导致问题的纹理

问题描述

我正在尝试在OpenGL中创建表格并将纹理放置到表格上。当我使用OpenGL颜色而不是纹理创建表格时，它工作得很好。但是，当我添加纹理代码时，一切都坏了。现在桌子看起来像一张被压成球的纸。看来程序不了解顶点应该去哪里？

这是我编写的代码：

// Header Inclusions
#include <iostream>
#include <GL/glew.h>
#include <GL/freeglut.h>

// GLM Math Header inclusions
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>

// SOIL Image loader Inclusion
#include "SOIL2/SOIL2.h"

using namespace std; // Standard namespace

#define WINDOW_TITLE "Zane's CameraOrbit" // Window title Macro

// Shader program Macro
#ifndef GLSL
#define GLSL(Version,Source) "#version " #Version "\n" #Source
#endif

// Variable declarations for shader,window size initialization,buffer and array objects
GLint shaderProgram,WindowWidth = 800,WindowHeight = 600;
GLuint VBO,VAO,texture;
GLfloat degrees = glm::radians(-45.0f); // Converts float to degrees

GLfloat cameraSpeed = 0.0005f; // Movement speed per frame

GLchar currentKey; // will store key pressed
bool proj = true;


GLfloat lastMouseX = 400,lastMouseY = 300; // Locks mouse cursor at the center of the screen
GLfloat mouseXOffset,mouseYOffset,yaw = 0.0f,pitch = 0.0f; // mouse offset,yaw,and pitch variables
GLfloat sensitivity = 0.005f; // Used for mouse / camera rotation sensitivity
bool mouseDetected = true; // Initially true when mouse movement is detected

// Global vector declarations
glm::vec3 cameraPosition = glm::vec3(0.0f,0.0f,0.0f); // Initial camera position. Placed 5 units in Z
glm::vec3 CameraUpY = glm::vec3(0.0f,1.0f,0.0f); // Temporary y unit vector
glm::vec3 CameraForwardZ = glm::vec3(0.0f,-1.0f); // Temporary Z unit vector
glm::vec3 front; // Temporary Z unit vector for mouse


// Function prototypes
void UResizeWindow(int,int);
void URenderGraphics(void);
void UCreateShader(void);
void UCreateBuffers(void);
void UGenerateTexture(void);
void UKeyboard(unsigned char key,int x,int y);
void UKeyReleased(unsigned char key,int y);

void UMouseMove(int x,int y);


// Vertex Shader Source Code
const GLchar * vertexShaderSource = GLSL(330,layout (location = 0) in vec3 position; // Vertex data from Vertex Attrib Pointer 0
    layout (location = 2) in vec2 textureCoordinate;

    out vec2 mobileTextureCoordinate;

    //Global variables for the transform matrices
        uniform mat4 model;
        uniform mat4 view;
        uniform mat4 projection;

void main(){
        gl_Position = projection * view * model * vec4(position,1.0f); // transforms vertices to clip coordinates
        mobileTextureCoordinate = vec2(textureCoordinate.x,1.0f - textureCoordinate.y); // flips the texture horizontal
    }
);


// Fragment Shader Source Code
const GLchar * fragmentShaderSource = GLSL(330,in vec2 mobileTextureCoordinate;

        out vec4 gpuTexture; // Variable to pass color data to the GPU

        uniform sampler2D uTexture; // Useful when working with multiple textures

    void main(){

        gpuTexture = texture(uTexture,mobileTextureCoordinate);
    }
);

// Main program
int main(int argc,char* argv[])
{
    glutInit(&argc,argv);
    glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA);
    glutInitWindowSize(WindowWidth,WindowHeight);
    glutCreateWindow(WINDOW_TITLE);

    glutReshapeFunc(UResizeWindow);

    glewExperimental = GL_TRUE;
        if (glewInit() != GLEW_OK)
        {
            std::cout << "Failed to initialize GLEW" << std::endl;
            return -1;
        }

    UCreateShader();

    UCreateBuffers();

    UGenerateTexture();

    // Use the Shader program
    glUseProgram(shaderProgram);

    glClearColor(0.0f,1.0f); // Set background color

    glutDisplayFunc(URenderGraphics);

    glutKeyboardFunc(UKeyboard);

    glutKeyboardUpFunc(UKeyReleased);

    glutPassiveMotionFunc(UMouseMove); // Detects mouse movement

    glutMainLoop();

