/*
 * pbrt source code Copyright(c) 1998-2005 Matt Pharr and Greg Humphreys
 *
 * All Rights Reserved.
 * For educational use only; commercial use expressly forbidden.
 * NO WARRANTY, express or implied, for this software.
 * (See file License.txt for complete license)
 */

// Debug integrator by Greg Humphreys

// debug.cpp*

#include "pbrt.h"
#include "transport.h"
#include "scene.h"

typedef enum {
	DEBUG_U, DEBUG_V,
	DEBUG_GEOM_NORMAL_X,
	DEBUG_GEOM_NORMAL_Y,
	DEBUG_GEOM_NORMAL_Z,
	DEBUG_SHAD_NORMAL_X,
	DEBUG_SHAD_NORMAL_Y,
	DEBUG_SHAD_NORMAL_Z,
	DEBUG_ONE,
	DEBUG_ZERO,
	DEBUG_HIT_SOMETHING
} DebugVariable;

class DebugIntegrator : public SurfaceIntegrator {
public:
	// DebugIntegrator Public Methods
	Spectrum Li(const Scene *scene, const RayDifferential &ray,
			const Sample *sample, float *alpha) const;
	DebugIntegrator( DebugVariable v[3] )
	{ 
		debug_variable[0] = v[0];
		debug_variable[1] = v[1];
		debug_variable[2] = v[2];
	}
private:
	DebugVariable debug_variable[3];
};

Spectrum DebugIntegrator::Li(const Scene *scene,
		const RayDifferential &ray, const Sample *sample,
		float *alpha) const {
	Intersection isect;
	Spectrum L(0.);
	bool hitSomething;
	BSDF *bsdf = NULL;

	if (alpha) *alpha = 1;

	hitSomething = scene->Intersect(ray, &isect);
	if (hitSomething) {
		bsdf = isect.GetBSDF(ray);
	}

	float color[3] = {0,0,0};

	int i;
	for (i = 0 ; i < 3 ; i++)
	{
		if (debug_variable[i] == DEBUG_HIT_SOMETHING)
		{
			color[i] = hitSomething ? 1 : 0;
		}
		else if (debug_variable[i] == DEBUG_ONE)
		{
			color[i] = 1;
		}
		else if (debug_variable[i] == DEBUG_ZERO)
		{
			color[i] = 0;
		}
		else if (hitSomething)
		{
			switch( debug_variable[i] )
			{
				case DEBUG_U:
					color[i] = isect.dg.u;
					break;
				case DEBUG_V:
					color[i] = isect.dg.v;
					break;
				case DEBUG_GEOM_NORMAL_X:
					color[i] = fabsf(isect.dg.nn.x);
					break;
				case DEBUG_GEOM_NORMAL_Y:
					color[i] = fabsf(isect.dg.nn.y);
					break;
				case DEBUG_GEOM_NORMAL_Z:
					color[i] = fabsf(isect.dg.nn.z);
					break;
				case DEBUG_SHAD_NORMAL_X:
					color[i] = fabsf(bsdf->dgShading.nn.x);
					break;
				case DEBUG_SHAD_NORMAL_Y:
					color[i] = fabsf(bsdf->dgShading.nn.y);
					break;
				case DEBUG_SHAD_NORMAL_Z:
					color[i] = fabsf(bsdf->dgShading.nn.z);
					break;
				default:
					break;
			}
		}
		if (color[i] < 0)
		{
			Severe( "i = %d\ndebug_variable[i] = %d\nhit_something = %d\ncolor[i] = %f", i, debug_variable[i], hitSomething, color[i] );
		}
	}

	L = Spectrum(color);
	return L;
}

extern "C" DLLEXPORT SurfaceIntegrator *CreateSurfaceIntegrator(const ParamSet &params)
{
	string strs[3];
	strs[0] = params.FindOneString( "red", "u" );
	strs[1] = params.FindOneString( "green", "v" );
	strs[2] = params.FindOneString( "blue", "zero" );

	DebugVariable vars[3];

	int i;
	for (i = 0 ; i < 3 ; i++)
	{
		if (strs[i] == "u") { vars[i] = DEBUG_U; }
		else if (strs[i] == "v") { vars[i] = DEBUG_V; }
		else if (strs[i] == "nx") { vars[i] = DEBUG_GEOM_NORMAL_X; }
		else if (strs[i] == "ny") { vars[i] = DEBUG_GEOM_NORMAL_Y; }
		else if (strs[i] == "nz") { vars[i] = DEBUG_GEOM_NORMAL_Z; }
		else if (strs[i] == "snx") { vars[i] = DEBUG_SHAD_NORMAL_X; }
		else if (strs[i] == "sny") { vars[i] = DEBUG_SHAD_NORMAL_Y; }
		else if (strs[i] == "snz") { vars[i] = DEBUG_SHAD_NORMAL_Z; }
		else if (strs[i] == "hit") { vars[i] = DEBUG_HIT_SOMETHING; }
		else if (strs[i] == "zero") { vars[i] = DEBUG_ZERO; }
		else if (strs[i] == "one") { vars[i] = DEBUG_ONE; }
		else
		{
			Error( "Unknown debug type \"%s\", defaulting to zero.", strs[i].c_str() );
			vars[i] = DEBUG_ZERO;
		}
	}

	return new DebugIntegrator(vars);
}