Question

我正在使用WaveFront .obj Loader，我的第一个目标是从下面的.obj文件中加载所有顶点和索引（显示带有弯曲边缘的立方体）。

# Blender v2.62 (sub 0) OBJ File: 'Cube.blend'
# www.blender.org
o Cube
v 0.900000 -1.000000 -0.900000
v 0.900000 -1.000000 0.900000
v -0.900000 -1.000000 0.900000
v -0.900000 -1.000000 -0.900000
v 0.900000 1.000000 -0.900000
v 0.899999 1.000000 0.900001
v -0.900000 1.000000 0.900000
v -0.900000 1.000000 -0.900000
v 1.000000 -0.900000 -1.000000
v 1.000000 -0.900000 1.000000
v -1.000000 -0.900000 1.000000
v -1.000000 -0.900000 -1.000000
v 1.000000 0.905000 -0.999999
v 0.999999 0.905000 1.000001
v -1.000000 0.905000 1.000000
v -1.000000 0.905000 -1.000000
f 1//1 2//1 3//1
f 1//1 3//1 4//1
f 13//2 9//2 12//2
f 13//2 12//2 16//2
f 5//3 13//3 16//3
f 5//3 16//3 8//3
f 15//4 7//4 8//4
f 15//5 8//5 16//5
f 11//6 15//6 16//6
f 11//6 16//6 12//6
f 14//7 6//7 7//7
f 14//7 7//7 15//7
f 10//8 14//8 11//8
f 14//8 15//8 11//8
f 13//9 5//9 6//9
f 13//9 6//9 14//9
f 9//10 13//10 10//10
f 13//11 14//11 10//11
f 9//12 1//12 4//12
f 9//12 4//12 12//12
f 3//13 11//13 12//13
f 3//14 12//14 4//14
f 2//15 10//15 11//15
f 2//15 11//15 3//15
f 1//16 9//16 10//16
f 1//16 10//16 2//16
f 5//17 8//17 7//17
f 5//17 7//17 6//17

我已将所有顶点和索引加载到名为verticesVec和indicesVec的两个向量中，并且我已经检查了它们两者（它们的输入顺序正确，verticesVec [0] = 0.9且indicesVec [0] = 1）。我将顶点加载到VertexBufferObject中，并将VerticArrayObject中的索引与着色器字段设置一起加载。

然而，当我渲染立方体时，我得到以下图像，这是不正确的。我已经重新检查了我的所有代码，但我找不到我出错的部分。它与向量和向量的字节大小有关吗？

wrong cube http://imageshack.us/a/img850/6249/wrongcube.png

以下代码来自我的Draw / Render方法，它执行所有渲染。

    glUseProgram(theProgram);
    GLuint modelToCameraMatrixUnif = glGetUniformLocation(theProgram, "modelToCameraMatrix");
    GLuint perspectiveMatrixUnif = glGetUniformLocation(theProgram, "cameraToClipMatrix");
    glUniformMatrix4fv(perspectiveMatrixUnif, 1, GL_FALSE, glm::value_ptr(cameraToClipMatrix));

    glm::mat4 identity(1.0f);
    glutil::MatrixStack stack(identity); // Load identity Matrix

    // Push for Camera Stuff
    glutil::PushStack camera(stack);
    stack.Translate(glm::vec3(camX, camY, camZ));

    //Push one step further to fix object 1
    glutil::PushStack push(stack);

    stack.Translate(glm::vec3(0.0f, 0.0f, 3.0f));
    // Draw Blender object
    glBindVertexArray(this->load.vertexArrayOBject);
    glUniformMatrix4fv(modelToCameraMatrixUnif, 1, GL_FALSE, glm::value_ptr(stack.Top()));
    glDrawElements(GL_TRIANGLES, this->load.indicesVec.size(), GL_UNSIGNED_SHORT, 0);

    // Pop camera (call destructor to de-initialize all dynamic memory)
    camera.~PushStack();

    // Now reset all buffers/programs
    glBindVertexArray(0);
    glUseProgram(0);

我的.obj加载器中缓冲区对象的初始化：

void Loader::generateVertexBufferObjects()
{
     // Fils the vertex buffer object with data
    glGenBuffers(1, &vertexBufferObject);
    glBindBuffer(GL_ARRAY_BUFFER, vertexBufferObject);
    glBufferData(GL_ARRAY_BUFFER, verticesVec.size() * 4, &verticesVec[0], GL_STATIC_DRAW);
    glBindBuffer(GL_ARRAY_BUFFER, 0);


    // Fills the index buffer object with its data
    glGenBuffers(1, &indexBufferObject);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexBufferObject);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, indicesVec.size() * 4, &indicesVec[0], GL_STATIC_DRAW);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
}

void Loader::generateVertexArrayObjects()
{
    glGenVertexArrays(1, &vertexArrayOBject);
    glBindVertexArray(vertexArrayOBject);

    glBindBuffer(GL_ARRAY_BUFFER, vertexBufferObject);
    glEnableVertexAttribArray(0);
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, 0);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexBufferObject);

    glBindVertexArray(0);
}

Answer 1

您将索引创建为无符号整数，但是您传递的是OpenGL，它们的类型为GL_UNSIGNED_SHORT。 glDrawElements的type参数必须与上传到索引缓冲区的数据类型相匹配。

WaveFront .obj加载器不会显示对象（VBO和VAO）

1 个答案: