Add a new raytracer that bounces using path tracing

src/framework/tarray.h

@@ -274,8 +274,14 @@ public:
 	// returns address of first element
 	T* Data() const
 	{
-		return &Array[0];
+		return Array;
 	}
+
+	T* begin() { return Array; }
+	T* end() { return Array + Count; }
+	const T* begin() const { return Array; }
+	const T* end() const { return Array + Count; }
+
 private:
 	T *Array;
 	unsigned int Most;

src/framework/templates.h

@@ -179,3 +179,15 @@ T clamp (const T in, const T min, const T max)
 {
 	return in <= min ? min : in >= max ? max : in;
 }
+
+template<class T>
+T smoothstep(const T edge0, const T edge1, const T x)
+{
+	auto t = clamp<T>((x - edge0) / (edge1 - edge0), T(0.0), T(1.0));
+	return t * t * (T(3.0) - T(2.0) * t);
+}
+
+inline float radians(float degrees)
+{
+	return degrees * 3.14159265359f / 180.0f;
+}

src/level/doomdata.h

@@ -2,10 +2,14 @@
 #pragma once
 
 #include "framework/tarray.h"
+#include "framework/templates.h"
 #include "math/mathlib.h"
 #include <memory>
+#include <cmath>
 #undef MIN
 #undef MAX
+#undef min
+#undef max
 
 enum
 {
@@ -271,6 +275,44 @@ struct ThingLight
 	bool            bCeiling;
 	IntSector       *sector;
 	MapSubsectorEx  *ssect;
+
+	Vec3 LightOrigin() const
+	{
+		float originZ;
+		if (!bCeiling)
+			originZ = sector->floorplane.zAt(origin.x, origin.y) + height;
+		else
+			originZ = sector->ceilingplane.zAt(origin.x, origin.y) - height;
+		return Vec3(origin.x, origin.y, originZ);
+	}
+
+	float LightRadius() const
+	{
+		return radius + radius; // 2.0 because gzdoom's dynlights do this and we want them to match
+	}
+
+	float SpotAttenuation(const Vec3& dir) const
+	{
+		float spotAttenuation = 1.0f;
+		if (outerAngleCos > -1.0f)
+		{
+			float negPitch = -radians(mapThing->pitch);
+			float xyLen = std::cos(negPitch);
+			Vec3 spotDir;
+			spotDir.x = -std::cos(radians(mapThing->angle)) * xyLen;
+			spotDir.y = -std::sin(radians(mapThing->angle)) * xyLen;
+			spotDir.z = -std::sin(negPitch);
+			float cosDir = Vec3::Dot(dir, spotDir);
+			spotAttenuation = smoothstep(outerAngleCos, innerAngleCos, cosDir);
+			spotAttenuation = std::max(spotAttenuation, 0.0f);
+		}
+		return spotAttenuation;
+	}
+
+	float DistAttenuation(float distance) const
+	{
+		return std::max(1.0f - (distance / LightRadius()), 0.0f);
+	}
 };
 
 struct SurfaceLightDef

src/level/level.cpp

@@ -20,6 +20,7 @@
 
 #include "level/level.h"
 #include "lightmap/lightmap.h"
+#include "lightmap/raytracer.h"
 //#include "rejectbuilder.h"
 #include <memory>
 
@@ -690,8 +691,13 @@ void FProcessor::BuildLightmaps()
 {
 	Level.SetupLights();
 	LightmapMesh = std::make_unique<LevelMesh>(Level, Samples, LMDims);
+#if 1
 	DLightRaytracer raytracer;
 	raytracer.Raytrace(LightmapMesh.get());
+#else
+	Raytracer raytracer;
+	raytracer.Raytrace(LightmapMesh.get());
+#endif
 	LightmapMesh->CreateTextures();
 }
 

src/lightmap/lightmap.cpp

@@ -121,18 +121,6 @@ bool DLightRaytracer::EmitFromCeiling(const Surface *surface, const Vec3 &origin
 	return true;
 }
 
