bumpmap.fsh

uniform float uAmbient;uniform float uBumpDensity; // glman slider uniform variablesuniform float  uBumpSize;uniform  vec4  uSurfaceColor;uniform  float  uAng;uniform  float  uHeight;in vec3 vBTNx, vBTNy, vBTNz;in vec3 vLightDir;in vec2 vST;out vec4 fFragColor;const float PI = 3.14159265;float Cang, Sang;vec3ToXyz( vec3 btn ){ float xp = btn.x*Cang - btn.y*Sang;  // rotate by +Ang btn.y   = btn.x*Sang + btn.y*Cang; btn.x   = xp; btn = normalize( btn ); vec3 xyz; xyz.x = dot( vBTNx, btn ); // convert surface local to              // eye coords xyz.y = dot( vBTNy, btn ); xyz.z = dot( vBTNz, btn ); return normalize( xyz );}void main( ){ vec2 st = vST;  // locate the bumps based on (s,t) float Swidth = 1. / uBumpDensity; float Theight = 1. / uBumpDensity; float numInS = floor( st.s / Swidth ); float numInT = floor( st.t / Theight ); vec2 center; center.s = numInS * Swidth + Swidth/2.; center.t = numInT * Theight + Theight/2.; st -= center;    // st is now wrt the center of the bump Cang = cos(uAng);Sang = sin(uAng); vec2 stp;     // st’ = st rotated by -Ang stp.s = st.s*Cang + st.t*Sang; stp.t = -st.s*Sang + st.t*Cang; float theta = atan( stp.t, stp.s ); // this is the normal of the parts of the object // that are not in a pyramid: vec3 normal = ToXyz( vec3( 0., 0., 1. ) ); // figure out what part of the pyramid we are in and // get the normal there; then transform it to eye cords if( abs(stp.s) > Swidth/4. || abs(stp.t) > Theight/4. ) {  normal = ToXyz( vec3( 0., 0., 1. ) ); } else {  if( PI/4. <= theta && theta <= 3.*PI/4. )  {   normal = ToXyz( vec3( 0., uHeight, Theight/4. ) );  }  else if( -PI/4. <= theta && theta <= PI/4. )  {   normal = ToXyz( vec3( uHeight, 0., Swidth/4. ) );  }  else if( -3.*PI/4. <= theta && theta <= -PI/4. )  {   normal = ToXyz( vec3( 0., -uHeight, Theight/4. ) );  }  else if( theta >= 3.*PI/4. || theta <= -3.*PI/4. )  {   normal = ToXyz( vec3( -uHeight, 0., Swidth/4. ) );  } } float intensity = uAmbient + (1.-uAmbient)*         dot(normal, vLightDir); vec3 litColor = uSurfaceColor.rgb * intensity; fFragColor = vec4( litColor, uSurfaceColor.a );}