我正在使用下面的代码（使用VAO（顶点缓冲区对象）和glDrawArraysInstanced方法）
如果我设置useVao = false，那就没关系。但是当我将其设置为true时，我有以下异常：
javax.media.opengl.GLException：线程[AWT-EventQueue-0,6，main] glGetError（）在调用glVertexAttribPointer后返回以下错误代码（GLArrayDataWrapper [mgl_MultiTexCoord，index -1，location 1，isVertexAttribute true] ，dataType 0x1406，bufferClazz类java.nio.FloatBuffer，元素4，组件2，stride 20b 5c，mappedElementCount 0，缓冲区java.nio.DirectFloatBufferU [pos = 0 lim = 20 cap = 40]，vboEnabled true，vboName 1，vboUsage 0x88e4，vboTarget 0x8892，vboOffset 12，alive true]）：GL_INVALID_OPERATION（1282 0x502），
我认为glVertexAttribPointer（）的最后一个参数（0和Buffers.SIZEOF_FLOAT * 3）是可疑的，但我无法纠正它。
我的试验：
而且我不确定我是否可以同时使用VAO和glDrawArraysInstanced方法。
有什么建议吗？
package demos.triangle;
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.nio.FloatBuffer;
import javax.media.opengl.DebugGL3;
import javax.media.opengl.GL3;
import javax.media.opengl.GLAutoDrawable;
import javax.media.opengl.GLCapabilities;
import javax.media.opengl.GLEventListener;
import javax.media.opengl.GLProfile;
import javax.media.opengl.awt.GLJPanel;
import javax.media.opengl.fixedfunc.GLMatrixFunc;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
import com.jogamp.common.nio.Buffers;
import com.jogamp.opengl.util.FPSAnimator;
import com.jogamp.opengl.util.PMVMatrix;
public class MultTriangleVAOInstancedExperiment implements GLEventListener {
private final JFrame frame;
private final FPSAnimator animator;
private final GLJPanel panel;
private final Dimension dim = new Dimension(1024, 768);
private double t0 = System.currentTimeMillis();
private float theta;
private int shaderProgram;
private int vertShader;
private int fragShader;
private int modelViewProjectionMatrixLocation;
private int transformMatrixLocation;
private static final int locPos = 1;
private static final int locCol = 2;
private static final boolean useVao = false;
// private static final boolean useVao = true;
private int[] vbo;
private int[] vao;
public static void main(String[] s){
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
new MultTriangleVAOInstancedExperiment();
}
});
}
public MultTriangleVAOInstancedExperiment() {
frame = new JFrame(this.getClass().getSimpleName());
frame.setLayout(new BorderLayout());
frame.addWindowListener(new WindowAdapter() {
@Override
public void windowClosing(WindowEvent e) {
animator.stop();
System.exit(0);
}
});
GLProfile profile = GLProfile.get(GLProfile.GL3);
panel = new GLJPanel(new GLCapabilities(profile));
panel.addGLEventListener(this);
panel.setPreferredSize(dim);
frame.add(panel, BorderLayout.CENTER);
frame.pack();
frame.setVisible(true);
animator = new FPSAnimator(panel, 60, true);
animator.start();
}
@Override
public void init(GLAutoDrawable drawable) {
GL3 gl = drawable.getGL().getGL3();
drawable.setGL(new DebugGL3(gl));
gl.glClearColor(1, 1, 1, 1);
gl.glClearDepth(1.0f);
System.err.println("Chosen GLCapabilities: " + drawable.getChosenGLCapabilities());
System.err.println("INIT GL IS: " + gl.getClass().getName());
System.err.println("GL_VENDOR: " + gl.glGetString(GL3.GL_VENDOR));
System.err.println("GL_RENDERER: " + gl.glGetString(GL3.GL_RENDERER));
System.err.println("GL_VERSION: " + gl.glGetString(GL3.GL_VERSION));
vertShader = gl.glCreateShader(GL3.GL_VERTEX_SHADER);
fragShader = gl.glCreateShader(GL3.GL_FRAGMENT_SHADER);
String[] vlines = new String[] { vertexShaderString };
int[] vlengths = new int[] { vlines[0].length() };
gl.glShaderSource(vertShader, vlines.length, vlines, vlengths, 0);
gl.glCompileShader(vertShader);
