Faces now have a vertex index list, which is more space-efficient and allows easy rewrites of polygon topology.

Also works quite well with the scratchpad RAM setup.

ps1bsp.h

@@ -22,7 +22,7 @@ Probable rendering process:
 typedef struct
 {
 	unsigned short numVertices;
-	unsigned short numTriangles;
+	unsigned short numFaceVertIndices;
 	unsigned short numFaces;
 } ps1bsp_header_t;
 
@@ -62,11 +62,8 @@ typedef struct
 
 typedef struct
 {
-	unsigned short firstTriangleId;	// TODO: could also just do first-index, num-indices here. No real need for a triangle_t struct.
-	unsigned short numTriangles;
-
-	unsigned short firstQuadId;		// For if/when we decide to add quads to the mix
-	unsigned short numQuads;
+	unsigned short firstVertexIndex;
+	unsigned short numVertices;
 } ps1bsp_face_t;
 
 // Pre-parsed and encoded entity data (this runs the risk of becoming too bloated)

world.c

@@ -31,8 +31,8 @@ void world_load(const u_long *data, world_t *world)
     world->vertices = (ps1bsp_vertex_t*)bytes;
     bytes += sizeof(ps1bsp_vertex_t) * world->header->numVertices;
 
-    world->triangles = (ps1bsp_triangle_t*)bytes;
-    bytes += sizeof(ps1bsp_triangle_t) * world->header->numTriangles;
+    world->faceVertIndices = (unsigned short*)bytes;
+    bytes += sizeof(unsigned short) * world->header->numFaceVertIndices;
 
     world->faces = (ps1bsp_face_t*)bytes;
     bytes += sizeof(ps1bsp_face_t) * world->header->numFaces;
@@ -46,35 +46,26 @@ void world_draw(const world_t *world)
     gte_SetRotMatrix(&vp_matrix);
 	gte_SetTransMatrix(&vp_matrix);
 
-    char *scratch = scratchpad;
-    SVECTOR *vecs = (SVECTOR*)mem_scratch(&scratch, sizeof(SVECTOR) * 3);
-
     for (int faceIdx = 0; faceIdx < world->header->numFaces; ++faceIdx)
     {
         const ps1bsp_face_t *face = &world->faces[faceIdx];
         const CVECTOR *col = &colors[faceIdx % numColors];
 
-        const ps1bsp_triangle_t *tri = &world->triangles[face->firstTriangleId];
-        for (int triangleIdx = 0; triangleIdx < face->numTriangles; ++triangleIdx, ++tri)
+        char *scratch = scratchpad;
+        SVECTOR *vecs = (SVECTOR*)mem_scratch(&scratch, sizeof(SVECTOR) * face->numVertices);
+
+        // Copy this face's vertices into scratch RAM for fast reuse
+        unsigned short *faceVertIndex = &world->faceVertIndices[face->firstVertexIndex];
+        for (int vertIdx = 0; vertIdx < face->numVertices; ++vertIdx, ++faceVertIndex)
         {
-            // Naively draw the triangle with GTE, nothing special or optimized about this
-            const ps1bsp_vertex_t *v0 = &world->vertices[tri->vertex0];
-            const ps1bsp_vertex_t *v1 = &world->vertices[tri->vertex1];
-            const ps1bsp_vertex_t *v2 = &world->vertices[tri->vertex2];
-
-            vecs[0].vx = v0->x; vecs[0].vy = v0->y; vecs[0].vz = v0->z;
-            vecs[1].vx = v1->x; vecs[1].vy = v1->y; vecs[1].vz = v1->z;
-            vecs[2].vx = v2->x; vecs[2].vy = v2->y; vecs[2].vz = v2->z;
-            gte_ldv3c(vecs);
-
-            // This method *should* work but it doesn't on real hardware, for some reason.
-            // Perhaps the PS1 doesn't like loading data from random far-off memory locations directly into GTE registers?
-            // We probably want to use the scratchpad memory to prepare the vertex data for the GTE anyway.
-            // SVECTOR *v0 = (SVECTOR*)&world->vertices[tri->vertex0];
-            // SVECTOR *v1 = (SVECTOR*)&world->vertices[tri->vertex1];
-            // SVECTOR *v2 = (SVECTOR*)&world->vertices[tri->vertex2];
-            // gte_ldv3(v0, v1, v2);
+            vecs[vertIdx] = *((SVECTOR*)&world->vertices[*faceVertIndex]);
+        }
 
+        // Draw the face as a triangle fan
+        for (int vertIdx = 1; vertIdx < face->numVertices - 1; ++vertIdx)
+        {
+            // Naively draw the triangle with GTE, nothing special or optimized about this
+            gte_ldv3(&vecs[0], &vecs[vertIdx], &vecs[vertIdx + 1]);
             gte_rtpt();     // Rotation, translation, perspective projection
 
             // Normal clipping for backface culling

world.h

@@ -7,7 +7,7 @@ typedef struct
 {
     ps1bsp_header_t *header;
     ps1bsp_vertex_t *vertices;
-    ps1bsp_triangle_t *triangles;
+    unsigned short *faceVertIndices;
     ps1bsp_face_t *faces;
 } world_t;