OpenGL ES 2.0的上下文中的Android [英] OpenGL ES 2.0 Context in Android
本文介绍了OpenGL ES 2.0的上下文中的Android的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我是新来的OpenGL在Android和我已经阅读大量文件样本，我有点明白了。但是，试图做任何事情复杂之前，我想画一个简单的2D白色矩形，黑色bacground。仅此而已。
我被困在此错误：没有当前上下文，这似乎是我打电话从非OpenGL的<东西调用的OpenGL ES API code>发。问题是，我不知道是什么原因来自OpenGL 发调用。因此，这里是我的code
// ==============活动================== //
公共类MainActivity延伸活动{
公共静态字符串变量= MainActivity.class.getSimpleName（）;
MyGLSurfaceView表面;
@覆盖
保护无效的onCreate（包savedInstanceState）{
super.onCreate（savedInstanceState）;
requestWindowFeature（Window.FEATURE_NO_TITLE）;
getWindow（）。setFlags（
WindowManager.LayoutParams.FLAG_FULLSCREEN，
WindowManager.LayoutParams.FLAG_FULLSCREEN
）;
表面=新MyGLSurfaceView（本）;
的setContentView（面）;
}
@覆盖
保护无效的onPause（）{
super.onPause（）;
surface.onPause（）;
}
@覆盖
保护无效onResume（）{
super.onResume（）;
surface.onResume（）;
}
}
// ==================== GLSurfaceView ======================== //
公共类MyGLSurfaceView扩展GLSurfaceView {
MyGLSurfaceRenderer渲染器;
公共MyGLSurfaceView（上下文的背景下）{
超（上下文）;
setEGLContextClientVersion（2）;
渲染器=新MyGLSurfaceRenderer（本）;
setRenderer（渲染）;
}
}
// ==================渲染========================== //
公共类MyGLSurfaceRenderer实现GLSurfaceView.Renderer {
大大方方=新广场（）;
公共MyGLSurfaceRenderer（MyGLSurfaceView面）{
}
@覆盖
公共无效onDrawFrame（GL10 GL）{
GLES20.glClear（GLES20.GL_COLOR_BUFFER_BIT）;
square.draw（）;
}
@覆盖
公共无效onSurfaceChanged（GL10 GL，诠释的宽度，高度INT）{
// TODO自动生成方法存根
}
@覆盖
公共无效onSurfaceCreated（GL10 GL，EGLConfig配置）{
GLES20.glClearColor（0.0，0.0，0.0，1.0F）;
}
}
// ====================广场======================== //
公共类方{
私人FloatBuffer vertexBuffer;
私人ShortBuffer drawListBuffer;
//此数组中每个顶点的坐标数量
静态最终诠释COORDS_PER_VERTEX = 3;
静浮squareCoords [] = {-0.5f，0.5F，0.0，//左上
-0.5f，-0.5f，0.0，//左下
0.5F，-0.5f，0.0，//右下
0.5F，0.5F，0.0}; // 右上
私人短DRAWORDER [] = {0，1，2，0，2,3}; //为了绘制顶点
浮色[] = {0.63671875f，0.76953125f，0.22265625f，1.0F};
私人最终字符串vertexShader code =
属性vec4 vPosition; +
无效的主要（）{+
GL_POSITION = vPosition; +
};
私人最终字符串fragmentShader code =
precision mediump浮动; +
统一vec4 vColor; +
无效的主要（）{+
gl_FragColor = vColor; +
};
INT mProgram;
静态最终诠释vertexStride = COORDS_PER_VERTEX * 4;
静态最终诠释vertexCount = 4;
市民广场（）{
//初始化为形状坐标顶点字节的缓冲区
ByteBuffer的BB = ByteBuffer.allocateDirect（squareCoords.length * 4）; //（＃坐标值* 4％的浮动字节）
bb.order（ByteOrder.nativeOrder（））;
vertexBuffer = bb.asFloatBuffer（）;
vertexBuffer.put（squareCoords）;
vertexBuffer.position（0）;
//初始化字节的缓冲区的抽奖名单
ByteBuffer的DLB = ByteBuffer.allocateDirect（drawOrder.length * 2）; //（＃坐标值的每个短* 2字节）
dlb.order（ByteOrder.nativeOrder（））;
drawListBuffer = dlb.asShortBuffer（）;
drawListBuffer.put（DRAWORDER）;
drawListBuffer.position（0）;
INT vertexShader = loadShader（GLES20.GL_VERTEX_SHADER，vertexShader code）;
INT fragmentShader = loadShader（GLES20.GL_FRAGMENT_SHADER，fragmentShader code）;
mProgram = GLES20.glCreateProgram（）; //创建空的OpenGL ES项目
GLES20.glAttachShader（mProgram，vertexShader）; //添加顶点着色器程序
GLES20.glAttachShader（mProgram，fragmentShader）; //添加片段着色器进行编程
GLES20.glLinkProgram（mProgram）; //创建OpenGL ES的可执行程序
}
公共静态INT loadShader（整型，字符串着色器code）{
//创建一个顶点着色器类型（GLES20.GL_VERTEX_SHADER）
//或片段着色器类型（GLES20.GL_FRAGMENT_SHADER）
INT着色器= GLES20.glCreateShader（类型）;
//添加源$ C $ C到着色器和编译
GLES20.glShaderSource（着色，着色器code）;
GLES20.glCompileShader（着色）;
返回着色器;
}
公共无效平局（）{
//添加程序OpenGL ES的环境
GLES20.glUseProgram（mProgram）;
//得到处理到顶点着色器的vPosition成员
INT mPositionHandle = GLES20.glGetAttribLocation（mProgramvPosition）;
//启用句柄三角形顶点
GLES20.glEnableVertexAttribArray（mPositionHandle）;
// prepare三角坐标数据
GLES20.glVertexAttribPointer（mPositionHandle，COORDS_PER_VERTEX，
GLES20.GL_FLOAT，假的，
vertexStride，vertexBuffer）;
//得到处理，以片段着色器的vColor成员
INT mColorHandle = GLES20.glGetUniformLocation（mProgramvColor）;
//设置颜色绘制三角形
GLES20.glUniform4fv（mColorHandle，1，颜色，0）;
//绘制三角形
GLES20.glDrawArrays（GLES20.GL_TRIANGLES，0，vertexCount）;
//禁用顶点数组
GLES20.glDisableVertexAttribArray（mPositionHandle）;
}
}
解决方案
该问题可能是这一行：
广场万=新广场（）;
由于它被调用setRenderer之前初始化。该构造广场调用GLES20方法，这可能是造成问题的原因。尝试调用后实例化setRenderer（渲染）;或onSurfaceCreated方法中。
I'm new to OpenGL on Android and I have read heavily documented samples, and I kinda understand it. But before trying to do anything complex, I want to draw a simple 2D white rectangle on a black bacground. Nothing else.
I'm stuck at this error: call to OpenGL ES API with no current context, which seems to be that I'm calling something from the non-OpenGL Thread. The thing is that I'm not sure what is called from the OpenGL Thread. So here's my code
//============== Activity ==================//
public class MainActivity extends Activity {
public static String TAG = MainActivity.class.getSimpleName();
MyGLSurfaceView surface;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(
WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN
);
surface = new MyGLSurfaceView(this);
setContentView(surface);
}
@Override
protected void onPause() {
super.onPause();
surface.onPause();
}
@Override
protected void onResume() {
super.onResume();
surface.onResume();
}
}
//==================== GLSurfaceView ========================//
public class MyGLSurfaceView extends GLSurfaceView {
MyGLSurfaceRenderer renderer;
public MyGLSurfaceView(Context context) {
super(context);
setEGLContextClientVersion(2);
renderer = new MyGLSurfaceRenderer(this);
setRenderer(renderer);
}
}
//================== Renderer ==========================//
public class MyGLSurfaceRenderer implements GLSurfaceView.Renderer {
Square square = new Square();
public MyGLSurfaceRenderer(MyGLSurfaceView surface) {
}
@Override
public void onDrawFrame(GL10 gl) {
GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);
square.draw();
}
@Override
public void onSurfaceChanged(GL10 gl, int width, int height) {
// TODO Auto-generated method stub
}
@Override
public void onSurfaceCreated(GL10 gl, EGLConfig config) {
GLES20.glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
}
}
//==================== Square ========================//
public class Square {
private FloatBuffer vertexBuffer;
private ShortBuffer drawListBuffer;
// number of coordinates per vertex in this array
static final int COORDS_PER_VERTEX = 3;
static float squareCoords[] = { -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
private short drawOrder[] = { 0, 1, 2, 0, 2, 3 }; // order to draw vertices
float color[] = { 0.63671875f, 0.76953125f, 0.22265625f, 1.0f };
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;" +
"}";
int mProgram;
static final int vertexStride = COORDS_PER_VERTEX * 4;
static final int vertexCount = 4;
public Square() {
// initialize vertex byte buffer for shape coordinates
ByteBuffer bb = ByteBuffer.allocateDirect(squareCoords.length * 4); // (# of coordinate values * 4 bytes per float)
bb.order(ByteOrder.nativeOrder());
vertexBuffer = bb.asFloatBuffer();
vertexBuffer.put(squareCoords);
vertexBuffer.position(0);
// initialize byte buffer for the draw list
ByteBuffer dlb = ByteBuffer.allocateDirect(drawOrder.length * 2); // (# of coordinate values * 2 bytes per short)
dlb.order(ByteOrder.nativeOrder());
drawListBuffer = dlb.asShortBuffer();
drawListBuffer.put(drawOrder);
drawListBuffer.position(0);
int vertexShader = loadShader(GLES20.GL_VERTEX_SHADER, vertexShaderCode);
int fragmentShader = loadShader(GLES20.GL_FRAGMENT_SHADER, fragmentShaderCode);
mProgram = GLES20.glCreateProgram(); // create empty OpenGL ES Program
GLES20.glAttachShader(mProgram, vertexShader); // add the vertex shader to program
GLES20.glAttachShader(mProgram, fragmentShader); // add the fragment shader to program
GLES20.glLinkProgram(mProgram); // creates OpenGL ES program executables
}
public static int loadShader(int type, String shaderCode){
// create a vertex shader type (GLES20.GL_VERTEX_SHADER)
// or a fragment shader type (GLES20.GL_FRAGMENT_SHADER)
int shader = GLES20.glCreateShader(type);
// add the source code to the shader and compile it
GLES20.glShaderSource(shader, shaderCode);
GLES20.glCompileShader(shader);
return shader;
}
public void draw() {
// Add program to OpenGL ES environment
GLES20.glUseProgram(mProgram);
// get handle to vertex shader's vPosition member
int 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
int mColorHandle = GLES20.glGetUniformLocation(mProgram, "vColor");
// Set color for drawing the triangle
GLES20.glUniform4fv(mColorHandle, 1, color, 0);
// Draw the triangle
GLES20.glDrawArrays(GLES20.GL_TRIANGLES, 0, vertexCount);
// Disable vertex array
GLES20.glDisableVertexAttribArray(mPositionHandle);
}
}
解决方案
The problem may be this line:
Square square = new Square();
Because it gets initialized before the call to "setRenderer". The constructor for Square calls GLES20 methods, which could be causing the problem. Try instantiating it after the call to "setRenderer(render);" or inside the "onSurfaceCreated" method.
这篇关于OpenGL ES 2.0的上下文中的Android的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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