59 lines
2.2 KiB
TypeScript
59 lines
2.2 KiB
TypeScript
export interface ViewportOrbitState {
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yaw: number;
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pitch: number;
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distance: number;
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target: [number, number, number];
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}
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export interface ViewportCameraState extends ViewportOrbitState {
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position: [number, number, number];
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}
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export const VIEWPORT_DEFAULT_ORBIT: Readonly<ViewportOrbitState> = Object.freeze({
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yaw: -Math.PI / 4,
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pitch: 0.55,
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distance: 7,
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target: [0, 0, 0] as [number, number, number],
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});
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export const VIEWPORT_ORBIT_ROTATE_SENSITIVITY = 0.008;
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export const VIEWPORT_ORBIT_ZOOM_SENSITIVITY = 0.001;
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export const VIEWPORT_ORBIT_MIN_DISTANCE = 0.2;
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export const VIEWPORT_ORBIT_MAX_DISTANCE = 500;
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export function orbitPosition(state: Pick<ViewportOrbitState, "yaw" | "pitch" | "distance" | "target">): [number, number, number] {
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const horizontal = state.distance * Math.cos(state.pitch);
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return [
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state.target[0] + horizontal * Math.cos(state.yaw),
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state.target[1] + horizontal * Math.sin(state.yaw),
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state.target[2] + state.distance * Math.sin(state.pitch),
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];
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}
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export function cameraState(state: ViewportOrbitState): ViewportCameraState {
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return { ...state, target: [...state.target] as [number, number, number], position: orbitPosition(state) };
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}
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export function orbitStateFromPosition(position: readonly number[], target: readonly number[] = [0, 0, 0]): ViewportOrbitState {
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const dx = position[0] - target[0];
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const dy = position[1] - target[1];
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const dz = position[2] - target[2];
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const distance = Math.max(VIEWPORT_ORBIT_MIN_DISTANCE, Math.hypot(dx, dy, dz));
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return {
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yaw: Math.atan2(dy, dx),
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pitch: Math.asin(Math.max(-1, Math.min(1, dz / distance))),
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distance,
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target: [target[0], target[1], target[2]],
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};
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}
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export function applyOrbitDelta(state: ViewportOrbitState, deltaX: number, deltaY: number, zoom: number): ViewportOrbitState {
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return {
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...state,
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yaw: state.yaw - deltaX * VIEWPORT_ORBIT_ROTATE_SENSITIVITY,
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pitch: Math.max(-1.45, Math.min(1.45, state.pitch + deltaY * VIEWPORT_ORBIT_ROTATE_SENSITIVITY)),
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distance: Math.max(VIEWPORT_ORBIT_MIN_DISTANCE, Math.min(VIEWPORT_ORBIT_MAX_DISTANCE, state.distance * Math.exp(zoom * VIEWPORT_ORBIT_ZOOM_SENSITIVITY))),
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target: [...state.target] as [number, number, number],
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};
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}
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