OpenGL：Assimp網格不正確

Question

我正在嘗試使用Assimp導入網格。出於某種原因，它顯示不正確。我試圖加載蘇珊：

這是Open3D模型瀏覽器截圖 - 它也使用Assimp。這意味着模型文件是正確的。現在，當我嘗試加載它，它看起來像這樣（以線框渲染）：

我一直想很多東西這就是爲什麼我的代碼減少到最低限度（沒有法線，texcoords等），爲什麼我沒有使用任何我有（除着色器類的類，這是廣泛的測試和罰款）的：

auto pScene = importer.ReadFile("../assets/models/suzanne/suzanne.obj", 
    aiProcess_Triangulate | 
    aiProcess_JoinIdenticalVertices | 
    aiProcess_SortByPType 
); 
//aiProcess_GenNormals); 

// Meshes 
for (size_t stMeshIndex = 0; stMeshIndex < pScene->mNumMeshes; stMeshIndex++) 
{ 
    auto pMeshData = pScene->mMeshes[stMeshIndex]; 

    // Vertices 
    std::vector<float> vertices; 

    for (size_t stIndex = 0; stIndex < pMeshData->mNumVertices; stIndex ++) 
    { 
     vertices.push_back(pMeshData->mVertices[stIndex].x); 
     vertices.push_back(pMeshData->mVertices[stIndex].y); 
     vertices.push_back(pMeshData->mVertices[stIndex].z); 
    } 

    // Indices 
    std::vector<uint32_t> indices; 
    for (size_t stIndex = 0; stIndex < pMeshData->mNumFaces; stIndex++) 
    { 
     indices.push_back(pMeshData->mFaces[stIndex].mIndices[0]); 
     indices.push_back(pMeshData->mFaces[stIndex].mIndices[1]); 
     indices.push_back(pMeshData->mFaces[stIndex].mIndices[2]); 
    } 

    GLuint gl_vao; 
    GLuint gl_vbo; 
    GLuint gl_ibo; 

    // Vertex Array 
    glGenVertexArrays(1, &gl_vao); 
    glGenBuffers(1, &gl_vbo); 
    glGenBuffers(1, &gl_ibo); 

    // Shader 
    auto pVertexShader = pRenderer->CreateShader(ShaderType::Vertex); 
    if (!pVertexShader->CompileFromFile("shader/default_simple.vs")) 
     return; 

    auto pFragmentShader = pRenderer->CreateShader(ShaderType::Fragment); 
    if (!pFragmentShader->CompileFromFile("shader/default.fs")) 
     return; 

    auto pShaderProgram = pRenderer->CreateShaderProgram(); 
    pShaderProgram->AttachShader(pVertexShader); 
    pShaderProgram->AttachShader(pFragmentShader); 
    if (!pShaderProgram->Link()) 
     return; 

    glm::vec2 viewportSize = { 800,600 };// pRenderer->GetContext()->GetViewportSize(); 
    auto matProjection = glm::perspective(
     glm::radians(45.0f), 
     viewportSize.x/viewportSize.y, 
     0.1f, 
     1000.0f); 

    auto matView = glm::lookAt(glm::vec3(3, 3, 0), 
     glm::vec3(), 
     glm::vec3(0, 1, 0)); 

    auto matModel = glm::mat4(1.0f); 

    auto matMVP = matProjection * matView * matModel; 
    pShaderProgram->Use(); 
    pShaderProgram->GetUniform(ShaderUniformRole::TransformMVP)->SetValue(matMVP); 

    glBindBuffer(GL_ARRAY_BUFFER, gl_vbo); 
    glBufferData(GL_ARRAY_BUFFER, sizeof(float) * pMeshData->mNumVertices, &vertices[0], GL_STATIC_DRAW); 

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, gl_ibo); 
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(uint32_t) * pMeshData->mNumFaces * 3, &indices[0], GL_STATIC_DRAW); 

    glBindVertexArray(gl_vao); 
    glEnableVertexAttribArray(0); 
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (GLvoid*)0); 

    while (!pRenderer->GetContext()->GetWindow()->ShouldClose()) 
    { 
     glClearColor(0.05f, 0.05f, 0.05f, 1.0f); 
     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); 

     pShaderProgram->Use(); 

     glBindVertexArray(gl_vao); 
     glBindBuffer(GL_ARRAY_BUFFER, gl_vbo); 

     glPolygonMode(GL_FRONT_AND_BACK, GL_LINE); // Wireframe 

     glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, gl_ibo); 
     glDrawElements(GL_TRIANGLES, pMeshData->mNumFaces * 3, GL_UNSIGNED_INT, 0); 

     pRenderer->GetContext()->GetWindow()->SwapBuffers(); 
     glfwPollEvents(); 
    } 
} 

的着色器minimalized太：

#version 410 
layout(location = 0) in vec3 vp; 
uniform mat4 MVP; 

void main() { 
    gl_Position = MVP * vec4(vp, 1.0); 
} 

#version 410 
out vec4 color; 

void main() 
{  
    color = vec4(1,0,0,1); 
} 

這是Assimp的日誌輸出：

Answer 1

沒有測試。但我猜想這是因爲這樣：

glBufferData(... sizeof(float) * pMeshData->mNumVertices ...); 

你忘了繁殖mNumVertices由3：

glBufferData(... sizeof(float) * pMeshData->mNumVertices * 3 ...); 

既然你已經有了vertices，你也可以這樣做：

glBufferData(... sizeof(float) * vertices.size() ...);