【发布时间】：2012-01-23 01:17:49
【问题描述】：
在 Android 上，我试图让一个简单的 OpenGL ES 2.0 应用程序运行，它使用顶点缓冲区对象，但我失败了。
我是从这个项目开始的：
http://developer.android.com/resources/tutorials/opengl/opengl-es20.html
一切都得到了很好的解释，并且按照描述的方式工作。很好。
我添加了一些代码，以交替使用 glDrawElements 命令而不是 glDrawArrays 进行渲染。 我成功了。
现在下一步：我想使用顶点缓冲区对象来做同样的事情。
所以我添加了这个：
-
新变量：
私有 int[] mVBOid = new int[2]; // VBO 和索引缓冲区对象需要 2 个 id 私有 ShortBuffer mIndices； // 使用的索引
-
添加了创建 VBO 的代码：
ByteBuffer vbb = ByteBuffer.allocateDirect( triangleCoords.length * SIZEOF_FLOAT); vbb.order(ByteOrder.nativeOrder());// use the device hardware's native byte order mTriangleVB = vbb.asFloatBuffer(); // create a floating point buffer from the ByteBuffer mTriangleVB.put(triangleCoords); // add the coordinates to the FloatBuffer mTriangleVB.position(0); // set the buffer to read the first coordinate ByteBuffer ibb = ByteBuffer.allocateDirect( indices.length * SIZEOF_SHORT); ibb.order(ByteOrder.nativeOrder()); // use the device hardware's native byte order mIndices = ibb.asShortBuffer(); // create a short buffer from the ByteBuffer mIndices.put(indices); // add the indices to the Buffer mIndices.position(0); // set the buffer to read the first index GLES20.glGenBuffers(2, mVBOid, 0); GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER, mVBOid[0]); GLES20.glBufferData(GLES20.GL_ARRAY_BUFFER, numComponentsPerVertex * SIZEOF_FLOAT, mTriangleVB, GLES20.GL_STATIC_DRAW); GLES20.glBindBuffer(GLES20.GL_ELEMENT_ARRAY_BUFFER, mVBOid[1]); GLES20.glBufferData(GLES20.GL_ELEMENT_ARRAY_BUFFER, mNumIndices * SIZEOF_SHORT, mIndices, GLES20.GL_STATIC_DRAW); -
添加了绘制几何图形的代码：
GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER, mVBOid[0]); GLES20.glVertexAttribPointer(maPositionHandle, nc, GLES20.GL_FLOAT, false, stride, 0); GLES20.glEnableVertexAttribArray(maPositionHandle); GLES20.glBindBuffer(GLES20.GL_ELEMENT_ARRAY_BUFFER, mVBOid[1]); GLES20.glDrawElements(GLES20.GL_TRIANGLE_FAN, mNumIndices, GLES20.GL_UNSIGNED_SHORT, 0);
注意：由于第一个使用 glDrawElements 渲染几何图形而不使用 VBO 的新功能正在运行，我知道 mTriangleVB 和 mIndices 变量正确填充了所需的数据。 maPositionHandle 和 muMVPMatrixHandle 也是正确的。 在我的代码中，我检查了 GL 错误 - 没有找到
我的问题：VBO 技术不起作用；屏幕上什么都看不到，除了清晰的颜色。 在更复杂的应用程序中，我会遇到更多问题：
当引入基于 VBO 的几何时，其他未使用正确渲染的 VBO 的几何是不可见的
偶尔会报告分段错误。试图找出确切原因，我注释掉了很多代码，最后发现，即使根本没有渲染几何图形，也会发生崩溃。 崩溃的原因一定是 VBO 的初始化 - 虽然崩溃不是立即发生，而是在一段时间后发生。
但我仍然无法弄清楚为什么它不起作用。
这里有更多信息：
-
我的环境：
- Android 2.3.3
- 构建目标：Android 2.3.3
- Android SDK 工具：第 15 版
- Android SDK 平台工具：修订版 9
- 设备：华为 Ideos X3 智能手机
SimpleOpenGLES20Renderer 类的完整源代码。
代码基于此示例：
http://developer.android.com/resources/tutorials/opengl/opengl-es20.html
package com.hugo.simplegles20;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;
import java.nio.ShortBuffer;
import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.opengles.GL10;
import android.opengl.GLES20;
import android.opengl.GLSurfaceView;
import android.opengl.Matrix;
import android.util.Log;
public class SimpleOpenGLES20Renderer implements GLSurfaceView.Renderer {
public float mAngle;
static String TAG = "SimpleTest";
final int SIZEOF_FLOAT = Float.SIZE / 8;
final int SIZEOF_SHORT = Short.SIZE / 8;
private int[] mVBOid = new int[2]; // 2 ids needed for VBO and index buffer oject
enum TestType {
USE_ARRAY, // (almost) the original code
