如何处理索引缓冲中的OpenGL ES 1.1 [英] How to handle index buffer in OpenGL ES 1.1
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问题描述
我想渲染使用的OpenGL ES 1.1为Android的obj文件加载的模型。我有个顶点，顶点法线和面孔。当我使用GL10.GL_POINTS模型的模型看起来很好：
I want to render a model loaded from an .obj file using OPENGL ES 1.1 for Android. I have vertices, vertice normals and faces. When I render the model using GL10.GL_POINTS the model looks fine:
当我使用GL10.GL_TRIANGLES我得到形状的搞成这个样子：
When I use GL10.GL_TRIANGLES I get a mess of shapes like this:
下面是我的画法。我想这两个调用glDrawArrays与glDrawElements和却得到了相同的结果。
Here's my drawing method. I tried both glDrawArrays and glDrawElements but got the same results.
public void draw(GL10 gl){
gl.glEnable(GL10.GL_CULL_FACE);
gl.glFrontFace(GL10.GL_CCW);
gl.glCullFace(GL10.GL_BACK);
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
gl.glVertexPointer(COORDS_PER_VERTEX, GL10.GL_FLOAT, BYTES_PER_VERTEX, m_vertexBuffer);
gl.glEnableClientState(GL10.GL_NORMAL_ARRAY);
gl.glNormalPointer(COORDS_PER_VERTEX, BYTES_PER_VERTEX, m_normalBuffer);
gl.glColor4f(m_color[0], m_color[1], m_color[2], m_color[3]);
gl.glScalef(0.1f, 0.1f, 0.1f);
// gl.glDrawArrays(GL10.GL_TRIANGLES, 0, m_numNormals);
gl.glDrawElements(GL10.GL_TRIANGLES, m_numIndices, GL10.GL_UNSIGNED_SHORT, m_indexBuffer);
gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
gl.glDisableClientState(GL10.GL_NORMAL_ARRAY);
gl.glDisable(GL10.GL_CULL_FACE);
}
下面的示例行从obj文件：
Here are sample lines from the .obj file:
v 1.012781 -1.591947 1.752353
...
vn 0.495193 0.342204 0.798517
...
# same indices within pairs
f 14978//14978 14977//14977 22659//22659
...
# different indices
f 34422//34418 34375//34371 34374//34370
有趣的关于面部线条，有时诉对// VN由相同的指数，有时他们不这样做。此外，在总有比顶点少4法线。我怀疑这是什么造成的问题。但我怎么处理呢？当我与glDrawElements用，我应该通过哪些指标？
What's interesting about the face lines is that sometimes the pairs of v//vn consist of the same indices and sometimes they don't. Also in total there are 4 normals less than vertices. I suspect this is what's causing the problems. But how would I deal with that? When I use glDrawElements, which indices should I pass?
这是我如何初始化我的缓冲区：
This is how I initialize my Buffers:
public void setVertices(float[] coordinates, int size){
final ByteBuffer bb = ByteBuffer.allocateDirect(size * 4);
bb.order(ByteOrder.nativeOrder());
m_vertexBuffer = bb.asFloatBuffer();
m_vertexBuffer.put(coordinates, 0, size);
m_vertexBuffer.position(0);
m_numVertices = size / COORDS_PER_VERTEX;
}
public void setNormals(float[] coordinates, int size){
final ByteBuffer bb = ByteBuffer.allocateDirect(size * 4);
bb.order(ByteOrder.nativeOrder());
m_normalBuffer = bb.asFloatBuffer();
m_normalBuffer.put(coordinates, 0, size);
m_normalBuffer.position(0);
m_numNormals = size / COORDS_PER_VERTEX;
}
// array contains vertices and normals in the order read from the .obj file
// ie every even index is a vertex, every odd index is a normal
public void setIndices(int[] array, int size){
m_numIndices = size / 2;
final ByteBuffer bb = ByteBuffer.allocateDirect(m_numIndices * 4);
bb.order(ByteOrder.nativeOrder());
m_indexBuffer = bb.asIntBuffer();
for(int i = 0; i < size; i+=2)
m_indexBuffer.put(array[i]);
m_indexBuffer.position(0);
}
你也许可以给我一个提示如何初始化和使用索引缓冲？
Can you maybe give me a hint how to initialize and use the index buffer?