int[] compiled = new int[1];
gl.glGetShaderiv(vertShader, GL3.GL_COMPILE_STATUS, compiled, 0);
if(compiled[0] != 0) {
System.out.println("Vertex shader compiled");
} else {
int[] logLength = new int[1];
gl.glGetShaderiv(vertShader, GL3.GL_INFO_LOG_LENGTH, logLength, 0);
byte[] log = new byte[logLength[0]];
gl.glGetShaderInfoLog(vertShader, logLength[0], (int[])null, 0, log, 0);
System.err.println("Error compiling the vertex shader: " + new String(log));
System.exit(1);
}
String[] flines = new String[] { fragmentShaderString };
int[] flengths = new int[] { flines[0].length() };
gl.glShaderSource(fragShader, flines.length, flines, flengths, 0);
gl.glCompileShader(fragShader);
gl.glGetShaderiv(fragShader, GL3.GL_COMPILE_STATUS, compiled, 0);
if(compiled[0] != 0){
System.out.println("Fragment shader compiled.");
} else {
int[] logLength = new int[1];
gl.glGetShaderiv(fragShader, GL3.GL_INFO_LOG_LENGTH, logLength, 0);
byte[] log = new byte[logLength[0]];
gl.glGetShaderInfoLog(fragShader, logLength[0], (int[])null, 0, log, 0);
System.err.println("Error compiling the fragment shader: " + new String(log));
System.exit(1);
}
shaderProgram = gl.glCreateProgram();
gl.glAttachShader(shaderProgram, vertShader);
gl.glAttachShader(shaderProgram, fragShader);
gl.glBindAttribLocation(shaderProgram, locPos, "VertexPosition");
gl.glBindAttribLocation(shaderProgram, locCol, "VertexColor");
gl.glLinkProgram(shaderProgram);
modelViewProjectionMatrixLocation = gl.glGetUniformLocation(shaderProgram, "uniform_Projection");
System.out.println("modelViewProjectionMatrixLocation:" + modelViewProjectionMatrixLocation);
transformMatrixLocation = gl.glGetUniformLocation(shaderProgram, "uniform_Transform");
System.out.println("transformMatrixLocation:" + transformMatrixLocation);
FloatBuffer interleavedBuffer = Buffers.newDirectFloatBuffer(vertices.length + colors.length);
for(int i = 0; i < vertices.length/3; i++) {
for(int j = 0; j < 3; j++) {
interleavedBuffer.put(vertices[i*3 + j]);
}
for(int j = 0; j < 4; j++) {
interleavedBuffer.put(colors[i*4 + j]);
}
}
interleavedBuffer.flip();
vao = new int[1];
gl.glGenVertexArrays(1, vao , 0); // was 2
gl.glBindVertexArray(vao[0]);
vbo = new int[1];
gl.glGenBuffers(1, vbo, 0); //was 2
gl.glBindBuffer(GL3.GL_ARRAY_BUFFER, vbo[0]);
gl.glBufferData(GL3.GL_ARRAY_BUFFER, interleavedBuffer.limit() * Buffers.SIZEOF_FLOAT, interleavedBuffer, GL3.GL_STATIC_DRAW);
gl.glEnableVertexAttribArray(locPos);
gl.glEnableVertexAttribArray(locCol);
//
int stride = Buffers.SIZEOF_FLOAT * (3+4);
long arg0 = Buffers.SIZEOF_FLOAT * 3;
//suspicious
gl.glVertexAttribPointer( locPos, 3, GL3.GL_FLOAT, false, stride, 0);
gl.glVertexAttribPointer( locCol, 4, GL3.GL_FLOAT, false, stride, arg0);
if(!useVao) { //added
gl.glDisableVertexAttribArray(locPos);
gl.glDisableVertexAttribArray(locCol);
}
}
@Override
public void reshape(GLAutoDrawable drawable, int x, int y, int width, int height) {
System.out.println("Window resized to width=" + width + " height=" + height);
GL3 gl = drawable.getGL().getGL3();
gl.glViewport(0, 0, width, height);
}
@Override
public void display(GLAutoDrawable drawable) {
double t1 = System.currentTimeMillis();
theta += (t1-t0)*0.005f;
t0 = t1;
GL3 gl = drawable.getGL().getGL3();
gl.glClear(GL3.GL_COLOR_BUFFER_BIT | GL3.GL_DEPTH_BUFFER_BIT);
gl.glUseProgram(shaderProgram);
float[] instanceTransform0 = new float[16];
float[] instanceTransform1 = new float[16];
//I use PMVMatrix class in order to calculate model-view matrix.
