message: fix vertex color/overpaint in direct-volume shader
diff: @@ -270,16 +270,16 @@ vec4 raymarch(vec3 startLoc, vec3 step, vec3 rayDir) {
  #elif defined(dColorType_groupInstance)
  material.rgb = readFromTexture(tColor, vInstance * float(uGroupCount) + group, uColorTexDim).rgb;
  #elif defined(dColorType_vertex)
  - material.rgb = texture3dFrom1dTrilinear(tColor, isoPos, uGridDim, uColorTexDim, 0.0).rgb;
  + material.rgb = texture3dFrom1dTrilinear(tColor, unitPos, uGridDim, uColorTexDim, 0.0).rgb;
  #elif defined(dColorType_vertexInstance)
  - material.rgb = texture3dFrom1dTrilinear(tColor, isoPos, uGridDim, uColorTexDim, vInstance * float(uVertexCount)).rgb;
  + material.rgb = texture3dFrom1dTrilinear(tColor, unitPos, uGridDim, uColorTexDim, vInstance * float(uVertexCount)).rgb;
  #endif
  #ifdef dOverpaint
  #if defined(dOverpaintType_groupInstance)
  overpaint = readFromTexture(tOverpaint, vInstance * float(uGroupCount) + group, uOverpaintTexDim);
  #elif defined(dOverpaintType_vertexInstance)
  - overpaint = texture3dFrom1dTrilinear(tOverpaint, isoPos, uGridDim, uOverpaintTexDim, vInstance * float(uVertexCount));
  + overpaint = texture3dFrom1dTrilinear(tOverpaint, unitPos, uGridDim, uOverpaintTexDim, vInstance * float(uVertexCount));
  #endif
  material.rgb = mix(material.rgb, overpaint.rgb, overpaint.a);
  