1.OpenGL ES簡介
OpenGL Es學習,首先要了解Android的基本架構,如下圖:
在Android的第三層的Libraries裏面就有OpenGL ES庫。OpenGL ES是一個跨平臺的圖形API,給3D圖形處理硬件指定了一個標準的軟件接口。
2.OpenGL ES在Android的使用
Android提供了兩個類:GLSufaceView和GLSurfaceView.Renderer.
2.1GLSurfaceView
GlSurfaceView就是一個surfaceView ,只是增加了Render,用OpenGL來顯示渲染。
2.2GLSurfaceView.Renderer
使用GLSurfaceView.setRenderer()將其附加到GLSurfaceView實例。
GLSurfaceView.Renderer要求實現以下方法:
- onSurfaceCreated():創建GLSurfaceView時,系統調用一次該方法。使用此方法執行只需要執行一次的操作,例如設置OpenGL環境參數或初始化OpenGL圖形對象。
- onDrawFrame():系統在每次重畫GLSurfaceView時調用這個方法。使用此方法作爲繪製(和重新繪製)圖形對象的主要執行方法。
- onSurfaceChanged():當GLSurfaceView的發生變化時,系統調用此方法,這些變化包括GLSurfaceView的大小或設備屏幕方向的變化。例如:設備從縱向變爲橫向時,系統調用此方法。我們應該使用此方法來響應GLSurfaceView容器的改變。
使用GlSurfaceView步驟:
- 創建一個GlSurfaceView。
- 設置渲染
- 在GlSurfaceView.renderder中繪製處理顯示數據
3.OpenGL ES繪製圖形
在Android使用OpenGL ES的步驟:
- 在Manifest中聲明OpenGL ES使用,我使用OpenGL ES2.0的API
<uses-feature android:glEsVersion="0x00020000" android:required="true" />
如果要使用問了要是添加
<supports-gl-texture android:name="GL_OES_compressed_ETC1_RGB8_texture" /> <supports-gl-texture android:name="GL_OES_compressed_paletted_texture" />
- 設置相關的渲染Renderer,Renderer有三個方法:
- onSurfaceCreated() - 在View的OpenGL環境被創建的時候調用。
- onDrawFrame() - 每一次View的重繪都會調用
- onSurfaceChanged() - 如果視圖的幾何形狀發生變化(例如,當設備的屏幕方向改變時),則調用此方法。
繪製圖形
示例代碼:
public class GlSurfaceViewActivity extends AppCompatActivity {
private GLSurfaceView gLsurfaceview;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_gl_surface_view);
gLsurfaceview = findViewById(R.id.gLsurfaceview);
gLsurfaceview.setEGLContextClientVersion(2);
// gLsurfaceview.setRenderer(new Trianglerenderer());//三角形
//gLsurfaceview.setRenderer(new SquareRenderer());//正方形
gLsurfaceview.setRenderer(new CircleRenderer());//圓
gLsurfaceview.setRenderMode(GLSurfaceView.RENDERMODE_WHEN_DIRTY);
}
@Override
protected void onResume() {
super.onResume(); gLsurfaceview.onResume();
}
@Override
protected void onPause() {
super.onPause();
gLsurfaceview.onPause();
}
}
三角形的Renderer:
public class Trianglerenderer extends BackgroundRender {
private int mProgram;
private FloatBuffer vertexBuffer;
private final String vertexShaderCode =
"attribute vec4 vPosition;" +
"void main() {" +
" gl_Position = vPosition;" +
"}";
private final String fragmentShaderCode =
"precision mediump float;" +
"uniform vec4 vColor;" +
"void main() {" +
" gl_FragColor = vColor;" +
"}";
static float triangleCoords[] = {
0.0f, 0.6f, 0.0f, // top
-0.5f, -0.3f, 0.0f, // bottom left
0.5f, -0.3f, 0.0f // bottom right
};
//設置顏色,依次爲紅綠藍和透明通道
float color[] = { 0.0f, 1.0f, 0.0f, 1.0f ,
1.0f, 0.0f, 0.0f, 1.0f,
0.0f, 0.0f, 1.0f, 1.0f };
static final int COORDS_PER_VERTEX = 3;
private int mPositionHandle;
private int mColorHandle;
//頂點個數
