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Commit a6276fdd authored by Jack Palevich's avatar Jack Palevich
Browse files

A library for encoding and decoding ETC1 textures. 

The ETC1 compressed texture format is commonly
supported by OpenGL ES 2.0-capable devices.
parent 8eb3ea65

api/current.xml

+395 −0
Original line number Diff line number Diff line
@@ -88168,6 +88168,401 @@ 
</package>

<package name="android.opengl"

>

<class name="ETC1"

 extends="java.lang.Object"

 abstract="false"

 static="false"

 final="false"

 deprecated="not deprecated"

 visibility="public"

>

<constructor name="ETC1"

 type="android.opengl.ETC1"

 static="false"

 final="false"

 deprecated="not deprecated"

 visibility="public"

>

</constructor>

<method name="decodeBlock"

 return="void"

 abstract="false"

 native="true"

 synchronized="false"

 static="true"

 final="false"

 deprecated="not deprecated"

 visibility="public"

>

<parameter name="in" type="java.nio.Buffer">

</parameter>

<parameter name="out" type="java.nio.Buffer">

</parameter>

</method>

<method name="decodeImage"

 return="void"

 abstract="false"

 native="true"

 synchronized="false"

 static="true"

 final="false"

 deprecated="not deprecated"

 visibility="public"

>

<parameter name="in" type="java.nio.Buffer">

</parameter>

<parameter name="out" type="java.nio.Buffer">

</parameter>

<parameter name="width" type="int">

</parameter>

<parameter name="height" type="int">

</parameter>

<parameter name="pixelSize" type="int">

</parameter>

<parameter name="stride" type="int">

</parameter>

</method>

<method name="encodeBlock"

 return="void"

 abstract="false"

 native="true"

 synchronized="false"

 static="true"

 final="false"

 deprecated="not deprecated"

 visibility="public"

>

<parameter name="in" type="java.nio.Buffer">

</parameter>

<parameter name="validPixelMask" type="int">

</parameter>

<parameter name="out" type="java.nio.Buffer">

</parameter>

</method>

<method name="encodeImage"

 return="void"

 abstract="false"

 native="true"

 synchronized="false"

 static="true"

 final="false"

 deprecated="not deprecated"

 visibility="public"

>

<parameter name="in" type="java.nio.Buffer">

</parameter>

<parameter name="width" type="int">

</parameter>

<parameter name="height" type="int">

</parameter>

<parameter name="pixelSize" type="int">

</parameter>

<parameter name="stride" type="int">

</parameter>

<parameter name="out" type="java.nio.Buffer">

</parameter>

</method>

<method name="formatHeader"

 return="void"

 abstract="false"

 native="true"

 synchronized="false"

 static="true"

 final="false"

 deprecated="not deprecated"

 visibility="public"

>

<parameter name="header" type="java.nio.Buffer">

</parameter>

<parameter name="width" type="int">

</parameter>

<parameter name="height" type="int">

</parameter>

</method>

<method name="getEncodedDataSize"

 return="int"

 abstract="false"

 native="true"

 synchronized="false"

 static="true"

 final="false"

 deprecated="not deprecated"

 visibility="public"

>

<parameter name="width" type="int">

</parameter>

<parameter name="height" type="int">

</parameter>

</method>

<method name="getHeight"

 return="int"

 abstract="false"

 native="true"

 synchronized="false"

 static="true"

 final="false"

 deprecated="not deprecated"

 visibility="public"

>

<parameter name="header" type="java.nio.Buffer">

</parameter>

</method>

<method name="getWidth"

 return="int"

 abstract="false"

 native="true"

 synchronized="false"

 static="true"

 final="false"

 deprecated="not deprecated"

 visibility="public"

>

<parameter name="header" type="java.nio.Buffer">

</parameter>

</method>

<method name="isValid"

 return="boolean"

 abstract="false"

 native="true"

 synchronized="false"

 static="true"

 final="false"

 deprecated="not deprecated"

 visibility="public"

>

<parameter name="header" type="java.nio.Buffer">

</parameter>

</method>

<field name="DECODED_BLOCK_SIZE"

 type="int"

 transient="false"

 volatile="false"

 value="48"

 static="true"

 final="true"

 deprecated="not deprecated"

 visibility="public"

>

</field>

<field name="ENCODED_BLOCK_SIZE"

 type="int"

 transient="false"

 volatile="false"

 value="8"

 static="true"

 final="true"

 deprecated="not deprecated"

 visibility="public"

>

</field>

<field name="ETC1_RGB8_OES"

 type="int"

 transient="false"

 volatile="false"

 value="36196"

 static="true"

 final="true"

 deprecated="not deprecated"

 visibility="public"

>

</field>

<field name="ETC_PKM_HEADER_SIZE"

 type="int"

 transient="false"

 volatile="false"

 value="16"

 static="true"

 final="true"

 deprecated="not deprecated"

 visibility="public"

>

</field>

</class>

<class name="ETC1Util"

 extends="java.lang.Object"

 abstract="false"

 static="false"

 final="false"

 deprecated="not deprecated"

 visibility="public"

>

<constructor name="ETC1Util"

 type="android.opengl.ETC1Util"

 static="false"

 final="false"

 deprecated="not deprecated"

 visibility="public"

>

</constructor>

<method name="compressTexture"

 return="android.opengl.ETC1Util.ETC1Texture"

 abstract="false"

 native="false"

 synchronized="false"

 static="true"

 final="false"

 deprecated="not deprecated"

 visibility="public"

>

<parameter name="input" type="java.nio.Buffer">

</parameter>

<parameter name="width" type="int">

</parameter>

<parameter name="height" type="int">

</parameter>

<parameter name="pixelSize" type="int">

</parameter>

<parameter name="stride" type="int">

</parameter>

</method>

<method name="createTexture"

 return="android.opengl.ETC1Util.ETC1Texture"

 abstract="false"

 native="false"

 synchronized="false"

 static="true"

 final="false"

 deprecated="not deprecated"

 visibility="public"

>

<parameter name="input" type="java.io.InputStream">

</parameter>

<exception name="IOException" type="java.io.IOException">

</exception>

</method>

<method name="isETC1Supported"

 return="boolean"

 abstract="false"

 native="false"

 synchronized="false"

 static="true"

 final="false"

 deprecated="not deprecated"

 visibility="public"

>

</method>

<method name="loadTexture"

 return="void"

 abstract="false"

 native="false"

 synchronized="false"

 static="true"

 final="false"

 deprecated="not deprecated"

 visibility="public"

>

<parameter name="target" type="int">

</parameter>

<parameter name="level" type="int">

</parameter>

<parameter name="border" type="int">

</parameter>

<parameter name="fallbackFormat" type="int">

</parameter>

<parameter name="fallbackType" type="int">

</parameter>

<parameter name="input" type="java.io.InputStream">

</parameter>

<exception name="IOException" type="java.io.IOException">

</exception>

</method>

<method name="loadTexture"

 return="void"

 abstract="false"

 native="false"

 synchronized="false"

 static="true"

 final="false"

 deprecated="not deprecated"

 visibility="public"

>

<parameter name="target" type="int">

</parameter>

<parameter name="level" type="int">

</parameter>

<parameter name="border" type="int">

</parameter>

<parameter name="fallbackFormat" type="int">

</parameter>

<parameter name="fallbackType" type="int">

</parameter>

<parameter name="texture" type="android.opengl.ETC1Util.ETC1Texture">

</parameter>

</method>

<method name="writeTexture"

 return="void"

 abstract="false"

 native="false"

 synchronized="false"

 static="true"

 final="false"

 deprecated="not deprecated"

 visibility="public"

>

<parameter name="texture" type="android.opengl.ETC1Util.ETC1Texture">

</parameter>

<parameter name="output" type="java.io.OutputStream">

</parameter>

<exception name="IOException" type="java.io.IOException">

</exception>

</method>

</class>

<class name="ETC1Util.ETC1Texture"

 extends="java.lang.Object"

 abstract="false"

 static="true"

 final="false"

 deprecated="not deprecated"

 visibility="public"

>

<constructor name="ETC1Util.ETC1Texture"

 type="android.opengl.ETC1Util.ETC1Texture"

 static="false"

 final="false"

 deprecated="not deprecated"

 visibility="public"

>

<parameter name="width" type="int">

</parameter>

<parameter name="height" type="int">

</parameter>

<parameter name="data" type="java.nio.ByteBuffer">

</parameter>

</constructor>

<method name="getData"

 return="java.nio.ByteBuffer"

 abstract="false"

 native="false"

 synchronized="false"

 static="false"

 final="false"

 deprecated="not deprecated"

 visibility="public"

>

</method>

<method name="getHeight"

 return="int"

 abstract="false"

 native="false"

 synchronized="false"

 static="false"

 final="false"

 deprecated="not deprecated"

 visibility="public"

>

</method>

<method name="getWidth"

 return="int"

 abstract="false"

 native="false"

 synchronized="false"

 static="false"

 final="false"

 deprecated="not deprecated"

 visibility="public"

>

</method>

</class>

<class name="GLDebugHelper"

 extends="java.lang.Object"

 abstract="false"

core/jni/Android.mk

+1 −0
Original line number Diff line number Diff line
@@ -165,6 +165,7 @@ LOCAL_SHARED_LIBRARIES := \ 
	libEGL \

	libGLESv1_CM \

	libGLESv2 \

	libETC1 \

	libhardware \

	libhardware_legacy \

	libsonivox \

core/jni/android/opengl/util.cpp

+309 −0
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ 
#include <dlfcn.h>



#include <GLES/gl.h>

#include <ETC1/etc1.h>



#include <core/SkBitmap.h>
@@ -39,6 +40,7 @@ namespace android { 


static jclass gIAEClass;

static jclass gUOEClass;

static jclass gAIOOBEClass;



static inline

void mx4transform(float x, float y, float z, float w, const float* pM, float* pDest) {
@@ -711,6 +713,297 @@ static jint util_texSubImage2D(JNIEnv *env, jclass clazz, 
    return 0;

}



/*

 * ETC1 methods.

 */



static jclass nioAccessClass;

static jclass bufferClass;

static jmethodID getBasePointerID;

static jmethodID getBaseArrayID;

static jmethodID getBaseArrayOffsetID;

static jfieldID positionID;

static jfieldID limitID;

static jfieldID elementSizeShiftID;



/* Cache method IDs each time the class is loaded. */



static void

nativeClassInitBuffer(JNIEnv *_env)

{

    jclass nioAccessClassLocal = _env->FindClass("java/nio/NIOAccess");

    nioAccessClass = (jclass) _env->NewGlobalRef(nioAccessClassLocal);



    jclass bufferClassLocal = _env->FindClass("java/nio/Buffer");

    bufferClass = (jclass) _env->NewGlobalRef(bufferClassLocal);



    getBasePointerID = _env->GetStaticMethodID(nioAccessClass,

            "getBasePointer", "(Ljava/nio/Buffer;)J");

    getBaseArrayID = _env->GetStaticMethodID(nioAccessClass,

            "getBaseArray", "(Ljava/nio/Buffer;)Ljava/lang/Object;");

    getBaseArrayOffsetID = _env->GetStaticMethodID(nioAccessClass,

            "getBaseArrayOffset", "(Ljava/nio/Buffer;)I");

    positionID = _env->GetFieldID(bufferClass, "position", "I");

    limitID = _env->GetFieldID(bufferClass, "limit", "I");

    elementSizeShiftID =

        _env->GetFieldID(bufferClass, "_elementSizeShift", "I");

}



static void *

getPointer(JNIEnv *_env, jobject buffer, jint *remaining)

