42 lines
1.1 KiB
SourcePawn
42 lines
1.1 KiB
SourcePawn
//
|
|
|
|
const float M_PI = 3.141592653589793;
|
|
|
|
vec4 SRGBtoLINEAR(vec4 srgbIn) {
|
|
vec3 linOut = pow(srgbIn.xyz,vec3(2.2));
|
|
|
|
return vec4(linOut, srgbIn.a);
|
|
}
|
|
|
|
// http://www.thetenthplanet.de/archives/1180
|
|
// modified to fix handedness of the resulting cotangent frame
|
|
mat3 cotangentFrame( vec3 N, vec3 p, vec2 uv ) {
|
|
// get edge vectors of the pixel triangle
|
|
vec3 dp1 = dFdx( p );
|
|
vec3 dp2 = dFdy( p );
|
|
vec2 duv1 = dFdx( uv );
|
|
vec2 duv2 = dFdy( uv );
|
|
|
|
// solve the linear system
|
|
vec3 dp2perp = cross( dp2, N );
|
|
vec3 dp1perp = cross( N, dp1 );
|
|
vec3 T = dp2perp * duv1.x + dp1perp * duv2.x;
|
|
vec3 B = dp2perp * duv1.y + dp1perp * duv2.y;
|
|
|
|
// construct a scale-invariant frame
|
|
float invmax = inversesqrt( max( dot(T,T), dot(B,B) ) );
|
|
|
|
// calculate handedness of the resulting cotangent frame
|
|
float w = (dot(cross(N, T), B) < 0.0) ? -1.0 : 1.0;
|
|
|
|
// adjust tangent if needed
|
|
T = T * w;
|
|
|
|
return mat3( T * invmax, B * invmax, N );
|
|
}
|
|
|
|
vec3 perturbNormal(vec3 n, vec3 v, vec3 normalSample, vec2 uv) {
|
|
vec3 map = normalize( 2.0 * normalSample - vec3(1.0) );
|
|
mat3 TBN = cotangentFrame(n, v, uv);
|
|
return normalize(TBN * map);
|
|
}
|