Java VAO不使用着色器渲染颜色

我最近开始学习OpenGL，我一直在尝试编写一个程序，使用VAOs和VBOs以及着色器在屏幕上显示钻石。我的代码主要基于本教程： 我还使用了教程中的着色器。钻石应该使用顶点数组对象的颜色信息绘制，但它只是以白色绘制。着色器似乎加载良好，因此我认为顶点和缓冲区数组对象存在问题。有人能解释一下为什么我的代码没有按照我的预期工作，或者给出一个清晰的示例，说明如何使用颜色属性数组中的颜色渲染VAO

package windows;

import java.awt.Frame;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.nio.FloatBuffer;
import java.nio.IntBuffer;

import javax.media.opengl.GL2;
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.GLCanvas;
import javax.media.opengl.glu.GLU;

import shaders.ShaderControl2;

import com.jogamp.common.nio.Buffers;

public class Test4 implements GLEventListener{

ShaderControl2 sc;
FloatBuffer vertexPos, vertexCol;
IntBuffer vao, vbo; 
GLU glu = new GLU();

public static void main(String[] args){
    GLProfile glp = GLProfile.getDefault();
    GLCapabilities caps = new GLCapabilities(glp);
    GLCanvas canvas = new GLCanvas(caps);

    Test4 t = new Test4();

    canvas.addGLEventListener(t);

    Frame f = new Frame("TEST #4");
    f.setSize(400,400);
    f.add(canvas);
    f.setVisible(true);
    f.addWindowListener(new WindowAdapter(){
        public void windowClosing(WindowEvent e){
            System.exit(0);
        }
    });
}


@Override
public void display(GLAutoDrawable drawable) {
    GL2 gl = drawable.getGL().getGL2();
    gl.glClearColor(0, 0, 0, 1f);
    gl.glClear(GL2.GL_COLOR_BUFFER_BIT);

    sc.useShader(gl);

    gl.glBindVertexArray(vao.get(0));
    gl.glEnableVertexAttribArray(0);
    gl.glEnableVertexAttribArray(1);
    gl.glDrawArrays(GL2.GL_LINE_LOOP, 0 , 4);

    sc.dontUseShader(gl);

}

@Override
public void dispose(GLAutoDrawable drawable) {
    // TODO Auto-generated method stub

}

@Override
public void init(GLAutoDrawable drawable) {
    GL2 gl = drawable.getGL().getGL2();
    System.out.println(gl.glGetString(GL2.GL_VERSION));

    vertexPos = Buffers.newDirectFloatBuffer(8);
    vertexPos.put(new float[]{0f, 1f});
    vertexPos.put(new float[]{1f, 0f});
    vertexPos.put(new float[]{0f, -1f});
    vertexPos.put(new float[]{-1f, 0});
    vertexPos.flip();

    vertexCol = Buffers.newDirectFloatBuffer(12);
    vertexCol.put(new float[]{1f, 0f, 0f});
    vertexCol.put(new float[]{0f, 1f, 0f});
    vertexCol.put(new float[]{0f, 0f, 1f});
    vertexCol.put(new float[]{1f, 1f, 1f});
    vertexCol.flip();

    vao = IntBuffer.allocate(1);
    vbo = IntBuffer.allocate(2);

    gl.glGenVertexArrays(1, vao);
    gl.glGenBuffers(2, vbo);

    int bytesPerFloat = Float.SIZE/Byte.SIZE;

    gl.glBindBuffer(GL2.GL_ARRAY_BUFFER,  vbo.get(0));
    gl.glBufferData(GL2.GL_ARRAY_BUFFER, vertexPos.capacity() * bytesPerFloat, vertexPos, GL2.GL_STATIC_DRAW);

    gl.glBindBuffer(GL2.GL_ARRAY_BUFFER, vbo.get(1));
    gl.glBufferData(GL2.GL_ARRAY_BUFFER, vertexCol.capacity() * bytesPerFloat, vertexCol, GL2.GL_STATIC_DRAW);

    gl.glBindBuffer(GL2.GL_ARRAY_BUFFER, 0);

    gl.glBindVertexArray(vao.get());
    gl.glEnableVertexAttribArray(0);
    gl.glEnableVertexAttribArray(1);

