Question

我正在使用Vertex Indices来渲染我的网格。我没有问题传递顶点索引和顶点位置。

但我想知道在纹理坐标的情况下，我是否应该使用Indices传递它们？

编辑：我正在尝试传递和渲染OBJ文件，并对如何处理“f x / y / z”中描述的纹理坐标感到困惑

例如，在立方体的情况下，我传递我的顶点坐标：

* 8顶点坐标

* 36顶点指数：

当传递纹理（甚至法线）时，我应该将它们传递为：

* （8个纹理坐标+36个纹理坐标索引）。如果是这样，如何在渲染期间分配它们？

或

* （36个纹理坐标）？

这是我的抽象网格类

public class AbstractMesh3D {
    //private int buffers[]={0,0};
    private int vbVertices[]=new int[1];
    private int vbIndices[]=new int[1];
    private int vbNormals[]=new int[1];
    private int vbColors[]=new int[1];
    private int vbTextureCords[]=new int[1];
    private boolean bVertices=false;
    private boolean bIndices=false;
    private boolean bNormals=false;
    private int numOfVertices;
    private int numOfIndices;
    private int numOfNormals;
    private World3D _world;
    private String textureId;

    public void setTextureId(String textureId) {
        this.textureId = textureId;
    }




    public AbstractMesh3D(){


    }
    public void setWorld(World3D world){
        this._world=world;
    }
    public void setVertexBuffer(float vertexData[]){
        GLES20.glGenBuffers(1, vbVertices, 0);
        //Short
        FloatBuffer vertexFloatBuffer=ByteBuffer.allocateDirect(vertexData.length*4).order(ByteOrder.nativeOrder()).asFloatBuffer();
        vertexFloatBuffer.put(vertexData);
        vertexFloatBuffer.position(0);

        //GLES20.glGenBuffers(1, vbVertices, 0);
        GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER, vbVertices[0]);
        GLES20.glBufferData(GLES20.GL_ARRAY_BUFFER, vertexData.length*4, vertexFloatBuffer, GLES20.GL_STATIC_DRAW);
        numOfVertices=vertexData.length/3;
        bVertices=true;

        GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER, 0);
        GLES20.glBindBuffer(GLES20.GL_ELEMENT_ARRAY_BUFFER, 0);


        //vertexFloatBuffer.
    }

    public void setNormalBuffer(float normalData[]){
        GLES20.glGenBuffers(1, vbNormals, 0);
        //Short
        FloatBuffer vertexFloatBuffer=ByteBuffer.allocateDirect(normalData.length*4).order(ByteOrder.nativeOrder()).asFloatBuffer();
        vertexFloatBuffer.put(normalData);
        vertexFloatBuffer.position(0);

        GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER, vbNormals[0]);
        GLES20.glBufferData(GLES20.GL_ARRAY_BUFFER, normalData.length*4, vertexFloatBuffer, GLES20.GL_STATIC_DRAW);
        bNormals=true;
        numOfNormals=normalData.length/3;

        GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER, 0);
        GLES20.glBindBuffer(GLES20.GL_ELEMENT_ARRAY_BUFFER, 0);

    }

    public void setIndices(short indices[]){
        GLES20.glGenBuffers(1, vbIndices, 0);
        ShortBuffer vertexFloatBuffer=ByteBuffer.allocateDirect(indices.length*2).order(ByteOrder.nativeOrder()).asShortBuffer();
        vertexFloatBuffer.put(indices);
        vertexFloatBuffer.position(0);

        //GLES20.glGenBuffers(1, buffers[1], 0);
        GLES20.glBindBuffer(GLES20.GL_ELEMENT_ARRAY_BUFFER, vbIndices[0]);
        GLES20.glBufferData(GLES20.GL_ELEMENT_ARRAY_BUFFER, indices.length*2, vertexFloatBuffer, GLES20.GL_STATIC_DRAW);
        numOfIndices=indices.length;
        bIndices=true;

        GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER, 0);
        GLES20.glBindBuffer(GLES20.GL_ELEMENT_ARRAY_BUFFER, 0);

    }

    public void render(){
        int posHandle=_world.getOgl_aPositionHandle();
        int normalHandle=_world.getOgl_aNormalHandle();

        GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER, vbVertices[0]);
        GLES20.glEnableVertexAttribArray(posHandle);
        GLES20.glVertexAttribPointer(posHandle, 3, GLES20.GL_FLOAT, false, 12, 0);

        if(bNormals){
            GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER, vbNormals[0]);
            GLES20.glEnableVertexAttribArray(normalHandle);
            GLES20.glVertexAttribPointer(normalHandle, 3, GLES20.GL_FLOAT, false, 12, 0);
        }

        if(bIndices){   
            //System.out.println("render indices");
            GLES20.glBindBuffer(GLES20.GL_ELEMENT_ARRAY_BUFFER, vbIndices[0]);

            GLES20.glDrawElements(GLES20.GL_TRIANGLES, numOfIndices, GLES20.GL_UNSIGNED_SHORT, 0);          

        }else{
            GLES20.glDrawArrays(GLES20.GL_TRIANGLES, 0, numOfVertices);
        }
        GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER, 0);
        GLES20.glBindBuffer(GLES20.GL_ELEMENT_ARRAY_BUFFER, 0);

        GLES20.glDisableVertexAttribArray(posHandle);
        GLES20.glDisableVertexAttribArray(normalHandle);
        //System.out.println("rendered");





    }

}

Answer 1

您必须重新排序texcoords和顶点，使它们共享相同的索引。您不能为不同的属性使用单独的索引。

始终顶点的数量必须等于texcoords的数量必须等于法线的数量等。

解析OBJ时，这将涉及复制一些顶点/ texcoords，以便您可以满足此要求。

OpenGL ES2：顶点指数和纹理坐标？

1 个答案: