有人有在每张脸上具有不同纹理的立方体的代码示例？ （OpenGL ES 1）

Question

我需要了解如何在立方体的每个面上放置不同的纹理（OpenGL ES 1）。但我找不到怎么办呢

大气压我发现怎么画立方体的所有面相同的纹理的例子例子，但我不认为需要

这是实际的代码我有：

public class Cube { 

/** The buffer holding the vertices */ 
private FloatBuffer vertexBuffer; 
/** The buffer holding the texture coordinates */ 
private FloatBuffer textureBuffer; 
/** The buffer holding the indices */ 
private ByteBuffer indexBuffer; 

/** Our texture pointer */ 
private int[] textures = new int[1]; 

/** 
* The initial vertex definition 
* 
* Note that each face is defined, even 
* if indices are available, because 
* of the texturing we want to achieve 
*/ 
private float vertices[] = { 
        //Vertices according to faces 
        -1.0f, -1.0f, 1.0f, //Vertex 0 
        1.0f, -1.0f, 1.0f, //v1 
        -1.0f, 1.0f, 1.0f, //v2 
        1.0f, 1.0f, 1.0f, //v3 

        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, 
             }; 

/** The initial texture coordinates (u, v) */ 
private float texture[] = {   
        //Mapping coordinates for the vertices 
        0.0f, 0.0f, 
        0.0f, 1.0f, 
        1.0f, 0.0f, 
        1.0f, 1.0f, 

        0.0f, 0.0f, 
        0.0f, 1.0f, 
        1.0f, 0.0f, 
        1.0f, 1.0f, 

        0.0f, 0.0f, 
        0.0f, 1.0f, 
        1.0f, 0.0f, 
        1.0f, 1.0f, 

        0.0f, 0.0f, 
        0.0f, 1.0f, 
        1.0f, 0.0f, 
        1.0f, 1.0f, 

        0.0f, 0.0f, 
        0.0f, 1.0f, 
        1.0f, 0.0f, 
        1.0f, 1.0f, 

        0.0f, 0.0f, 
        0.0f, 1.0f, 
        1.0f, 0.0f, 
        1.0f, 1.0f, 

             }; 

/** The initial indices definition */ 
private byte indices[] = { 
        //Faces definition 
        0,1,3, 0,3,2,   //Face front 
        4,5,7, 4,7,6,   //Face right 
        8,9,11, 8,11,10,  //... 
        12,13,15, 12,15,14,  
        16,17,19, 16,19,18,  
        20,21,23, 20,23,22,  
             }; 

/** 
* The Cube constructor. 
* 
* Initiate the buffers. 
*/ 
public Cube() { 
    // 
    ByteBuffer byteBuf = ByteBuffer.allocateDirect(vertices.length * 4); 
    byteBuf.order(ByteOrder.nativeOrder()); 
    vertexBuffer = byteBuf.asFloatBuffer(); 
    vertexBuffer.put(vertices); 
    vertexBuffer.position(0); 

    // 
    byteBuf = ByteBuffer.allocateDirect(texture.length * 4); 
    byteBuf.order(ByteOrder.nativeOrder()); 
    textureBuffer = byteBuf.asFloatBuffer(); 
    textureBuffer.put(texture); 
    textureBuffer.position(0); 

    // 
    indexBuffer = ByteBuffer.allocateDirect(indices.length); 
    indexBuffer.put(indices); 
    indexBuffer.position(0); 
} 

/** 
* The object own drawing function. 
* Called from the renderer to redraw this instance 
* with possible changes in values. 
* 
* @param gl - The GL Context 
*/ 
public void draw(GL10 gl) { 
    //Bind our only previously generated texture in this case 
    gl.glBindTexture(GL10.GL_TEXTURE_2D, textures[0]); 

    //Point to our buffers 
    gl.glEnableClientState(GL10.GL_VERTEX_ARRAY); 
    gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY); 

    //Set the face rotation 
    gl.glFrontFace(GL10.GL_CCW); 

    //Enable the vertex and texture state 
    gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertexBuffer); 
    gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, textureBuffer); 

    //Draw the vertices as triangles, based on the Index Buffer information 
    gl.glDrawElements(GL10.GL_TRIANGLES, indices.length, GL10.GL_UNSIGNED_BYTE, indexBuffer); 

    //Disable the client state before leaving 
    gl.glDisableClientState(GL10.GL_VERTEX_ARRAY); 
    gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY); 
} 

/** 
* Load the textures 
* 
* @param gl - The GL Context 
* @param context - The Activity context 
*/ 
public void loadGLTexture(GL10 gl, Context context) { 
    //Get the texture from the Android resource directory 
    InputStream is = context.getResources().openRawResource(R.drawable.nehe); 
    Bitmap bitmap = null; 
    try { 
     //BitmapFactory is an Android graphics utility for images 
     bitmap = BitmapFactory.decodeStream(is); 

    } finally { 
     //Always clear and close 
     try { 
      is.close(); 
      is = null; 
     } catch (IOException e) { 
     } 
    } 

    //Generate one texture pointer... 
    gl.glGenTextures(1, textures, 0); 
    //...and bind it to our array 
    gl.glBindTexture(GL10.GL_TEXTURE_2D, textures[0]); 

    //Create Nearest Filtered Texture 
    gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER, GL10.GL_NEAREST); 
    gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MAG_FILTER, GL10.GL_LINEAR); 

    //Different possible texture parameters, e.g. GL10.GL_CLAMP_TO_EDGE 
    gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_S, GL10.GL_REPEAT); 
    gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_T, GL10.GL_REPEAT); 

    //Use the Android GLUtils to specify a two-dimensional texture image from our bitmap 
    GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bitmap, 0); 

    //Clean up 
    bitmap.recycle(); 
} 
} 

Answer 1

您正在绘制一个调用glDrawElements的立方体的所有12个三角形。在一次调用glDrawElements的过程中，GL渲染状态保持不变，这包括绑定纹理。这意味着，在调用glDrawElements期间，不能更改用于渲染的纹理。因此，要为每个立方体使用不同的纹理，您需要单独调用glDrawElements。每次调用之前，您都需要更改绑定的纹理。

还有更高级的方法可以让你只用一个电话来提高效率，但是现在我们不用担心这些。