OpenSpace/modules/iswa/shaders/dataplane_fs.glsl

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 * OpenSpace                                                                             *
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 * Copyright (c) 2014-2024                                                               *
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#include "PowerScaling/powerScaling_fs.hglsl"
#include "fragment.glsl"

in vec2 vs_st;
in vec4 vs_position;

uniform sampler2D textures[6];
uniform sampler2D transferFunctions[6];

uniform int numTextures;
uniform int numTransferFunctions;
uniform vec2 backgroundValues;
uniform float transparency;

const vec4 Transparent = vec4(0.0);


Fragment getFragment() {
  vec4 position = vs_position;
  float depth = pscDepth(position);
  vec4 diffuse = Transparent;

  float x = backgroundValues.x;
  float y = backgroundValues.y;

  if (numTextures > 0) {
    if ((numTransferFunctions == 1) || (numTextures > numTransferFunctions)) {
      float v = 0.0;
      for (int i = 0; i < numTextures; i++) {
        v += texture(textures[i], vs_st).r;
      }
      v /= numTextures;

      vec4 color = texture(transferFunctions[0], vec2(v, 0.0));
      if ((v < (x + y)) && v > (x - y)) {
        diffuse = Transparent;
      }
      else {
        diffuse = texture(transferFunctions[0], vec2(v, 0.0));
      }
    }
    else {
      float v = 0.0;
      for (int i = 0; i < numTextures; i++) {
        v = texture(textures[i], vs_st).r;
        vec4 color = texture(transferFunctions[i], vec2(v, 0.0));
        if ((v < (x + y)) && v > (x - y)) {
          color = Transparent;
        }
        diffuse += color;
      }
    }
  }

  if (diffuse.a <= backgroundValues.y) {
    discard;
  }

  Fragment frag;
  frag.color = diffuse * vec4(1.0, 1.0, 1.0, transparency);
  frag.depth = depth;
  return frag;
}