@openhps/core
Version:
Open Hybrid Positioning System - Core component
49 lines (33 loc) • 1.39 kB
JavaScript
"use strict";
Object.defineProperty(exports, "__esModule", {
value: true
});
exports.default = void 0;
var _default = exports.default = /* glsl */`
uniform sampler2D bumpMap;
uniform float bumpScale;
// Bump Mapping Unparametrized Surfaces on the GPU by Morten S. Mikkelsen
// https://mmikk.github.io/papers3d/mm_sfgrad_bump.pdf
// Evaluate the derivative of the height w.r.t. screen-space using forward differencing (listing 2)
vec2 dHdxy_fwd() {
vec2 dSTdx = dFdx( vBumpMapUv );
vec2 dSTdy = dFdy( vBumpMapUv );
float Hll = bumpScale * texture2D( bumpMap, vBumpMapUv ).x;
float dBx = bumpScale * texture2D( bumpMap, vBumpMapUv + dSTdx ).x - Hll;
float dBy = bumpScale * texture2D( bumpMap, vBumpMapUv + dSTdy ).x - Hll;
return vec2( dBx, dBy );
}
vec3 perturbNormalArb( vec3 surf_pos, vec3 surf_norm, vec2 dHdxy, float faceDirection ) {
// normalize is done to ensure that the bump map looks the same regardless of the texture's scale
vec3 vSigmaX = normalize( dFdx( surf_pos.xyz ) );
vec3 vSigmaY = normalize( dFdy( surf_pos.xyz ) );
vec3 vN = surf_norm; // normalized
vec3 R1 = cross( vSigmaY, vN );
vec3 R2 = cross( vN, vSigmaX );
float fDet = dot( vSigmaX, R1 ) * faceDirection;
vec3 vGrad = sign( fDet ) * ( dHdxy.x * R1 + dHdxy.y * R2 );
return normalize( abs( fDet ) * surf_norm - vGrad );
}
`;