USE_ELEMENTS, // rendering, using glDrawElements call
USE_VBO_ELEMENTS // using a vertex buffer object (VBO)
}
private TestType mUsage = TestType.USE_VBO_ELEMENTS;
private boolean mFourComponents = true;
private int mNumIndices = 0;
private FloatBuffer mTriangleVB;
private ShortBuffer mIndices;
private final String vertexShaderCode =
// This matrix member variable provides a hook to manipulate
// the coordinates of the objects that use this vertex shader
"uniform mat4 uMVPMatrix; \n" +
"attribute vec4 vPosition; \n" +
"void main(){ \n" +
// the matrix must be included as a modifier of gl_Position
" gl_Position = uMVPMatrix * vPosition; \n" +
"} \n";
private final String fragmentShaderCode =
"precision mediump float; \n" +
"void main(){ \n" +
" gl_FragColor = vec4 (0.63671875, 0.76953125, 0.22265625, 1.0); \n" +
"} \n";
private int mProgram;
private int maPositionHandle;
private int muMVPMatrixHandle;
private float[] mMVPMatrix = new float[16];
private float[] mMMatrix = new float[16];
private float[] mVMatrix = new float[16];
private float[] mProjMatrix = new float[16];
public static void checkGLError(String msg) {
int e = GLES20.glGetError();
if (e != GLES20.GL_NO_ERROR) {
Log.d(TAG, "GLES20 ERROR: " + msg + " " + e);
Log.d(TAG, errString(e));
}
}
public static String errString(int ec) {
switch (ec) {
case GLES20.GL_NO_ERROR:
return "No error has been recorded.";
case GLES20.GL_INVALID_ENUM:
return "An unacceptable value is specified for an enumerated argument.";
case GLES20.GL_INVALID_VALUE:
return "A numeric argument is out of range.";
case GLES20.GL_INVALID_OPERATION:
return "The specified operation is not allowed in the current state.";
case GLES20.GL_INVALID_FRAMEBUFFER_OPERATION:
return "The command is trying to render to or read from the framebuffer" +
" while the currently bound framebuffer is not framebuffer complete (i.e." +
" the return value from glCheckFramebufferStatus is not" +
" GL_FRAMEBUFFER_COMPLETE).";
case GLES20.GL_OUT_OF_MEMORY:
return "There is not enough memory left to execute the command." +
" The state of the GL is undefined, except for the state" +
" of the error flags, after this error is recorded.";
default :
return "UNKNOW ERROR";
}
}
@Override
public void onSurfaceCreated(GL10 uu, EGLConfig config) {
// Set the background frame color
GLES20.glClearColor(0.5f, 0.5f, 0.5f, 1.0f);
checkGLError("onSurfaceCreated 1");
initShapes();
Log.d(TAG, "load vertex shader");
int vertexShader = loadShader(GLES20.GL_VERTEX_SHADER, vertexShaderCode);
Log.d(TAG, "load fragment shader");
int fragmentShader = loadShader(GLES20.GL_FRAGMENT_SHADER, fragmentShaderCode);
mProgram = GLES20.glCreateProgram(); // create empty OpenGL Program
checkGLError("onSurfaceCreated 2");
GLES20.glAttachShader(mProgram, vertexShader); // add the vertex shader to program
checkGLError("onSurfaceCreated 3");
GLES20.glAttachShader(mProgram, fragmentShader); // add the fragment shader to program
checkGLError("onSurfaceCreated 4");
GLES20.glLinkProgram(mProgram); // creates OpenGL program executables
checkGLError("onSurfaceCreated 5");
// get handle to the vertex shader's vPosition member
maPositionHandle = GLES20.glGetAttribLocation(mProgram, "vPosition");
checkGLError("onSurfaceCreated 6");