    gl.glBindBuffer(GL2.GL_ARRAY_BUFFER, vbo.get(0));
    gl.glVertexAttribPointer(0, 2, GL2.GL_FLOAT, false, 0, 0);

    gl.glBindBuffer(GL2.GL_ARRAY_BUFFER, vbo.get(1));
    gl.glVertexAttribPointer(1, 3, GL2.GL_FLOAT, false, 0, 0);

    gl.glBindBuffer(GL2.GL_ARRAY_BUFFER, 0);


    sc = new ShaderControl2();
    sc.vSrc = sc.loadShader("v.txt");
    sc.fSrc = sc.loadShader("f.txt");

}

@Override
public void reshape(GLAutoDrawable drawable, int x, int y, int width,
        int height) {

}

}

ShaderControl 2代码：

package shaders;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.nio.ByteBuffer;
import java.nio.IntBuffer;

import javax.media.opengl.*;

public class ShaderControl2 {

private int vertexShaderProg, fragmentShaderProg, shaderProg;
public String[] vSrc, fSrc;

public String[] loadShader(String sFile){
    String line = new String();
    StringBuilder fileContent = new StringBuilder();

    try{
        InputStream is = getClass().getResourceAsStream(sFile);
        BufferedReader br = new BufferedReader(new InputStreamReader(is));
        while((line = br.readLine()) != null){
            fileContent.append(line + "\n");
        }
        is.close();
    } catch(Exception e){
        e.printStackTrace();
    }
    System.out.println("Shader file content:\n" + fileContent);
    return new String[]{fileContent.toString()};
}

public void attachShader(GL2 gl){
    IntBuffer isCompiledVS = IntBuffer.allocate(1), isCompiledFS = IntBuffer.allocate(1), isLinked = IntBuffer.allocate(1);
    IntBuffer vLogLength = IntBuffer.allocate(1), fLogLength = IntBuffer.allocate(1), linkLogLength = IntBuffer.allocate(1);
    ByteBuffer vertexInfoLog, fragmentInfoLog, linkInfoLog;
    int size;

    vertexShaderProg = gl.glCreateShader(GL2.GL_VERTEX_SHADER);

    gl.glShaderSource(vertexShaderProg, 1, vSrc, null);
    gl.glCompileShader(vertexShaderProg);

    gl.glGetShaderiv(vertexShaderProg, GL2.GL_COMPILE_STATUS, isCompiledVS);
    if(isCompiledVS.get(0) == 0){
        System.out.println("Failed to compile vertexShaderProg");

        gl.glGetShaderiv(vertexShaderProg, GL2.GL_INFO_LOG_LENGTH, vLogLength); 
        size = vLogLength.get(0);
        vertexInfoLog = ByteBuffer.allocate(size);
        gl.glGetShaderInfoLog(vertexShaderProg, size, vLogLength, vertexInfoLog);

        for(byte b : vertexInfoLog.array()){
            System.err.print((char)b);
        }
    }

    fragmentShaderProg = gl.glCreateShader(GL2.GL_VERTEX_SHADER);

    gl.glShaderSource(fragmentShaderProg, 1, vSrc, null);
    gl.glCompileShader(fragmentShaderProg);

    gl.glGetShaderiv(fragmentShaderProg, GL2.GL_COMPILE_STATUS, isCompiledFS);
    if(isCompiledFS.get(0) == 0){
        System.out.println("Failed to compile fragmentShaderProg");

        gl.glGetShaderiv(fragmentShaderProg, GL2.GL_INFO_LOG_LENGTH, fLogLength);   
        size = fLogLength.get(0);
        fragmentInfoLog = ByteBuffer.allocate(size);
        gl.glGetShaderInfoLog(fragmentShaderProg, size, fLogLength, fragmentInfoLog);

        for(byte b : fragmentInfoLog.array()){
            System.err.print((char)b);
        }

