tileBreakingNeyret property

String tileBreakingNeyret

Implementation

final String tileBreakingNeyret = '''
  #define rnd22(p) fract(sin((p) * mat2(127.1, 311.7, 269.5, 183.3)) * 43758.5453)
  // TODO: Figure out if this is correct for three.js
  #define srgb2rgb(V) pow(max(V, 0.), vec4(2.2)) // RGB <-> sRGB conversions
  #define rgb2srgb(V) pow(max(V, 0.), vec4(1. / 2.2))

  // (textureGrad handles MIPmap through patch borders)
  #define C(I)  (srgb2rgb(textureGrad(samp, U / hexTilingPatchScale - rnd22(I), Gx, Gy)) - meanColor * float(hexTilingUseContrastCorrectedBlending))

  uniform bool hexTilingUseContrastCorrectedBlending; // https://www.shadertoy.com/view/4dcSDr
  uniform float hexTilingPatchScale;
  uniform float hexTilingLookupSkipThreshold;
  uniform float hexTilingTextureSampleCoefficientExponent;

  vec4 textureNoTileNeyret(sampler2D samp, vec2 uv) {
      mat2 M0 = mat2(1, 0, .5, sqrt(3.) / 2.);
      mat2 M = inverse(M0);
      vec2 U = uv * hexTilingPatchScale / 8. * exp2(4. * 0.2 + 1.);
      vec2 V = M * U;
      vec2 I = floor(V);
      vec2 Gx = dFdx(U / hexTilingPatchScale), Gy = dFdy(U / hexTilingPatchScale);

      vec4 meanColor = hexTilingUseContrastCorrectedBlending ? srgb2rgb(texture(samp, U, 99.)) : vec4(0.);

      vec3 F = vec3(fract(V), 0), W;
      F.z = 1. - F.x - F.y;
      vec4 fragColor = vec4(0.);

      if (F.z > 0.) {
          W = vec3(F.z, F.y, F.x);
          W = pow(W, vec3(hexTilingTextureSampleCoefficientExponent));
          W = W / dot(W, vec3(1.));

          if (W.x > hexTilingLookupSkipThreshold) {
              fragColor += C(I) * W.x;
          }
          if (W.y > hexTilingLookupSkipThreshold) {
              fragColor += C(I + vec2(0, 1)) * W.y;
          }
          if (W.z > hexTilingLookupSkipThreshold) {
              fragColor += C(I + vec2(1, 0)) * W.z;
          }
      } else {
          W = vec3(-F.z, 1. - F.y, 1. - F.x);
          W = pow(W, vec3(hexTilingTextureSampleCoefficientExponent));
          W = W / dot(W, vec3(1.));

          if (W.x > hexTilingLookupSkipThreshold) {
              fragColor += C(I + 1.) * W.x;
          }
          if (W.y > hexTilingLookupSkipThreshold) {
              fragColor += C(I + vec2(1, 0)) * W.y;
          }
          if (W.z > hexTilingLookupSkipThreshold) {
              fragColor += C(I + vec2(0, 1)) * W.z;
          }
      }

      fragColor = hexTilingUseContrastCorrectedBlending ? meanColor + fragColor / length(W) : fragColor;

      fragColor = clamp(rgb2srgb(fragColor), 0., 1.);

      return fragColor;
  }
''';