-template<class T>
-T smoothstep(const T edge0, const T edge1, const T x)
-{
-	auto t = clamp<T>((x - edge0) / (edge1 - edge0), 0.0, 1.0);
-	return t * t * (3.0 - 2.0 * t);
-}
-
-static float radians(float degrees)
-{
-	return degrees * 3.14159265359f / 180.0f;
-}
-
 // Traces a line from the texel's origin to the sunlight direction and against all nearby thing lights
 Vec3 DLightRaytracer::LightTexelSample(const Vec3 &origin, Surface *surface)
 {
@@ -147,13 +135,7 @@ Vec3 DLightRaytracer::LightTexelSample(const Vec3 &origin, Surface *surface)
 	{
 		ThingLight *tl = &mesh->map->ThingLights[i];
 
-		float originZ;
-		if (!tl->bCeiling)
-			originZ = tl->sector->floorplane.zAt(tl->origin.x, tl->origin.y) + tl->height;
-		else
-			originZ = tl->sector->ceilingplane.zAt(tl->origin.x, tl->origin.y) - tl->height;
-
-		Vec3 lightOrigin(tl->origin.x, tl->origin.y, originZ);
+		Vec3 lightOrigin = tl->LightOrigin();
 
 		if (surface && plane.Distance(lightOrigin) - plane.d < 0)
 		{
@@ -161,8 +143,7 @@ Vec3 DLightRaytracer::LightTexelSample(const Vec3 &origin, Surface *surface)
 			continue;
 		}
 
-		float radius = tl->radius * 2.0f; // 2.0 because gzdoom's dynlights do this and we want them to match
-		float intensity = tl->intensity;
+		float radius = tl->LightRadius();
 
 		if (origin.DistanceSq(lightOrigin) > (radius*radius))
 		{
@@ -174,23 +155,9 @@ Vec3 DLightRaytracer::LightTexelSample(const Vec3 &origin, Surface *surface)
 		float dist = dir.Unit();
 		dir.Normalize();
 
-		float spotAttenuation = 1.0f;
-		if (tl->outerAngleCos > -1.0f)
-		{
-			float negPitch = -radians(tl->mapThing->pitch);
-			float xyLen = std::cos(negPitch);
-			Vec3 spotDir;
-			spotDir.x = -std::cos(radians(tl->mapThing->angle)) * xyLen;
-			spotDir.y = -std::sin(radians(tl->mapThing->angle)) * xyLen;
-			spotDir.z = -std::sin(negPitch);
-			float cosDir = Vec3::Dot(dir, spotDir);
-			spotAttenuation = smoothstep(tl->outerAngleCos, tl->innerAngleCos, cosDir);
-			if (spotAttenuation <= 0.0f)
-			{
-				// outside spot light
+		float spotAttenuation = tl->SpotAttenuation(dir);
+		if (spotAttenuation == 0.0f)
 			continue;
-			}
-		}
 
 		if (mesh->TraceAnyHit(lightOrigin, origin))
 		{
@@ -202,7 +169,7 @@ Vec3 DLightRaytracer::LightTexelSample(const Vec3 &origin, Surface *surface)
 		attenuation *= spotAttenuation;
 		if (surface)
 			attenuation *= plane.Normal().Dot(dir);
-		attenuation *= intensity;
+		attenuation *= tl->intensity;
 
