Venz :
I'm new to OpenGL, and I am trying to load a .obj file into my Android application and display it using OpenGLES 2. The object is rendered. But there are some spaces in it like the below image. How can I fix this?
This is the actual object.
Here is my code (additional: I'm using this in MaxST Instant tracker)
objLoader = new ObjLoader(context, "andy.obj");
numFaces = objLoader.numFaces;
positions = ByteBuffer.allocateDirect(objLoader.positions.length * mBytesPerFloat)
.order(ByteOrder.nativeOrder()).asFloatBuffer();
positions.put(objLoader.positions).position(0);
normals = ByteBuffer.allocateDirect(objLoader.normals.length * mBytesPerFloat)
.order(ByteOrder.nativeOrder()).asFloatBuffer();
normals.put(objLoader.normals).position(0);
textureCoordinates = ByteBuffer.allocateDirect(objLoader.textureCoordinates.length * mBytesPerFloat)
.order(ByteOrder.nativeOrder()).asFloatBuffer();
textureCoordinates.put(objLoader.textureCoordinates).position(0);
ByteBuffer bb = ByteBuffer.allocateDirect(objLoader.positions.length * Float.SIZE / 8);
bb.order(ByteOrder.nativeOrder());
vertexBuffer = bb.asFloatBuffer();
vertexBuffer.put(positions);
vertexBuffer.position(0);
bb = ByteBuffer.allocateDirect(objLoader.textureCoordinates.length * Float.SIZE / 8);
bb.order(ByteOrder.nativeOrder());
textureCoordBuff = bb.asFloatBuffer();
textureCoordBuff.put(textureCoordinates);
textureCoordBuff.position(0);
shaderProgramId = ShaderUtil.createProgram(VERTEX_SHADER_SRC, FRAGMENT_SHADER_SRC);
positionHandle = GLES20.glGetAttribLocation(shaderProgramId, "a_position");
textureCoordHandle = GLES20.glGetAttribLocation(shaderProgramId, "a_texCoord");
mvpMatrixHandle = GLES20.glGetUniformLocation(shaderProgramId, "u_mvpMatrix");
textureHandle = GLES20.glGetUniformLocation(shaderProgramId, "u_texture");
textureNames = new int[1];
GLES20.glGenTextures(1, textureNames, 0);
GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textureNames[0]);
GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MIN_FILTER, GLES20.GL_LINEAR);
GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MAG_FILTER, GLES20.GL_LINEAR);
GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_WRAP_S, GLES20.GL_CLAMP_TO_EDGE);
GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_WRAP_T, GLES20.GL_CLAMP_TO_EDGE);
(ObjLoader class is from here)
Here is my draw method
@Override
public void draw() {
GLES20.glUseProgram(shaderProgramId);
GLES20.glVertexAttribPointer(positionHandle, 3, GLES20.GL_FLOAT, false,
0, vertexBuffer);
GLES20.glEnableVertexAttribArray(positionHandle);
GLES20.glVertexAttribPointer(textureCoordHandle, 2, GLES20.GL_FLOAT, false,
0, textureCoordBuff);
GLES20.glEnableVertexAttribArray(textureCoordHandle);
Matrix.setIdentityM(modelMatrix, 0);
Matrix.multiplyMM(modelMatrix, 0, translation, 0, rotation, 0);
Matrix.multiplyMM(modelMatrix, 0, modelMatrix, 0, scale, 0);
Matrix.multiplyMM(modelMatrix, 0, transform, 0, modelMatrix, 0);
Matrix.multiplyMM(localMvpMatrix, 0, projectionMatrix, 0, modelMatrix, 0);
GLES20.glUniformMatrix4fv(mvpMatrixHandle, 1, false, localMvpMatrix, 0);
GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
GLES20.glUniform1i(textureHandle, 0);
GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textureNames[0]);
GLES20.glDrawArrays(GLES20.GL_TRIANGLES, 0, objLoader.positions.length / 3);
GLES20.glDisableVertexAttribArray(positionHandle);
GLES20.glDisableVertexAttribArray(textureCoordHandle);
GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, 0);
}
Rabbid76 :
The model file seems to consist of quads. If the faces are quads, the you have to generate 2 triangles for each face.
Adapt the object loader. e.g.:
class ObjLoader {
// [...]
public ObjLoader(Context context, String file) {
// [...]
switch (parts[0]) {
// [...]
case "f":
// faces: vertex/texture/normal
if (parts.length == 5) {
// triangle 1
faces.add(parts[1]);
faces.add(parts[2]);
faces.add(parts[3]);
// triangle 2
faces.add(parts[1]);
faces.add(parts[3]);
faces.add(parts[4]);
}
else {
faces.add(parts[1]);
faces.add(parts[2]);
faces.add(parts[3]);
}
break;
}
// [...]
}
}
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