编辑：这里的模型： bunny.obj
推荐答案
也许这会帮助你，我用它来导入obj文件，并将其与纹理和一切工作，你将不得不选择它拆开来什么有关到你的项目其扎成所有这些其他类，如GLGame的实例，并GLGraphics用于文件的输入和获得GL10，好运气的一个实例，希望这有助于
maybe this will help you i used it to import an .obj file and it worked with a texture and everything, you will have to pick it apart to whats relevant to your project its tied into all these other classes, like the instance of GLGame and GLGraphics are used for file input and getting an instance of GL10, good luck, hope this helps
对象装载机
public class ObjLoader {
public static Vertices3 load(GLGame game, String file) {
InputStream in = null;
try {
in = game.getFileIO().readAsset(file);
List<String> lines = readLines(in);
float[] vertices = new float[lines.size() * 3];
float[] normals = new float[lines.size() * 3];
float[] uv = new float[lines.size() * 2];
int numVertices = 0;
int numNormals = 0;
int numUV = 0;
int numFaces = 0;
int[] facesVerts = new int[lines.size() * 3];
int[] facesNormals = new int[lines.size() * 3];
int[] facesUV = new int[lines.size() * 3];
int vertexIndex = 0;
int normalIndex = 0;
int uvIndex = 0;
int faceIndex = 0;
for (int i = 0; i < lines.size(); i++) {
String line = lines.get(i);
if (line.startsWith("v ")) {
String[] tokens = line.split("[ ]+");
vertices[vertexIndex] = Float.parseFloat(tokens[1]);
vertices[vertexIndex + 1] = Float.parseFloat(tokens[2]);
vertices[vertexIndex + 2] = Float.parseFloat(tokens[3]);
vertexIndex += 3;
numVertices++;
continue;
}
if (line.startsWith("vn ")) {
String[] tokens = line.split("[ ]+");
normals[normalIndex] = Float.parseFloat(tokens[1]);
normals[normalIndex + 1] = Float.parseFloat(tokens[2]);
normals[normalIndex + 2] = Float.parseFloat(tokens[3]);
normalIndex += 3;
numNormals++;
continue;
}
if (line.startsWith("vt")) {
String[] tokens = line.split("[ ]+");
uv[uvIndex] = Float.parseFloat(tokens[1]);
uv[uvIndex + 1] = Float.parseFloat(tokens[2]);
uvIndex += 2;
numUV++;
continue;
}
if (line.startsWith("f ")) {
String[] tokens = line.split("[ ]+");
String[] parts = tokens[1].split("/");
facesVerts[faceIndex] = getIndex(parts[0], numVertices);
if (parts.length > 2)
facesNormals[faceIndex] = getIndex(parts[2], numNormals);
if (parts.length > 1)
facesUV[faceIndex] = getIndex(parts[1], numUV);
faceIndex++;
parts = tokens[2].split("/");
facesVerts[faceIndex] = getIndex(parts[0], numVertices);
if (parts.length > 2)
facesNormals[faceIndex] = getIndex(parts[2], numNormals);
if (parts.length > 1)
facesUV[faceIndex] = getIndex(parts[1], numUV);
faceIndex++;
parts = tokens[3].split("/");
facesVerts[faceIndex] = getIndex(parts[0], numVertices);
if (parts.length > 2)
facesNormals[faceIndex] = getIndex(parts[2], numNormals);
if (parts.length > 1)
facesUV[faceIndex] = getIndex(parts[1], numUV);
faceIndex++;
numFaces++;
continue;
}
}
float[] verts = new float[(numFaces * 3)
* (3 + (numNormals > 0 ? 3 : 0) + (numUV > 0 ? 2 : 0))];
for (int i = 0, vi = 0; i < numFaces * 3; i++) {
int vertexIdx = facesVerts[i] * 3;
verts[vi++] = vertices[vertexIdx];
verts[vi++] = vertices[vertexIdx + 1];
verts[vi++] = vertices[vertexIdx + 2];
if (numUV > 0) {
int uvIdx = facesUV[i] * 2;
verts[vi++] = uv[uvIdx];
verts[vi++] = 1 - uv[uvIdx + 1];
}
if (numNormals > 0) {
int normalIdx = facesNormals[i] * 3;
verts[vi++] = normals[normalIdx];
verts[vi++] = normals[normalIdx + 1];
verts[vi++] = normals[normalIdx + 2];
}
}
Vertices3 model = new Vertices3(game.getGLGraphics(), numFaces * 3,
0, false, numUV > 0, numNormals > 0);
model.setVertices(verts, 0, verts.length);
return model;
} catch (Exception ex) {
throw new RuntimeException("couldn't load '" + file + "'", ex);
} finally {
if (in != null)
try {
in.close();
} catch (Exception ex) {
}
}
}
static int getIndex(String index, int size) {
int idx = Integer.parseInt(index);
if (idx < 0)
return size + idx;
else
return idx - 1;
}
static List<String> readLines(InputStream in) throws IOException {
List<String> lines = new ArrayList<String>();
BufferedReader reader = new BufferedReader(new InputStreamReader(in));
String line = null;
while ((line = reader.readLine()) != null)
lines.add(line);
return lines;
}
}
vertices3
vertices3
public class Vertices3 {
final GLGraphics glGraphics;
final boolean hasColor;
final boolean hasTexCoords;
final boolean hasNormals;
final int vertexSize;
final IntBuffer vertices;
final int[] tmpBuffer;
final ShortBuffer indices;
public Vertices3(GLGraphics glGraphics, int maxVertices, int maxIndices,
boolean hasColor, boolean hasTexCoords, boolean hasNormals) {
this.glGraphics = glGraphics;
this.hasColor = hasColor;
this.hasTexCoords = hasTexCoords;
this.hasNormals = hasNormals;
this.vertexSize = (3 + (hasColor ? 4 : 0) + (hasTexCoords ? 2 : 0) + (hasNormals ? 3
: 0)) * 4;
this.tmpBuffer = new int[maxVertices * vertexSize / 4];
ByteBuffer buffer = ByteBuffer.allocateDirect(maxVertices * vertexSize);
buffer.order(ByteOrder.nativeOrder());
vertices = buffer.asIntBuffer();
if (maxIndices > 0) {
buffer = ByteBuffer.allocateDirect(maxIndices * Short.SIZE / 8);
buffer.order(ByteOrder.nativeOrder());
indices = buffer.asShortBuffer();
} else {
indices = null;
}
}
public void setVertices(float[] vertices, int offset, int length) {
this.vertices.clear();
int len = offset + length;
for (int i = offset, j = 0; i < len; i++, j++)
tmpBuffer[j] = Float.floatToRawIntBits(vertices[i]);
this.vertices.put(tmpBuffer, 0, length);
this.vertices.flip();
}
public void setIndices(short[] indices, int offset, int length) {
this.indices.clear();
this.indices.put(indices, offset, length);
this.indices.flip();
}
public void bind() {
GL10 gl = glGraphics.getGL();
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
vertices.position(0);
gl.glVertexPointer(3, GL10.GL_FLOAT, vertexSize, vertices);
if (hasColor) {
gl.glEnableClientState(GL10.GL_COLOR_ARRAY);
vertices.position(3);
gl.glColorPointer(4, GL10.GL_FLOAT, vertexSize, vertices);
}
if (hasTexCoords) {
gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
vertices.position(hasColor ? 7 : 3);
gl.glTexCoordPointer(2, GL10.GL_FLOAT, vertexSize, vertices);
}
if (hasNormals) {
gl.glEnableClientState(GL10.GL_NORMAL_ARRAY);
int offset = 3;
if (hasColor)
offset += 4;
if (hasTexCoords)
offset += 2;
vertices.position(offset);
gl.glNormalPointer(GL10.GL_FLOAT, vertexSize, vertices);
}
}
public void draw(int primitiveType, int offset, int numVertices) {
GL10 gl = glGraphics.getGL();
if (indices != null) {
indices.position(offset);
gl.glDrawElements(primitiveType, numVertices,
GL10.GL_UNSIGNED_SHORT, indices);
} else {
gl.glDrawArrays(primitiveType, offset, numVertices);
}
}
public void unbind() {
GL10 gl = glGraphics.getGL();
if (hasTexCoords)
gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
if (hasColor)
gl.glDisableClientState(GL10.GL_COLOR_ARRAY);
if (hasNormals)
gl.glDisableClientState(GL10.GL_NORMAL_ARRAY);
}
public int getNumIndices() {
return indices.limit();
}
public int getNumVertices() {
return vertices.limit() / (vertexSize / 4);
}
}
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