add boundary patch
This commit is contained in:
Mike Reed
173
graphics/java/android/graphics/utils/BoundaryPatch.java
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173
graphics/java/android/graphics/utils/BoundaryPatch.java
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/*
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* Copyright (C) 2009 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package android.graphics.utils;
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import android.graphics.Bitmap;
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import android.graphics.BitmapShader;
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import android.graphics.Canvas;
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import android.graphics.Paint;
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import android.graphics.Shader;
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import android.graphics.Xfermode;
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/**
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* @hide
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*/
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public class BoundaryPatch {
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private Paint mPaint;
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private Bitmap mTexture;
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private int mRows;
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private int mCols;
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private float[] mCubicPoints;
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private boolean mDirty;
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// these are the computed output of the native code
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private float[] mVerts;
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private short[] mIndices;
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public BoundaryPatch() {
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mRows = mCols = 2; // default minimum
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mCubicPoints = new float[24];
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mPaint = new Paint();
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mPaint.setDither(true);
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mPaint.setFilterBitmap(true);
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mDirty = true;
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}
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/**
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* Set the boundary to be 4 cubics. This takes a single array of floats,
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* and picks up the 12 pairs starting at offset, and treats them as
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* the x,y coordinates of the cubic control points. The points wrap around
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* a patch, as follows. For documentation purposes, pts[i] will mean the
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* x,y pair of floats, as if pts[] were an array of "points".
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*
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* Top: pts[0..3]
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* Right: pts[3..6]
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* Bottom: pts[6..9]
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* Right: pts[9..11], pts[0]
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*
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* The coordinates are copied from the input array, so subsequent changes
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* to pts[] will not be reflected in the boundary.
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*
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* @param pts The src array of x,y pairs for the boundary cubics
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* @param offset The index into pts of the first pair
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* @param rows The number of points across to approximate the boundary.
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* Must be >= 2, though very large values may slow down drawing
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* @param cols The number of points down to approximate the boundary.
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* Must be >= 2, though very large values may slow down drawing
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*/
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public void setCubicBoundary(float[] pts, int offset, int rows, int cols) {
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if (rows < 2 || cols < 2) {
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throw new RuntimeException("rows and cols must be >= 2");
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}
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System.arraycopy(pts, offset, mCubicPoints, 0, 24);
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if (mRows != rows || mCols != cols) {
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mRows = rows;
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mCols = cols;
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}
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mDirty = true;
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}
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/**
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* Reference a bitmap texture to be mapped onto the patch.
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*/
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public void setTexture(Bitmap texture) {
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if (mTexture != texture) {
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if (mTexture == null ||
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mTexture.getWidth() != texture.getWidth() ||
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mTexture.getHeight() != texture.getHeight()) {
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// need to recompute texture coordinates
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mDirty = true;
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}
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mTexture = texture;
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mPaint.setShader(new BitmapShader(texture,
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Shader.TileMode.CLAMP,
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Shader.TileMode.CLAMP));
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}
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}
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/**
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* Return the paint flags for the patch
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*/
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public int getPaintFlags() {
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return mPaint.getFlags();
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}
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/**
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* Set the paint flags for the patch
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*/
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public void setPaintFlags(int flags) {
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mPaint.setFlags(flags);
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}
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/**
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* Set the xfermode for the patch
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*/
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public void setXfermode(Xfermode mode) {
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mPaint.setXfermode(mode);
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}
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/**
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* Set the alpha for the patch
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*/
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public void setAlpha(int alpha) {
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mPaint.setAlpha(alpha);
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}
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/**
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* Draw the patch onto the canvas.
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*
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* setCubicBoundary() and setTexture() must be called before drawing.
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*/
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public void draw(Canvas canvas) {
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if (mDirty) {
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buildCache();
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mDirty = false;
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}
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// cut the count in half, since mVerts.length is really the length of
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// the verts[] and tex[] arrays combined
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// (tex[] are stored after verts[])
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int vertCount = mVerts.length >> 1;
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canvas.drawVertices(Canvas.VertexMode.TRIANGLES, vertCount,
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mVerts, 0, mVerts, vertCount, null, 0,
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mIndices, 0, mIndices.length,
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mPaint);
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}
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private void buildCache() {
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// we need mRows * mCols points, for verts and another set for textures
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// so *2 for going from points -> floats, and *2 for verts and textures
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int vertCount = mRows * mCols * 4;
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if (mVerts == null || mVerts.length != vertCount) {
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mVerts = new float[vertCount];
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}
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int indexCount = (mRows - 1) * (mCols - 1) * 6;
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if (mIndices == null || mIndices.length != indexCount) {
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mIndices = new short[indexCount];
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}
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nativeComputeCubicPatch(mCubicPoints,
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mTexture.getWidth(), mTexture.getHeight(),
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mRows, mCols, mVerts, mIndices);
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}
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private static native
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void nativeComputeCubicPatch(float[] cubicPoints,
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int texW, int texH, int rows, int cols,
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float[] verts, short[] indices);
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}
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