OpenGL纹理加载,但未应用(?)

时间:2013-05-19 19:49:25

标签: opengl

纹理有点问题。

我通过assimp加载网格,效果非常好,模型看起来应该是这样......但它是黑色的..

所以,首先我加载着色器然后开始加载网格,包括顶点,面和紫外线。 为了保持最低限度,我只会显示与纹理相关的代码。

    texID = glGetUniformLocation(shaderProgram, "myTextureSampler");
    loadScene(modelPath);

loadScene现在将导入我们通过模型路径获得的整个模型。

所以,第一部分,我不认为这是问题,但它可能是,也许我错过了什么,而调试一切似乎很好。 我使用FreeImage库来寻找纹理。

bool loadGLTextures(const aiScene* scene)
{

    /* unload image first */
    if (pImage) 
    {
        FreeImage_Unload(pImage);
        pImage = 0;
    }

    if (scene->HasTextures()) 
    {
        std::cerr << "Support for meshes with embedded textures is not (yet)
            implemented" << std::endl;
        return false;
    }

    /* getTexture Filenames and Numb of Textures */
    for (unsigned int m=0; m < scene->mNumMaterials; m++)
    {
        int texIndex = 0;
        aiReturn texFound = AI_SUCCESS;

        aiString path;  // filename

        while (texFound == AI_SUCCESS)
        {
            texFound = scene->mMaterials[m]->GetTexture(aiTextureType_DIFFUSE,
                texIndex, &path);
        textureIdMap[path.data] = NULL;
        //fill map with textures, pointers still NULL yet
        texIndex++;
        }
    }

    int numTextures = textureIdMap.size();

    /* create and fill array with GL texture ids */
    textureIds = new GLuint[numTextures];
    glGenTextures(numTextures, textureIds); /* Texture name generation */

    /* get iterator */
    std::map<std::string, GLuint*>::iterator itr = textureIdMap.begin();

    for (int i=0; i < numTextures; i++)
    {
        std::string filename = (*itr).first;  // get filename
        (*itr).second = &textureIds[i]; // save texture id for filename in map
        itr++; // next texture

        std::string fileloc = basepath + filename;  /* Loading of image */

        // Check the file signature and deduce its format.  
        FREE_IMAGE_FORMAT fif = FreeImage_GetFileType(fileloc.c_str(), 0);  

        // If still unknown, try to guess the file format from the file extension.  
        if(fif == FIF_UNKNOWN)  
        {  
            fif = FreeImage_GetFIFFromFilename(fileloc.c_str());  
        }  

        // If still unkown, return failure.  
        if(fif == FIF_UNKNOWN)  
        {  
            return false;  
        }  

        // Check that the plugin has reading capabilities and load the file.  
        if(FreeImage_FIFSupportsReading(fif))  
        {  
            pImage = FreeImage_Load(fif, fileloc.c_str());  
        } 

        if (pImage != 0) /* If no error occured: */
        {
            glBindTexture(GL_TEXTURE_2D, textureIds[i]);

            unsigned int width = pImage ? FreeImage_GetWidth(pImage) : 0;
            unsigned int height = pImage ? FreeImage_GetHeight(pImage) : 0;
            const BYTE *bits = pImage ? FreeImage_GetBits(pImage) : 0;

            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_MAG_FILTER, GL_LINEAR);
            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,
                GL_LINEAR_MIPMAP_LINEAR); 
            // Initialise texture with image data.  
            glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, 
                GL_UNSIGNED_BYTE, bits);
            }
            else
            {
                /* Error occured */
                std::cerr << "Couldn't load image: " + fileloc << std::endl;
            }
        }

    //return success;
    return true;
}

在我们得到纹理之后,我选择了网格,但唯一相关的部分是uv部分和绑定,所以让我们跳到材料加载 - 因为没有光,我把它保持在最低限度。

void initMaterial(const aiMaterial* mtl)
{

    int texIndex = 0;
    aiString texPath; //contains filename of texture

    if(AI_SUCCESS == mtl->GetTexture(aiTextureType_DIFFUSE, texIndex, &texPath))
    {
        //bind texture
        GLuint texId = *textureIdMap[texPath.data];
        glBindTexture(GL_TEXTURE_2D, texId);
        glActiveTexture(GL_TEXTURE0);
    }
}

所以,下面的部分也会考虑顶点和法线,但它们对我来说并不重要,顶点有效,而纹理不起作用......

glUseProgram(shaderProgram);

glUniform1i(texID, 0);

glEnableVertexAttribArray(1);
glBindBuffer(GL_ARRAY_BUFFER, tbo);
glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 0, (void*)0);

glDisableVertexAttribArray(1);

glUseProgram(shaderProgram); glUniform1i(texID, 0); glEnableVertexAttribArray(1); glBindBuffer(GL_ARRAY_BUFFER, tbo); glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 0, (void*)0); glDisableVertexAttribArray(1);

为了完成,着色器,它们现在保持基本,只是为了测试纹理。

vertexshader

fragmentshader

layout(location = 1) in vec2 vertexUV;

// Output data ; will be interpolated for each fragment.
out vec2 UV;

void main(){

....

    // UV of the vertex. No special space for this one.
    UV = vertexUV;
}

所以,就是这样。正如我所说,我没有得到任何错误,一切都很好地显示,但显示但不是纹理我只会变黑。

1 个答案:

答案 0 :(得分:4)

您指定GL_LINEAR_MIPMAP_LINEAR微型过滤器,但您的纹理不是mipmap完成,因为您只指定级别0(我假设您的图像大于1x1)。有几种选择:

  1. 使用其他过滤条件GL_LINEAR。这对于快速测试来说特别有用,以确定它是否开始工作。
  2. 提供整套mipmap leves。每个级别的宽度为前一个级别的1/2和高度的1/2,直到达到1x1。
  3. 让GL通过glGenerateMipmap()生成mipmap级别。