我正在尝试创建一个简单的应用程序，它允许您从 .obj 加载 3d 模型并通过触摸屏幕缩放/旋转它。
我设法编写了从文件加载 3d 模型并检测手势的代码，但现在我不确定如何通过触摸屏幕启用缩放/旋转功能。
这是我现在的代码:
public class RenderObjApp implements ApplicationListener, GestureDetector.GestureListener {
public static int SCREEN_WIDTH = 800;
public static int SCREEN_HEIGHT = 600;
private static final String TAG = RenderObjApp.class.getSimpleName();
private Mesh model;
private PerspectiveCamera camera;
private float scale = 1f;
@Override
public void create() {
model = ObjLoader.loadObj(Gdx.files.internal("data/cessna.obj").read(), true);
Gdx.gl.glEnable(GL10.GL_DEPTH_TEST);
Gdx.input.setInputProcessor(new GestureDetector(this));
}
@Override
public void dispose() {
}
@Override
public void pause() {
}
@Override
public void render() {
Gdx.gl.glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
camera.update();
camera.apply(Gdx.gl10);
model.render(GL10.GL_TRIANGLES);
}
@Override
public void resize(int arg0, int arg1) {
float aspectRatio = (float) arg0 / (float) arg1;
camera = new PerspectiveCamera(75, 2f * aspectRatio, 2f);
camera.near = 0.1f;
camera.translate(0, 0, 0);
}
@Override
public void resume() {
}
@Override
public boolean touchDown(float x, float y, int pointer) {
Gdx.app.log(TAG, "touchDown: ");
return false;
}
@Override
public boolean tap(float x, float y, int count, int pointer, int button) {
Gdx.app.log(TAG, "tap: ");
return false;
}
@Override
public boolean longPress(float x, float y) {
Gdx.app.log(TAG, "zoom: ");
return false;
}
@Override
public boolean fling(float velocityX, float velocityY, int pointer, int button) {
Gdx.app.log(TAG, "fling: ");
return false;
}
@Override
public boolean pan(float x, float y, float deltaX, float deltaY) {
Gdx.app.log(TAG, "pan: ");
return false;
}
@Override
public boolean zoom(float initialDistance, float distance) {
Gdx.app.log(TAG, "zoom: initialDistance=" + initialDistance + ", distance=" + distance);
return false;
}
@Override
public boolean pinch(Vector2 initialPointer1, Vector2 initialPointer2, Vector2 pointer1, Vector2 pointer2) {
Gdx.app.log(TAG, "pinch: ");
return false;
}
}
所以我正在研究如何旋转 PerspectiveCamera 和 Mesh 本身。
最佳答案
我一直在研究一种“Blender 风格”的相机，它具有双指缩放功能以及(在桌面上)Blender 相机的大部分功能。这是一项正在进行的工作——它还没有完全模仿 Blender 相机的行为(目前)。我认为这会让你指向正确的方向。你应该知道的一些事情:
您可能需要平移模型，使其位于原点。除非您平移相机，否则它会一直指向原点。 (您只能在桌面上翻译，目前还不能在安卓上翻译)；
我在此处获得了大部分双指缩放处理代码:https://code.google.com/p/libgdx-users/wiki/PinchToZoom .