muMVPMatrixHandle = GLES20.glGetUniformLocation(mProgram, "uMVPMatrix");
checkGLError("onSurfaceCreated 7");
}
@Override
public void onSurfaceChanged(GL10 unused, int width, int height) {
GLES20.glViewport(0, 0, width, height);
float ratio = (float) width / height;
// this projection matrix is applied to object coordinates
// in the onDrawFrame() method
Matrix.frustumM(mProjMatrix, 0, -ratio, ratio, -1, 1, 3, 7);
Matrix.setLookAtM(mVMatrix, 0, 0, 0, -3, 0f, 0f, 0f, 0f, 1.0f, 0.0f);
}
@Override
public void onDrawFrame(GL10 uu) {
GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT | GLES20.GL_DEPTH_BUFFER_BIT);
checkGLError("onDrawFrame 1");
// Add program to OpenGL environment
GLES20.glUseProgram(mProgram);
checkGLError("onDrawFrame 2");
// Use the mAngle member as the rotation value
Matrix.setRotateM(mMMatrix, 0, mAngle, 0, 0, 1.0f);
// Apply a ModelView Projection transformation
Matrix.multiplyMM(mMVPMatrix, 0, mVMatrix, 0, mMMatrix, 0);
Matrix.multiplyMM(mMVPMatrix, 0, mProjMatrix, 0, mMVPMatrix, 0);
GLES20.glUniformMatrix4fv(muMVPMatrixHandle, 1, false, mMVPMatrix, 0);
checkGLError("onDrawFrame 3");
int nc = mFourComponents ? 4 : 3;
int stride = nc * SIZEOF_FLOAT;
switch (mUsage) {
case USE_ARRAY:
// Prepare the triangle data
GLES20.glVertexAttribPointer(maPositionHandle, nc, GLES20.GL_FLOAT, false, stride, mTriangleVB);
checkGLError("onDrawFrame 4");
GLES20.glEnableVertexAttribArray(maPositionHandle);
checkGLError("onDrawFrame 5");
// Draw the triangle
GLES20.glDrawArrays(GLES20.GL_TRIANGLE_FAN, 0, mNumIndices);
checkGLError("onDrawFrame 6");
break;
case USE_ELEMENTS:
// Prepare the triangle data
GLES20.glVertexAttribPointer(maPositionHandle, nc, GLES20.GL_FLOAT, false, stride, mTriangleVB);
checkGLError("onDrawFrame 7");
GLES20.glEnableVertexAttribArray(maPositionHandle);
checkGLError("onDrawFrame 8");
// Draw the triangle
// int indicesSizeInBytes = SIZEOF_SHORT * mNumIndices;
GLES20.glDrawElements(GLES20.GL_TRIANGLE_FAN, mNumIndices, GLES20.GL_UNSIGNED_SHORT, mIndices);
checkGLError("onDrawFrame 9");
break;
case USE_VBO_ELEMENTS:
GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER, mVBOid[0]);
checkGLError("onDrawFrame 14");
GLES20.glVertexAttribPointer(maPositionHandle, nc, GLES20.GL_FLOAT, false, stride, 0);
checkGLError("onDrawFrame 15");
GLES20.glEnableVertexAttribArray(maPositionHandle);
checkGLError("onDrawFrame 16");
GLES20.glBindBuffer(GLES20.GL_ELEMENT_ARRAY_BUFFER, mVBOid[1]);
checkGLError("onDrawFrame 17");
GLES20.glDrawElements(GLES20.GL_TRIANGLE_FAN, mNumIndices, GLES20.GL_UNSIGNED_SHORT, 0);
checkGLError("onDrawFrame 18");
break;
}
}
private void initShapes(){
float triangleCoords3[] = {
// X, Y, Z
-0.5f, -0.5f, 0,
-0.5f, 0.5f, 0,
-0.2f, -0.2f, 0,
0.5f, -0.5f, 0
};
float triangleCoords4[] = {
// X, Y, Z, W
-0.5f, -0.5f, 0, 1,
-0.5f, 0.5f, 0, 1,
-0.2f, -0.2f, 0, 1,
0.5f, -0.5f, 0, 1
};
short[] indices = {0,1,2,3};
float[] triangleCoords;
int numComponentsPerVertex;
if (mFourComponents) {
triangleCoords = triangleCoords4;
numComponentsPerVertex = 4;
} else {
triangleCoords = triangleCoords3;
numComponentsPerVertex = 3;
}
mNumIndices = triangleCoords.length / numComponentsPerVertex;
Log.d(TAG, "Components per Vertex: " + numComponentsPerVertex);
Log.d(TAG, "Number of Indices : " + mNumIndices);
switch (mUsage) {
case USE_ARRAY:
{
Log.d(TAG, "using array");
// initialize vertex Buffer for triangle
ByteBuffer vbb = ByteBuffer.allocateDirect(
// (# of coordinate values * 4 bytes per float)
triangleCoords.length * SIZEOF_FLOAT);
vbb.order(ByteOrder.nativeOrder());// use the device hardware's native byte order
mTriangleVB = vbb.asFloatBuffer(); // create a floating point buffer from the ByteBuffer
mTriangleVB.put(triangleCoords); // add the coordinates to the FloatBuffer
mTriangleVB.position(0); // set the buffer to read the first coordinate
break;
}
case USE_ELEMENTS:
{
Log.d(TAG, "using VBO elements");
// initialize vertex Buffer for triangle
ByteBuffer vbb = ByteBuffer.allocateDirect(
// (# of coordinate values * 4 bytes per float)
triangleCoords.length * SIZEOF_FLOAT);
vbb.order(ByteOrder.nativeOrder());// use the device hardware's native byte order
mTriangleVB = vbb.asFloatBuffer(); // create a floating point buffer from the ByteBuffer
mTriangleVB.put(triangleCoords); // add the coordinates to the FloatBuffer
mTriangleVB.position(0); // set the buffer to read the first coordinate
vbb = ByteBuffer.allocateDirect(
// (# of coordinate values * 2 bytes per short)
indices.length * SIZEOF_SHORT);
vbb.order(ByteOrder.nativeOrder()); // use the device hardware's native byte order
mIndices = vbb.asShortBuffer(); // create a short buffer from the ByteBuffer
mIndices.put(indices); // add the indices to the Buffer
mIndices.position(0); // set the buffer to read the first index
break;
}
case USE_VBO_ELEMENTS:
{
Log.d(TAG, "using VBO elements");
ByteBuffer vbb = ByteBuffer.allocateDirect(
// (# of coordinate values * 4 bytes per float)
triangleCoords.length * SIZEOF_FLOAT);
vbb.order(ByteOrder.nativeOrder());// use the device hardware's native byte order
mTriangleVB = vbb.asFloatBuffer(); // create a floating point buffer from the ByteBuffer
mTriangleVB.put(triangleCoords); // add the coordinates to the FloatBuffer
mTriangleVB.position(0); // set the buffer to read the first coordinate
ByteBuffer ibb = ByteBuffer.allocateDirect(
indices.length * SIZEOF_SHORT);
ibb.order(ByteOrder.nativeOrder()); // use the device hardware's native byte order
mIndices = ibb.asShortBuffer(); // create a short buffer from the ByteBuffer
mIndices.put(indices); // add the indices to the Buffer
mIndices.position(0); // set the buffer to read the first index
GLES20.glGenBuffers(2, mVBOid, 0);
checkGLError("initShapes 4");
GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER, mVBOid[0]);
checkGLError("initShapes 5");
GLES20.glBufferData(GLES20.GL_ARRAY_BUFFER,
numComponentsPerVertex * SIZEOF_FLOAT,
mTriangleVB,
GLES20.GL_STATIC_DRAW);
checkGLError("initShapes 6");
GLES20.glBindBuffer(GLES20.GL_ELEMENT_ARRAY_BUFFER, mVBOid[1]);
checkGLError("initShapes 7");
GLES20.glBufferData(GLES20.GL_ELEMENT_ARRAY_BUFFER,
mNumIndices * SIZEOF_SHORT,
mIndices,
GLES20.GL_STATIC_DRAW);
checkGLError("initShapes 8");
break;
}
}
}
private 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);
checkGLError("loadShader 1");
// add the source code to the shader and compile it
GLES20.glShaderSource(shader, shaderCode);
checkGLError("loadShader 2");
GLES20.glCompileShader(shader);
checkGLError("loadShader 3");
// Get the compilation status.
final int[] compileStatus = new int[1];
GLES20.glGetShaderiv(shader, GLES20.GL_COMPILE_STATUS, compileStatus, 0);
checkGLError("loadShader 4");
// If the compilation failed, delete the shader.
if (compileStatus[0] == 0)
{
Log.e(TAG, "Error compiling shader: " + GLES20.glGetShaderInfoLog(shader));
GLES20.glDeleteShader(shader);
checkGLError("loadShader 5");
shader = 0;
}
return shader;
}
}
-
故障转储： 12-18 14:59:02.790: I/DEBUG(85): * ** * ** * ** * ** * * * *
12-18 14:59:02.790: I/DEBUG(85): 构建指纹: 'Huawei/U8510/hwu8510:2.3.3/HuaweiU8510/C169B831:user/ota-rel-keys,release-keys'
12-18 14:59:02.790: I/DEBUG(85): pid: 1638, tid: 1646 >>> com.gles20.step1 12-18 14:59:02.860: I/DEBUG(85): 443ef994 811bd8b0
12-18 14:59:02.860: I/DEBUG(85): 443ef998 000000c6
12-18 14:59:02.860: I/DEBUG(85): 443ef99c 443efb68
12-18 14:59:02.860: I/DEBUG(85): 443ef9a0 4360beb4
12-18 14:59:02.860: I/DEBUG(85): 443ef9a4 4360bea0
12-18 14:59:02.860: I/DEBUG(85): 443ef9a8 428da7b4
12-18 14:59:02.870: I/DEBUG(85): 443ef9ac 81089e25 /system/lib/egl/libGLESv2_adreno200.so 12-18 14:59:02.870: I/DEBUG(85): 443ef9b0 001e8cc8
12-18 14:59:02.870: I/DEBUG(85): 443ef9b4 443efa6c
12-18 14:59:02.870: I/DEBUG(85): 443ef9b8 00000001
12-18 14:59:02.870: I/DEBUG(85): 443ef9bc 00000001
12-18 14:59:02.870: I/DEBUG(85): 443ef9c0 0000018c
12-18 14:59:02.870: I/DEBUG(85): 443ef9c4 afd10f08 /system/lib/libc.so 12-18 14:59:02.870: I/DEBUG(85): 443ef9c8 df002777
12-18 14:59:02.870: I/DEBUG(85): 443ef9cc e3a070ad
12-18 14:59:02.870: I/DEBUG(85): #00 443ef9d0 00000000
12-18 14:59:02.870: I/DEBUG(85): 443ef9d4 000a3000
12-18 14:59:02.870: I/DEBUG(85): 443ef9d8 0018b834
12-18 14:59:02.870: I/DEBUG(85): 443ef9dc 443efb68
12-18 14:59:02.870: I/DEBUG(85): 443ef9e0 4360beb4
12-18 14:59:02.870: I/DEBUG(85): 443ef9e4 4360bea0
12-18 14:59:02.870: I/DEBUG(85): 443ef9e8 428da7b4
12-18 14:59:02.870: I/DEBUG(85): 443ef9ec 44aac000
12-18 14:59:02.870: I/DEBUG(85): 443ef9f0 00000000
12-18 14:59:02.870: I/DEBUG(85): 443ef9f4 80e02a08 /system/lib/libgsl.so 12-18 14:59:02.870: I/DEBUG(85): #01 443ef9f8 001e9320
12-18 14:59:02.870: I/DEBUG(85): 443ef9fc 00000001
12-18 14:59:02.870: I/DEBUG(85): 443efa00 001e9320
12-18 14:59:02.870: I/DEBUG(85): 443efa04 00000001
12-18 14:59:02.870: I/DEBUG(85): 443efa08 001e9328
12-18 14:59:02.870: I/DEBUG(85): 443efa0c 81089de3 /system/lib/egl/libGLESv2_adreno200.so
【问题讨论】：
标签： android opengl-es-2.0 shader vbo