Vuforia: How to change teapot with a text in the image targets example?

问题

How do I change the teapot with a text content in Vuforia's Image Target example?

The example is available at : https://developer.vuforia.com/resources/sample-apps/image-targets-sample-app

回答1:

I tried to access the links mbrenon gave. Unfortunately they didn't load.

My solution:

The reason why you have a Teapot is because Vuforia is using that class as the image to be shown. In order to have a plane text, I created my own PlaneTextClass.

Go to src->main->java->com.qualcomm.vuforia.samples->SampleApplication->utils. There you could find the objects you can use.

Add a class named "TextPlane" and extended from "MeshObject"

public class TextPlane extends MeshObject {

  private final static double planeVertices[] =
        {
                -50f, -50f, 0.0f, 50f, -50f, 0.0f, 50f, 50f, 0.0f, -50f, 50f, 0.0f
        };
  private final static double planeTexcoords[] =
        {
                0, 0, 1, 0, 1, 1, 0, 1
        };
  private final static double planeNormals[] =
        {
                0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1
        };
  private final static short planeIndices[] =
        {
                0, 1, 2, 0, 2, 3
        };


  private Buffer mVertBuff;
  private Buffer mTexCoordBuff;
  private Buffer mNormBuff;
  private Buffer mIndBuff;

  public TextPlane(){
    mVertBuff = fillBuffer(planeVertices);
    mTexCoordBuff = fillBuffer(planeTexcoords);
    mNormBuff = fillBuffer(planeNormals);
    mIndBuff = fillBuffer(planeIndices);
  }

  @Override
  public Buffer getBuffer(BUFFER_TYPE bufferType) {
    Buffer result = null;
    switch (bufferType)
    {
        case BUFFER_TYPE_VERTEX:
            result = mVertBuff;
            break;
        case BUFFER_TYPE_TEXTURE_COORD:
            result = mTexCoordBuff;
            break;
        case BUFFER_TYPE_INDICES:
            result = mIndBuff;
            break;
        case BUFFER_TYPE_NORMALS:
            result = mNormBuff;
        default:
            break;
     }
    return result;
  }

  @Override
  public int getNumObjectVertex() {
      return planeVertices.length / 3;
  }

  @Override
  public int getNumObjectIndex() {
      return planeIndices.length;
  }}

If you want to change the size of the image, change the values in PlaneVertices[].

Go to src->main->java->com.qualcomm.vuforia.samples->VuforiaSamples->app->ImageTargets->ImageTargetRenderer.java
Add your new class in ImageTargetRenderer.java:

private TextPlane mTextPlane;

Initilize mTextPlane inside the method initRendering()

mTextPlane = new TextPlane();

Replace the teapot code with you new textplane code:

Replace this:

GLES20.glVertexAttribPointer(vertexHandle, 3, GLES20.GL_FLOAT,
                        false, 0, mTeapot.getVertices());
                GLES20.glVertexAttribPointer(normalHandle, 3, GLES20.GL_FLOAT,
                        false, 0, mTeapot.getNormals());
                GLES20.glVertexAttribPointer(textureCoordHandle, 2,
                        GLES20.GL_FLOAT, false, 0, mTeapot.getTexCoords());

with this:

GLES20.glVertexAttribPointer(vertexHandle, 3, GLES20.GL_FLOAT,
                        false, 0, mTextPlane.getVertices());
                GLES20.glVertexAttribPointer(normalHandle, 3, GLES20.GL_FLOAT,
                        false, 0, mTextPlane.getNormals());
                GLES20.glVertexAttribPointer(textureCoordHandle, 2,
                        GLES20.GL_FLOAT, false, 0, mTextPlane.getTexCoords());

Replace this:

GLES20.glDrawElements(GLES20.GL_TRIANGLES, mTeapot.getNumObjectIndex(), GLES20.GL_UNSIGNED_SHORT, mTeapot.getIndices());

With this:

GLES20.glDrawElements(GLES20.GL_TRIANGLES,
                            mTextPlane.getNumObjectIndex(), GLES20.GL_UNSIGNED_SHORT,
                            mTextPlane.getIndices());

Try it. It should work!

来源：https://stackoverflow.com/questions/17939607/vuforia-how-to-change-teapot-with-a-text-in-the-image-targets-example

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