Try flipping the texture image vertically, that's a common problem.

- Kim

ksiva wrote:

Hmm, that shouldn't happen. The texture should be mapped to the vertices regardless of their location in world space. Are you using a custom shader? Are you sure the texture was applied correctly before the rotation?

- Kim

Hi Kim,

Yes you are right - the texture was applied wrongly even before the rotation! No I wasn't using the custom shader. What I did was:
1. get a 3d car model in obj format from the internet
2. run the Perl script to generate the *.h file
3. Do the necessary changes to replace the teapot with this car model.

But I find that the texture was applied wrongly, irregardless of the rotation. I am really not sure why that's the case. I've noticed the same thing even for the banana.h file - seems like the texture isn't at its right place either.

Hmm, that shouldn't happen. The texture should be mapped to the vertices regardless of their location in world space. Are you using a custom shader? Are you sure the texture was applied correctly before the rotation?

- Kim

ksiva wrote:

You need to adjust the translation and rotation of the modelview matrix. See the renderFrame method. You can add a rotate like this:

        SampleUtils::translatePoseMatrix(0.0f, 0.0f, kObjectScale,
                                         &modelViewMatrix.data[0]);
        SampleUtils::scalePoseMatrix(kObjectScale, kObjectScale, kObjectScale,
                                     &modelViewMatrix.data[0]);
        SampleUtils::rotatePoseMatrix(90.0f, 1.0f, 0.0f, 0.0f,
                                      &modelViewMatrix.data[0]);
        SampleUtils::multiplyMatrix(&projectionMatrix.data[0],
                                    &modelViewMatrix.data[0] ,
                                    &modelViewProjection.data[0]);

That rotates 90 degrees around the X axis, then scales by kObjectScale, and then translates up the Z axis by kObjectScale.

- Kim

Hi Kim,

I followed the above method to render a car 3d model. If I did not do the rotation around x-axis, the car got rendered correctly, only that it lies sideway and in the middle of the air. If I did do the rotation around x-axis (as per your code up there), I get the car object rendered at the right orientation, but however, the texture is still binded in the old orientation (pre-rotation), and hence I get a car with its sideview rendered on the car roof etc. How I solve this problem?

Rgds,
tapiocaflash

Have a look at http://ar.qualcomm.at/node/2000880 thread.

Hello,

I'm also trying to get the banana object out from the Heiko Behrens's project but to no avail.

May I know how do you render out the banana in opengl ? (I'm using the ImageTarget as a framework)

Thanks

You need to adjust the translation and rotation of the modelview matrix. See the renderFrame method. You can add a rotate like this:

        SampleUtils::translatePoseMatrix(0.0f, 0.0f, kObjectScale,
                                         &modelViewMatrix.data[0]);
        SampleUtils::scalePoseMatrix(kObjectScale, kObjectScale, kObjectScale,
                                     &modelViewMatrix.data[0]);
        SampleUtils::rotatePoseMatrix(90.0f, 1.0f, 0.0f, 0.0f,
                                      &modelViewMatrix.data[0]);
        SampleUtils::multiplyMatrix(&projectionMatrix.data[0],
                                    &modelViewMatrix.data[0] ,
                                    &modelViewProjection.data[0]);

That rotates 90 degrees around the X axis, then scales by kObjectScale, and then translates up the Z axis by kObjectScale.

- Kim

Hi,Kim.
Thanks,I got a big banana with setting the kObjectScale.
The new problem is the banana is vertical and float in the air now, But I want a horizontal one and close to the image. So, what should I do ?:confused:
many thanks~~

ksiva wrote:

Try setting the kObjectScale in ImageTargets.cpp to something larger.

- Kim

Try setting the kObjectScale in ImageTargets.cpp to something larger.

- Kim

I didn't test this but I think you can tweak the size values in config.xml