draw (gl, shader, camera, sun) {
+    // Set model transform matrix uniform
+    gl.uniformMatrix4fv(shader.getUniformLocation(gl, 'uModelMatrix'), false, this.transform)
+    this.setUniforms(gl, shader, camera, sun)
 
     // Draw the mesh
     gl.enable(gl.BLEND)
@@ -53,6 +56,11 @@ class Atmosphere extends MeshInstance {
     this.mesh.postdraw(gl, shader)
 
     gl.disable(gl.BLEND)
+    gl.cullFace(gl.BACK)
+  }
+
+  setupPlanetShader (gl, shader, camera, sun) {
+    this.setUniforms(gl, shader, camera, sun)
   }
 }
 

src/engine/components/planet/index.js

@@ -219,6 +219,39 @@ class CubePlanet {
       this.faces[i].draw(gl, shader)
     }
   }
+
+  prepare (gl, shader) {
+    if (!this.material) return
+    this.material.apply(gl, shader)
+  }
+
+  static drawPlanetAtmosphere (gl, planet, atmosphere, camera, sun, atmosShader, planetShader, surfaceShader, surfaceEnvironment) {
+    const height = vec3.length(subv3(camera.pos, atmosphere.pos))
+
+    // Render the atmosphere
+    atmosShader.use(gl)
+    camera.draw(gl, atmosShader)
+    atmosphere.draw(gl, atmosShader, camera, sun)
+
+    if (height > atmosphere.innerRadius + (atmosphere.outerRadius - atmosphere.innerRadius) / 3) {
+      // Draw the planet from space
+      // TODO: maybe separate atmosphere from space and ground shaders?
+
+      planetShader.use(gl)
+      camera.draw(gl, planetShader)
+      atmosphere.setupPlanetShader(gl, planetShader, camera, sun)
+      planet.prepare(gl, planetShader)
+      planet.draw(gl, planetShader)
+    } else {
+      // Draw the planet within the atmosphere
+      surfaceShader.use(gl)
+      surfaceEnvironment.draw(gl, surfaceShader)
+      camera.draw(gl, surfaceShader)
+
+      planet.prepare(gl, surfaceShader)
+      planet.draw(gl, surfaceShader)
+    }
+  }
 }
 
 export { CubePlanet, CubeFace, PlanetGenerator }

src/index.js

@@ -30,6 +30,7 @@ async function pipeline () {
   const terrainShader = await game.shaders.createShaderFromFiles(game.gl, 'terrain', false)
   const skyboxShader = await game.shaders.createShaderFromFiles(game.gl, 'skybox', false)
   const atmosShader = await game.shaders.createShaderFromFiles(game.gl, 'atmosphere', false)
+  const planetShader = await game.shaders.createShaderFromFiles(game.gl, 'planet', false)
 
   entity.setRotation([0.0, 0.0, -90.0])
 
@@ -97,6 +98,7 @@ async function pipeline () {
   // Planet test
   const planet = new CubePlanet([0.0, 0.0, 0.0], new PlanetGenerator(16, 1000, hmap))
   const atmosphere = new Atmosphere([0.0, 0.0, 0.0], 1000, 1025, [0.650, 0.570, 0.475])
+  planet.material = material
 
   // Update function for camera and terrain
   let fpsTimer = 0
@@ -157,28 +159,21 @@ async function pipeline () {
     game.prepare()
 
     // Draw the skybox
-    //skyboxShader.use(gl)
-    //skybox.draw(gl, skyboxShader, cam)
+    // skyboxShader.use(gl)
+    // skybox.draw(gl, skyboxShader, cam)
 
     // Use terrain shader
-    terrainShader.use(gl)
+    // terrainShader.use(gl)
     // Set environment variables in shader
-    env.draw(gl, terrainShader)
+    // env.draw(gl, terrainShader)
     // Set the viewport uniforms
-    cam.draw(gl, terrainShader)
+    // cam.draw(gl, terrainShader)
     // Draw terrain
     // terrain.draw(gl, terrainShader)
-
     // entity.draw(gl, terrainShader)
-
     // block.draw(gl, terrainShader)
 
-    material.apply(gl, terrainShader)
-    planet.draw(gl, terrainShader)
-
-    atmosShader.use(gl)
-    cam.draw(gl, atmosShader)
-    atmosphere.draw(gl, atmosShader, cam, env.sun, true)
+    CubePlanet.drawPlanetAtmosphere(gl, planet, atmosphere, cam, env.sun, atmosShader, planetShader, terrainShader, env)
   }
 
   // Render function for the triangle