diff options
Diffstat (limited to 'backend/update.go')
| -rw-r--r-- | backend/update.go | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/backend/update.go b/backend/update.go new file mode 100644 index 0000000..d51b115 --- /dev/null +++ b/backend/update.go @@ -0,0 +1,179 @@ +package backend + +import ( + "database/sql" + "fmt" + "git.darknebu.la/GalaxySimulator/structs" + "log" +) + +// updateTotalMass gets a tree index and returns the nodeID of the trees root node +func UpdateTotalMass(database *sql.DB, index int64) { + db = database + rootNodeID := getRootNodeID(index) + log.Printf("RootID: %d", rootNodeID) + updateTotalMassNode(rootNodeID) +} + +// updateTotalMassNode updates the total mass of the given node +func updateTotalMassNode(nodeID int64) float64 { + var totalmass float64 + + // get the subnode ids + var subnode [4]int64 + + query := fmt.Sprintf("SELECT subnode[1], subnode[2], subnode[3], subnode[4] FROM nodes WHERE node_id=%d", nodeID) + err := db.QueryRow(query).Scan(&subnode[0], &subnode[1], &subnode[2], &subnode[3]) + if err != nil { + log.Fatalf("[ E ] updateTotalMassNode query: %v\n\t\t\t query: %s\n", err, query) + } + // TODO: implement the getSubtreeIDs(nodeID) []int64 {...} function + // iterate over all subnodes updating their total masses + for _, subnodeID := range subnode { + fmt.Println("----------------------------") + fmt.Printf("SubdnodeID: %d\n", subnodeID) + if subnodeID != 0 { + totalmass += updateTotalMassNode(subnodeID) + } else { + // get the starID for getting the star mass + starID := getStarID(nodeID) + fmt.Printf("StarID: %d\n", starID) + if starID != 0 { + mass := getStarMass(starID) + log.Printf("starID=%d \t mass: %f", starID, mass) + totalmass += mass + } + + // break, this stops a star from being counted multiple (4) times + break + } + fmt.Println("----------------------------") + } + + query = fmt.Sprintf("UPDATE nodes SET total_mass=%f WHERE node_id=%d", totalmass, nodeID) + rows, err := db.Query(query) + defer rows.Close() + if err != nil { + log.Fatalf("[ E ] insert total_mass query: %v\n\t\t\t query: %s\n", err, query) + } + + fmt.Printf("nodeID: %d \t totalMass: %f\n", nodeID, totalmass) + + return totalmass +} + +// updateCenterOfMass recursively updates the center of mass of all the nodes starting at the node with the given +// root index +func UpdateCenterOfMass(database *sql.DB, index int64) { + db = database + rootNodeID := getRootNodeID(index) + log.Printf("RootID: %d", rootNodeID) + updateCenterOfMassNode(rootNodeID) +} + +// updateCenterOfMassNode updates the center of mass of the node with the given nodeID recursively +// center of mass := ((x_1 * m) + (x_2 * m) + ... + (x_n * m)) / m +func updateCenterOfMassNode(nodeID int64) structs.Vec2 { + fmt.Println("++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++") + + var centerOfMass structs.Vec2 + + // get the subnode ids + var subnode [4]int64 + var starID int64 + + query := fmt.Sprintf("SELECT subnode[1], subnode[2], subnode[3], subnode[4], star_id FROM nodes WHERE node_id=%d", nodeID) + err := db.QueryRow(query).Scan(&subnode[0], &subnode[1], &subnode[2], &subnode[3], &starID) + if err != nil { + log.Fatalf("[ E ] updateCenterOfMassNode query: %v\n\t\t\t query: %s\n", err, query) + } + + // if the nodes does not contain a star but has children, update the center of mass + if subnode != ([4]int64{0, 0, 0, 0}) { + log.Println("[ ] recursing deeper") + + // define variables storing the values of the subnodes + var totalMass float64 + var centerOfMassX float64 + var centerOfMassY float64 + + // iterate over all the subnodes and calculate the center of mass of each node + for _, subnodeID := range subnode { + subnodeCenterOfMass := updateCenterOfMassNode(subnodeID) + + if subnodeCenterOfMass.X != 0 && subnodeCenterOfMass.Y != 0 { + fmt.Printf("SubnodeCenterOfMass: (%f, %f)\n", subnodeCenterOfMass.X, subnodeCenterOfMass.Y) + subnodeMass := getNodeTotalMass(subnodeID) + totalMass += subnodeMass + + centerOfMassX += subnodeCenterOfMass.X * subnodeMass + centerOfMassY += subnodeCenterOfMass.Y * subnodeMass + } + } + + // calculate the overall center of mass of the subtree + centerOfMass = structs.Vec2{ + X: centerOfMassX / totalMass, + Y: centerOfMassY / totalMass, + } + + // else, use the star as the center of mass (this can be done, because of the rule defining that there + // can only be one star in a cell) + } else { + log.Println("[ ] using the star in the node as the center of mass") + log.Printf("[ ] NodeID: %v", nodeID) + starID := getStarID(nodeID) + + if starID == 0 { + log.Println("[ ] StarID == 0...") + centerOfMass = structs.Vec2{ + X: 0, + Y: 0, + } + } else { + log.Printf("[ ] NodeID: %v", starID) + star := GetStar(starID) + centerOfMassX := star.C.X + centerOfMassY := star.C.Y + centerOfMass = structs.Vec2{ + X: centerOfMassX, + Y: centerOfMassY, + } + } + } + + // build the query + query = fmt.Sprintf("UPDATE nodes SET center_of_mass='{%f, %f}' WHERE node_id=%d", centerOfMass.X, centerOfMass.Y, nodeID) + + // Execute the query + rows, err := db.Query(query) + defer rows.Close() + if err != nil { + log.Fatalf("[ E ] update center of mass query: %v\n\t\t\t query: %s\n", err, query) + } + + fmt.Printf("[ ] CenterOfMass: (%f, %f)\n", centerOfMass.X, centerOfMass.Y) + + return centerOfMass +} + +// updateStarForce updates the force acting on the star +func updateStarForce(db *sql.DB, starID int64, force structs.Vec2) structs.Star2D { + + star := GetStar(starID) + newStar := structs.Star2D{ + structs.Vec2{star.C.X, star.C.Y}, + structs.Vec2{force.X, force.Y}, + star.M, + } + + // updated the stars Force + query := fmt.Sprintf("UPDATE stars SET vx=%f, vy=%f WHERE star_id=%d", force.X, force.Y, starID) + rows, err := db.Query(query) + defer rows.Close() + if err != nil { + log.Fatalf("[ E ] updateStarForce query: %v\n\t\t\t query: %s\n", err, query) + } + + return newStar +} |
