java - 当我尝试使用着色器 (Java) 时，OpenGL 向我发送堆栈下溢错误

Question

我正在用 java 中的 lwjgl 3 开发一个游戏，它运行良好，但是当我想使用着色器时，OpenGL 发送一个 STACK_UNDERFLOW 错误（1284）。

我正在使用 3 个缓冲区：顶点缓冲区、颜色缓冲区、索引缓冲区；

我的旧代码：

private int vbo;
private int cbo;
private int ibo;
private FloatBuffer buffer;
private FloatBuffer colorBuffer;
private IntBuffer indexBuffer;

private IcoSphere sphere;
int radius = 200;

@Override
public void init() {
    sphere = new IcoSphere(9, radius);
    sphere.generate();
    generateBuffer();
}

private void generateBuffer() {
    buffer = BufferUtils.createFloatBuffer(sphere.getVertexCount() * 3);
    colorBuffer = BufferUtils.createFloatBuffer(sphere.getFacesCount() * 4 * 4);
    indexBuffer = BufferUtils.createIntBuffer(sphere.getFacesCount());

    Random r = new Random();
    OpenSimplexNoise noise = new OpenSimplexNoise();

    ArrayList<Vector3f> vertex = sphere.getVertex();
    float[] v = new float[vertex.size() * 3];
    for (int i = 0; i < vertex.size(); i++) {
        vertex.get(i).normalize();
        vertex.get(i).mul(sphere.getRadius() + (float) noise.eval(
                vertex.get(i).x * 8,
                vertex.get(i).y * 8,
                vertex.get(i).z * 8
            ) * 12);
        v[i * 3 + 0] = vertex.get(i).x;
        v[i * 3 + 1] = vertex.get(i).y;
        v[i * 3 + 2] = vertex.get(i).z;
    }
    buffer.put(sphere.getVertexArray());

    indexBuffer.put(sphere.getIndexArray());

    for (int i = 0; i < sphere.getFacesCount(); i++) {
        colorBuffer.put(new float[] {
                r.nextFloat(), r.nextFloat(), r.nextFloat(), 1,
                r.nextFloat(), r.nextFloat(), r.nextFloat(), 1,
                r.nextFloat(), r.nextFloat(), r.nextFloat(), 1
        });
    }

    buffer.flip();
    colorBuffer.flip();
    indexBuffer.flip();

    createBuffer();
}

private void createBuffer() {
    vbo = glGenBuffers();
    cbo = glGenBuffers();
    ibo = glGenBuffers();

    glBindBuffer(GL_ARRAY_BUFFER, vbo);
    glBufferData(GL_ARRAY_BUFFER, buffer, GL_STATIC_DRAW);

    glBindBuffer(GL_ARRAY_BUFFER, cbo);
    glBufferData(GL_ARRAY_BUFFER, colorBuffer, GL_STATIC_DRAW);

    glBindBuffer(GL_ARRAY_BUFFER, 0);

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibo);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, indexBuffer, GL_STATIC_DRAW);

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
}

@Override
public void update() {

}

@Override
public void render() {
    glEnableClientState(GL_VERTEX_ARRAY);
    glEnableClientState(GL_COLOR_ARRAY);

    glBindBuffer(GL_ARRAY_BUFFER, vbo);
    glVertexPointer(3, GL_FLOAT, 0, 0);

    glBindBuffer(GL_ARRAY_BUFFER, cbo);
    glColorPointer(4, GL_FLOAT, 0, 0);

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibo);

    glDrawElements(GL_TRIANGLES, sphere.getFacesCount() * 3, GL_UNSIGNED_INT, 0);

    glDisableClientState(GL_VERTEX_ARRAY);
    glDisableClientState(GL_COLOR_ARRAY);
}

添加着色器后我的新代码：

GlUtils.glCall(() -> ..);用于捕获 opengl 错误。

private int vbo;
private int cbo;
private int ibo;
private FloatBuffer buffer;
private FloatBuffer colorBuffer;
private IntBuffer indexBuffer;

private IcoSphere sphere;
int radius = 200;

@Override
public void init() {
    sphere = new IcoSphere(9, radius);
    sphere.generate();
    generateBuffer();
}

private void generateBuffer() {
    buffer = BufferUtils.createFloatBuffer(sphere.getVertexCount() * 3);
    colorBuffer = BufferUtils.createFloatBuffer(sphere.getFacesCount() * 4 * 4);
    indexBuffer = BufferUtils.createIntBuffer(sphere.getFacesCount());

    Random r = new Random();
    OpenSimplexNoise noise = new OpenSimplexNoise();

    ArrayList<Vector3f> vertex = sphere.getVertex();
    float[] v = new float[vertex.size() * 3];
    for (int i = 0; i < vertex.size(); i++) {
        vertex.get(i).normalize();
        vertex.get(i).mul(sphere.getRadius() + (float) noise.eval(
                vertex.get(i).x * 8,
                vertex.get(i).y * 8,
                vertex.get(i).z * 8
            ) * 12);
        v[i * 3 + 0] = vertex.get(i).x;
        v[i * 3 + 1] = vertex.get(i).y;
        v[i * 3 + 2] = vertex.get(i).z;
    }
    buffer.put(sphere.getVertexArray());

    indexBuffer.put(sphere.getIndexArray());

    for (int i = 0; i < sphere.getFacesCount(); i++) {
        colorBuffer.put(new float[] {
                r.nextFloat(), r.nextFloat(), r.nextFloat(), 1,
                r.nextFloat(), r.nextFloat(), r.nextFloat(), 1,
                r.nextFloat(), r.nextFloat(), r.nextFloat(), 1
        });
    }

    buffer.flip();
    colorBuffer.flip();
    indexBuffer.flip();

    createBuffer();
}

private void createBuffer() {

    vbo = glGenBuffers();
    cbo = glGenBuffers();
    ibo = glGenBuffers();

