Enhance: make shading method a runtime option instead of compile time

src/Options.cpp

@@ -75,6 +75,10 @@ try{
   po::options_description orthographic ("Orthographic Camera options");
   orthographic.add_options()
     ("pixelsize,p", po::value<float>(&garg_pixelsize)->default_value(0.005f), "Override the pixelsize setting in file");
+
+  po::options_description shading("Shading method options");
+  shading.add_options()
+    ("shadingMethod,s", po::value<string>(&shadingMethod)->default_value("blinn_phong_shadow"), "Select shading method, allowed value:\nsimple: assume light is at view point\nblinn_phong: using blinn-phong model\nblinn_phong_shadow: using blinn-phong model with hard shadow");
 
   po::options_description misc("Miscellaneous options");
   misc.add_options()
@@ -86,7 +90,7 @@ try{
     ;
 
   po::options_description all("All allowed options");
-  all.add(generic).add(required).add(perspective).add(orthographic).add(misc);
+  all.add(generic).add(required).add(shading).add(perspective).add(orthographic).add(misc);
 
   po::options_description show("Options");
   show.add(generic).add(required);
@@ -148,7 +152,10 @@ std::string& Options::getOutputDepthFileName()
   return depth;
 }
 
-
+std::string& Options::getShadingMethod()
+{
+  return shadingMethod;
+}
 
 
 /*

src/Options.hpp

@@ -20,12 +20,14 @@ class Options
   std::string& getInputFileName();
   std::string& getOutputFileName();
   std::string& getOutputDepthFileName();
+  std::string& getShadingMethod();
   //int getXres(){return xres;}
   //int getYres(){return yres;}
 private:
   std::string input;
   std::string output;
   std::string depth;
+  std::string shadingMethod;
   //int xres;
   //int yres;
   std::string config_file;

src/Shader.cpp

@@ -3,7 +3,17 @@
 #include <boost/foreach.hpp>
 #include "Light.hpp"
 #include "Scene.hpp"
+#include <iostream>
 #include <algorithm>
+Shader* Shader::getShader(std::string shadingMethod,Scene& scene)
+{
+    if ( shadingMethod == "simple" ) return new SimpleDiffuseShader();
+    if ( shadingMethod == "blinn_phong" ) return new PhongShader(scene);
+    if ( shadingMethod == "blinn_phong_shadow" )
+      return new PhongShaderWithShadow(scene);
+    std::cout<<"unknown shading method:"<<shadingMethod<<std::endl;
+    exit(4);
+}
 Color
 SimpleDiffuseShader::doShading(Ray& ray)
 {

src/Shader.hpp

@@ -18,6 +18,7 @@ class Shader
 {
 public:
   Shader(){}
+  static Shader* getShader(std::string shadingMethod,Scene& scene);
   virtual Color doShading(Ray& ray)=0;
   virtual ~Shader(){};
 };

src/main.cpp

@@ -12,9 +12,7 @@ main(int argc, char *argv[])
       ParseDriver pd(scene);
       pd.parse(opt.getInputFileName());
       ImageBuffer image(garg_xres,garg_yres);
-      //Shader* shaderp = new SimpleDiffuseShader();
-      //Shader* shaderp = new PhongShader(scene);
-      Shader* shaderp = new PhongShaderWithShadow(scene);
+      Shader* shaderp=Shader::getShader(opt.getShadingMethod(),scene);
       Raytracer tracer=Raytracer(&scene,&image,shaderp);
       tracer.doRaytrace();
       image.outputImage(opt.getOutputFileName());