PMVMatrix mat0 = new PMVMatrix();
mat0.glMatrixMode(GLMatrixFunc.GL_MODELVIEW);
mat0.glLoadIdentity();
mat0.glTranslatef(0.25f, 0f, 0f);
mat0.glRotatef(15f*theta, 0.0f, 0.0f, 1.0f);
mat0.glScalef(0.8f, 0.8f, 1f);
mat0.glGetFloatv(GLMatrixFunc.GL_MODELVIEW, instanceTransform0, 0);
PMVMatrix mat1 = new PMVMatrix();
mat1.glMatrixMode(GLMatrixFunc.GL_MODELVIEW);
mat1.glLoadIdentity();
mat1.glTranslatef(-0.25f, 0f, 0f);
mat1.glRotatef(10f*theta, 0.0f, 0.0f, 1.0f);
mat1.glScalef(0.5f, 0.5f, 1f);
mat1.glGetFloatv(GLMatrixFunc.GL_MODELVIEW, instanceTransform1, 0);
//concatnate 2 float arrays.
float[] instanceTransformConcatnated = concatnateArrays(instanceTransform0, instanceTransform1);
gl.glUniformMatrix4fv(transformMatrixLocation, instanceTransformConcatnated.length, false, instanceTransformConcatnated , 0);
if(useVao) {
gl.glBindVertexArray(vao[0]);
} else {
gl.glEnableVertexAttribArray(locPos);
gl.glEnableVertexAttribArray(locCol);
}
gl.glDrawArraysInstanced(GL3.GL_TRIANGLES, 0, 3, 2);
if(useVao) {
//EDIT: after removing the next line, the exception disappears.
//gl.glBindVertexArray(0);
} else {
gl.glDisableVertexAttribArray(locPos);
gl.glDisableVertexAttribArray(locCol);
}
gl.glUseProgram(0);
}
@Override
public void dispose(GLAutoDrawable drawable){
GL3 gl = drawable.getGL().getGL3();
gl.glUseProgram(0);
gl.glDeleteBuffers(2, vbo, 0);
gl.glDetachShader(shaderProgram, vertShader);
gl.glDeleteShader(vertShader);
gl.glDetachShader(shaderProgram, fragShader);
gl.glDeleteShader(fragShader);
gl.glDeleteProgram(shaderProgram);
}
private float[] concatnateArrays(float[] arg0, float[] arg1) {
float[] result = new float[arg0.length + arg1.length];
System.arraycopy(arg0, 0, result, 0, arg0.length);
System.arraycopy(arg1, 0, result, arg0.length, arg1.length);
return result;
}
private final String vertexShaderString =
"#version 330 \n" +
"\n" +
"uniform mat4 uniform_Projection; \n" + //not used
"uniform mat4 uniform_Transform[2]; \n" +
"in vec4 VertexPosition; \n" +
"in vec4 VertexColor; \n" +
"out vec4 tmpColor; \n" +
"void main(void) \n" +
"{ \n" +
" tmpColor = VertexColor; \n" +
//" gl_Position = uniform_Projection * VertexPosition; \n" +
" gl_Position = uniform_Transform[gl_InstanceID] * VertexPosition; \n" +
"} ";
private final String fragmentShaderString =
"#version 330\n" +
"\n" +
"in vec4 tmpColor; \n" +
"out vec4 outColor; \n" +
"void main (void) \n" +
"{ \n" +
" outColor = tmpColor; \n" +
"} ";
private final float[] vertices = {
1.0f, 0.0f, 0,
-0.5f, 0.866f, 0,
-0.5f, -0.866f, 0
};
private final float[] colors = {
1.0f, 0.0f, 0.0f, 1.0f,
0.0f, 1.0f, 0.0f, 1.0f,
0f, 0f, 1.0f, 1f
};
}
答案 0 :(得分：1)
我不清楚具体的异常消息，但是您肯定有一个问题：在init()方法的末尾，您为两个顶点属性调用glDisableVertexAttribArray()。此时，您的VAO受到约束。属性启用/禁用状态是VAO状态的一部分。因此，当您稍后在glBindVertexArray()方法中调用display()时，顶点属性将被禁用，您可以在没有任何已启用属性的情况下进行glDrawArraysInstanced()调用。
要解决此问题，您应该在glDisableVertexAttribArray()条件结束时进行init()次调用：
if (!useVao) {
gl.glDisableVertexAttribArray(locPos);
gl.glDisableVertexAttribArray(locCol);
}