[英]OpenGL ES2 : Vertex Indices and Texture coordinates?
我使用顶点索引来渲染我的网格。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,我是否应该使用指数将它们传递给它们?
编辑:我试图传递和渲染OBJ文件,并混淆如何处理“fx / y / z”中描述的纹理坐标
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:
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个纹理坐标指数) 。 如果是这样,如何在渲染过程中分配它们?
要么
* (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");
}
}
您必须重新排序texcoords和顶点,以便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。
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