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
|
/*
* Copyright (C) 2012 The Android Open Source Project
*
* 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.example.android.snake;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.View;
import java.util.Arrays;
/**
* Background View: Draw 4 full-screen RGBY triangles
*/
public class BackgroundView extends View {
private int[] mColors = new int[4];
private final short[] mIndices =
{ 0, 1, 2, 0, 3, 4, 0, 1, 4 // Corner points for triangles (with offset = 2)
};
private float[] mVertexPoints = null;
public BackgroundView(Context context, AttributeSet attrs) {
super(context, attrs);
setFocusable(true);
// retrieve colors for 4 segments from styleable properties
TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.BackgroundView);
mColors[0] = a.getColor(R.styleable.BackgroundView_colorSegmentOne, Color.RED);
mColors[1] = a.getColor(R.styleable.BackgroundView_colorSegmentTwo, Color.YELLOW);
mColors[2] = a.getColor(R.styleable.BackgroundView_colorSegmentThree, Color.BLUE);
mColors[3] = a.getColor(R.styleable.BackgroundView_colorSegmentFour, Color.GREEN);
a.recycle();
}
@Override
protected void onDraw(Canvas canvas) {
assert(mVertexPoints != null);
// Colors for each vertex
int[] mFillColors = new int[mVertexPoints.length];
for (int triangle = 0; triangle < mColors.length; triangle++) {
// Set color for all vertex points to current triangle color
Arrays.fill(mFillColors, mColors[triangle]);
// Draw one triangle
canvas.drawVertices(Canvas.VertexMode.TRIANGLES, mVertexPoints.length, mVertexPoints,
0, null, 0, // No Textures
mFillColors, 0, mIndices,
triangle * 2, 3, // Use 3 vertices via Index Array with offset 2
new Paint());
}
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
// Construct our center and four corners
mVertexPoints = new float[] {
w / 2, h / 2,
0, 0,
w, 0,
w, h,
0, h
};
}
}
|
