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Turns out the issue is a bit more involved and is caused by having zero lights in the scene.

All of the do-while loops scattered across nearly every material assume there is at least light in the scene and the states returned by the Hard shadow algorithm do not differentiate between one light and zero lights: both set the state to Finished after the first pass, but when their are zero lights the shadow ray packet is filled with whatever uninitialized garbage was in memory where it was created; the do loop happily carries on until its while condition.

So what is the right way to fix this? We could wrap every do-while idiom in the codebase with a check to make sure there is at least one light. We could change the behavior of ShadowAlgorithms to differentiate between zero lights and one light in their state setting. What do we think? It seems to me those do-while loops should probably check their state at the beginning of the loop (just a plain while loop) and the Finished state shouldn't be set on the same pass that does work.

~Austin

Austin Robison wrote:

Looks like there are some SSE bugs in Dielectric, fire this up:

bin/manta -scene "lib/libscene_hdri.dylib(-floor -glass_sphere)" -np 2

~Austin

arobison@sci.utah.edu wrote:

Author: arobison
Date: Mon Dec 24 12:12:33 2007
New Revision: 1944

Modified:
   trunk/scenes/hdritest.cc
Log:
Adding some new features to this scene: a floor, glass balls, selectable mapping types.


Modified: trunk/scenes/hdritest.cc
==============================================================================
--- trunk/scenes/hdritest.cc    (original)
+++ trunk/scenes/hdritest.cc    Mon Dec 24 12:12:33 2007
@@ -26,24 +26,57 @@
 #include <Model/Textures/Constant.h>
 #include <Model/Textures/ImageTexture.h>
 #include <Model/Textures/MarbleTexture.h>
+#include <Model/Textures/TileTexture.h>
+#include <Model/Textures/CheckerTexture.h>
+#include <Model/TexCoordMappers/LinearMapper.h>
#include <iostream>
using namespace Manta;
-#define Rect(material, center, dir1, dir2) \
- Parallelogram(material, (center) - (dir1) - (dir2), (dir1)*2, (dir2)*2)
-
-
 void addSphere(Group* group)
 {
Material* metal = new MetalMaterial( Color( RGB(0.3, 0.3, 0.3) ), 10 );
- Object* sphere = new Sphere( metal, Vector(0,0,0), 1.0f );
+  Object* sphere = new Sphere( metal, Vector(0,0,-1.5), 1.0f );
group->add(sphere);
 }
+void addDielectricSphere(Group* group)
+{
+  Material* glass1 = new Dielectric( 1.4, 1.0, Color(RGB(.7,.2,.2)) );
+  Object* sphere1 = new Sphere( glass1, Vector(1.5, -.5, 2), .5 );
+
+  Material* glass2 = new Dielectric( 1.1, 1.0, Color(RGB(.2,.7,.2)) );
+  Object* sphere2 = new Sphere( glass2, Vector(-.5, -.3, 1.3), .7 );
+
+  Material* glass3 = new Dielectric( 1.8, 1.0, Color(RGB(.2,.2,.7)) );
+  Object* sphere3 = new Sphere( glass3, Vector(1.15, -.6, .4), .4 );
+
+  Material* glass4 = new Dielectric( 1.2, 1.0, Color::white()*.9 );
+  Object* sphere4 = new Sphere( glass4, Vector(-1.4, -.2, -.2), .8 );
+  +  group->add(sphere1);
+  group->add(sphere2);
+  group->add(sphere3);
+  group->add(sphere4);
+}
+
+void addFloor(Group* group)
+{
+ Texture<Color>* tile_tex = new CheckerTexture<Color>(Color::white(), Color::black(), + Vector(4,0,0), Vector(0,4,0));
+
+ Material* tile = new Phong( tile_tex, new Constant<Color>(Color::white()*.8), 20, new Constant<ColorComponent>(.2) );
+
+ Primitive* floor = new Parallelogram(tile, Vector(-2.5, -1.05, -2.5), Vector(5, 0, 0), Vector(0, 0, 5));
+
+ floor->setTexCoordMapper( new LinearMapper( Vector(-2.5,-1.05,-2.5), Vector(1,0,0), Vector(0, 0, 1), Vector(0,1,0)) );
+                            +  group->add(floor);
+}
+
 void addLights( LightSet* lights)
 {
lights->add( new PointLight( Vector(0, 0, 30) , Color( RGB(0.8,0.8,0.8) ) ) );
@@ -55,9 +88,30 @@
 {
std::string env_filename = "";
+ EnvMapBackground::MappingType mapping_type = EnvMapBackground::CylindricalEqualArea;
+  bool create_floor = false;
+  bool create_glass = false;
+
   for(size_t i = 0; i < args.size(); ++i) {
     std::string arg = args[i];
-    env_filename = arg;
+    if(arg == "-file") {
+      if(!getStringArg(i, args, env_filename))
+        throw IllegalArgument("scene hdritest -file", i , args);
+    } else if (arg == "-cylindrical") {
+      mapping_type = EnvMapBackground::CylindricalEqualArea;
+    } else if (arg == "-latlon") {
+      mapping_type = EnvMapBackground::LatLon;
+    } else if (arg == "-sphere") {
+      mapping_type = EnvMapBackground::DebevecSphere;
+    } else if (arg == "-old") {
+      mapping_type = EnvMapBackground::OldBehavior;
+    } else if (arg == "-floor") {
+      create_floor = true;
+    } else if (arg == "-glass_sphere") {
+      create_glass = true;
+    } else {
+      std::cerr << "Unknown option: " << arg << "\n";
+    }
   }
Vector up( 0.0f, 1.0f, 0.0f );
@@ -72,19 +126,26 @@
ImageTexture<Color>* t = LoadColorImageTexture( env_filename, &std::cerr );
scene->setBackground( new EnvMapBackground( t,
-          EnvMapBackground::CylindricalEqualArea, right, up ) );
+          mapping_type, right, up ) );
   } else {
scene->setBackground( new ConstantBackground( Color(RGB(.3, .3, .9) ) ) );
   }
addSphere(all);
+
+  if(create_floor)
+    addFloor(all);
+
+  if(create_glass)
+    addDielectricSphere(all);
+
   scene->setObject(all);
LightSet* lights = new LightSet();
-  addLights( lights );
+  //addLights( lights );
- lights->setAmbientLight(new ConstantAmbient( Color( RGB(0.5, 0.5, 0) ) ) );
+ lights->setAmbientLight(new ConstantAmbient( Color( RGB(0.2, 0.2, 0.2) ) ) );
scene->setLights(lights);

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• [Manta] r1944 - trunk/scenes, arobison, 12/24/2007
  • Re: [Manta] r1944 - trunk/scenes, Austin Robison, 12/24/2007
    • Re: [Manta] r1944 - trunk/scenes, Austin Robison, 12/24/2007

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