private final int vertexCount = triangleCoords.length / COORDS_PER_VERTEX;
//頂點之間的偏移量
private final int vertexStride = COORDS_PER_VERTEX * 4; // 每個頂點四個字節
@Override
public void onSurfaceCreated(GL10 gl10, EGLConfig eglConfig) {
//將背景設置爲灰色
GLES20.glClearColor(0.5f,0.5f,0.5f,1.0f);
//申請底層空間
ByteBuffer bb = ByteBuffer.allocateDirect(triangleCoords.length * 4);
bb.order(ByteOrder.nativeOrder());
//將座標數據轉換爲FloatBuffer,用以傳入OpenGL ES程序
vertexBuffer = bb.asFloatBuffer();
vertexBuffer.put(triangleCoords);
vertexBuffer.position(0);
int vertexShader = loadShader(GLES20.GL_VERTEX_SHADER,vertexShaderCode);
int fragmentShader = loadShader(GLES20.GL_FRAGMENT_SHADER,fragmentShaderCode);
//創建一個空的OpenGLES程序
mProgram = GLES20.glCreateProgram();
//將頂點着色器加入到程序
GLES20.glAttachShader(mProgram,vertexShader);
//將片元着色器加入到程序中
GLES20.glAttachShader(mProgram,fragmentShader);
//連接到着色器程序
GLES20.glLinkProgram(mProgram);
}
@Override
public void onSurfaceChanged(GL10 gl10, int width, int height) {
GLES20.glViewport(0,0,width,height);
}
@Override
public void onDrawFrame(GL10 gl10) {
//將程序加入到OpenGLES2.0環境
GLES20.glUseProgram(mProgram);
//獲取頂點着色器的vPosition成員句柄
mPositionHandle = GLES20.glGetAttribLocation(mProgram, "vPosition");
//啓用三角形頂點的句柄
GLES20.glEnableVertexAttribArray(mPositionHandle);
//準備三角形的座標數據
GLES20.glVertexAttribPointer(mPositionHandle, COORDS_PER_VERTEX,
GLES20.GL_FLOAT, false,
vertexStride, vertexBuffer);
//獲取片元着色器的vColor成員的句柄
mColorHandle = GLES20.glGetUniformLocation(mProgram, "vColor");
//設置繪製三角形的顏色
GLES20.glUniform4fv(mColorHandle, 1, color, 0);
//繪製三角形
GLES20.glDrawArrays(GLES20.GL_TRIANGLES, 0, vertexCount);
//禁止頂點數組的句柄
GLES20.glDisableVertexAttribArray(mPositionHandle);
}
}
正方形的Renderer:
public class SquareRenderer extends BackgroundRender implements GLSurfaceView.Renderer {
private FloatBuffer vertexBuffer;
private ShortBuffer indexBuffer;
private final String vertexShaderCode =
"attribute vec4 vPosition;" +
"uniform mat4 vMatrix;" +
"void main() {" +
" gl_Position = vMatrix*vPosition;" +
"}";
private final String fragmentShaderCode =
"precision mediump float;" +
"uniform vec4 vColor;" +
"void main() {" +
" gl_FragColor = vColor;" +
"}";
private int mProgram;
static final int COORDS_PER_VERTEX = 3;
static float triangleCoords[] = {
-0.5f, 0.5f, 0.0f, // top left
-0.5f, -0.5f, 0.0f, // bottom left
0.5f, -0.5f, 0.0f, // bottom right
0.5f, 0.5f, 0.0f // top right
};
static short index[] = {
0, 1, 2, 0, 2, 3
};
private int mPositionHandle;
private int mColorHandle;
private float[] mViewMatrix = new float[16];
private float[] mProjectMatrix = new float[16];
private float[] mMVPMatrix = new float[16];
//頂點個數
private final int vertexCount = triangleCoords.length / COORDS_PER_VERTEX;
