Question

我一直在阅读这里的opengl教程： http://www.opengl-tutorial.org/beginners-tutorials/tutorial-5-a-textured-cube/

该站点为您提供了每个教程的完整版本，以便您可以与自己的实现进行比较。不幸的是，教程5对我来说似乎不起作用（我的实现和提供的都没有）。我附上了我认为它应该是什么样子的图片以及当我运行从他们的代码生成的可执行文件时得到的内容。

我正在使用运行Windows 10的2015款MacBook Pro，使用英特尔的Iris 6100集成GPU在VS2015中进行编译。

以下代码来自教程。

// Include standard headers
#include <stdio.h>
#include <stdlib.h>

// Include GLEW
#include <GL/glew.h>

// Include GLFW
#include <glfw3.h>
GLFWwindow* window;

// Include GLM
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
using namespace glm;

#include <common/shader.hpp>
#include <common/texture.hpp>

int main( void )
{
    // Initialise GLFW
if( !glfwInit() )
{
    fprintf( stderr, "Failed to initialize GLFW\n" );
    return -1;
}

glfwWindowHint(GLFW_SAMPLES, 4);
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE); // To make MacOS happy; should not be needed
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

// Open a window and create its OpenGL context
window = glfwCreateWindow( 1024, 768, "Tutorial 05 - Textured Cube", NULL, NULL);
if( window == NULL ){
    fprintf( stderr, "Failed to open GLFW window. If you have an Intel GPU, they are not 3.3 compatible. Try the 2.1 version of the tutorials.\n" );
    glfwTerminate();
    return -1;
}
glfwMakeContextCurrent(window);

// Initialize GLEW
glewExperimental = true; // Needed for core profile
if (glewInit() != GLEW_OK) {
    fprintf(stderr, "Failed to initialize GLEW\n");
    return -1;
}

// Ensure we can capture the escape key being pressed below
glfwSetInputMode(window, GLFW_STICKY_KEYS, GL_TRUE);

// Dark blue background
glClearColor(0.0f, 0.0f, 0.4f, 0.0f);

// Enable depth test
glEnable(GL_DEPTH_TEST);
// Accept fragment if it closer to the camera than the former one
glDepthFunc(GL_LESS); 

GLuint VertexArrayID;
glGenVertexArrays(1, &VertexArrayID);
glBindVertexArray(VertexArrayID);

// Create and compile our GLSL program from the shaders
GLuint programID = LoadShaders( "TransformVertexShader.vertexshader", "TextureFragmentShader.fragmentshader" );

// Get a handle for our "MVP" uniform
GLuint MatrixID = glGetUniformLocation(programID, "MVP");

// Projection matrix : 45° Field of View, 4:3 ratio, display range : 0.1 unit <-> 100 units
glm::mat4 Projection = glm::perspective(45.0f, 4.0f / 3.0f, 0.1f, 100.0f);
// Camera matrix
glm::mat4 View       = glm::lookAt(
                            glm::vec3(4,3,3), // Camera is at (4,3,3), in World Space
                            glm::vec3(0,0,0), // and looks at the origin
                            glm::vec3(0,1,0)  // Head is up (set to 0,-1,0 to look upside-down)
                       );
// Model matrix : an identity matrix (model will be at the origin)
glm::mat4 Model      = glm::mat4(1.0f);
// Our ModelViewProjection : multiplication of our 3 matrices
glm::mat4 MVP        = Projection * View * Model; // Remember, matrix multiplication is the other way around

// Load the texture using any two methods
//GLuint Texture = loadBMP_custom("uvtemplate.bmp");
GLuint Texture = loadDDS("uvtemplate.DDS");

// Get a handle for our "myTextureSampler" uniform
GLuint TextureID  = glGetUniformLocation(programID, "myTextureSampler");

// Our vertices. Tree consecutive floats give a 3D vertex; Three consecutive vertices give a triangle.
// A cube has 6 faces with 2 triangles each, so this makes 6*2=12 triangles, and 12*3 vertices
static const GLfloat g_vertex_buffer_data[] = { 
    -1.0f,-1.0f,-1.0f,
    -1.0f,-1.0f, 1.0f,
    -1.0f, 1.0f, 1.0f,
     1.0f, 1.0f,-1.0f,
    -1.0f,-1.0f,-1.0f,
    -1.0f, 1.0f,-1.0f,
     1.0f,-1.0f, 1.0f,
    -1.0f,-1.0f,-1.0f,
     1.0f,-1.0f,-1.0f,
     1.0f, 1.0f,-1.0f,
     1.0f,-1.0f,-1.0f,
    -1.0f,-1.0f,-1.0f,
    -1.0f,-1.0f,-1.0f,
    -1.0f, 1.0f, 1.0f,
    -1.0f, 1.0f,-1.0f,
     1.0f,-1.0f, 1.0f,
    -1.0f,-1.0f, 1.0f,
    -1.0f,-1.0f,-1.0f,
    -1.0f, 1.0f, 1.0f,
    -1.0f,-1.0f, 1.0f,
     1.0f,-1.0f, 1.0f,
     1.0f, 1.0f, 1.0f,
     1.0f,-1.0f,-1.0f,
     1.0f, 1.0f,-1.0f,
     1.0f,-1.0f,-1.0f,
     1.0f, 1.0f, 1.0f,
     1.0f,-1.0f, 1.0f,
     1.0f, 1.0f, 1.0f,
     1.0f, 1.0f,-1.0f,
    -1.0f, 1.0f,-1.0f,
     1.0f, 1.0f, 1.0f,
    -1.0f, 1.0f,-1.0f,
    -1.0f, 1.0f, 1.0f,
     1.0f, 1.0f, 1.0f,
    -1.0f, 1.0f, 1.0f,
     1.0f,-1.0f, 1.0f
};