    GlUtils.glCall(() -> glBindBuffer(GL_ARRAY_BUFFER, vbo));
    GlUtils.glCall(() -> glBufferData(GL_ARRAY_BUFFER, buffer, GL_STATIC_DRAW));
    GlUtils.glCall(() -> glVertexAttribPointer(0, 3, GL_FLOAT, false, 0, 0));

    GlUtils.glCall(() -> glBindBuffer(GL_ARRAY_BUFFER, cbo));
    GlUtils.glCall(() -> glBufferData(GL_ARRAY_BUFFER, colorBuffer, GL_STATIC_DRAW));
    GlUtils.glCall(() -> glVertexAttribPointer(1, 4, GL_FLOAT, false, 0, 0));

    GlUtils.glCall(() -> glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibo));
    GlUtils.glCall(() -> glBufferData(GL_ELEMENT_ARRAY_BUFFER, indexBuffer, GL_STATIC_DRAW));

    GlUtils.glCall(() -> glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0));
    GlUtils.glCall(() -> glBindBuffer(GL_ARRAY_BUFFER, 0));

}

@Override
public void update() {

}

@Override
public void render() {
    Shader.MAIN.bind();

    GlUtils.glCall(() -> glVertexAttribPointer(0, 3, GL_FLOAT, false, 0, 0));

    GlUtils.glCall(() -> glEnableVertexAttribArray(0));
    GlUtils.glCall(() -> glEnableVertexAttribArray(1));


    GlUtils.glCall(() -> glDrawElements(GL_TRIANGLES, indexBuffer));

    GlUtils.glCall(() -> glDisableVertexAttribArray(0));
    GlUtils.glCall(() -> glDisableVertexAttribArray(1));

    Shader.MAIN.unbind();
}

我的着色器：

碎片

#version 410

out vec4 vertColor;

void main(){
    gl_FragColor = vertColor;
}

垂直

#version 410

layout (location=0) in vec3 position;

void main()
{
    gl_Position = vec4(position, 1.0);
}

标签： javaopenglshaderlwjgl

Answer 1

当您使用着色器程序时，您可以使用客户端功能以与之前相同的方式绘制网格。
您所要做的就是使用glEnableVertexAttribArrayandglVertexAttribPointer而不是glEnableClientState, glVertexPointerand glColorPointer：

创建缓冲区：

vbo = glGenBuffers();
cbo = glGenBuffers();
ibo = glGenBuffers();

glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBufferData(GL_ARRAY_BUFFER, buffer, GL_STATIC_DRAW);

glBindBuffer(GL_ARRAY_BUFFER, cbo);
glBufferData(GL_ARRAY_BUFFER, colorBuffer, GL_STATIC_DRAW);

glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibo);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, indexBuffer, GL_STATIC_DRAW);

绘制网格

glBindBuffer(GL_ARRAY_BUFFER, vbo);
glVertexAttribPointer(0, 3, GL_FLOAT, false, 0, 0);

glBindBuffer(GL_ARRAY_BUFFER, cbo);
glVertexAttribPointer(1, 4, GL_FLOAT, false, 0, 0);

glEnableVertexAttribArray(0);
glEnableVertexAttribArray(1);

glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibo);
glDrawElements(GL_TRIANGLES, sphere.getFacesCount() * 3, GL_UNSIGNED_INT, 0);

glDisableVertexAttribArray(0);
glDisableVertexAttribArray(1);

您实际做的是使用默认的顶点数组对象(0) 作为规范。请注意，默认 VAO (0) 仅在兼容性配置文件OpenGL Context中有效。

---

这可以通过使用命名的Vertex Array Object来改善。请注意，您必须在核心配置文件OpenGL Context中使用命名 VAO ：

private int vao;

vao = glGenVertexArrays();
vbo = glGenBuffers();
cbo = glGenBuffers();
ibo = glGenBuffers();

glBindVertexArray(vao);

glEnableVertexAttribArray(0);
glEnableVertexAttribArray(1);

glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBufferData(GL_ARRAY_BUFFER, buffer, GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, false, 0, 0);

glBindBuffer(GL_ARRAY_BUFFER, cbo);
glBufferData(GL_ARRAY_BUFFER, colorBuffer, GL_STATIC_DRAW);
glVertexAttribPointer(1, 4, GL_FLOAT, false, 0, 0);

glBindBuffer(GL_ARRAY_BUFFER, 0);

glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibo);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, indexBuffer, GL_STATIC_DRAW);

glBindVertexArray(0);

顶点数组规范在顶点数组对象中说明。因此不需要glDisableVertexAttribArray.
此外，索引缓冲区( GL_ELEMENT_ARRAY_BUFFER) 在 VAO 中也有说明。glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);会破坏绑定。

现在在绘制网格时绑定 VAO 就足够了：

glBindVertexArray(vao);
glDrawElements(GL_TRIANGLES, sphere.getFacesCount() * 3, GL_UNSIGNED_INT, 0);
glBindVertexArray(0);

---

您有 2 个颜色属性，顶点坐标和颜色。这 2 个属性是Vertex Shader的输入。顶点坐标用于设置gl_Position。颜色必须传递给片段着色器。它是顶点着色器的输出和片段着色器的输入。在片段着色器中，颜色被写入输出fragColor。片段着色器的输出被写入帧缓冲区：

顶点着色器：

layout (location=0) in vec3 position;
layout (location=1) in vec4 color;

out vec4 vertColor;

void main()
{
    vertColor = color;
    gl_Position = vec4(position, 1.0);
}

片段着色器：

#version 410

in vec4 vertColor;
out vec4 fragColor;

void main()
{
    fragColor = vertColor;
}