我正在尝试在Android上构建一个小的Open GL2.0演示应用程序，但我收到以下错误
日志cat中的
07-02 20:50:40.110: E/libEGL(1252): call to OpenGL ES API with no current context (logged once per thread)
07-02 20:50:40.110: E/libEGL(1252): call to OpenGL ES API with no current context (logged once per thread)
07-02 20:50:40.110: E/libEGL(1252): call to OpenGL ES API with no current context (logged once per thread)
07-02 20:50:40.110: E/libEGL(1252): call to OpenGL ES API with no current context (logged once per thread)
07-02 20:50:40.110: E/libEGL(1252): call to OpenGL ES API with no current context (logged once per thread)
07-02 20:50:40.110: E/libEGL(1252): call to OpenGL ES API with no current context (logged once per thread)
07-02 20:50:40.110: E/libEGL(1252): call to OpenGL ES API with no current context (logged once per thread)
07-02 20:50:40.110: E/libEGL(1252): call to OpenGL ES API with no current context (logged once per thread)
07-02 20:50:40.110: E/libEGL(1252): call to OpenGL ES API with no current context (logged once per thread)
07-02 20:50:40.110: E/libEGL(1252): call to OpenGL ES API with no current context (logged once per thread)
[2012-07-02 20:50:44 - Emulator] development/tools/emulator/opengl/host/libs/Translator/GLES_V2/GLESv2Imp.cpp:glGetAttribLoc ation:826 error 0x501
[2012-07-02 20:50:44 - Emulator] development/tools/emulator/opengl/host/libs/Translator/GLES_V2/GLESv2Imp.cpp:glGetUniformLocation:1383 error 0x501
我的代码
查看
package limitliss.graphics.play;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;
import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.opengles.GL10;
import android.content.Context;
import android.opengl.GLES20;
import android.opengl.GLSurfaceView;
import android.opengl.GLSurfaceView.Renderer;
import android.opengl.GLU;
public class OGLView extends GLSurfaceView implements Renderer {
private int mColorType = 0;
private float rotx = 0.0f;
private float roty = 0.0f;
Triangle tri = new Triangle();
public OGLView(Context context) {
super(context);
setEGLContextClientVersion(2);
this.setRenderer(this);
setRenderMode(GLSurfaceView.RENDERMODE_WHEN_DIRTY);
// TODO Auto-generated constructor stub
}
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 onSurfaceCreated(GL10 unused, EGLConfig config) {
// Set the background frame color
GLES20.glClearColor(0.5f, 0.5f, 0.5f, 1.0f);
tri.draw();
}
public void onDrawFrame(GL10 unused) {
// Redraw background color
GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);
tri.draw();
}
public void onSurfaceChanged(GL10 unused, int width, int height) {
GLES20.glViewport(0, 0, width, height);
}
}
Triangle
package limitliss.graphics.play;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;
import javax.microedition.khronos.opengles.GL10;
import android.opengl.GLES20;
public class Triangle {
float color[] = { 0.63671875f, 0.76953125f, 0.22265625f, 1.0f };
private FloatBuffer vertexBuffer;
int mProgram;
int mPositionHandle;
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;" +
"}";
// number of coordinates per vertex in this array
static final int COORDS_PER_VERTEX = 3;
static float triangleCoords[] = { // in counterclockwise order:
0.0f, 0.622008459f, 0.0f, // top
-0.5f, -0.311004243f, 0.0f, // bottom left
0.5f, -0.311004243f, 0.0f}; // bottom right
public Triangle() {
// initialize vertex byte buffer for shape coordinates
ByteBuffer bb = ByteBuffer.allocateDirect(
// (number of coordinate values * 4 bytes per float)
triangleCoords.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();
// add the coordinates to the FloatBuffer
vertexBuffer.put(triangleCoords);
// set the buffer to read the first coordinate
vertexBuffer.position(0);
int vertexShader = OGLView.loadShader(GLES20.GL_VERTEX_SHADER, vertexShaderCode);
int fragmentShader = OGLView.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);
}
public void draw() {
// Add program to OpenGL ES 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,
COORDS_PER_VERTEX, 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, 3);
// Disable vertex array
GLES20.glDisableVertexAttribArray(mPositionHandle);
}
public void render(GL10 gl){
gl.glPushMatrix();
gl.glColor4f(this.color[0],this.color[1],this.color[2],this.color[3]);
gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertexBuffer);
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
gl.glDrawArrays(GL10.GL_TRIANGLE_FAN, 0, 3);
gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
gl.glPopMatrix();
}
}
答案 0 :(得分：16)
您收到call to OpenGL ES API with no current context错误，因为您在OpenGL线程之外创建了三角形Triangle tri = new Triangle();（并且三角形构造函数正在进行opengl调用）。只有OpenGL回调中的代码（onSurfaceCreated，onDrawFrame等）才会在opengl线程上执行。
将tri = new Triangle()放在onSurfaceCreated内，这些错误应该消失。
答案 1 :(得分：-1)
添加私人最终上下文上下文; 就在下面的“公共类OGLView扩展GLSurfaceView实现Renderer {”