打开GL纹理，纹理坐标与渲染的内容不正确

Question

我正在使用opengl渲染场景，并使用一些示例代码和FreeImage API加载纹理。

这是我看到的的链接

[图像已删除]

我可以确认，所有纹理坐标都是根据需要提供给glTexCoord2f的，在0.0f和1.0f之间，以及顶点坐标。

每个渲染的三角形似乎都粘贴了完整的纹理（并重复），而不是坐标指定的纹理区域。

纹理为1024x1024。

这是加载纹理的功能

bool loadImageToTexture(const char* image_path, unsigned int &handle)
{
    if(!image_path)
        return false;
    FREE_IMAGE_FORMAT fif = FIF_UNKNOWN;
    FIBITMAP* dib(0);
    BYTE* bits(0);
    unsigned int width(0), height(0);
    //open the file
    fif = FreeImage_GetFileType(image_path, 0);
    if(fif == FIF_UNKNOWN)
        fif = FreeImage_GetFIFFromFilename(image_path);
    if(fif == FIF_UNKNOWN)
        return false;
    if(FreeImage_FIFSupportsReading(fif))
        dib = FreeImage_Load(fif, image_path);
    if(!dib)
        return false;
    //is the file of the correct type
    FREE_IMAGE_COLOR_TYPE type = FreeImage_GetColorType(dib);
    if(FIC_RGBALPHA != type)
    {
        //convert to type
        FIBITMAP* ndib = FreeImage_ConvertTo32Bits(dib);
        dib = ndib;
    }
    //get data for glTexImage2D
    bits = FreeImage_GetBits(dib);
    width = FreeImage_GetWidth(dib);
    height = FreeImage_GetHeight(dib);
    if((bits == 0) || (width == 0) || (height == 0))
        return false;
    //create the texture in open gl
    glGenTextures(1, &handle);
    glBindTexture(GL_TEXTURE_2D, handle);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    glPixelStorei(GL_TEXTURE_2D, 4);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height,
                 0, GL_RGBA, GL_UNSIGNED_BYTE, bits);
    //unload the image now loaded
    FreeImage_Unload(dib);
    return true;
}

这些是呈现的功能

inline void glTexture(float textureSize, float t, float u)
{
    glTexCoord2f(u/textureSize, (textureSize - t)/textureSize);
}
void processTriangle(const btVector3* triangle, const textureCoord* tc, const btVector3& normal,
                     const int partId, const int triangleIndex, const bool wireframe)
{
    if(wireframe)
    {
        glBegin(GL_LINES);
        glColor3f(1, 0, 0);
        glVertex3d(triangle[0].getX(), triangle[0].getY(), triangle[0].getZ());
        glVertex3d(triangle[1].getX(), triangle[1].getY(), triangle[1].getZ());
        glColor3f(0, 1, 0);
        glVertex3d(triangle[2].getX(), triangle[2].getY(), triangle[2].getZ());
        glVertex3d(triangle[1].getX(), triangle[1].getY(), triangle[1].getZ());
        glColor3f(0, 0, 1);
        glVertex3d(triangle[2].getX(), triangle[2].getY(), triangle[2].getZ());
        glVertex3d(triangle[0].getX(), triangle[0].getY(), triangle[0].getZ());
        glEnd();
    }
    else
    {
        glBegin(GL_TRIANGLES);
        glColor3f(1, 1, 1);
        //Normals are per triangle
        glNormal3f(normal.getX(), normal.getY(), normal.getZ());
        glTexture(1024.0f, tc[0].t, tc[0].u);
        glVertex3d(triangle[0].getX(), triangle[0].getY(), triangle[0].getZ());
        glTexture(1024.0f, tc[1].t, tc[1].u);
        glVertex3d(triangle[1].getX(), triangle[1].getY(), triangle[1].getZ());
        glTexture(1024.0f, tc[2].t, tc[2].u);
        glVertex3d(triangle[2].getX(), triangle[2].getY(), triangle[2].getZ());
        glEnd();
    }
}
void processAllTriangles(const btVector3& worldBoundsMin, const btVector3& worldBoundsMax)
{
    btVector3 triangle[3];
    textureCoord tc[3];
    //go through the index list build triangles and draw them
    unsigned int k = 0;
    for(unsigned int i = 0; i<dVertices.size(); i+=3, k++)
    {
        //first vertex
        triangle[0] = dVertices[i];
        tc[0] = dTexCoords[i];
        //second vertex
        triangle[1] = dVertices[i+1];
        tc[1] = dTexCoords[i+1];
        //third vertex
        triangle[2] = dVertices[i+2];
        tc[2] = dTexCoords[i+2];
        processTriangle(triangle, tc, dNormals[k], 0, 0, false);
    }
}
//draw the world given the players position
void render(btScalar* m, const btCollisionShape* shape, const btVector3& color, int debugMode,
            const btVector3& worldBoundsMin, const btVector3& worldBoundsMax)
{
    //render the world using the generated OpenGL lists
    //enable and specify pointers to vertex arrays
    glPushMatrix();
    glMultMatrixf(m);
    glMatrixMode(GL_TEXTURE);
    glLoadIdentity();
    glMatrixMode(GL_MODELVIEW);
    glEnable(GL_TEXTURE_2D);
    glShadeModel(GL_SMOOTH);
    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    glBindTexture(GL_TEXTURE_2D, m_texturehandle);
    processAllTriangles(worldBoundsMin, worldBoundsMax);
    glPopMatrix();
}

Answer 1

我在一个更大的代码库中工作，不同区域的纹理处理方式不同——与其他纹理对象的平均状态没有被禁用。

在完成逐顶点纹理之前，请确保关闭其他种类的纹理。

glDisable(GL_TEXTURE_GEN_S);
glDisable(GL_TEXTURE_GEN_T);
glDisable(GL_TEXTURE_GEN_R);