@thewtex/vtk.js-esm/Rendering/OpenGL/ReplacementShaderMapper.js

Visualization Toolkit for the Web

import vtkShaderProgram from './ShaderProgram.js';

function implementReplaceShaderCoincidentOffset(publicAPI, model) {

  publicAPI.replaceShaderCoincidentOffset = function (shaders, ren, actor) {
    var cp = publicAPI.getCoincidentParameters(ren, actor); // if we need an offset handle it here
    // The value of .000016 is suitable for depth buffers
    // of at least 16 bit depth. We do not query the depth
    // right now because we would need some mechanism to
    // cache the result taking into account FBO changes etc.

    if (cp && (cp.factor !== 0.0 || cp.offset !== 0.0)) {
      var FSSource = shaders.Fragment;
      FSSource = vtkShaderProgram.substitute(FSSource, '//VTK::Coincident::Dec', ['uniform float cfactor;', 'uniform float coffset;']).result;

      if (model.context.getExtension('EXT_frag_depth')) {
        if (cp.factor !== 0.0) {
          FSSource = vtkShaderProgram.substitute(FSSource, '//VTK::UniformFlow::Impl', ['float cscale = length(vec2(dFdx(gl_FragCoord.z),dFdy(gl_FragCoord.z)));', '//VTK::UniformFlow::Impl'], false).result;
          FSSource = vtkShaderProgram.substitute(FSSource, '//VTK::Depth::Impl', 'gl_FragDepthEXT = gl_FragCoord.z + cfactor*cscale + 0.000016*coffset;').result;
        } else {
          FSSource = vtkShaderProgram.substitute(FSSource, '//VTK::Depth::Impl', 'gl_FragDepthEXT = gl_FragCoord.z + 0.000016*coffset;').result;
        }
      }

      if (model.openGLRenderWindow.getWebgl2()) {
        if (cp.factor !== 0.0) {
          FSSource = vtkShaderProgram.substitute(FSSource, '//VTK::UniformFlow::Impl', ['float cscale = length(vec2(dFdx(gl_FragCoord.z),dFdy(gl_FragCoord.z)));', '//VTK::UniformFlow::Impl'], false).result;
          FSSource = vtkShaderProgram.substitute(FSSource, '//VTK::Depth::Impl', 'gl_FragDepth = gl_FragCoord.z + cfactor*cscale + 0.000016*coffset;').result;
        } else {
          FSSource = vtkShaderProgram.substitute(FSSource, '//VTK::Depth::Impl', 'gl_FragDepth = gl_FragCoord.z + 0.000016*coffset;').result;
        }
      }

      shaders.Fragment = FSSource;
    }
  };
}

var vtkReplacementShaderMapper = {
  implementReplaceShaderCoincidentOffset: implementReplaceShaderCoincidentOffset
};

export default vtkReplacementShaderMapper;