message: Fix shader compilation in albedo table generation
  The albedo table shader fails to compile because DIRECTIONAL_ALBEDO_METHOD is not defined.
  DIRECTIONAL_ALBEDO_METHOD gets defined if and only if lighting nodes are found (see GlslShaderGenerator::requiresLighting)
diff: @@ -519,8 +519,17 @@ void GlslShaderGenerator::emitPixelStage(const ShaderGraph& graph, GenContext& c
  emitInclude("stdlib/" + GlslShaderGenerator::TARGET + "/lib/mx_math.glsl", context, stage);
  emitLineBreak(stage);
  - // Add lighting support
  + // Determine whether lighting is required
  bool lighting = requiresLighting(graph);
  +
  + // Define directional albedo approach
  + if (lighting || context.getOptions().hwWriteAlbedoTable)
  + {
  + emitLine("#define DIRECTIONAL_ALBEDO_METHOD " + std::to_string(int(context.getOptions().hwDirectionalAlbedoMethod)), stage, false);
  + emitLineBreak(stage);
  + }
  +
  + // Add lighting support
  if (lighting)
  {
  if (context.getOptions().hwMaxActiveLightSources > 0)
  @@ -528,8 +537,6 @@ void GlslShaderGenerator::emitPixelStage(const ShaderGraph& graph, GenContext& c
  const unsigned int maxLights = std::max(1u, context.getOptions().hwMaxActiveLightSources);
  emitLine("#define " + HW::LIGHT_DATA_MAX_LIGHT_SOURCES + " " + std::to_string(maxLights), stage, false);
  }
  - emitLine("#define DIRECTIONAL_ALBEDO_METHOD " + std::to_string(int(context.getOptions().hwDirectionalAlbedoMethod)), stage, false);
  - emitLineBreak(stage);
  emitSpecularEnvironment(context, stage);
  if (context.getOptions().hwMaxActiveLightSources > 0)
  