{

    jint position;

    jint limit;

    jint elementSizeShift;

    jlong pointer;

    jint offset;

    void *data;



    position = _env->GetIntField(buffer, positionID);

    limit = _env->GetIntField(buffer, limitID);

    elementSizeShift = _env->GetIntField(buffer, elementSizeShiftID);

    *remaining = (limit - position) << elementSizeShift;

    pointer = _env->CallStaticLongMethod(nioAccessClass,

            getBasePointerID, buffer);

    if (pointer != 0L) {

        return (void *) (jint) pointer;

    }

    return NULL;

}



class BufferHelper {

public:

    BufferHelper(JNIEnv *env, jobject buffer) {

        mEnv = env;

        mBuffer = buffer;

        mData = NULL;

        mRemaining = 0;

    }



    bool checkPointer(const char* errorMessage) {

        if (mBuffer) {

            mData = getPointer(mEnv, mBuffer, &mRemaining);

            if (mData == NULL) {

                mEnv->ThrowNew(gIAEClass, errorMessage);

            }

            return mData != NULL;

        } else {

            mEnv->ThrowNew(gIAEClass, errorMessage);

            return false;

        }

    }



    inline void* getData() {

        return mData;

    }



    inline jint remaining() {

        return mRemaining;

    }



private:

    JNIEnv* mEnv;

    jobject mBuffer;

    void* mData;

    jint mRemaining;

};



/**

 * Encode a block of pixels.

 *

 * @param in a pointer to a ETC1_DECODED_BLOCK_SIZE array of bytes that represent a

 * 4 x 4 square of 3-byte pixels in form R, G, B. Byte (3 * (x + 4 * y) is the R

 * value of pixel (x, y).

 *

 * @param validPixelMask is a 16-bit mask where bit (1 << (x + y * 4)) indicates whether

 * the corresponding (x,y) pixel is valid. Invalid pixel color values are ignored when compressing.

 *

 * @param out an ETC1 compressed version of the data.

 *

 */

static void etc1_encodeBlock(JNIEnv *env, jclass clazz,

        jobject in, jint validPixelMask, jobject out) {

    if (validPixelMask < 0 || validPixelMask > 15) {

        env->ThrowNew(gIAEClass, "validPixelMask");

        return;

    }

    BufferHelper inB(env, in);

    BufferHelper outB(env, out);

    if (inB.checkPointer("in") && outB.checkPointer("out")) {

        if (inB.remaining() < ETC1_DECODED_BLOCK_SIZE) {

            env->ThrowNew(gIAEClass, "in's remaining data < DECODED_BLOCK_SIZE");

        } else if (outB.remaining() < ETC1_ENCODED_BLOCK_SIZE) {

            env->ThrowNew(gIAEClass, "out's remaining data < ENCODED_BLOCK_SIZE");

        } else {

            etc1_encode_block((etc1_byte*) inB.getData(), validPixelMask,

                    (etc1_byte*) outB.getData());

        }

    }

}



/**

 * Decode a block of pixels.

 *

 * @param in an ETC1 compressed version of the data.

 *

 * @param out a pointer to a ETC_DECODED_BLOCK_SIZE array of bytes that represent a

 * 4 x 4 square of 3-byte pixels in form R, G, B. Byte (3 * (x + 4 * y) is the R

 * value of pixel (x, y).

 */

static void etc1_decodeBlock(JNIEnv *env, jclass clazz,

        jobject in, jobject out){

    BufferHelper inB(env, in);

    BufferHelper outB(env, out);

    if (inB.checkPointer("in") && outB.checkPointer("out")) {

        if (inB.remaining() < ETC1_ENCODED_BLOCK_SIZE) {

            env->ThrowNew(gIAEClass, "in's remaining data < ENCODED_BLOCK_SIZE");

        } else if (outB.remaining() < ETC1_DECODED_BLOCK_SIZE) {

            env->ThrowNew(gIAEClass, "out's remaining data < DECODED_BLOCK_SIZE");

        } else {

            etc1_decode_block((etc1_byte*) inB.getData(),

                    (etc1_byte*) outB.getData());

        }

    }

}



/**

 * Return the size of the encoded image data (does not include size of PKM header).

 */

static jint etc1_getEncodedDataSize(JNIEnv *env, jclass clazz,

        jint width, jint height) {

    return etc1_get_encoded_data_size(width, height);

}



/**

 * Encode an entire image.

 * @param in pointer to the image data. Formatted such that

 *           pixel (x,y) is at pIn + pixelSize * x + stride * y + redOffset;

 * @param out pointer to encoded data. Must be large enough to store entire encoded image.

 */

static void etc1_encodeImage(JNIEnv *env, jclass clazz,

        jobject in, jint width, jint height,

        jint pixelSize, jint stride, jobject out) {

    if (pixelSize < 2 || pixelSize > 3) {

        env->ThrowNew(gIAEClass, "pixelSize must be 2 or 3");

        return;

    }

    BufferHelper inB(env, in);

    BufferHelper outB(env, out);

    if (inB.checkPointer("in") && outB.checkPointer("out")) {

        jint imageSize = stride * height;

        jint encodedImageSize = etc1_get_encoded_data_size(width, height);

        if (inB.remaining() < imageSize) {

            env->ThrowNew(gIAEClass, "in's remaining data < image size");

        } else if (outB.remaining() < encodedImageSize) {

            env->ThrowNew(gIAEClass, "out's remaining data < encoded image size");

        } else {

            int result = etc1_encode_image((etc1_byte*) inB.getData(),

                    width, height, pixelSize,

                    stride,

                    (etc1_byte*) outB.getData());

        }

    }

}



/**

 * Decode an entire image.

 * @param in the encoded data.

 * @param out pointer to the image data. Will be written such that

 *            pixel (x,y) is at pIn + pixelSize * x + stride * y. Must be

 *            large enough to store entire image.

 */

static void etc1_decodeImage(JNIEnv *env, jclass clazz,

        jobject  in, jobject out,

        jint width, jint height,

        jint pixelSize, jint stride) {

    if (pixelSize < 2 || pixelSize > 3) {

        env->ThrowNew(gIAEClass, "pixelSize must be 2 or 3");

        return;

    }

    BufferHelper inB(env, in);

    BufferHelper outB(env, out);

    if (inB.checkPointer("in") && outB.checkPointer("out")) {

        jint imageSize = stride * height;

        jint encodedImageSize = etc1_get_encoded_data_size(width, height);

        if (inB.remaining() < encodedImageSize) {

            env->ThrowNew(gIAEClass, "in's remaining data < encoded image size");

        } else if (outB.remaining() < imageSize) {

            env->ThrowNew(gIAEClass, "out's remaining data < image size");

        } else {

            int result = etc1_decode_image((etc1_byte*) inB.getData(),

                    (etc1_byte*) outB.getData(),

                    width, height, pixelSize,

                    stride);

        }

    }

}



/**

 * Format a PKM header

 */

static void etc1_formatHeader(JNIEnv *env, jclass clazz,

        jobject header, jint width, jint height) {

    BufferHelper headerB(env, header);

    if (headerB.checkPointer("header") ){

        if (headerB.remaining() < ETC_PKM_HEADER_SIZE) {

            env->ThrowNew(gIAEClass, "header's remaining data < ETC_PKM_HEADER_SIZE");

        } else {

            etc1_pkm_format_header((etc1_byte*) headerB.getData(), width, height);

        }

    }

}



/**

 * Check if a PKM header is correctly formatted.

 */

static jboolean etc1_isValid(JNIEnv *env, jclass clazz,

        jobject header) {

    jboolean result = false;

    BufferHelper headerB(env, header);

    if (headerB.checkPointer("header") ){

        if (headerB.remaining() < ETC_PKM_HEADER_SIZE) {

            env->ThrowNew(gIAEClass, "header's remaining data < ETC_PKM_HEADER_SIZE");

        } else {

            result = etc1_pkm_is_valid((etc1_byte*) headerB.getData());

        }

    }

    return result;

}



/**

 * Read the image width from a PKM header

 */

static jint etc1_getWidth(JNIEnv *env, jclass clazz,

        jobject header) {

    jint result = 0;

    BufferHelper headerB(env, header);

    if (headerB.checkPointer("header") ){

        if (headerB.remaining() < ETC_PKM_HEADER_SIZE) {

            env->ThrowNew(gIAEClass, "header's remaining data < ETC_PKM_HEADER_SIZE");

        } else {

            result = etc1_pkm_get_width((etc1_byte*) headerB.getData());

        }

    }

    return result;

}



/**

 * Read the image height from a PKM header

 */

static int etc1_getHeight(JNIEnv *env, jclass clazz,

        jobject header) {

    jint result = 0;

    BufferHelper headerB(env, header);

    if (headerB.checkPointer("header") ){

        if (headerB.remaining() < ETC_PKM_HEADER_SIZE) {

            env->ThrowNew(gIAEClass, "header's remaining data < ETC_PKM_HEADER_SIZE");

        } else {

            result = etc1_pkm_get_height((etc1_byte*) headerB.getData());

        }

    }

    return result;

}



/*

 * JNI registration

 */
@@ -721,6 +1014,8 @@ lookupClasses(JNIEnv* env) { 
            env->FindClass("java/lang/IllegalArgumentException"));

    gUOEClass = (jclass) env->NewGlobalRef(

            env->FindClass("java/lang/UnsupportedOperationException"));

    gAIOOBEClass = (jclass) env->NewGlobalRef(

            env->FindClass("java/lang/ArrayIndexOutOfBoundsException"));

}



static JNINativeMethod gMatrixMethods[] = {
@@ -742,6 +1037,18 @@ static JNINativeMethod gUtilsMethods[] = { 
    { "native_texSubImage2D", "(IIIILandroid/graphics/Bitmap;II)I", (void*)util_texSubImage2D },

};



static JNINativeMethod gEtc1Methods[] = {

    { "encodeBlock", "(Ljava/nio/Buffer;ILjava/nio/Buffer;)V", (void*) etc1_encodeBlock },

    { "decodeBlock", "(Ljava/nio/Buffer;Ljava/nio/Buffer;)V", (void*) etc1_decodeBlock },

    { "getEncodedDataSize", "(II)I", (void*) etc1_getEncodedDataSize },

    { "encodeImage", "(Ljava/nio/Buffer;IIIILjava/nio/Buffer;)V", (void*) etc1_encodeImage },

    { "decodeImage", "(Ljava/nio/Buffer;Ljava/nio/Buffer;IIII)V", (void*) etc1_decodeImage },

    { "formatHeader", "(Ljava/nio/Buffer;II)V", (void*) etc1_formatHeader },

    { "isValid", "(Ljava/nio/Buffer;)Z", (void*) etc1_isValid },

    { "getWidth", "(Ljava/nio/Buffer;)I", (void*) etc1_getWidth },

    { "getHeight", "(Ljava/nio/Buffer;)I", (void*) etc1_getHeight },

};



typedef struct _ClassRegistrationInfo {

    const char* classPath;

    JNINativeMethod* methods;
@@ -752,11 +1059,13 @@ static ClassRegistrationInfo gClasses[] = { 
        {"android/opengl/Matrix", gMatrixMethods, NELEM(gMatrixMethods)},

        {"android/opengl/Visibility", gVisiblityMethods, NELEM(gVisiblityMethods)},

        {"android/opengl/GLUtils", gUtilsMethods, NELEM(gUtilsMethods)},

        {"android/opengl/ETC1", gEtc1Methods, NELEM(gEtc1Methods)},

};



int register_android_opengl_classes(JNIEnv* env)

{

    lookupClasses(env);

    nativeClassInitBuffer(env);

    int result = 0;

    for (int i = 0; i < NELEM(gClasses); i++) {

        ClassRegistrationInfo* cri = &gClasses[i];

opengl/include/ETC1/etc1.h

0 → 100644
+106 −0
Original line number Diff line number Diff line 
// Copyright 2009 Google Inc.

//

// 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.



#ifndef __etc1_h__

#define __etc1_h__



#define ETC1_ENCODED_BLOCK_SIZE 8

#define ETC1_DECODED_BLOCK_SIZE 48



#ifndef ETC1_RGB8_OES

#define ETC1_RGB8_OES 0x8D64

#endif



typedef unsigned char etc1_byte;

typedef int etc1_bool;

typedef unsigned int etc1_uint32;



#ifdef __cplusplus

extern "C" {

#endif



// Encode a block of pixels.

//

// pIn is a pointer to a ETC_DECODED_BLOCK_SIZE array of bytes that represent a

// 4 x 4 square of 3-byte pixels in form R, G, B. Byte (3 * (x + 4 * y) is the R

// value of pixel (x, y).

//

// validPixelMask is a 16-bit mask where bit (1 << (x + y * 4)) indicates whether

// the corresponding (x,y) pixel is valid. Invalid pixel color values are ignored when compressing.

//

// pOut is an ETC1 compressed version of the data.



void etc1_encode_block(const etc1_byte* pIn, etc1_uint32 validPixelMask, etc1_byte* pOut);



// Decode a block of pixels.

//

// pIn is an ETC1 compressed version of the data.

//

// pOut is a pointer to a ETC_DECODED_BLOCK_SIZE array of bytes that represent a

// 4 x 4 square of 3-byte pixels in form R, G, B. Byte (3 * (x + 4 * y) is the R

// value of pixel (x, y).



void etc1_decode_block(const etc1_byte* pIn, etc1_byte* pOut);



// Return the size of the encoded image data (does not include size of PKM header).



etc1_uint32 etc1_get_encoded_data_size(etc1_uint32 width, etc1_uint32 height);



// Encode an entire image.

// pIn - pointer to the image data. Formatted such that

//       pixel (x,y) is at pIn + pixelSize * x + stride * y;

// pOut - pointer to encoded data. Must be large enough to store entire encoded image.

// pixelSize can be 2 or 3. 2 is an GL_UNSIGNED_SHORT_5_6_5 image, 3 is a GL_BYTE RGB image.

// returns non-zero if there is an error.



int etc1_encode_image(const etc1_byte* pIn, etc1_uint32 width, etc1_uint32 height,

        etc1_uint32 pixelSize, etc1_uint32 stride, etc1_byte* pOut);



// Decode an entire image.

// pIn - pointer to encoded data.

// pOut - pointer to the image data. Will be written such that

//        pixel (x,y) is at pIn + pixelSize * x + stride * y. Must be

//        large enough to store entire image.

// pixelSize can be 2 or 3. 2 is an GL_UNSIGNED_SHORT_5_6_5 image, 3 is a GL_BYTE RGB image.

// returns non-zero if there is an error.



int etc1_decode_image(const etc1_byte* pIn, etc1_byte* pOut,

        etc1_uint32 width, etc1_uint32 height,

        etc1_uint32 pixelSize, etc1_uint32 stride);



// Size of a PKM header, in bytes.



#define ETC_PKM_HEADER_SIZE 16



// Format a PKM header



void etc1_pkm_format_header(etc1_byte* pHeader, etc1_uint32 width, etc1_uint32 height);



// Check if a PKM header is correctly formatted.



etc1_bool etc1_pkm_is_valid(const etc1_byte* pHeader);



// Read the image width from a PKM header



etc1_uint32 etc1_pkm_get_width(const etc1_byte* pHeader);



// Read the image height from a PKM header



etc1_uint32 etc1_pkm_get_height(const etc1_byte* pHeader);



#ifdef __cplusplus

}

#endif



#endif

opengl/java/android/opengl/ETC1.java

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