 		// accumulate results
 		color += tl->rgb * attenuation;

src/lightmap/raytracer.cpp

@@ -28,4 +28,231 @@ Raytracer::~Raytracer()
 void Raytracer::Raytrace(LevelMesh* level)
 {
 	mesh = level;
+
+	printf("Tracing light probes\n");
+
+	Worker::RunJob((int)mesh->lightProbes.size(), [=](int id) {
+		RaytraceProbeSample(&mesh->lightProbes[id]);
+	});
+
+	printf("Tracing surfaces (%d bounces)\n", LightBounce);
+
+	struct SurfaceTask
+	{
+		int surf, x, y;
+	};
+	std::vector<SurfaceTask> tasks;
+
+	for (size_t i = 0; i < mesh->surfaces.size(); i++)
+	{
+		Surface* surface = mesh->surfaces[i].get();
+		int sampleWidth = surface->lightmapDims[0];
+		int sampleHeight = surface->lightmapDims[1];
+		for (int y = 0; y < sampleHeight; y++)
+		{
+			for (int x = 0; x < sampleWidth; x++)
+			{
+				SurfaceTask task;
+				task.surf = (int)i;
+				task.x = x;
+				task.y = y;
+				tasks.push_back(task);
+			}
+		}
+	}
+
+	Worker::RunJob((int)tasks.size(), [=](int id) {
+		const SurfaceTask& task = tasks[id];
+		RaytraceSurfaceSample(mesh->surfaces[task.surf].get(), task.x, task.y);
+	});
+
+	printf("Raytrace complete\n");
+}
+
+void Raytracer::RaytraceProbeSample(LightProbeSample* probe)
+{
+	Vec3 color(0.0f, 0.0f, 0.0f);
+
+	for (ThingLight& light : mesh->map->ThingLights)
+	{
+		Vec3 lightOrigin = light.LightOrigin();
+		float lightRadius = light.LightRadius();
+
+		if (probe->Position.DistanceSq(lightOrigin) > (lightRadius * lightRadius))
+			continue;
+
+		if (mesh->TraceAnyHit(lightOrigin, probe->Position))
+			continue; // this light is occluded by something
+
+		Vec3 dir = (lightOrigin - probe->Position);
+		float dist = dir.Unit();
+		dir.Normalize();
+
+		color += light.rgb * (light.SpotAttenuation(dir) * light.DistAttenuation(dist) * light.intensity);
+	}
+
+	probe->Color = color;
+}
+
+void Raytracer::RaytraceSurfaceSample(Surface* surface, int x, int y)
+{
+	Vec3 normal = surface->plane.Normal();
+	Vec3 pos = surface->lightmapOrigin + normal + surface->lightmapSteps[0] * (float)x + surface->lightmapSteps[1] * (float)y;
+
+	Vec3 incoming(0.0f, 0.0f, 0.0f);
+	if (LightBounce > 0)
+	{
+		float totalWeight = 0.0f;
+		for (int i = 0; i < SAMPLE_COUNT; i++)
+		{
+			Vec2 Xi = Hammersley(i, SAMPLE_COUNT);
+			Vec3 H = ImportanceSampleGGX(Xi, normal, 1.0f);
+			Vec3 L = Vec3::Normalize(H * (2.0f * Vec3::Dot(normal, H)) - normal);
+			float NdotL = std::max(Vec3::Dot(normal, L), 0.0f);
+			if (NdotL > 0.0f)
+			{
+				incoming += TracePath(pos, L, i) * NdotL;
+				totalWeight += NdotL;
+			}
+		}
+		incoming = incoming / totalWeight / (float)LightBounce;
+	}
+
+	incoming = incoming + GetSurfaceEmittance(surface, 0.0f) + GetLightEmittance(surface, pos);
+
+	size_t sampleWidth = surface->lightmapDims[0];
+	surface->samples[x + y * sampleWidth] = incoming;
+}
+
+Vec3 Raytracer::GetLightEmittance(Surface* surface, const Vec3& pos)
+{
+	Vec3 emittance = Vec3(0.0f);
+	for (ThingLight& light : mesh->map->ThingLights)
+	{
+		Vec3 lightOrigin = light.LightOrigin();
+		float lightRadius = light.LightRadius();
+
+		if (surface->plane.Distance(lightOrigin) - surface->plane.d < 0)
+			continue; // completely behind the plane
+
+		if (pos.DistanceSq(lightOrigin) > (lightRadius * lightRadius))
+			continue; // light too far away
+
+		Vec3 dir = (lightOrigin - pos);
+		float dist = dir.Unit();
+		dir.Normalize();
+
+		float attenuation = light.SpotAttenuation(dir) * light.DistAttenuation(dist) * surface->plane.Normal().Dot(dir);
+		if (attenuation <= 0.0f)
+			continue;
+
+		if (mesh->TraceAnyHit(lightOrigin, pos))
+			continue; // this light is occluded by something
+
+		emittance += light.rgb * (attenuation * light.intensity);
+	}
+	return emittance;
+}
+
+Vec3 Raytracer::TracePath(const Vec3& pos, const Vec3& dir, int sampleIndex, int depth)
+{
+	if (depth >= LightBounce)
+		return Vec3(0.0f);
+
+	LevelTraceHit hit = mesh->Trace(pos, pos + dir * 1000.0f);
+	if (hit.fraction == 1.0f)
+		return Vec3(0.0f);
+
+	Vec3 normal = hit.hitSurface->plane.Normal();
+	Vec3 hitpos = hit.start * (1.0f - hit.fraction) + hit.end * hit.fraction + normal * 0.1f;
+
+	Vec3 emittance = GetSurfaceEmittance(hit.hitSurface, pos.Distance(hitpos)) + GetLightEmittance(hit.hitSurface, hitpos) * 0.5f;
+
+	Vec2 Xi = Hammersley(sampleIndex, SAMPLE_COUNT);
+	Vec3 H = ImportanceSampleGGX(Xi, normal, 1.0f);
+	Vec3 L = Vec3::Normalize(H * (2.0f * Vec3::Dot(normal, H)) - normal);
+
+	float NdotL = std::max(Vec3::Dot(normal, L), 0.0f);
+	if (NdotL <= 0.0f)
+		return emittance;
+
+	const float p = 1 / (2 * M_PI);
+	Vec3 incoming = TracePath(hitpos, normal, (sampleIndex + depth + 1) % SAMPLE_COUNT, depth + 1);
+
+	return emittance + incoming * NdotL / p;
+}
+
+float Raytracer::RadicalInverse_VdC(uint32_t bits)
+{
+	bits = (bits << 16u) | (bits >> 16u);
+	bits = ((bits & 0x55555555u) << 1u) | ((bits & 0xAAAAAAAAu) >> 1u);
+	bits = ((bits & 0x33333333u) << 2u) | ((bits & 0xCCCCCCCCu) >> 2u);
+	bits = ((bits & 0x0F0F0F0Fu) << 4u) | ((bits & 0xF0F0F0F0u) >> 4u);
+	bits = ((bits & 0x00FF00FFu) << 8u) | ((bits & 0xFF00FF00u) >> 8u);
+	return float(bits) * 2.3283064365386963e-10f; // / 0x100000000
+}
+
+Vec2 Raytracer::Hammersley(uint32_t i, uint32_t N)
+{
+	return Vec2(float(i) / float(N), RadicalInverse_VdC(i));
+}
+
+Vec3 Raytracer::ImportanceSampleGGX(Vec2 Xi, Vec3 N, float roughness)
+{
+	float a = roughness * roughness;
+
+	float phi = 2.0f * M_PI * Xi.x;
+	float cosTheta = sqrt((1.0f - Xi.y) / (1.0f + (a * a - 1.0f) * Xi.y));
+	float sinTheta = sqrt(1.0f - cosTheta * cosTheta);
+
+	// from spherical coordinates to cartesian coordinates
+	Vec3 H(std::cos(phi) * sinTheta, std::sin(phi) * sinTheta, cosTheta);
+
+	// from tangent-space vector to world-space sample vector
+	Vec3 up = std::abs(N.z) < 0.999f ? Vec3(0.0f, 0.0f, 1.0f) : Vec3(1.0f, 0.0f, 0.0f);
+	Vec3 tangent = Vec3::Normalize(Vec3::Cross(up, N));
+	Vec3 bitangent = Vec3::Cross(N, tangent);
+
+	Vec3 sampleVec = tangent * H.x + bitangent * H.y + N * H.z;
+	return Vec3::Normalize(sampleVec);
+}
+
+Vec3 Raytracer::GetSurfaceEmittance(Surface* surface, float distance)
+{
+	SurfaceLightDef* def = nullptr;
+	if (surface->type >= ST_MIDDLESIDE && surface->type <= ST_LOWERSIDE)
+	{
+		int lightdefidx = mesh->map->Sides[surface->typeIndex].lightdef;
+		if (lightdefidx != -1)
+		{
+			def = &mesh->map->SurfaceLights[lightdefidx];
+		}
+	}
+	else if (surface->type == ST_FLOOR || surface->type == ST_CEILING)
+	{
+		MapSubsectorEx* sub = &mesh->map->GLSubsectors[surface->typeIndex];
+		IntSector* sector = mesh->map->GetSectorFromSubSector(sub);
+
+		if (sector && surface->numVerts > 0)
+		{
+			if (sector->floorlightdef != -1 && surface->type == ST_FLOOR)
+			{
+				def = &mesh->map->SurfaceLights[sector->floorlightdef];
+			}
+			else if (sector->ceilinglightdef != -1 && surface->type == ST_CEILING)
+			{
+				def = &mesh->map->SurfaceLights[sector->ceilinglightdef];
+			}
+		}
+	}
+
+	if (def)
+	{
+		float attenuation = std::max(1.0f - (distance / def->distance), 0.0f);
+		return def->rgb * (attenuation * def->intensity);
+	}
+	else
+	{
+		return Vec3(0.0f);
+	}
 }

src/lightmap/raytracer.h

@@ -12,5 +12,18 @@ public:
 	void Raytrace(LevelMesh* level);
 
 private:
+	void RaytraceProbeSample(LightProbeSample* probe);
+	void RaytraceSurfaceSample(Surface* surface, int x, int y);
+	Vec3 TracePath(const Vec3& pos, const Vec3& dir, int sampleIndex, int depth = 0);
+
+	Vec3 GetLightEmittance(Surface* surface, const Vec3& pos);
+	Vec3 GetSurfaceEmittance(Surface* surface, float distance);
+
+	static float RadicalInverse_VdC(uint32_t bits);
+	static Vec2 Hammersley(uint32_t i, uint32_t N);
+	static Vec3 ImportanceSampleGGX(Vec2 Xi, Vec3 N, float roughness);
+
+	int SAMPLE_COUNT = 1024;// 128;// 1024;
+
 	LevelMesh* mesh = nullptr;
 };

src/main.cpp

@@ -457,7 +457,7 @@ static void ParseArgs(int argc, char **argv)
 		case 'B':
 			LightBounce = atoi(optarg);
 			if (LightBounce < 0) LightBounce = 0;
-			if (LightBounce > 1) LightBounce = 1;
+			if (LightBounce > 8) LightBounce = 8;
 			break;
 		case 'i':
 			GridSize = std::stof(optarg);
@@ -510,7 +510,7 @@ static void ShowUsage()
 		"  -S, --size=NNN           lightmap texture dimensions for width and height\n"
 		"                           must be in powers of two (1, 2, 4, 8, 16, etc)\n"
 		"  -M, --multisample=NNN    Number of samples to use per texel (default %d)\n"
-		"  -B, --bounce=NNN         Number of indirect light bounces (default %d, max 1)\n"
+		"  -B, --bounce=NNN         Number of indirect light bounces (default %d, max 8)\n"
 		"  -i, --gridsize=NNN       Automatic light probe grid size, floating point\n"
 		"                           Lower values increase granularity at the expense of performance\n"
 		"                           Recommended: 32.0, 64.0, 128.0, etc (default %.1f)\n"