    }

    shaderProg = gl.glCreateProgram();
    gl.glAttachShader(shaderProg, vertexShaderProg);
    gl.glAttachShader(shaderProg, fragmentShaderProg);

    gl.glBindAttribLocation(shaderProg, 0, "in_Position");
    gl.glBindAttribLocation(shaderProg, 1, "in_Color");

    gl.glLinkProgram(shaderProg);

    gl.glGetProgramiv(shaderProg, GL2.GL_LINK_STATUS, isLinked);
    if(isLinked.get(0) == 0){
        System.out.println("Failed to link shaderProg");

        gl.glGetShaderiv(shaderProg, GL2.GL_INFO_LOG_LENGTH, linkLogLength);
        size = linkLogLength.get(0);
        linkInfoLog = ByteBuffer.allocate(size);
        gl.glGetProgramInfoLog(shaderProg, size, linkLogLength, linkInfoLog);

        for(byte b : linkInfoLog.array()){
            System.err.print((char)b);
        }
    }       
}

public int useShader(GL2 gl){
    gl.glUseProgram(shaderProg);
    return shaderProg;
}

public void dontUseShader(GL2 gl){
    gl.glUseProgram(0);
}
}

着色器代码

f、 txt:

#version 210
// It was expressed that some drivers required this next line to function properly
precision highp float;

in  vec3 ex_Color;
out vec4 gl_FragColor;

void main(void) {
    // Pass through our original color with full opacity.
    gl_FragColor = vec4(ex_Color,1.0);
}

v、 txt:

#version 210
// in_Position was bound to attribute index 0 and in_Color was bound to attribute index 1
in  vec2 in_Position;
in  vec3 in_Color;

// We output the ex_Color variable to the next shader in the chain
out vec3 ex_Color;
void main(void) {
// Since we are using flat lines, our input only had two points: x and y.
// Set the Z coordinate to 0 and W coordinate to 1

gl_Position = vec4(in_Position.x, in_Position.y, 0.0, 1.0);

// GLSL allows shorthand use of vectors too, the following is also valid:
// gl_Position = vec4(in_Position, 0.0, 1.0);
// We're simply passing the color through unmodified

ex_Color = in_Color;
}

---

之所以只看到白线，是因为根本没有使用着色器程序

我看不出您在哪里调用附加着色器您从未调用sc.attachShadergl，我在init方法的末尾添加了sc.attachShadergl

现在会出现很多错误

在attachshader中，当您创建fragmentShaderProg时，您将其创建为GL_VERTEX_着色器，它应该是GL_FRAGMENT_着色器，并在其下方发送顶点着色器的源以代替片段着色器

GLSL语言的版本210不存在，请将其更改为版本130。GLSL版本的问题在于它独立于OpenGL版本

现在添加到init方法的末尾

sc.attachShader(gl) 

改变

fragmentShaderProg = gl.glCreateShader(GL2.GL_VERTEX_SHADER);
gl.glShaderSource(fragmentShaderProg, 1, vSrc, null);

为了

现在它起作用了

---

是否确定“颜色”属性位于位置1？您可以使用顶点着色器代码中的位置布局限定符或链接着色器程序之前的GLBindAttributeLocation调用来设置位置。是的，在连接两个着色器之后和链接程序之前，我使用GLBindAttributeLocationShaderProg，0，in_Position和gl.GLBindAttributeLocationShaderProg，1设置位置，在ShaderControl2的attachShaders方法中，这段代码看起来不错。可以添加着色器吗？另外两个提示，第一：无需在显示中重新启用顶点属性，因为这已存储在vao中。第二：我会在初始化后解除vao的绑定，以确保以后的调用会影响它的状态。谢谢提示。我有一种感觉，我在使用一些不需要的方法调用。我在原始帖子中发布了我的着色器代码和ShaderControl 2中的代码。也许问题就出在那段代码里..210版？非常感谢你！我知道这些可能看起来像是愚蠢的错误，但我自己却很难弄清楚，因为我甚至不知道我所做的代码是否正确。不客气，我学习opengl已经有一段时间了，相信我，我对这些错误并不陌生

fragmentShaderProg = gl.glCreateShader(GL2.GL_VERTEX_SHADER);
gl.glShaderSource(fragmentShaderProg, 1, vSrc, null);

fragmentShaderProg = gl.glCreateShader(GL2.GL_FRAGMENT_SHADER);
gl.glShaderSource(fragmentShaderProg, 1, fSrc, null);