顶点着色器和纹理生成顺序

opengl

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顶点着色器处理顺序

$$\begin{align} & \text{GenVertexArrays}\left(\scriptsize{VAO}\right)\\ \to & \text{GenBuffers}\left(\scriptsize{VBO}\right)\\ \to & \text{BindBuffer}\\ \to & \text{glBufferData}\\ \to & \text{BindVertexArray}\\ \to & \text{glVertexAttribPointer}\\ \to & \text{EnableVertexAttribArray}\\ \to & \text{glBindVertexArray(0)}({\scriptsize\text{release VAO}}) \end{align}$$

• 样例：

    GLuint VBO, containerVAO;
    glGenVertexArrays(1, &containerVAO);
    glGenBuffers(1, &VBO);
    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
    glBindVertexArray(containerVAO);
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)0);
    glEnableVertexAttribArray(0);
    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)(3 * sizeof(GLfloat)));
    glEnableVertexAttribArray(1);
    glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)(6 * sizeof(GLfloat)));
    glEnableVertexAttribArray(2);
    glBindVertexArray(0);

贴图顺序

$$\begin{align} & 生成\text{Texture ID}\\ \to & 导入图像\\ \to & \text{Bind Texture}\\ \to & \text{glTexImage2D读取绑定图像数据}\\ \to & \text{Mipmap处理}\\ \to & \text{设置Mipmap及WRAP参数} \end{align}$$

• 函数调用顺序：

$$\begin{align} & \text{glGenTexture}\\ \to & \text{SOIL_load_image}\\ \to & \text{glBindTexture}\\ \to & \text{glTexImage2D}\\ \to & \text{glGenerateMipmap}\\ \to & \text{SOIL_free_image_data}\\ \to & \text{glTexParameteri} \end{align}$$

• 样例：

    image = SOIL_load_image("container.png", &width, &height, 0, SOIL_LOAD_RGB);
    glBindTexture(GL_TEXTURE_2D, diffuseMap);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, image);
    glGenerateMipmap(GL_TEXTURE_2D);
    SOIL_free_image_data(image);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST_MIPMAP_NEAREST);