抱歉出现了魔数(Magic Number)。我将在未来使这些常量成为常量。
如果您或其他任何人改进了此代码，请与我分享一份副本。
抽象类:
/* Author: Christopher Grabowski, yourchristopher6334 gmail.com */
package ...;
import com.badlogic.gdx.InputProcessor;
import com.badlogic.gdx.graphics.PerspectiveCamera;
import com.badlogic.gdx.input.GestureDetector.GestureListener;
import com.badlogic.gdx.math.Vector2;
abstract public class ControllableCamera extends PerspectiveCamera implements InputProcessor{
abstract public void resize(int width, int height);
abstract public void render();
public ControllableCamera(int fieldOfView, int width, int height) {
super(fieldOfView, width, height);
}
@Override
public boolean keyDown(int keyCode) {
return false;
}
@Override
public boolean keyTyped(char arg0) {
return false;
}
@Override
public boolean keyUp(int arg0) {
return false;
}
@Override
public boolean touchDown(int x, int y, int pointer, int button) {
return false;
}
@Override
public boolean touchDragged(int screenX, int screenY, int pointer) {
return false;
}
@Override
public boolean touchUp(int x, int y, int pointer, int button) {
return false;
}
@Override
public boolean mouseMoved(int arg0, int arg1) {
return false;
}
@Override
public boolean scrolled(int direction) {
return false;
}
}
具体类:
/* Author: Christopher Grabowski, yourchristopher6334 gmail.com */
package ...;
import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.Input.Keys;
import com.badlogic.gdx.math.Vector3;
/*
* the pause, resize, and render methods must be called within their corresponding
* methods in the ApplicationListener
*/
public class BlenderStyleCamera extends ControllableCamera {
public static final Vector3 ORIGIN = new Vector3(0, 0, 0);
private static boolean shiftIsPressed = false, controlIsPressed = false,
isScrollingUp = false, isScrollingDown = false,
isSingleTouched = false, justSingleTouched = false;
private float aspectRatio;
private int x = -1, y = -1;
private float dx = 0.0f, dy = 0.0f;
private final Vector3 tmp = new Vector3();
// fields related to pinch-to-zoom
private int numberOfFingers = 0;
private int fingerOnePointer;
private int fingerTwoPointer;
private float lastDistance = 0;
private final Vector3 fingerOne = new Vector3();
private final Vector3 fingerTwo = new Vector3();
public BlenderStyleCamera(int fieldOfView, int width, int height) {
super(fieldOfView, width, height);
aspectRatio = viewportHeight / viewportWidth;
Gdx.input.setInputProcessor(this);
up.set(0.0f, 1.0f, 0.0f);
position.set(0.0f, 0.0f, 30.0f);
far = 300.0f;
lookAt(0, 0, 0);
translate(0.0f, 0.0f, 2.1f);
lookAt(0, 0, 0);
update();
}
public void pause() {
numberOfFingers = 0;
}
@Override
public void resize(int width, int height) {
viewportWidth = width;
viewportHeight = height;
aspectRatio = viewportHeight / viewportWidth;
update();
}
@Override
public void render() {
if (isSingleTouched) {
// This gets the change in touch position and
// compensates for the aspect ratio.
if (x == -1 || y == -1 || justSingleTouched) {
x = Gdx.input.getX();
y = Gdx.input.getY();
} else {
dx = (x - Gdx.input.getX());
dy = (y - Gdx.input.getY()) / aspectRatio;
}
// This zooms when control is pressed.
if (controlIsPressed && dy > 0) {
scrollIn();
} else if (controlIsPressed && dy < 0) {
scrollOut();
}
// This translates the camera blender-style
// if shift is pressed.
// Note that this will look weird with a
// perspective camera.
else if (shiftIsPressed) {
translateTangentially();
}
// Default is to rotate the object
// (actually rotate the camera about a sphere
// that surrounds the object).
else {
travelAround();
}
x = Gdx.input.getX();
y = Gdx.input.getY();
justSingleTouched = false;
}
// this zooms when the mouse wheel is rotated
if (isScrollingUp) {
scrollIn();
isScrollingUp = false;
} else if (isScrollingDown) {
scrollOut();
isScrollingDown = false;
}
// Some key controls
if (Gdx.input.isKeyPressed(Keys.LEFT) || Gdx.input.isKeyPressed(Keys.A)) {
translateTangentially(1, 0);
} else if (Gdx.input.isKeyPressed(Keys.RIGHT)
|| Gdx.input.isKeyPressed(Keys.D)) {
translateTangentially(-1, 0);
}
if (Gdx.input.isKeyPressed(Keys.UP) || Gdx.input.isKeyPressed(Keys.W)) {
translateTangentially(0, 1);
} else if (Gdx.input.isKeyPressed(Keys.DOWN)
|| Gdx.input.isKeyPressed(Keys.S)) {
translateTangentially(0, -1);
}
update();
}
// These methods create the pinch zoom
// and set some flags for logic in render method.
@Override
public boolean touchDown(int x, int y, int pointer, int button) {
// for pinch-to-zoom
numberOfFingers++;
if (numberOfFingers == 1) {
isSingleTouched = true;
justSingleTouched = true;
fingerOnePointer = pointer;
fingerOne.set(x, y, 0);
} else if (numberOfFingers == 2) {
isSingleTouched = false;
fingerTwoPointer = pointer;
fingerTwo.set(x, y, 0);
float distance = fingerOne.dst(fingerTwo);
lastDistance = distance;
}
return true;
}
@Override
public boolean touchDragged(int x, int y, int pointer) {
if (numberOfFingers > 1) {
if (pointer == fingerOnePointer) {
fingerOne.set(x, y, 0);
}
if (pointer == fingerTwoPointer) {
fingerTwo.set(x, y, 0);
}
float distance = fingerOne.dst(fingerTwo);
if (lastDistance > distance) {
scrollOut();
} else if (lastDistance < distance) {
scrollIn();
}
lastDistance = distance;
update();
}
return true;
}
@Override
public boolean touchUp(int x, int y, int pointer, int button) {
isSingleTouched = false;
if (numberOfFingers == 1) {
Vector3 touchPoint = new Vector3(x, y, 0);
unproject(touchPoint);
}
numberOfFingers--;
// just some error prevention... clamping number of fingers (ouch! :-)
if (numberOfFingers < 0) {
numberOfFingers = 0;
}
lastDistance = 0;
return false;
}
// These methods set flags for logic in render method.
@Override
public boolean keyDown(int keycode) {
switch (keycode) {
case (Keys.SHIFT_LEFT):
case (Keys.SHIFT_RIGHT):
shiftIsPressed = true;
break;
case (Keys.CONTROL_LEFT):
case (Keys.CONTROL_RIGHT):
controlIsPressed = true;
break;
case (Keys.O):
this.up.set(0.0f, 1.0f, 0.0f);
this.position.set(0.0f, 0.0f, 30.0f);
this.lookAt(0, 0, 0);
this.update();
}
return true;
}
@Override
public boolean keyUp(int arg0) {
shiftIsPressed = controlIsPressed = false;
return true;
}
@Override
public boolean scrolled(int direction) {
if (direction == -1) {
isScrollingUp = true;
} else if (direction == 1) {
isScrollingDown = true;
}
return true;
}
// The rest of the methods translate the camera.
public void scrollIn() {
float magnitude = 1.0f;
scrollIn(magnitude);
}
public void scrollIn(float magnitude) {
if (position.dst2(ORIGIN) > 2.0f) {
tmp.set(position);
tmp.nor();
this.translate(-tmp.x * magnitude, -tmp.y * magnitude, -tmp.z
* magnitude);
update();
}
}
public void scrollOut() {
float magnitude = 1.0f;
scrollOut(magnitude);
}
public void scrollOut(float magnitude) {
tmp.set(position);
tmp.nor();
this.translate(tmp.x * magnitude, tmp.y * magnitude, tmp.z * magnitude);
update();
}
private void travelAround() {
tmp.set(up);
rotateAround(ORIGIN, tmp, dx);
tmp.crs(position).nor();
rotateAround(ORIGIN, tmp, dy);
}
private void translateTangentially() {
translateTangentially(dx, dy);
}
private void translateTangentially(float dx, float dy) {
tmp.set(up);
tmp.crs(position);
if (dx > 0) {
translate(tmp.x / 15.0f, tmp.y / 15.0f, tmp.z / 15.0f);
} else if (dx < 0) {
translate(-tmp.x / 15.0f, -tmp.y / 15.0f, -tmp.z / 15.0f);
}
if (dy > 0) {
translate(-up.x, -up.y, -up.z);
} else if (dy < 0) {
translate(up);
}
}
}
关于java - libgdx 如何在触摸时缩放和旋转 3d 模型，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/13420787/