// Two UV coordinatesfor each vertex. They were created withe Blender.
static const GLfloat g_uv_buffer_data[] = { 
    0.000059f, 1.0f-0.000004f, 
    0.000103f, 1.0f-0.336048f, 
    0.335973f, 1.0f-0.335903f, 
    1.000023f, 1.0f-0.000013f, 
    0.667979f, 1.0f-0.335851f, 
    0.999958f, 1.0f-0.336064f, 
    0.667979f, 1.0f-0.335851f, 
    0.336024f, 1.0f-0.671877f, 
    0.667969f, 1.0f-0.671889f, 
    1.000023f, 1.0f-0.000013f, 
    0.668104f, 1.0f-0.000013f, 
    0.667979f, 1.0f-0.335851f, 
    0.000059f, 1.0f-0.000004f, 
    0.335973f, 1.0f-0.335903f, 
    0.336098f, 1.0f-0.000071f, 
    0.667979f, 1.0f-0.335851f, 
    0.335973f, 1.0f-0.335903f, 
    0.336024f, 1.0f-0.671877f, 
    1.000004f, 1.0f-0.671847f, 
    0.999958f, 1.0f-0.336064f, 
    0.667979f, 1.0f-0.335851f, 
    0.668104f, 1.0f-0.000013f, 
    0.335973f, 1.0f-0.335903f, 
    0.667979f, 1.0f-0.335851f, 
    0.335973f, 1.0f-0.335903f, 
    0.668104f, 1.0f-0.000013f, 
    0.336098f, 1.0f-0.000071f, 
    0.000103f, 1.0f-0.336048f, 
    0.000004f, 1.0f-0.671870f, 
    0.336024f, 1.0f-0.671877f, 
    0.000103f, 1.0f-0.336048f, 
    0.336024f, 1.0f-0.671877f, 
    0.335973f, 1.0f-0.335903f, 
    0.667969f, 1.0f-0.671889f, 
    1.000004f, 1.0f-0.671847f, 
    0.667979f, 1.0f-0.335851f
};

GLuint vertexbuffer;
glGenBuffers(1, &vertexbuffer);
glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer);
glBufferData(GL_ARRAY_BUFFER, sizeof(g_vertex_buffer_data), g_vertex_buffer_data, GL_STATIC_DRAW);

GLuint uvbuffer;
glGenBuffers(1, &uvbuffer);
glBindBuffer(GL_ARRAY_BUFFER, uvbuffer);
glBufferData(GL_ARRAY_BUFFER, sizeof(g_uv_buffer_data), g_uv_buffer_data, GL_STATIC_DRAW);

do{

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

    // Use our shader
    glUseProgram(programID);

    // Send our transformation to the currently bound shader, 
    // in the "MVP" uniform
    glUniformMatrix4fv(MatrixID, 1, GL_FALSE, &MVP[0][0]);

    // Bind our texture in Texture Unit 0
    glActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_2D, Texture);
    // Set our "myTextureSampler" sampler to user Texture Unit 0
    glUniform1i(TextureID, 0);

    // 1rst attribute buffer : vertices
    glEnableVertexAttribArray(0);
    glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer);
    glVertexAttribPointer(
        0,                  // attribute. No particular reason for 0, but must match the layout in the shader.
        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. No particular reason for 1, but must match the layout in the shader.
        2,                                // size : U+V => 2
        GL_FLOAT,                         // type
        GL_FALSE,                         // normalized?
        0,                                // stride
        (void*)0                          // array buffer offset
    );

    // Draw the triangle !
    glDrawArrays(GL_TRIANGLES, 0, 12*3); // 12*3 indices starting at 0 -> 12 triangles

    glDisableVertexAttribArray(0);
    glDisableVertexAttribArray(1);

    // Swap buffers
    glfwSwapBuffers(window);
    glfwPollEvents();

} // Check if the ESC key was pressed or the window was closed
while( glfwGetKey(window, GLFW_KEY_ESCAPE ) != GLFW_PRESS &&
       glfwWindowShouldClose(window) == 0 );

// Cleanup VBO and shader
glDeleteBuffers(1, &vertexbuffer);
glDeleteBuffers(1, &uvbuffer);
glDeleteProgram(programID);
glDeleteTextures(1, &TextureID);
glDeleteVertexArrays(1, &VertexArrayID);

// Close OpenGL window and terminate GLFW
glfwTerminate();

return 0;
}

非常感谢任何帮助。

Answer 1

我认为这是因为你没有反转UV-coords的y分量（因为与OpenGL相比，DDS有一个不同的基于D3D的坐标系）。您应该在片段着色器中反映它（就像1.0f-uv.y一样简单）或在压缩之前反转图像。查看该教程（顺便说一下，这很棒）。最后，它讨论了反转UV：

DXT压缩来自DirectX世界，与OpenGL相比，V纹理坐标被反转。因此，如果您使用压缩纹理，则必须使用（coord.u，1.0-coord.v）来获取正确的纹理元素。您可以随时执行此操作：在导出脚本中，在加载程序中，在着色器中...

OpenGL纹理多维数据集教程 - 示例代码不起作用

1 个答案: