1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180

/*******************************************************************************
 * Copyright 2011 See AUTHORS file.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 ******************************************************************************/

package com.badlogic.gdx.graphics;

import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.math.Matrix4;
import com.badlogic.gdx.math.Vector2;
import com.badlogic.gdx.math.Vector3;

/** A camera with orthographic projection.
 * 
 * @author mzechner */
public class OrthographicCamera extends Camera {
	/** the zoom of the camera **/
	public float zoom = 1;

	public OrthographicCamera () {
		this.near = 0;
	}

	/** Constructs a new OrthographicCamera, using the given viewport width and height. For pixel perfect 2D rendering just supply
	 * the screen size, for other unit scales (e.g. meters for box2d) proceed accordingly.
	 * 
	 * @param viewportWidth the viewport width
	 * @param viewportHeight the viewport height */
	public OrthographicCamera (float viewportWidth, float viewportHeight) {
		this.viewportWidth = viewportWidth;
		this.viewportHeight = viewportHeight;
		this.near = 0;
		update();
	}

	/** Constructs a new OrthographicCamera, using the given viewport width and height. This will create a camera useable for
	 * iso-metric views. The diamond angle is specifies the angle of a tile viewed isometrically.
	 * 
	 * @param viewportWidth the viewport width
	 * @param viewportHeight the viewport height
	 * @param diamondAngle the angle in degrees */
	public OrthographicCamera (float viewportWidth, float viewportHeight, float diamondAngle) {
		this.viewportWidth = viewportWidth;
		this.viewportHeight = viewportHeight;
		this.near = 0;
		findDirectionForIsoView(diamondAngle, 0.00000001f, 20);
		update();
	}

	public void findDirectionForIsoView (float targetAngle, float epsilon, int maxIterations) {
		float start = targetAngle - 5;
		float end = targetAngle + 5;
		float mid = targetAngle;

		int iterations = 0;
		float aMid = 0;
		while (Math.abs(targetAngle - aMid) > epsilon && iterations++ < maxIterations) {
			aMid = calculateAngle(mid);

			if (targetAngle < aMid) {
				end = mid;
			} else {
				start = mid;
			}
			mid = start + (end - start) / 2;
		}
		position.set(calculateDirection(mid));
		position.y = -position.y;
		lookAt(0, 0, 0);
		normalizeUp();
	}

	private float calculateAngle (float a) {
		Vector3 camPos = calculateDirection(a);
		position.set(camPos.mul(30));
		lookAt(0, 0, 0);
		normalizeUp();
		update();

		Vector3 orig = new Vector3(0, 0, 0);
		Vector3 vec = new Vector3(1, 0, 0);
		project(orig);
		project(vec);
		Vector2 d = new Vector2(vec.x - orig.x, -(vec.y - orig.y));
		return d.angle();
	}

	private Vector3 calculateDirection (float angle) {
		Matrix4 transform = new Matrix4();
		Vector3 dir = new Vector3(-1, 0, 1).nor();
		float rotAngle = (float)Math.toDegrees(Math.asin(Math.tan(Math.toRadians(angle))));
		transform.setToRotation(new Vector3(1, 0, 1).nor(), angle);
		dir.mul(transform).nor();
		return dir;
	}

	private final Vector3 tmp = new Vector3();

	@Override
	public void update () {
		projection.setToOrtho(zoom * -viewportWidth / 2, zoom * viewportWidth / 2, zoom * -viewportHeight / 2, zoom
			* viewportHeight / 2, Math.abs(near), Math.abs(far));
		view.setToLookAt(position, tmp.set(position).add(direction), up);
		combined.set(projection);
		Matrix4.mul(combined.val, view.val);
		invProjectionView.set(combined);
		Matrix4.inv(invProjectionView.val);
		frustum.update(invProjectionView);
	}

	@Override
	public void update (boolean updateFrustum) {
		projection.setToOrtho(zoom * -viewportWidth / 2, zoom * viewportWidth / 2, zoom * -viewportHeight / 2, zoom
			* viewportHeight / 2, Math.abs(near), Math.abs(far));
		view.setToLookAt(position, tmp.set(position).add(direction), up);
		combined.set(projection);
		Matrix4.mul(combined.val, view.val);

		if (updateFrustum) {
			invProjectionView.set(combined);
			Matrix4.inv(invProjectionView.val);
			frustum.update(invProjectionView);
		}
	}

	/** Sets this camera to an orthographic projection using a viewport fitting the screen resolution, centered at
	 * (Gdx.graphics.getWidth()/2, Gdx.graphics.getHeight()/2), with the y-axis pointing up or down.
	 * @param yDown whether y should be pointing down */
	public void setToOrtho (boolean yDown) {
		setToOrtho(yDown, Gdx.graphics.getWidth(), Gdx.graphics.getHeight());
	}

	/** Sets this camera to an orthographic projection, centered at (viewportWidth/2, viewportHeight/2), with the y-axis pointing up
	 * or down.
	 * @param yDown whether y should be pointing down.
	 * @param viewportWidth
	 * @param viewportHeight */
	public void setToOrtho (boolean yDown, float viewportWidth, float viewportHeight) {
		if (yDown) {
			up.set(0, -1, 0);
			direction.set(0, 0, 1);
		}
		position.set(viewportWidth / 2.0f, viewportHeight / 2.0f, 0);
		this.viewportWidth = viewportWidth;
		this.viewportHeight = viewportHeight;
		update();
	}
	
	/** Rotates the camera by the given angle around the direction vector. The direction and up vector
	 * will not be orthogonalized.
	 * @param angle */
	public void rotate (float angle)
	{
		rotate(direction, angle);	
	}
	
	/** Moves the camera by the given amount on each axis.
	 * @param x the displacement on the x-axis
	 * @param y the displacement on the y-axis */
	public void translate(float x, float y) {
		translate(x, y, 0);
	}
	
	/** Moves the camera by the given vector.
	 * @param vec the displacement vector */
	public void translate(Vector2 vec) {
		translate(vec.x, vec.y, 0);
	}
}