Rename surface map to collision mesh (#637)

include/common_structs.h

@@ -203,15 +203,17 @@ typedef struct {
         //bit 4: 1 = out of bounds
         //bit 3: 1 = player tumbles upon contact (may fall right through)
     /* 0x02 */ u16 surfaceType;
-    /* 0x04 */ s16 vtx31;
-               s16 vtx32;
-               s16 vtx33; //X, Y, Z of poly's third vertex
-               s16 vtx21;
-               s16 vtx22;
-    /* 0x0A */ s16 vtx23; //X, Y, Z of poly's second vertex
-    /* 0x10 */ Vtx *vtxPoly1; //pointer to the 3 vertices of this poly
-               Vtx *vtxPoly2;
-               Vtx *vtxPoly3;
+
+        // For AABB bounding-box style collision. Box style collision is cheaper than checking each vtx.
+    /* 0x04 */ s16 minX; // Minimum x coordinate
+               s16 minY; // Minimum y coordinate
+               s16 minZ; // Minimum z coordinate
+               s16 maxX; // Maximum x coordinate
+               s16 maxY; // Maximum y coordinate
+    /* 0x0A */ s16 maxZ; // Maximum z coordinate
+    /* 0x10 */ Vtx *vtx1; //pointer to the 3 vertices of this poly
+               Vtx *vtx2;
+               Vtx *vtx3;
         //unsure why this exists along with a copy of two of the vertices.
         //both are involved in hit detection.
     /* 0x1C */ f32 height;
@@ -227,17 +229,17 @@ typedef struct {
     /* 0x24 */ f32 rotation; //normally about -0.001. no idea what this actually is.
     /* 0x28 */ f32 height2; //changes Y position of all vertices (but not graphics or
         //Lakitu drop position). Normally set to (track_height * -1) + about 6.
-} mk64_surface_map_ram; // size = 0x2C
+} CollisionTriangle; // size = 0x2C
 
 typedef struct {
     /* 0x00 */ Vec3f cornerPos;
     // Type of surface the corner is above
     /* 0x0C */ u8  surfaceType;
-    // Close to being a copy of the top byte of the surface_map "flag" member
+    // Close to being a copy of the top byte of the CollisionTriangle "flags" member
     /* 0x0D */ u8  surfaceFlags;
     // Don't know if "tile" is right the right term
-    // gSurfaceMap is a pointer to an array of "tile" structs. This is an index to that array
-    /* 0x0E */ u16 surfaceMapIndex;
+    // gCollisionMesh is a pointer to an array of "tile" structs. This is an index to that array
+    /* 0x0E */ u16 collisionMeshIndex;
     // cornerPos places the corner "in the air" as it were, this member indicates the Y position of the corner's "on the ground" sibling
     // On flat ground this value should be cornerY - gKartBoundingBoxTable[characterId]
     /* 0x10 */ f32 cornerGroundY;