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ETC1Util.javaAPI DocAndroid 5.1 API9600Thu Mar 12 22:22:40 GMT 2015android.opengl

ETC1Util

public class ETC1Util extends Object
Utility methods for using ETC1 compressed textures.

Fields Summary
Constructors Summary
Methods Summary
public static android.opengl.ETC1Util$ETC1TexturecompressTexture(java.nio.Buffer input, int width, int height, int pixelSize, int stride)
Helper function that compresses an image into an ETC1Texture.

param
input a native order direct buffer containing the image data
param
width the width of the image in pixels
param
height the height of the image in pixels
param
pixelSize the size of a pixel in bytes (2 or 3)
param
stride the width of a line of the image in bytes
return
the ETC1 texture.

        int encodedImageSize = ETC1.getEncodedDataSize(width, height);
        ByteBuffer compressedImage = ByteBuffer.allocateDirect(encodedImageSize).
            order(ByteOrder.nativeOrder());
        ETC1.encodeImage(input, width, height, pixelSize, stride, compressedImage);
        return new ETC1Texture(width, height, compressedImage);
public static android.opengl.ETC1Util$ETC1TexturecreateTexture(java.io.InputStream input)
Create a new ETC1Texture from an input stream containing a PKM formatted compressed texture.

param
input an input stream containing a PKM formatted compressed texture.
return
an ETC1Texture read from the input stream.
throws
IOException

        int width = 0;
        int height = 0;
        byte[] ioBuffer = new byte[4096];
        {
            if (input.read(ioBuffer, 0, ETC1.ETC_PKM_HEADER_SIZE) != ETC1.ETC_PKM_HEADER_SIZE) {
                throw new IOException("Unable to read PKM file header.");
            }
            ByteBuffer headerBuffer = ByteBuffer.allocateDirect(ETC1.ETC_PKM_HEADER_SIZE)
                .order(ByteOrder.nativeOrder());
            headerBuffer.put(ioBuffer, 0, ETC1.ETC_PKM_HEADER_SIZE).position(0);
            if (!ETC1.isValid(headerBuffer)) {
                throw new IOException("Not a PKM file.");
            }
            width = ETC1.getWidth(headerBuffer);
            height = ETC1.getHeight(headerBuffer);
        }
        int encodedSize = ETC1.getEncodedDataSize(width, height);
        ByteBuffer dataBuffer = ByteBuffer.allocateDirect(encodedSize).order(ByteOrder.nativeOrder());
        for (int i = 0; i < encodedSize; ) {
            int chunkSize = Math.min(ioBuffer.length, encodedSize - i);
            if (input.read(ioBuffer, 0, chunkSize) != chunkSize) {
                throw new IOException("Unable to read PKM file data.");
            }
            dataBuffer.put(ioBuffer, 0, chunkSize);
            i += chunkSize;
        }
        dataBuffer.position(0);
        return new ETC1Texture(width, height, dataBuffer);
public static booleanisETC1Supported()
Check if ETC1 texture compression is supported by the active OpenGL ES context.

return
true if the active OpenGL ES context supports ETC1 texture compression.

        int[] results = new int[20];
        GLES10.glGetIntegerv(GLES10.GL_NUM_COMPRESSED_TEXTURE_FORMATS, results, 0);
        int numFormats = results[0];
        if (numFormats > results.length) {
            results = new int[numFormats];
        }
        GLES10.glGetIntegerv(GLES10.GL_COMPRESSED_TEXTURE_FORMATS, results, 0);
        for (int i = 0; i < numFormats; i++) {
            if (results[i] == ETC1.ETC1_RGB8_OES) {
                return true;
            }
        }
        return false;
public static voidloadTexture(int target, int level, int border, int fallbackFormat, int fallbackType, java.io.InputStream input)
Convenience method to load an ETC1 texture whether or not the active OpenGL context supports the ETC1 texture compression format.

param
target the texture target.
param
level the texture level
param
border the border size. Typically 0.
param
fallbackFormat the format to use if ETC1 texture compression is not supported. Must be GL_RGB.
param
fallbackType the type to use if ETC1 texture compression is not supported. Can be either GL_UNSIGNED_SHORT_5_6_5, which implies 16-bits-per-pixel, or GL_UNSIGNED_BYTE, which implies 24-bits-per-pixel.
param
input the input stream containing an ETC1 texture in PKM format.
throws
IOException

        loadTexture(target, level, border, fallbackFormat, fallbackType, createTexture(input));
public static voidloadTexture(int target, int level, int border, int fallbackFormat, int fallbackType, android.opengl.ETC1Util$ETC1Texture texture)
Convenience method to load an ETC1 texture whether or not the active OpenGL context supports the ETC1 texture compression format.

param
target the texture target.
param
level the texture level
param
border the border size. Typically 0.
param
fallbackFormat the format to use if ETC1 texture compression is not supported. Must be GL_RGB.
param
fallbackType the type to use if ETC1 texture compression is not supported. Can be either GL_UNSIGNED_SHORT_5_6_5, which implies 16-bits-per-pixel, or GL_UNSIGNED_BYTE, which implies 24-bits-per-pixel.
param
texture the ETC1 to load.

        if (fallbackFormat != GLES10.GL_RGB) {
            throw new IllegalArgumentException("fallbackFormat must be GL_RGB");
        }
        if (! (fallbackType == GLES10.GL_UNSIGNED_SHORT_5_6_5
                || fallbackType == GLES10.GL_UNSIGNED_BYTE)) {
            throw new IllegalArgumentException("Unsupported fallbackType");
        }

        int width = texture.getWidth();
        int height = texture.getHeight();
        Buffer data = texture.getData();
        if (isETC1Supported()) {
            int imageSize = data.remaining();
            GLES10.glCompressedTexImage2D(target, level, ETC1.ETC1_RGB8_OES, width, height,
                    border, imageSize, data);
        } else {
            boolean useShorts = fallbackType != GLES10.GL_UNSIGNED_BYTE;
            int pixelSize = useShorts ? 2 : 3;
            int stride = pixelSize * width;
            ByteBuffer decodedData = ByteBuffer.allocateDirect(stride*height)
                .order(ByteOrder.nativeOrder());
            ETC1.decodeImage(data, decodedData, width, height, pixelSize, stride);
            GLES10.glTexImage2D(target, level, fallbackFormat, width, height, border,
                    fallbackFormat, fallbackType, decodedData);
        }
public static voidwriteTexture(android.opengl.ETC1Util$ETC1Texture texture, java.io.OutputStream output)
Helper function that writes an ETC1Texture to an output stream formatted as a PKM file.

param
texture the input texture.
param
output the stream to write the formatted texture data to.
throws
IOException

        ByteBuffer dataBuffer = texture.getData();
        int originalPosition = dataBuffer.position();
        try {
            int width = texture.getWidth();
            int height = texture.getHeight();
            ByteBuffer header = ByteBuffer.allocateDirect(ETC1.ETC_PKM_HEADER_SIZE).order(ByteOrder.nativeOrder());
            ETC1.formatHeader(header, width, height);
            byte[] ioBuffer = new byte[4096];
            header.get(ioBuffer, 0, ETC1.ETC_PKM_HEADER_SIZE);
            output.write(ioBuffer, 0, ETC1.ETC_PKM_HEADER_SIZE);
            int encodedSize = ETC1.getEncodedDataSize(width, height);
            for (int i = 0; i < encodedSize; ) {
                int chunkSize = Math.min(ioBuffer.length, encodedSize - i);
                dataBuffer.get(ioBuffer, 0, chunkSize);
                output.write(ioBuffer, 0, chunkSize);
                i += chunkSize;
            }
        } finally {
            dataBuffer.position(originalPosition);
        }