Opengl的纹理问题

Question

我想从一些位图中拉伸或平铺一个opengl对象。我使用了位图的一部分图像。但我的戒指和中间纹理与平均颜色的图像。如果我改变图像颜色改变，但图像不显示。

和我的完整代码

  //  ..in init///

           gl.glEnable(GL10.GL_TEXTURE_2D);   
           textures = new int[3];
           bitmap = BitmapFactory.decodeResource(mContext.getResources(), R.drawable.pizzaf);
           bitmap = Bitmap.createBitmap(   bitmap, 0, 0,    bitmap.getWidth(),
                   bitmap.getHeight(), null, true);
           bitmap1 = BitmapFactory.decodeResource(mContext.getResources(), R.drawable.pizslice);
           bitmap1 = Bitmap.createBitmap(   bitmap1, 0, 0,    bitmap1.getWidth(),
                   bitmap1.getHeight(), null, true);
        // Tell OpenGL to generate textures.
           gl.glTexParameterf(GL10.GL_TEXTURE_2D,
                   GL10.GL_TEXTURE_WRAP_S,
                   GL10.GL_CLAMP_TO_EDGE);
//         gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER,
//                  GL10.GL_LINEAR);
//          gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MAG_FILTER,
//                  GL10.GL_LINEAR);
           gl.glGenTextures(1, textures, 0);
    }

和绘制函数

GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bitmap1, 0);
            gl.glBindTexture(GL10.GL_TEXTURE_2D, 0);
                 GLUT.glutSolidTorus(gl,0.175f, 0.95f, 12, 48);
                 gl.glTranslatef(0,0, 0.2f);
            GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bitmap, 0);
        gl.glBindTexture(GL10.GL_TEXTURE_2D, 0);
                GLUT.glutSolidCone(gl, 1,0.01f, 12, 48);
            gl.glTranslatef(0,0, -0.4f);
            gl.glRotatef (180.0f, 1.0f, 0.0f, 0.0f);
        GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bitmap1, 0);
        gl.glBindTexture(GL10.GL_TEXTURE_2D, 0);
        GLUT.glutSolidCone(gl, 1,0.01f, 12, 48);

请帮助任何人。我想创建一个3d比萨

Answer 1

你的代码中有3个问题:

1. 你没有正确使用纹理对象
2. 在每次绘制调用时重新初始化纹理
3. glutSolidCone不提供纹理坐标(意味着:你不能正确地纹理它)

修复(1)

纹理总是按照这个方案加载:

GLuint texture_object_name;
glGenTextures(1, 
              &texture_object_name); // you can create texture object names in batches
glBindTexture(GL_TEXTURE_2D, // may differ, depending on texture target (i.e. kind of texture)
              texture_object_name);
glPixelStorei(GL_UNPACK_ALIGNMENT, …);   // </ depends on data format
glPixelStorei(GL_UNPACK_ROW_LENGTH, …);  // <|
glPixelStorei(GL_UNPACK_SKIP_PIXELS, …); // <|
glPixelStorei(GL_UNPACK_SKIP_ROWS, …);   // <|
glTexImage2D(GL_TEXTURE_2D, // again the target, depends on the kind of texture creates
             0, // mipmap level
             GL_RGBA, // internal format, GL_RGBA is one possibility, there are others
             width, height, border, // border is usually 0
             GL_BGRA,                  // format of the data input
             GL_UNSIGNED_INT_8_8_8_8,  // type of the data input -- those must match the data
             texture_data );
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, …); // mipmapping on/off and other settings
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, …); // you should really set those

修复(2)

一旦你修复了(1)，你可以修复(2)。要在渲染时切换纹理，你只需要调用

glBindTexture(GL_TEXTURE_2D, texture_object_name);

在以后的绘图调用中使用。

修复(3)

(3)是通过自己定义几何来固定的，提供适当的纹理坐标。