Encapsulated GPC-based tesselation into a Tesselator class, which now also produces normalized UVs per vertex-texture pair and a list of Polygon structs with texture and vertex index data.

PS1BSP.vcxproj

@@ -144,6 +144,7 @@
     <ClCompile Include="gpc.cpp" />
     <ClCompile Include="lighting.cpp" />
     <ClCompile Include="main.cpp" />
+    <ClCompile Include="tesselate.cpp" />
     <ClCompile Include="texture.cpp" />
     <ClCompile Include="tim.cpp" />
   </ItemGroup>
@@ -160,6 +161,7 @@
     <ClInclude Include="rectpack\finders_interface.h" />
     <ClInclude Include="rectpack\insert_and_split.h" />
     <ClInclude Include="rectpack\rect_structs.h" />
+    <ClInclude Include="tesselate.h" />
     <ClInclude Include="texture.h" />
     <ClInclude Include="tim.h" />
   </ItemGroup>

PS1BSP.vcxproj.filters

@@ -33,6 +33,9 @@
     <ClCompile Include="gpc.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="tesselate.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="bsp.h">
@@ -77,6 +80,9 @@
     <ClInclude Include="gpc.h">
       <Filter>Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="tesselate.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <CopyFileToFolders Include="palette.lmp">

common.h

@@ -6,6 +6,7 @@
 #include <cmath>
 #include <cfloat>
 #include <vector>
+#include <map>
 #include <unordered_map>
 #include <unordered_set>
 
@@ -105,6 +106,17 @@ static bool operator==(const Vec3& lhs, const Vec3& rhs)
         fabs(rhs.z - lhs.z) < 0.001;
 }
 
+static bool operator<(const Vec3& lhs, const Vec3& rhs)
+{
+    if (fabs(rhs.x - lhs.x) < 0.001)
+        if (fabs(rhs.y - lhs.y) < 0.001)
+            return lhs.z < rhs.z;
+        else
+            return lhs.y < rhs.y;
+    else
+        return lhs.x < rhs.x;
+}
+
 static float halton(int32_t index, int32_t base)
 {
     float f = 1.0f, result = 0.0f;

main.cpp

@@ -4,12 +4,10 @@
 #include "ps1bsp.h"
 #include "lighting.h"
 #include "texture.h"
-#include "gpc.h"
+#include "tesselate.h"
 
 static char path[_MAX_PATH];
 
-void gpc_test(const world_t* world, const face_t* face);
-
 template<class TData> size_t writeMapData(const std::vector<TData>& data, ps1bsp_dentry_t& dentry, FILE* f)
 {
 	dentry.offset = (unsigned int)ftell(f);
@@ -110,6 +108,8 @@ int process_faces(const world_t* world, const std::vector<ps1bsp_texture_t>& tex
 
 		outVertices.push_back(outVertex);
 	}
+
+	Tesselator tesselator(world);
 	
 	// Convert faces defined by edges into faces defined by vertex indices
 	std::vector<ps1bsp_face_t> outFaces;
@@ -208,7 +208,7 @@ int process_faces(const world_t* world, const std::vector<ps1bsp_texture_t>& tex
 		outFace.center.pad = (short)(sqrt(area));
 		outFaces.push_back(outFace);
 
-		gpc_test(world, face);
+		auto tessPolys = tesselator.tesselateFace(face);
 	}
 
 	// Iterate over all faces again; now that we know the bounds of each face, we can calculate lighting for all of them
@@ -303,101 +303,6 @@ int process_faces(const world_t* world, const std::vector<ps1bsp_texture_t>& tex
 	return 1;
 }
 
-void gpc_test(const world_t* world, const face_t* face)
-{
-	const texinfo_t* texinfo = &world->texInfos[face->texinfo_id];
-	const miptex_t* miptex = &world->miptexes[texinfo->texture_id];
-	const plane_t* plane = &world->planes[face->plane_id];
-
-	double minS = DBL_MAX, minT = DBL_MAX;
-	double maxS = DBL_MIN, maxT = DBL_MIN;
-
-	gpc_polygon polygon = { 0 };
-	gpc_vertex_list contour;
-	contour.num_vertices = face->ledge_num;
-	contour.vertex = (gpc_vertex*)malloc(contour.num_vertices * sizeof(gpc_vertex));
-	if (contour.vertex == NULL)
-		return;
-
-	std::vector<Vec3> originalVecs;
-	for (int edgeListIdx = 0; edgeListIdx < face->ledge_num; ++edgeListIdx)
-	{
-		int edgeIdx = world->edgeList[face->ledge_id + edgeListIdx];
-
-		unsigned short vertIndex = edgeIdx > 0 ?
-			world->edges[edgeIdx].vertex0 :
-			world->edges[-edgeIdx].vertex1;
-
-		const vertex_t* vertex = &world->vertices[vertIndex];
-		Vec3 vertexPoint = vertex->toVec();
-		originalVecs.push_back(vertexPoint);
-
-		// Calculate texture UV bounds
-		double s = (vertexPoint.dotProduct(texinfo->vectorS) + texinfo->distS) / miptex->width;
-		double t = (vertexPoint.dotProduct(texinfo->vectorT) + texinfo->distT) / miptex->height;
-		if (s > maxS) maxS = s; if (s < minS) minS = s;
-		if (t > maxT) maxT = t; if (t < minT) minT = t;
-
-		contour.vertex[edgeListIdx] = gpc_vertex{ s, t };
-	}
-
-	gpc_add_contour(&polygon, &contour, 0);
-
-	std::vector<Vec3> vertices;
-	std::unordered_map<Vec3, size_t> vertexIndices;
-
-	// Create a virtual grid at the texture bounds and iterate over each cell to break up the face into repeating tiles
-	for (double y = floor(minT); y <= ceil(maxT); y += 1.0)
-	{
-		for (double x = floor(minS); x <= ceil(maxS); x += 1.0)
-		{
-			// Create a square polygon that covers the entire cell
-			gpc_polygon cell = { 0 };
-			gpc_vertex_list cell_bounds;
-			cell_bounds.num_vertices = 4;
-			cell_bounds.vertex = (gpc_vertex*)malloc(4 * sizeof(gpc_vertex));
-			cell_bounds.vertex[0] = gpc_vertex{ x, y };
-			cell_bounds.vertex[1] = gpc_vertex{ x + 1.0, y };
-			cell_bounds.vertex[2] = gpc_vertex{ x + 1.0, y + 1.0 };
-			cell_bounds.vertex[3] = gpc_vertex{ x, y + 1.0 };
-			gpc_add_contour(&cell, &cell_bounds, 0);
-			
-			// Take the intersection to get the chunk of the face that's inside this cell
-			gpc_polygon result;
-			gpc_polygon_clip(GPC_INT, &polygon, &cell, &result);
-
-			// We should get a polygon with exactly one contour as a result; if not, the face was not on this grid cell
-			if (result.num_contours <= 0)
-				continue;
-			
-			// Reconstruct the polygon's vertices in world space
-			for (int v = 0; v < result.contour[0].num_vertices; ++v)
-			{
-				const auto vert = &result.contour[0].vertex[v];
-				Vec3 newVert = 
-					plane->normal * plane->dist +
-					texinfo->vectorS * (float)(vert->x * miptex->width - texinfo->distS) +
-					texinfo->vectorT * (float)(vert->y * miptex->height - texinfo->distT);
-
-				// Make sure we don't store duplicate vertices
-				auto vertIter = vertexIndices.find(newVert);
-				if (vertIter == vertexIndices.end())
-				{
-					vertexIndices[newVert] = vertices.size();
-					vertices.push_back(newVert);
-				}
-
-				// Store the relevant (S, T) coordinates for each vertex-texinfo pair
-			}
-			
-			gpc_free_polygon(&result);
-			gpc_free_polygon(&cell);
-		}
-	}
-
-	gpc_free_polygon(&polygon);
-}
-
 int process_bsp(const world_t *world)
 {
 	// Test exporting texture data

tesselate.cpp

@@ -0,0 +1,119 @@
+#include "common.h"
+#include "bsp.h"
+#include "tesselate.h"
+#include "gpc.h"
+
+std::vector<Tesselator::Polygon> Tesselator::tesselateFace(const face_t* face)
+{
+	std::vector<Polygon> polygons;
+
+	const texinfo_t* texinfo = &world->texInfos[face->texinfo_id];
+	const miptex_t* miptex = &world->miptexes[texinfo->texture_id];
+	const plane_t* plane = &world->planes[face->plane_id];
+
+	double minS = DBL_MAX, minT = DBL_MAX;
+	double maxS = DBL_MIN, maxT = DBL_MIN;
+
+	gpc_polygon facePolygon = { 0 };
+	gpc_vertex_list contour;
+	contour.num_vertices = face->ledge_num;
+	contour.vertex = (gpc_vertex*)malloc(contour.num_vertices * sizeof(gpc_vertex));
+	if (contour.vertex == NULL)
+		return polygons;
+
+	// Build a polygon in normalized 2D texture space from the original face data
+	for (int edgeListIdx = 0; edgeListIdx < face->ledge_num; ++edgeListIdx)
+	{
+		int edgeIdx = world->edgeList[face->ledge_id + edgeListIdx];
+
+		unsigned short vertIndex = edgeIdx > 0 ?
+			world->edges[edgeIdx].vertex0 :
+			world->edges[-edgeIdx].vertex1;
+
+		const vertex_t* vertex = &world->vertices[vertIndex];
+		Vec3 vertexPoint = vertex->toVec();
+
+		// Calculate texture UV bounds
+		double s = (vertexPoint.dotProduct(texinfo->vectorS) + texinfo->distS) / miptex->width;
+		double t = (vertexPoint.dotProduct(texinfo->vectorT) + texinfo->distT) / miptex->height;
+		if (s > maxS) maxS = s; if (s < minS) minS = s;
+		if (t > maxT) maxT = t; if (t < minT) minT = t;
+
+		contour.vertex[edgeListIdx] = gpc_vertex{ s, t };
+	}
+
+	gpc_add_contour(&facePolygon, &contour, 0);
+
+	// Create a virtual grid at the texture bounds and iterate over each cell to break up the face into repeating tiles
+	for (double y = floor(minT); y <= ceil(maxT); y += 1.0)
+	{
+		for (double x = floor(minS); x <= ceil(maxS); x += 1.0)
+		{
+			// Create a square polygon that covers the entire cell
+			gpc_polygon cell = { 0 };
+			gpc_vertex_list cell_bounds;
+			cell_bounds.num_vertices = 4;
+			cell_bounds.vertex = (gpc_vertex*)malloc(4 * sizeof(gpc_vertex));
+			cell_bounds.vertex[0] = gpc_vertex{ x, y };
+			cell_bounds.vertex[1] = gpc_vertex{ x + 1.0, y };
+			cell_bounds.vertex[2] = gpc_vertex{ x + 1.0, y + 1.0 };
+			cell_bounds.vertex[3] = gpc_vertex{ x, y + 1.0 };
+			gpc_add_contour(&cell, &cell_bounds, 0);
+
+			// Take the intersection to get the chunk of the face that's inside this cell
+			gpc_polygon result;
+			gpc_polygon_clip(GPC_INT, &facePolygon, &cell, &result);
+
+			// We should get a polygon with exactly one contour as a result; if not, the face was not on this grid cell
+			if (result.num_contours <= 0)
+				continue;
+
+			Polygon newPoly;
+			newPoly.texinfo = texinfo;
+
+			// Reconstruct the polygon's vertices in 3D world space
+			for (int v = 0; v < result.contour[0].num_vertices; ++v)
+			{
+				const auto vert = &result.contour[0].vertex[v];
+				Vec3 newVert =
+					plane->normal * plane->dist +
+					texinfo->vectorS * (float)(vert->x * miptex->width - texinfo->distS) +
+					texinfo->vectorT * (float)(vert->y * miptex->height - texinfo->distT);
+
+				// Make sure we don't store duplicate vertices
+				size_t vertexIndex;
+				auto vertIter = vertexIndices.find(newVert);
+				if (vertIter != vertexIndices.end())
+				{
+					vertexIndex = vertIter->second;
+				}
+				else
+				{
+					vertexIndex = vertices.size();
+					vertexIndices[newVert] = vertexIndex;
+					vertices.push_back(newVert);
+				}
+
+				newPoly.indices.push_back(vertexIndex);
+
+				// Store the relevant (S, T) coordinates for each vertex-texinfo pair
+				VertexTexturePair uvPair{ newVert, texinfo };
+				auto vertUVIter = vertexUVs.find(uvPair);
+				if (vertUVIter == vertexUVs.end())
+				{
+					// Normalize the UV to fall within [0..1] range
+					Vec3 uv(vert->x - x, vert->y - y, 0);
+					vertexUVs[uvPair] = uv;
+				}
+			}
+
+			polygons.push_back(newPoly);
+
+			gpc_free_polygon(&result);
+			gpc_free_polygon(&cell);
+		}
+	}
+
+	gpc_free_polygon(&facePolygon);
+	return polygons;
+}

tesselate.h

@@ -0,0 +1,33 @@
+#pragma once
+
+class Tesselator
+{
+public:
+	typedef std::vector<Vec3> VertexList;
+	typedef std::unordered_map<Vec3, size_t> VertexIndexMap;
+	typedef std::pair<Vec3, const texinfo_t*> VertexTexturePair;
+	typedef std::map<VertexTexturePair, Vec3> VertexUVMap;
+
+	struct Polygon
+	{
+		const texinfo_t* texinfo;
+		std::vector<size_t> indices;
+	};
+
+	Tesselator(const world_t* world) : world(world)
+	{
+	}
+
+	const VertexList& getVertices() const { return vertices; }
+	const VertexIndexMap& getVertexIndices() const { return vertexIndices; }
+	const VertexUVMap& getVertexUVs() const { return vertexUVs; }
+
+	std::vector<Polygon> tesselateFace(const face_t* face);
+
+private:
+	const world_t* world;
+
+	VertexList vertices;
+	VertexIndexMap vertexIndices;
+	VertexUVMap vertexUVs;
+};