//頂點之間的偏移量
private final int vertexStride = COORDS_PER_VERTEX * 4; // 每個頂點四個字節
private int mMatrixHandler;
//設置顏色,依次爲紅綠藍和透明通道
float color[] = {0.0f, 1.0f, 0.0f, 1.0f ,
1.0f, 0.0f, 0.0f, 1.0f,
0.0f, 0.0f, 1.0f, 1.0f};
@Override
public void onSurfaceCreated(GL10 gl10, EGLConfig eglConfig) {
ByteBuffer bb = ByteBuffer.allocateDirect(
triangleCoords.length * 4);
bb.order(ByteOrder.nativeOrder());
vertexBuffer = bb.asFloatBuffer();
vertexBuffer.put(triangleCoords);
vertexBuffer.position(0);
ByteBuffer cc = ByteBuffer.allocateDirect(index.length * 2);
cc.order(ByteOrder.nativeOrder());
indexBuffer = cc.asShortBuffer();
indexBuffer.put(index);
indexBuffer.position(0);
int vertexShader = loadShader(GLES20.GL_VERTEX_SHADER,
vertexShaderCode);
int fragmentShader = loadShader(GLES20.GL_FRAGMENT_SHADER,
fragmentShaderCode);
//創建一個空的OpenGLES程序
mProgram = GLES20.glCreateProgram();
//將頂點着色器加入到程序
GLES20.glAttachShader(mProgram, vertexShader);
//將片元着色器加入到程序中
GLES20.glAttachShader(mProgram, fragmentShader);
//連接到着色器程序
GLES20.glLinkProgram(mProgram);
}
@Override
public void onSurfaceChanged(GL10 gl10, int width, int height) {
//計算寬高比
float ratio = (float) width / height;
//設置透視投影
Matrix.frustumM(mProjectMatrix, 0, -ratio, ratio, -1, 1, 3, 7);
//設置相機位置
Matrix.setLookAtM(mViewMatrix, 0, 0, 0, 7.0f, 0f, 0f, 0f, 0f, 1.0f, 0.0f);
//計算變換矩陣
Matrix.multiplyMM(mMVPMatrix, 0, mProjectMatrix, 0, mViewMatrix, 0);
}
@Override
public void onDrawFrame(GL10 gl10) {
//將程序加入到OpenGLES2.0環境
GLES20.glUseProgram(mProgram);
//獲取變換矩陣vMatrix成員句柄
mMatrixHandler = GLES20.glGetUniformLocation(mProgram, "vMatrix");
//指定vMatrix的值
GLES20.glUniformMatrix4fv(mMatrixHandler, 1, false, mMVPMatrix, 0);
//獲取頂點着色器的vPosition成員句柄
mPositionHandle = GLES20.glGetAttribLocation(mProgram, "vPosition");
//啓用三角形頂點的句柄
GLES20.glEnableVertexAttribArray(mPositionHandle);
//準備三角形的座標數據
GLES20.glVertexAttribPointer(mPositionHandle, COORDS_PER_VERTEX,
GLES20.GL_FLOAT, false,
vertexStride, vertexBuffer);
//獲取片元着色器的vColor成員的句柄
mColorHandle = GLES20.glGetUniformLocation(mProgram, "vColor");
//設置繪製三角形的顏色
GLES20.glUniform4fv(mColorHandle, 1, color, 0);
//繪製三角形
// GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, vertexCount);
//索引法繪製正方形
GLES20.glDrawElements(GLES20.GL_TRIANGLES, index.length, GLES20.GL_UNSIGNED_SHORT, indexBuffer);
//禁止頂點數組的句柄
GLES20.glDisableVertexAttribArray(mPositionHandle);
}
}
圓的Renderer:
public class CircleRenderer extends BackgroundRender implements GLSurfaceView.Renderer {
String vertexShaderCode = "attribute vec4 vPosition;\n" +
"uniform mat4 vMatrix;\n" +
"void main() {\n" +
" gl_Position = vMatrix*vPosition;\n" +
"}" ;
String fragmentShaderCode = "precision mediump float;\n" +
" uniform vec4 vColor;\n" +
" void main() {\n" +
" gl_FragColor = vColor;\n" +
" }";
int mProgram;
private FloatBuffer vertexBuffer;
private float[] circlrCoods;
float color[] = { 1.0f, 1.0f, 1.0f, 1.0f }; //頂點統一白色
public CircleRenderer() {
//設置所有座標
circlrCoods = createPositions();
//float[] → FloatBuffer
ByteBuffer bb = ByteBuffer.allocateDirect(circlrCoods.length * 4);
bb.order(ByteOrder.nativeOrder());
vertexBuffer = bb.asFloatBuffer();
vertexBuffer.put(circlrCoods);
vertexBuffer.position(0);
}
private float[] createPositions(){
ArrayList<Float> data=new ArrayList<>();
data.add(0.0f); //設置圓心座標
data.add(0.0f);
data.add(0.0f);
//分成100條邊,繪製出來應該很像圓了
float radius = 0.5f; //半徑1
float angDegSpan=360f/100; //依次遞加的角度
for(float i=0;i<360+angDegSpan;i+=angDegSpan){
data.add((float)(radius*Math.cos(i*Math.PI/180f))); //x
data.add((float) (radius*Math.sin(i*Math.PI/180f))); //y
data.add(0.0f); //z
}
float[] f=new float[data.size()];
for (int i=0;i<f.length;i++){
f[i]=data.get(i);
}
return f;
}
@Override
public void onSurfaceCreated(GL10 gl, EGLConfig config) {
int vetexShader = loadShader(GLES20.GL_VERTEX_SHADER , vertexShaderCode);
int fragmentShader = loadShader(GLES20.GL_FRAGMENT_SHADER , fragmentShaderCode);
//添加着色器
mProgram = GLES20.glCreateProgram();
GLES20.glAttachShader(mProgram,vetexShader);
GLES20.glAttachShader(mProgram,fragmentShader);
GLES20.glLinkProgram(mProgram);
}
private final float[] mMVPMatrix = new float[16];
private final float[] mProjectMatrix = new float[16];
private final float[] mViewMatrix = new float[16];
@Override
public void onSurfaceChanged(GL10 gl, int width, int height) {
GLES20.glViewport(0,0,width,height);
float ratio = (float) width/height;
//設置矩陣
Matrix.frustumM(mProjectMatrix,0,-ratio,ratio,-1,1,3,20);
Matrix.setLookAtM(mViewMatrix,0,0f,0f,7.0f,0f,0f,0f,0f,1.0f,0f);
Matrix.multiplyMM(mMVPMatrix,0,mProjectMatrix,0,mViewMatrix,0);
}
int mMatrixHandler;
int mPositionHandle;
int vColorHandle;
@Override
public void onDrawFrame(GL10 gl) {
Log.e("TAG","error");
GLES20.glUseProgram(mProgram);
mMatrixHandler = GLES20.glGetUniformLocation(mProgram,"vMatrix");
GLES20.glUniformMatrix4fv(mMatrixHandler,1,false,mMVPMatrix,0);
mPositionHandle = GLES20.glGetAttribLocation(mProgram,"vPosition");
GLES20.glEnableVertexAttribArray(mPositionHandle);
GLES20.glVertexAttribPointer(
mPositionHandle,
3,
GLES20.GL_FLOAT,
false,
12,
vertexBuffer
);
vColorHandle = GLES20.glGetUniformLocation(mProgram,"vColor");
GLES20.glUniform4fv(vColorHandle,1,color,0);
GLES20.glDrawArrays(GLES20.GL_TRIANGLE_FAN , 0 , circlrCoods.length/3);
GLES20.glDisableVertexAttribArray(mPositionHandle);
}
}
項目地址:https://github.com/ChloeDimen/AudioAndVideo