我从这个项目开始:
http://developer.android.com/resources/tutorials/opengl/opengl-es20.html
所有内容都被很好地解释并按描述运作。不错。
我添加了一些代码,使用glDrawElements命令而非glDrawArrays交替进行渲染。我成功了。
现在下一步:我想使用顶点缓冲对象来完成同样的事情。
于是我添加了这个:
new vars:
private int[] mVBOid = new int[2]; // 2 ids needed for VBO and index buffer oject private ShortBuffer mIndices; // indices used
added code to create the VBO:
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);
added code to draw the geometry:
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);
我的问题是:VBO技术不起作用;除了清晰的颜色外,屏幕上什么也看不到。在更复杂的应用程序中,我遇到了更多的问题:
- 当引入基于VBO的几何图形时,其他未使用VBO的几何图形将变得不可见。 - 偶尔会报告分段错误。试图找到确切的原因,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,崩溃仍然会发生。崩溃的原因必须是VBO的初始化-尽管崩溃不是立即发生,而是一段时间后发生。但我仍然无法弄清楚它为什么不起作用。
以下是更多信息:
我的开发环境:
- Android 2.3.3
- 构建目标: Android 2.3.3
- Android SDK工具:Rev. 15
- Android SDK平台工具:Rev. 9
- 设备:华为Ideos X3智能手机
SimpleOpenGLES20Renderer类的完整源代码。
该代码基于以下示例:
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;
}
}
The crash dump:
12-18 14:59:02.790: I/DEBUG(85): * ** * ** * ** * ** * ** *12-18 14:59:02.790: I/DEBUG(85): Build fingerprint: '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 14:59:02.790: I/DEBUG(85): signal 11 (SIGSEGV), code 1 (SEGV_MAPERR), fault addr 00368000 12-18 14:59:02.790: I/DEBUG(85): r0 44affc80 r1 00367ff0 r2 0004f03c r3 00000000 12-18 14:59:02.790: I/DEBUG(85): r4 00000000 r5 00000000 r6 00000000 r7 00000028 12-18 14:59:02.790: I/DEBUG(85): r8 00000000 r9 00000000 10 00000000 fp 00000000 12-18 14:59:02.790: I/DEBUG(85): ip 00368000 sp 443ef9d0 lr 80e02a08 pc afd0cd7c cpsr 20000010 12-18 14:59:02.790: I/DEBUG(85): d0 c420e36a40000000 d1 3f800000c4a0e36a 12-18 14:59:02.790: I/DEBUG(85): d2 000000003f800000 d3 000000003f800000 12-18 14:59:02.790: I/DEBUG(85): d4 0000000000000000 d5 0000000000000000 12-18 14:59:02.790: I/DEBUG(85): d6 3f80000000000000 d7 3f8000003f800000 12-18 14:59:02.790: I/DEBUG(85): d8 0000000000000000 d9 0000000000000000 12-18 14:59:02.800: I/DEBUG(85): d10 0000000000000000 d11 0000000000000000 12-18 14:59:02.800: I/DEBUG(85): d12 0000000000000000 d13 0000000000000000 12-18 14:59:02.800: I/DEBUG(85): d14 0000000000000000 d15 0000000000000000 12-18 14:59:02.800: I/DEBUG(85): scr 20000010 12-18 14:59:02.860: I/DEBUG(85): #00 pc 0000cd7c /system/lib/libc.so 12-18 14:59:02.860: I/DEBUG(85): #01 pc 00002a04 /system/lib/libgsl.so 12-18 14:59:02.860: I/DEBUG(85): #02 pc 00089de0 /system/lib/egl/libGLESv2_adreno200.so 12-18 14:59:02.860: I/DEBUG(85): #03 pc 00091a4a /system/lib/egl/libGLESv2_adreno200.so 12-18 14:59:02.860: I/DEBUG(85): #04 pc 000612ca /system/lib/egl/libGLESv2_adreno200.so 12-18 14:59:02.860: I/DEBUG(85): #05 pc 0006138a /system/lib/egl/libGLESv2_adreno200.so 12-18 14:59:02.860: I/DEBUG(85): #06 pc 00063d94 /system/lib/egl/libGLESv2_adreno200.so 12-18 14:59:02.860: I/DEBUG(85): #07 pc 000836aa /system/lib/egl/libGLESv2_adreno200.so 12-18 14:59:02.860: I/DEBUG(85): #08 pc 0003fd66 /system/lib/libandroid_runtime.so 12-18 14:59:02.860: I/DEBUG(85): #09 pc 00012174 /system/lib/libdvm.so 12-18 14:59:02.860: I/DEBUG(85): code around pc: 12-18 14:59:02.860: I/DEBUG(85): afd0cd5c e0422003 e2522020 3a000008 e3c1c01f 12-18 14:59:02.860: I/DEBUG(85): afd0cd6c e28cc040 e8b10ff0 f5dcf040 e2522020 12-18 14:59:02.860: I/DEBUG(85): afd0cd7c 849c3020 e8a00ff0 2afffff9 e2822020 12-18 14:59:02.860: I/DEBUG(85): afd0cd8c e312001f 0a00000c e1b0ce02 28b100f0 12-18 14:59:02.860: I/DEBUG(85): afd0cd9c 48b10300 28a000f0 48a00300 e1b0cf02 12-18 14:59:02.860: I/DEBUG(85): code around lr: 12-18 14:59:02.860: I/DEBUG(85): 80e029e8 e5906008 e0831001 e1510006 8a000006 12-18 14:59:02.860: I/DEBUG(85): 80e029f8 e5903000 e1a0100e e0830005 eb000a13 12-18 14:59:02.860: I/DEBUG(85): 80e02a08 e1a00004 e28dd008 e8bd8070 e59f104c 12-18 14:59:02.860: I/DEBUG(85): 80e02a18 e59fe04c e1a02005 e79c0001 e08f100e 12-18 14:59:02.860: I/DEBUG(85): 80e02a28 e58d6000 e28000a8 ebfffef8 e3e00000 12-18 14:59:02.860: I/DEBUG(85): stack: 12-18 14:59:02.860: I/DEBUG(85): 443ef990 0000018c
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