src/engine/Shaders.js

// Vertex Shader: Calcula tamaño y posición
export const vertexShader = `
    attribute float intensity;
    attribute float vertexIndex;
    varying float vIntensity;
    varying float vIsHighlight;
    uniform float highlightIndex;
    uniform float pointSpacing;
    uniform float dotSize; // Tamaño visual independiente del spacing

    void main() {
      vIntensity = intensity;

      // Use explicit attribute for index
      float index = vertexIndex;

      // Si este punto es el seleccionado, marcamos highlight
      if (abs(index - highlightIndex) < 0.1) vIsHighlight = 1.0;
      else vIsHighlight = 0.0;

      vec4 mvPosition = modelViewMatrix * vec4(position, 1.0);
      float dist = length(mvPosition.xyz);

      // Tamaño dinámico basado en dotSize (independiente del pointSpacing)
      float size = dotSize;
      if (vIsHighlight > 0.5) size *= 2.5;

      gl_PointSize = clamp(size * (300.0 / dist), 3.0, 120.0);
      gl_Position = projectionMatrix * mvPosition;
    }
`;

// Fragment Shader: Colormap perceptual Viridis
export const fragmentShader = `
    varying float vIntensity;
    varying float vIsHighlight;
    uniform float opacity;
    uniform vec3 color; // Base color from Uniform

    vec3 sampleViridis(float t) {
        float clampedT = clamp(t, 0.0, 1.0);
        float scaled = clampedT * 8.0;
        int idx = int(floor(scaled));
        float frac = fract(scaled);

        vec3 c0 = vec3(0.267004, 0.004874, 0.329415);
        vec3 c1 = vec3(0.282327, 0.160431, 0.457811);
        vec3 c2 = vec3(0.253935, 0.265254, 0.529983);
        vec3 c3 = vec3(0.191090, 0.364218, 0.548574);
        vec3 c4 = vec3(0.127568, 0.456911, 0.550996);
        vec3 c5 = vec3(0.121148, 0.547463, 0.506309);
        vec3 c6 = vec3(0.236780, 0.636730, 0.420680);
        vec3 c7 = vec3(0.460673, 0.723062, 0.303117);
        vec3 c8 = vec3(0.993248, 0.906157, 0.143936);

        if (idx == 0) return mix(c0, c1, frac);
        if (idx == 1) return mix(c1, c2, frac);
        if (idx == 2) return mix(c2, c3, frac);
        if (idx == 3) return mix(c3, c4, frac);
        if (idx == 4) return mix(c4, c5, frac);
        if (idx == 5) return mix(c5, c6, frac);
        if (idx == 6) return mix(c6, c7, frac);
        return mix(c7, c8, frac);
    }

    vec4 getActivationColor(float v) {
        float clampedV = clamp(v, -1.0, 1.0);
        float t01 = (clampedV + 1.0) * 0.5;
        vec3 col = sampleViridis(t01);
        return vec4(col, 1.0);
    }

    void main() {
      vec2 coord = gl_PointCoord - vec2(0.5);
      if (length(coord) > 0.5) discard; // Círculo perfecto

      vec4 activation = getActivationColor(vIntensity);
      vec3 finalColor = activation.rgb * opacity;
      float alpha = 1.0;

      // Si está seleccionado, brilla en BLANCO PURO
      if (vIsHighlight > 0.5) {
          finalColor = vec3(1.0, 1.0, 1.0);
      }

      gl_FragColor = vec4(finalColor, alpha);
    }
`;