Question

我正在尝试在安装了最新驱动程序的NVIDIA GTX 970上使用OpenGL 4.4实现延迟着色。
我的代码可以直接渲染到屏幕。为了添加第二遍，我创建了一个我渲染场景的FBO和一个渲染最终图像的四边形。当我尝试在第一遍中渲染任何东西并在第二遍之后绘制四边形时，四边形是可见的。当我尝试在第一次通过期间渲染网格（例如立方体）时，四边形消失。另外，我收到以下错误消息：
enter image description here

网格上装有AssImp 我使用以下代码创建VBO / VAO：

void Mesh::genGPUBuffers()
{
    glGenBuffers(1, &vertexbuffer);
    glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer);
    glBufferData(GL_ARRAY_BUFFER, vertices.size() * sizeof(vec3), &vertices[0], GL_STATIC_DRAW);
    glBindBuffer(GL_ARRAY_BUFFER, 0);

    glGenBuffers(1, &uvbuffer);
    glBindBuffer(GL_ARRAY_BUFFER, uvbuffer);
    glBufferData(GL_ARRAY_BUFFER, uvs.size() * sizeof(vec2), &uvs[0], GL_STATIC_DRAW);
    glBindBuffer(GL_ARRAY_BUFFER, 0);

    glGenBuffers(1, &normalbuffer);
    glBindBuffer(GL_ARRAY_BUFFER, normalbuffer);
    glBufferData(GL_ARRAY_BUFFER, normals.size() * sizeof(vec3), &normals[0], GL_STATIC_DRAW);
    glBindBuffer(GL_ARRAY_BUFFER, 0);

    glGenBuffers(1, &indexbuffer);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexbuffer);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, indices.size() * sizeof(unsigned short), &indices[0], GL_STATIC_DRAW);
    glBindBuffer(GL_ARRAY_BUFFER, 0);
}

我像这样渲染我的网格：

void Mesh::render()
{
    if (shader != nullptr)
    {
        shader->use();
        shader->setModelMatrix(modelMatrix);
    }

    for (int i = 0x1; i <= 0xB; i++)
    {
        if (texture[i] != nullptr)
        {
            glBindMultiTextureEXT(GL_TEXTURE0 + i, GL_TEXTURE_2D, texture[i]->getTextureID());
        }
    }

    // 1rst attribute buffer : vertices
    glEnableVertexAttribArray(0);
    glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer);
    glVertexAttribPointer(
        0,                  // attribute
        3,                  // size
        GL_FLOAT,           // type
        GL_FALSE,           // normalized?
        0,                  // stride
        (void*)0            // array buffer offset
    );

    // 2nd attribute buffer : UVs
    glEnableVertexAttribArray(1);
    glBindBuffer(GL_ARRAY_BUFFER, uvbuffer);
    glVertexAttribPointer(
        1,                                // attribute
        2,                                // size
        GL_FLOAT,                         // type
        GL_FALSE,                         // normalized?
        0,                                // stride
        (void*)0                          // array buffer offset
    );

    // 3rd attribute buffer : normals
    glEnableVertexAttribArray(2);
    glBindBuffer(GL_ARRAY_BUFFER, normalbuffer);
    glVertexAttribPointer(
        2,                                // attribute
        3,                                // size
        GL_FLOAT,                         // type
        GL_FALSE,                         // normalized?
        0,                                // stride
        (void*)0                          // array buffer offset
    );

    // Index buffer
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexbuffer);

    // Draw the triangles
    glDrawElements(
        GL_TRIANGLES,      // mode
        (GLsizei)indexCount,    // count
        GL_UNSIGNED_SHORT,   // type
        (void*)0           // element array buffer offset
    );

    glDisableVertexAttribArray(0);
    glDisableVertexAttribArray(1);
    glDisableVertexAttribArray(2);
}

使用gDEBugger，我发现错误消息来自glVertexAttribPointer。但是由于gDEBugger不支持OpenGL 4，它本身会抛出很多错误，并没有真正起作用。