    // Destroys Buffer objects once used
    glDeleteVertexArrays(1,&VAO);
    glDeleteBuffers(1,&VBO);

    return 0;
}


// Resizes the window
void UResizeWindow(int w,int h)
{
    WindowWidth = w;
    WindowHeight = h;
    glViewport(0,WindowWidth,WindowHeight);
}

// Renders graphics
void URenderGraphics(void)
{
    glEnable(GL_DEPTH_TEST); // Enable z-depth

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Clears the screen

    glBindVertexArray(VAO); // Activates the vertex array object before rednering and transforming them

    CameraForwardZ = front; // Replaces camera forward vector with Radians normalized as unit vector

    //Transforms the object
    glm::mat4 model;
    model = glm::translate(model,glm::vec3(0.0f,0.0f)); // Place the object at the center of the viewport
    model = glm::rotate(model,45.0f,glm::vec3(0.0,0.0f)); // Rotate the object 45 degrees on the X
    model = glm::scale(model,glm::vec3(2.0f,2.0f,2.0f)); // Increase the object size by a scale of 2

    // Transforms the camera THIS DIFFERS FROM TUTORIAL
    glm::mat4 view;
    view = glm::lookAt(CameraForwardZ,cameraPosition,CameraUpY);

    // Creates a perspective projection THIS DIFFERS FROM TUTORIAL
    glm::mat4 projection;
    if(proj)
        projection = glm::perspective(45.0f,(GLfloat)WindowWidth / (GLfloat)WindowHeight,0.1f,100.0f);

    else
        projection = glm::ortho(-5.0f,5.0f,-5.0f,100.0f);

    // Retrieves and passes transform matrices to the shader program
    GLint modelLoc = glGetUniformLocation(shaderProgram,"model");
    GLint viewLoc = glGetUniformLocation(shaderProgram,"view");
    GLint projLoc = glGetUniformLocation(shaderProgram,"projection");

    glUniformMatrix4fv(modelLoc,1,GL_FALSE,glm::value_ptr(model));
    glUniformMatrix4fv(viewLoc,glm::value_ptr(view));
    glUniformMatrix4fv(projLoc,glm::value_ptr(projection));

    glutPostRedisplay();

    glBindTexture(GL_TEXTURE_2D,texture);

    // Draws the triangles
    glDrawArrays(GL_TRIANGLES,156);

    glBindVertexArray(0); // Deactivate the Vertex Array Object

    glutSwapBuffers(); // Flips the back buffer with the front buffer every frame.
}

// Creates the Shader program
void UCreateShader()
{

    // Vertex shader
    GLint vertexShader = glCreateShader(GL_VERTEX_SHADER); // Creates the Vertex shader
    glShaderSource(vertexShader,&vertexShaderSource,NULL); // Attaches the Vertex shader to the source code
    glCompileShader(vertexShader); // Compiles the Vertex shader

    // Fragment shader
    GLint fragmentShader = glCreateShader(GL_FRAGMENT_SHADER); // Creates the Fragment shader
    glShaderSource(fragmentShader,&fragmentShaderSource,NULL); // Attaches the fragment shader to the source code
    glCompileShader(fragmentShader); // Compiles the fragment shader

    //Shader program
    shaderProgram = glCreateProgram(); // Creates the Shader program and returns an id
    glAttachShader(shaderProgram,vertexShader); // Attach Vertex shader to the shader program
    glAttachShader(shaderProgram,fragmentShader);; // Attach Fragment shader to the Shader program
    glLinkProgram(shaderProgram); // Link Vertex and Fragment shaders to Shader program

    // Delete the Veretx and Fragment shaders once linked
    glDeleteShader(vertexShader);
    glDeleteShader(fragmentShader);
}


void UCreateBuffers()
{
    GLfloat vertices[] = {

                                //Positions             //Color

                                //Back
                                -0.80f,-0.5f,-1.0f,0.80f,0.10f,-0.80f,//Front
                                -0.80f,//Left side
                                -0.80f,//Right side
                                0.80f,//Bottom
                                -0.80f,//Top
                                -0.80f,/*BOTTOM LEFT LEG(1)*/

                                // bottom left leg(1) left
                                -0.60f,-0.60f,// bottom left leg(1) front
                                -0.60f,-0.70f,-0.45f,// bottom left leg(1) right
                                -0.45f,// bottom left leg(1) back
                                -0.45f,// bottom left leg(1) bottom
                                -0.70f,/*BOTTOM RIGHT LEG(1)*/

                                // bottom right leg(1) left
                                0.60f,0.60f,// bottom right leg(1) front
                                0.60f,0.70f,0.45f,// bottom left leg(1) right
                                0.45f,// bottom left leg(1) back
                                0.45f,// bottom left leg(1) bottom
                                0.70f,/*BOTTOM LEFT LEG(2)*/

