我在opengl ES2.0中开发了一个
android应用程序.在这个应用程序中,我曾经通过GL surfaceView中的触摸事件绘制多个线条和圆圈.
由于opengl依赖于GPU,目前它在Google Nexus 7(ULP GeForce)中运行良好.
在三星Galaxy Note 2(MALI 400MP)中,我试图绘制多条线,但它清除了前一条线,并将当前线绘制为新线.
在Sony Xperia Neo V(Adreno 205)中,我试图画一条新线,它会使表面崩溃,如下图所示.
是否可以使其在所有设备上运行,或者我是否需要为单个GPU编写代码？
源代码
MainActivity.java
//in OnCreate method of my activity,i set the glsurfaceview and renderer
final ActivityManager activityManager =
( ActivityManager ) getSystemService( Context.ACTIVITY_SERVICE );
final ConfigurationInfo configurationInfo =
activityManager.getDeviceConfigurationInfo( );
final boolean supportsEs2 = ( configurationInfo.reqGlEsVersion >= 0x20000
|| Build.FINGERPRINT.startsWith( "generic" ) );
if( supportsEs2 ) {
Log.i( "JO","configurationInfo.reqGlEsVersion:"
+ configurationInfo.reqGlEsVersion + "supportsEs2:"
+ supportsEs2 );
// Request an OpenGL ES 2.0 compatible context.
myGlsurfaceView.setEGLContextClientVersion( 2 );
final DisplayMetrics displayMetrics = new DisplayMetrics( );
getWindowManager( ).getDefaultDisplay( ).getMetrics( displayMetrics );
// Set the renderer to our demo renderer,defined below.
myRenderer = new MyRenderer( this,myGlsurfaceView );
myGlsurfaceView.setRenderer( myRenderer,displayMetrics.density );
myGlsurfaceView.setRenderMode( GLSurfaceView.RENDERMODE_CONTINUOUSLY );
MyGLSurfaceView.java
//in this im getting the coordinates of my touch on the glSurfaceView to draw the line and //passing those points to the renderer class
public MyGLsurfaceview( Context context ) {
super( context );
Log.i( "JO","MyGLsurfaceview1" );
}
public MyGLsurfaceview(
Context context,AttributeSet attrs )
{
super( context,attrs );
con = context;
mActivity = new MainActivity( );
mActivity.myGlsurfaceView = this;
Log.i( "JO","MyGLsurfaceview2" );
}
public void setRenderer(
MyRenderer renderer,float density )
{
Log.i( "JO","setRenderer" );
myRenderer = renderer;
myDensity = density;
mGestureDetector = new GestureDetector( con,mGestureListener );
super.setRenderer( renderer );
setRenderMode( GLSurfaceView.RENDERMODE_CONTINUOUSLY );
}
@Override public boolean onTouchEvent( MotionEvent ev ) {
boolean retVal = mGestureDetector.onTouchEvent( ev );
if( myline ) {
switch ( ev.getAction( ) ) {
case MotionEvent.ACTION_DOWN:
isLUp = false;
if( count == 1 ) {
dx = ev.getX( );
dy = ev.getY( );
dx = ( dx / ( getWidth( ) / 2 ) ) - 1;
dy = 1 - ( dy / ( getHeight( ) / 2 ) );
firstX = dx;
firstY = dy;
} else if( count == 2 ) {
ux = ev.getX( );
uy = ev.getY( );
ux = ( ux / ( getWidth( ) / 2 ) ) - 1;
uy = 1 - ( uy / ( getHeight( ) / 2 ) );
secondX = ux;
secondY = uy;
myRenderer.dx = firstX;
myRenderer.dy = firstY;
myRenderer.ux = secondX;
myRenderer.uy = secondY;
midX = ( firstX + secondX ) / 2;
midY = ( firstY + secondY ) / 2;
Log.e( "JO","Line:firstX" + firstX +
"firstY" + firstY );
lp = new LinePoints( firstX,firstY,secondX,secondY,midX,midY );
lineArray.add( lp );
myRenderer.isNewClick = false;
myRenderer.isEnteredAngle = false;
myRenderer.myline = true;
myRenderer.mycircle = false;
myRenderer.mydashedline = false;
myRenderer.eraseCircle = false;
myRenderer.eraseLine = false;
myRenderer.eraseSelCir = false;
myRenderer.angle = angle;
myRenderer.length = length;
requestRender( );
count = 0;
}
count++;
break;
case MotionEvent.ACTION_MOVE:
isLUp = true;
break;
case MotionEvent.ACTION_UP:
if( isLUp ) {
ux = ev.getX( );
uy = ev.getY( );
ux = ( ux / ( getWidth( ) / 2 ) ) - 1;
uy = 1 - ( uy / ( getHeight( ) / 2 ) );
Log.i( "JO","line2:" + ux + "," + uy );
secondX = ux;
secondY = uy;
myRenderer.dx = firstX;
myRenderer.dy = firstY;
myRenderer.ux = secondX;
myRenderer.uy = secondY;
midX = ( firstX + secondX ) / 2;
midY = ( firstY + secondY ) / 2;
Log.e( "JO",midY );
lineArray.add( lp );
myRenderer.isNewClick = false;
myRenderer.isEnteredAngle = false;
myRenderer.myline = true;
myRenderer.mycircle = false;
myRenderer.mydashedline = false;
myRenderer.mysnaptoedge = false;
myRenderer.mysnaptoMiddle = false;
myRenderer.eraseCircle = false;
myRenderer.eraseLine = false;
myRenderer.eraseSelCir = false;
count = 1;
requestRender( );
}
break;
}
}
}
}
MyRenderer.java
//renderer class to render the line to the glsurfaceview
Lines line;
public MyRenderer(
MainActivity mainActivity,MyGLsurfaceview myGlsurfaceView )
{
Log.i( "JO","MyRenderer" );
this.main = mainActivity;
myGlsurface = myGlsurfaceView;
}
public void onDrawFrame(
GL10 gl )
{
line.draw( dx,dy,ux,uy );
}
@Override public void onSurfaceCreated(
GL10 gl,EGLConfig config )
{
Log.i( "JO","onSurfaceCreated" );
// Set the background frame color
GLES20.glClearColor( 0.0f,0.0f,1.0f );
// Create the GLText
glText = new GLText( main.getAssets( ) );
// Load the font from file (set size + padding),creates the texture
// NOTE: after a successful call to this the font is ready for
// rendering!
glText.load( "Roboto-Regular.ttf",14,2,2 ); // Create Font (Height: 14
// Pixels / X+Y Padding
// 2 Pixels)
// enable texture + alpha blending
GLES20.glEnable( GLES20.GL_BLEND );
GLES20.glBlendFunc( GLES20.GL_ONE,GLES20.GL_ONE_MINUS_SRC_ALPHA );
}
@Override public void onSurfaceChanged(
GL10 gl,int width,int height )
{
// Adjust the viewport based on geometry changes,// such as screen rotation
GLES20.glViewport( 0,width,height );
ratio = ( float ) width / height;
width_surface = width;
height_surface = height;
/*
* // this projection matrix is applied to object coordinates // in the
* onDrawFrame() method Matrix.frustumM(mProjMatrix,-ratio,ratio,* -1,1,3,7);
*/
// Take into account device orientation
if( width > height ) {
Matrix.frustumM( mProjMatrix,-1,10 );
} else {
Matrix.frustumM( mProjMatrix,-1 / ratio,1 / ratio,10 );
}
// Save width and height
this.width = width; // Save Current Width
this.height = height; // Save Current Height
int useForOrtho = Math.min( width,height );
// TODO: Is this wrong?
Matrix.orthoM( mVMatrix,-useForOrtho / 2,useForOrtho / 2,0.1f,100f );
}
Line.java
//Line class to draw line
public class Lines
{
final String vertexShaderCode = "attribute vec4 vPosition;"
+ "void main() {" + " gl_Position = vPosition;" + "}";
final String fragmentShaderCode = "precision mediump float;"
+ "uniform vec4 vColor;" + "void main() {"
+ " gl_FragColor = vColor;" + "}";
final FloatBuffer vertexBuffer;
final int mProgram;
int mPositionHandle;
int mColorHandle;
// number of coordinates per vertex in this array
final int COORDS_PER_VERTEX = 3;
float lineCoords[] = new float[6];
final int vertexCount = lineCoords.length / COORDS_PER_VERTEX;
final int vertexStride = COORDS_PER_VERTEX * 4; // bytes per vertex
// Set color with red,green,blue and alpha (opacity) values
float lcolor[] = { 1.0f,1.0f,1.0f };
public Lines(
)
{
// initialize vertex byte buffer for shape coordinates
ByteBuffer bb = ByteBuffer.allocateDirect(
// (number of coordinate values * 4 bytes per float)
lineCoords.
length * 4 );
// use the device hardware's native byte order
bb.order( ByteOrder.nativeOrder( ) );
// create a floating point buffer from the ByteBuffer
vertexBuffer = bb.asFloatBuffer( );
// prepare shaders and OpenGL program
int vertexShader =
MyRenderer.loadShader( GLES20.GL_VERTEX_SHADER,vertexShaderCode );
int fragmentShader =
MyRenderer.loadShader( GLES20.GL_FRAGMENT_SHADER,fragmentShaderCode );
mProgram = GLES20.glCreateProgram( ); // create empty OpenGL Program
GLES20.glAttachShader( mProgram,vertexShader ); // add the vertex shader
// to program
GLES20.glAttachShader( mProgram,fragmentShader ); // add the fragment
// shader to program
GLES20.glLinkProgram( mProgram ); // create OpenGL program executables
}
public void draw(
float dX,float dY,float uX,float uY )
{
lineCoords[0] = dX;
lineCoords[1] = dY;
lineCoords[2] = 0.0f;
lineCoords[3] = uX;
lineCoords[4] = uY;
lineCoords[5] = 0.0f;
Log.i( "JO","lineCoords:" + lineCoords[0] + "," + lineCoords[1] +
"," + lineCoords[3] + "," + lineCoords[4] );
vertexBuffer.put( lineCoords );
vertexBuffer.position( 0 );
// Add program to OpenGL environment
GLES20.glUseProgram( mProgram );
// get handle to vertex shader's vPosition member
mPositionHandle =
GLES20.glGetAttribLocation( mProgram,"vPosition" );
// Enable a handle to the triangle vertices
GLES20.glEnableVertexAttribArray( mPositionHandle );
// Prepare the triangle coordinate data
GLES20.glVertexAttribPointer( mPositionHandle,COORDS_PER_VERTEX,GLES20.GL_FLOAT,false,vertexStride,vertexBuffer );
// get handle to fragment shader's vColor member
mColorHandle =
GLES20.glGetUniformLocation( mProgram,"vColor" );
// Set color for drawing the triangle
GLES20.glUniform4fv( mColorHandle,lcolor,0 );
GLES20.glLineWidth( 3 );
// Draw the triangle
GLES20.glDrawArrays( GLES20.GL_LINES,vertexCount );
// Disable vertex array
GLES20.glDisableVertexAttribArray( mPositionHandle );
}
}
解决方法
好的,这里又一次：^ 1
OpenGL is not a scene graph. OpenGL does not maintain a scene,knows about objects or keeps tracks of geometry. OpenGL is a drawing API. You give it a canvas (in form of a Window or a PBuffer) and order it to draw points,lines or triangles and OpenGL does exactly that. Once a primitive (=point,line,triangle) has been drawn,OpenGL has no recollection about it whatsoever. If something changes,you have to redraw the whole thing.
重绘场景的正确步骤是：
>禁用模板测试,以便以下步骤在整个窗口上运行.
>使用glClear(位)清除帧缓冲区,其中位是位掩码,指定要清除画布的哪些部分.渲染新帧时,您要清除所有内容,因此位= GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT;
>设置视口,构建适当的投影矩阵
>为场景中的每个对象加载正确的模型视图矩阵,设置制服,选择顶点数组并进行绘图调用.
>通过冲洗管道完成渲染.如果使用单个缓冲窗口glFinish(),如果使用双缓冲窗口调用SwapBuffers.在更高级别框架的情况下,这可以由框架执行.
重要事项在双缓冲窗口上完成绘图后,您不能继续发送绘图操作,因为通过执行缓冲区交换,您绘制的后台缓冲区的内容是未定义的.因此,您必须重新开始绘图,从清除帧缓冲区开始(步骤1和2).
您的代码遗漏的正是这两个步骤.另外我的印象是你正在执行OpenGL绘图调用,直接对输入事件做出反应,可能在输入事件处理程序中.不要这样做！而是使用输入事件添加到要绘制的基元列表(在您的情况下为行),然后发送重绘事件,这使框架调用绘图函数.在绘图功能中迭代该列表以绘制所需的线条.
重绘整个场景在OpenGL中是规范的！
[1](geesh,我已经厌倦了每隔3个左右写一次这个问题……)
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