FBO的生成如下：

GLuint depthBuf;
Texture
    posTex(this),
    normTex(this),
    colorTex(this)
;

// Create and bind the FBO
glGenFramebuffers(1, &fbo);
glBindFramebuffer(GL_FRAMEBUFFER, fbo);

// The depth buffer
glGenRenderbuffers(1, &depthBuf);
glBindRenderbuffer(GL_RENDERBUFFER, depthBuf);
glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT, static_cast<GLsizei>(resolution.x), static_cast<GLsizei>(resolution.y));

// Create the textures for position, normal and color
posTex.createGBuf(GL_TEXTURE0, GL_RGB32F, static_cast<int>(resolution.x), static_cast<int>(resolution.y));
normTex.createGBuf(GL_TEXTURE1, GL_RGB32F, static_cast<int>(resolution.x), static_cast<int>(resolution.y));
colorTex.createGBuf(GL_TEXTURE2, GL_RGB8, static_cast<int>(resolution.x), static_cast<int>(resolution.y));

// Attach the textures to the framebuffer
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depthBuf);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, posTex.getTextureID(), 0);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT1, GL_TEXTURE_2D, normTex.getTextureID(), 0);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT2, GL_TEXTURE_2D, colorTex.getTextureID(), 0);

glBindFramebuffer(GL_FRAMEBUFFER, 0);

createGBuf（）函数如下所示：

void C0::Texture::createGBuf(GLenum texUnit, GLenum format, int width, int height)
{
    this->width = width;
    this->height = height;
    glActiveTexture(texUnit);
    glGenTextures(1, &textureID);
    glBindTexture(GL_TEXTURE_2D, textureID);
    glTexStorage2D(GL_TEXTURE_2D, 1, format, width, height);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
}

Answer 1

您的代码出错可能是因为您从未生成过VertexArrayObject，调用glGenVertexArray（1，你的vao指针）;如果你没有，现代的opengl会把它标记为一个错误，这可能是你发生的事情。生成一个顶点数组，然后用glBindVertexArray（你的vao）绑定它;

其次，您不应该在每个渲染周期缓冲数据。这非常低效。您应该创建多个VAO，将顶点数据绑定到它们然后取消绑定vao，当您渲染相应的网格时，只需重新绑定VAO和glDrawElements。

一个例子就是这个，

如果您有像这样的结构顶点

struct Vertex{
  vec3 position;
  vec2 uv;
  vec3 normal;
};
struct Mesh{
   std::vector<Vertex> vertices;
   std::vector<unsigned int> indices;

   GLuint VAO;

   void initializeVAO();
   void Render();
};

然后你这样初始化。

Mesh::initializeVAO(){
    GLuint vertexBuffer, indiceBuffer;
    glGenVertexArrays(1, &VAO);
    glBindVertexArray(VAO);

    glGenBuffers(1, &vertexBuffer);
    glGenBuffers(1, &indiceBuffer);

    glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer);
    glBufferData(GL_ARRAY_BUFFER, vertices.size()*sizeof(Vertex), &vertices[0], GL_STATIC_DRAW);
    glEnableVertexAttribArray(0);
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), 0);

    glEnableVertexAttribArray(1);
    glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void*)sizeof(vec3));

    glEnableVertexAttribArray(2);
    glVertexAttribPointer(2, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void*)(sizeof(:vec3) + sizeof(glm::vec2)));

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indiceBuffer);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, indices.size() * sizeof(unsigned int), &indices[0], GL_STATIC_DRAW);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indiceBuffer);

    glBindVertexArray(0);
    glDeleteBuffers(1, &vertexBuffer);
    glDeleteBuffers(1, &indiceBuffer);
}

然后渲染

Mesh::Render()
{
     glBindVertexArray(VAO);
     glDrawElements(GL_TRIANGLES, indices.size(), 0);
     glBindVertexArray(0);
}

如果您有任何疑问，请随时提出。

glVertexAttribPointer GL_INVALID_OPERATION无效的vao vbo指针用法

1 个答案: