uniform vec3 u_radii; uniform vec3 u_oneOverEllipsoidRadiiSquared; varying vec3 v_positionEC; vec4 computeEllipsoidColor(czm_ray ray, float intersection, float side) { vec3 positionEC = czm_pointAlongRay(ray, intersection); vec3 positionMC = (czm_inverseModelView * vec4(positionEC, 1.0)).xyz; vec3 geodeticNormal = normalize(czm_geodeticSurfaceNormal(positionMC, vec3(0.0), u_oneOverEllipsoidRadiiSquared)); vec3 sphericalNormal = normalize(positionMC / u_radii); vec3 normalMC = geodeticNormal * side; // normalized surface normal (always facing the viewer) in model coordinates vec3 normalEC = normalize(czm_normal * normalMC); // normalized surface normal in eye coordiantes vec2 st = czm_ellipsoidWgs84TextureCoordinates(sphericalNormal); vec3 positionToEyeEC = -positionEC; czm_materialInput materialInput; materialInput.s = st.s; materialInput.st = st; materialInput.str = (positionMC + u_radii) / u_radii; materialInput.normalEC = normalEC; materialInput.tangentToEyeMatrix = czm_eastNorthUpToEyeCoordinates(positionMC, normalEC); materialInput.positionToEyeEC = positionToEyeEC; czm_material material = czm_getMaterial(materialInput); return czm_phong(normalize(positionToEyeEC), material); } void main() { czm_ellipsoid ellipsoid = czm_ellipsoidNew(czm_modelView[3].xyz, u_radii); vec3 direction = normalize(v_positionEC); czm_ray ray = czm_ray(vec3(0.0), direction); czm_raySegment intersection = czm_rayEllipsoidIntersectionInterval(ray, ellipsoid); if (czm_isEmpty(intersection)) { discard; } // If the viewer is outside, compute outsideFaceColor, with normals facing outward. vec4 outsideFaceColor = (intersection.start != 0.0) ? computeEllipsoidColor(ray, intersection.start, 1.0) : vec4(0.0); // If the viewer either is inside or can see inside, compute insideFaceColor, with normals facing inward. vec4 insideFaceColor = (outsideFaceColor.a < 1.0) ? computeEllipsoidColor(ray, intersection.stop, -1.0) : vec4(0.0); gl_FragColor = mix(insideFaceColor, outsideFaceColor, outsideFaceColor.a); gl_FragColor.a = 1.0 - (1.0 - insideFaceColor.a) * (1.0 - outsideFaceColor.a); }