Question

我正在使用带有使用一些示例代码和FreeImage API加载的纹理的opengl渲染场景。

这是我正在看到的链接

[图片已删除]

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

每个渲染的三角形看起来都有粘贴在其上（并重复）的完整纹理，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;
}

这些是渲染的功能

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

我正在使用更大的代码库，并且在不同的区域中进行纹理处理的方式与其他纹理对象的状态不同。

在每个顶点纹理化完成之前，请确保关闭其他各种纹理。

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

打开GL纹理，纹理坐标对于渲染的内容不正确

1 个答案: