openGL ES JNI贴图 平移 旋转 缩放

采用demo为NDK sample下的hello-gl2。

1、修改gVertexShader

static const char gVertexShader[] =
"uniform mat4 uMVPMatrix;   \n"  //变换矩阵
"attribute vec2 a_position;   \n"
"attribute vec2 a_texCoord;   \n"
"varying vec2 v_texCoord;     \n"
"void main()                  \n"
"{                            \n"
"   gl_Position uMVPMatrix*vec4(a_position,0,1); \n"
"   v_texCoord = a_texCoord;  \n"
"}                            \n";

修改gFragmentShader

static const char gFragmentShader[] =
"precision mediump float;                            \n"
"varying vec2 v_texCoord;                            \n"
"uniform sampler2D s_texture;                        \n"
"void main()                                         \n"
"{                                                   \n"
"  gl_FragColor = texture2D( s_texture, v_texCoord );\n"
"}                                                   \n";

在函数setupGraphics里添加纹理信息

bool setupGraphics(int w, int h) {
printGLString("Version", GL_VERSION);
printGLString("Vendor", GL_VENDOR);
printGLString("Renderer", GL_RENDERER);
printGLString("Extensions", GL_EXTENSIONS);
LOGI("setupGraphics(%d, %d)", w, h);
gProgram = createProgram(gVertexShader, gFragmentShader);
if (!gProgram) {
LOGE("Could not create program.");
return false;
}
glViewport(0, 0, w, h);
checkGlError("glViewport");

gvPositionHandle = glGetAttribLocation(gProgram,"a_position");
gvTexCoordHandle =  glGetAttribLocation(gProgram,"a_texCoord");
gvSTexCoordHandle =  glGetUniformLocation(gProgram,"s_texture");
muMVPMatrixHandle =  glGetUniformLocation(gProgram, "uMVPMatrix");

glPixelStorei ( GL_UNPACK_ALIGNMENT, 1 );
glGenTextures ( 1, &textureId );
glBindTexture ( GL_TEXTURE_2D, textureId );
glTexImage2D ( GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, dataFromBmp );
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER,  GL_LINEAR );
return true;
}

4、设置renderFrame

void renderFrame() {
static float grey;
grey = 0.1f;
if (grey > 1.0f) {
grey = 0.0f;
}
glClearColor(grey, grey, grey, 1.0f);
checkGlError("glClearColor");
glClear( GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);
checkGlError("glClear");
glUseProgram(gProgram);
checkGlError("glUseProgram");
glVertexAttribPointer(gvPositionHandle,2, GL_FLOAT, GL_FALSE, 0,gTriangleVertices );
glVertexAttribPointer(gvTexCoordHandle,2, GL_FLOAT, GL_FALSE, 0, gTexCoords);
glUniformMatrix4fv(muMVPMatrixHandle, 1, GL_FALSE, mat4);
glEnableVertexAttribArray(gvPositionHandle);
glEnableVertexAttribArray(gvTexCoordHandle);
glActiveTexture ( GL_TEXTURE0 );
glBindTexture ( GL_TEXTURE_2D, textureId );
glUniform1i ( gvSTexCoordHandle, 0 );
// glUniform1i(muMVPMatrixHandle,0);
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
}

5、在GL2JNILib.java里声明NATIVE函数

public class GL2JNILib {

static {
System.loadLibrary("gl2jni");
}

/**
* @param width the current view width
* @param height the current view height
*/
public static native void init(int width, int height);
public static native void step();
public native static void  processBitmap(Bitmap bitmap);
public native static void rotate(float mat[]);
}

6、添加相关控件

7添加事件

在GL2JNIActivity里声明如下变量

GL2JNIView mView;
static float[] mMMatrix = new float[16];
static float[] moveMatrix = new float[16];//随便写的，就临时数组。
static float xAngle =0;//角度

这儿不能直接调用JNI，需要用GL线程来运行。故

需要调用

mView.queueEvent(new Runnable() {
@Override
public void run() {
GL2JNILib.rotate(mMMatrix);//JNI接口，最终的变换矩阵
}
});

public void moveRight(View v )
{
Matrix.setIdentityM(moveMatrix, 0);
Matrix.translateM(moveMatrix, 0, 0.1f, 0, 0);
Matrix.multiplyMM(mMMatrix,0,moveMatrix,0,mMMatrix,0);

button1.setText("向右");
mView.queueEvent(new Runnable() {
@Override
public void run() {
GL2JNILib.rotate(mMMatrix);
}
});
}
public void moveLeft(View v )
{
Matrix.setIdentityM(moveMatrix, 0);
Matrix.translateM(moveMatrix, 0, -0.1f, 0, 0);
Matrix.multiplyMM(mMMatrix,0,moveMatrix,0,mMMatrix,0);
button4.setText("向左");
mView.queueEvent(new Runnable() {
@Override
public void run() {
GL2JNILib.rotate(mMMatrix);
}
});
}
public void zoomOut(View v )
{
Matrix.setIdentityM(moveMatrix, 0);
Matrix.scaleM(moveMatrix,0,1.1f,1.1f,1.1f);
Matrix.multiplyMM(mMMatrix,0,moveMatrix,0,mMMatrix,0);
mView.queueEvent(new Runnable() {
@Override
public void run() {
GL2JNILib.rotate(mMMatrix);
}
});

button2.setText("放大");

}
public void zoomIn(View v )
{
Matrix.setIdentityM(moveMatrix, 0);
Matrix.scaleM(moveMatrix, 0, 0.9f, 0.9f, 0.9f);
Matrix.multiplyMM(mMMatrix,0,moveMatrix,0,mMMatrix,0);
mView.queueEvent(new Runnable() {
@Override
public void run() {
GL2JNILib.rotate(mMMatrix);
}
});
}

大体如此了。

补充：

需要 填充图片时，我没在JNI上找到现成.cpp 和.h文件来处理图片。所以 采用的是jni传入bitmap的方式。

void  Java_com_android_gl2jni_GL2JNILib_processBitmap(JNIEnv *env, jclass obj, jobject bmpObj)
{
//return ;
LOGE("-----------------------");
int ret;
AndroidBitmapInfo bmpInfo={0};
if(ret = AndroidBitmap_getInfo(env,bmpObj,&bmpInfo)<0)
{
LOGE("AndroidBitmap_getInfo() failed ! error=%d", ret);
return ;
}
width = bmpInfo.width;
height = bmpInfo.height;

if(ret = AndroidBitmap_lockPixels(env,bmpObj,(void**)&dataFromBmp))
{
LOGE("AndroidBitmap_lockPixels() failed ! error=%d", ret);
return;
}
AndroidBitmap_unlockPixels(env, bmpObj);
return ;
}