                                // bottom left leg(2) left
                                -0.60f,// bottom left leg(2) front
                                -0.60f,// bottom left leg(2) right
                                -0.45f,// bottom left leg(2) back
                                -0.60f,// bottom left leg(2) bottom
                                -0.80f,/*BOTTOM RIGHT LEG(2)*/

                                // bottom right leg(2) left
                                0.60f,// bottom right leg(2) front
                                0.60f,// bottom right leg(2) right
                                0.45f,// bottom right leg(2) back
                                0.60f,// bottom right leg(2) bottom
                                0.80f,1.0f



                    };

    //Generate buffer ids
    glGenVertexArrays(1,&VAO);
    glGenBuffers(1,&VBO);

    // Activates the Vertex Array Object before binding and setting any VBOs and Vertex Attribute Pointers.
    glBindVertexArray(VAO);

    //Activate the VBO
    glBindBuffer(GL_ARRAY_BUFFER,VBO);
    glBufferData(GL_ARRAY_BUFFER,sizeof(vertices),vertices,GL_STATIC_DRAW); // Copy vertices to VBO

    // Set attribute pointer 0 to hold Position data
    glVertexAttribPointer(0,3,GL_FLOAT,6 * sizeof(GLfloat),(GLvoid*)0);
    glEnableVertexAttribArray(0); // Enables vertex attribute

    // Set attribute pointer 2 to hold Color data
    glVertexAttribPointer(2,2,(GLvoid*)(3 * sizeof(GLfloat)));
    glEnableVertexAttribArray(2); // Enables vertex attribute

    glBindVertexArray(0); // Deactivates the VAO which is good practice
}

/*Generate and load the texture*/
void UGenerateTexture(){

            glGenTextures(1,&texture);
            glBindTexture(GL_TEXTURE_2D,texture);

            int width,height;

            unsigned char* image = SOIL_load_image("woodTable.jpg",&width,&height,SOIL_LOAD_RGB); // Loads texture file

            glTexImage2D(GL_TEXTURE_2D,GL_RGB,width,height,GL_UNSIGNED_BYTE,image);
            glGenerateMipmap(GL_TEXTURE_2D);
            SOIL_free_image_data(image);
            glBindTexture(GL_TEXTURE_2D,0); // Unbind the texture
}


void UKeyboard(unsigned char key,GLint x,GLint y)
{
    switch(key){
    case 'o':
        currentKey = key;
        proj = !proj;
        break;

    }
}

void UKeyReleased(unsigned char key,GLint y)
{
    cout<<"Key released" <<endl;
    currentKey = '0';
}

// Implements the UMouseMove function
void UMouseMove(int x,int y)
{
    // Immediately replaces center locked coordinates with new mouse coordinates
    if(mouseDetected)
        {
            lastMouseX = x;
            lastMouseY = y;
            mouseDetected = false;
        }

        // Gets the direction the mouse was moved in x and y
        mouseXOffset = x - lastMouseX;
        mouseYOffset = lastMouseY - y; // Inverted Y

        //Updates with new mouse coordinates
        lastMouseX = x;
        lastMouseY = y;

        // Applies sensitivity to mouse direction
        mouseXOffset *= sensitivity;
        mouseYOffset *= sensitivity;

        // Accumulates the yaw and pitch variables
        yaw += mouseXOffset;
        pitch += mouseYOffset;

        // Orbits around the center
        front.x = 10.0f * cos(yaw);
        front.y = 10.0f * sin(pitch);
        front.z = sin(yaw) * cos(pitch) * 10.f;
}

解决方法

顶点属性数组由具有3个分量（ x ， y ， z ）的顶点坐标和具有2个分量（ > u ， v ）。因此，属性元组具有5个分量（ x ， y ， z ， u ， v ）。
glVertexAttribPointer的 stride 参数指定连续的通用顶点属性之间的字节偏移量。因此，参数必须为5 * sizeof(GLfloat)（(3 + 2) * sizeof(GLfloat)）而非6 * sizeof(GLfloat)：

glVertexAttribPointer(0,3,GL_FLOAT,GL_FALSE,6 * sizeof(GLfloat),(GLvoid*)0);

glVertexAttribPointer(0,5 * sizeof(GLfloat),(GLvoid*)0);

和

glVertexAttribPointer(2,2,(GLvoid*)(3 * sizeof(GLfloat)));

glVertexAttribPointer(2,(GLvoid*)(3 * sizeof(GLfloat)));