The main shader: uniform vec3 mouse; uniform vec2 resolution; uniform sampler2D texture; vec3 computeNormal( vec4 n ) { // pixel scale vec2 un = 1.0 / re

The main shader: uniform vec3 mouse; uniform vec2 resolution; uniform sampler2D texture; vec3 computeNormal( vec4 n ) { // pixel scale vec2 un = 1.0 / resolution; vec2 uv = gl_FragCoord.xy / resolution; // tex sample neighbour-4; vec3 n_r = texture2D( texture, uv + vec2( 1., 0. ) * un ).xyz; vec3 n_l = texture2D( texture, uv - vec2( 1., 0. ) * un ).xyz; vec3 n_u = texture2D( texture, uv + vec2( 0., 1. ) * un ).xyz; vec3 n_d = texture2D( texture, uv - vec2( 0., 1. ) * un ).xyz; // partial differences n-4; vec4 dn = vec4( n.z ); dn -= vec4( n_r.z, n_l.z, n_u.z, n_d.z ); // right - left, up - down; vec2 xy = vec2( dn.x - dn.y, dn.z - dn.w ); xy += n_r.xy + n_l.xy + n_u.xy + n_d.xy; xy *= 0.89; float z = length(xy) * 0.1; return vec3( xy, z ) * 0.25; } void main() { vec2 uv = gl_FragCoord.xy / resolution; // normal sampling vec4 height = texture2D( texture, uv ); float vel = height.a; // previous velocity float elasticity = 0.002; float viscosity = 0.06; vel += - (height.z - 0.01) * elasticity - vel * viscosity; // compute normal advection vec3 normal = computeNormal( height ); normal.z += height.z + vel; float dist = distance( mouse.xy, gl_FragCoord.xy); float mouseRadius = 10.0; float peak = 1.9; // max-height if ( dist <= mouseRadius ) { float dst = ( mouseRadius - dist ) / mouseRadius; normal.z += pow( abs(dst), 1.9 ) * peak * 2.5; normal.xy -= normal.xy * pow( abs(dst), 1.9 ) * 0.1; normal.z = min( peak, normal.z ); } gl_FragColor = clamp( vec4( normal, vel ), -1.0, 1.0); }