How to construct a cubemap texture using QOpenGLTexture?

Question

I want to construct a cubemap texture using QOpenGLTexture using 6 images. I think I have placed them right.

I am using the following code to construct the cubemap

const QImage posx = QImage(":/images/posx.jpg").mirrored().convertToFormat(QImage::Format_RGBA8888);
const QImage posy = QImage(":/images/posy.jpg").mirrored().convertToFormat(QImage::Format_RGBA8888);
const QImage posz = QImage(":/images/posz.jpg").mirrored().convertToFormat(QImage::Format_RGBA8888);
const QImage negx = QImage(":/images/negx.jpg").mirrored().convertToFormat(QImage::Format_RGBA8888);
const QImage negy = QImage(":/images/negy.jpg").mirrored().convertToFormat(QImage::Format_RGBA8888);
const QImage negz = QImage(":/images/negz.jpg").mirrored().convertToFormat(QImage::Format_RGBA8888);

d->environment = new QOpenGLTexture(QOpenGLTexture::TargetCubeMap);
d->environment->create();
d->environment->setSize(posx.width(), posx.height(), posx.depth());
d->environment->setFormat(QOpenGLTexture::RGBA8_UNorm);
d->environment->allocateStorage();
d->environment->setData(0, 0, QOpenGLTexture::CubeMapPositiveX,
                        QOpenGLTexture::RGBA, QOpenGLTexture::UInt8,
                        (const void*)posx.constBits(), 0);
d->environment->setData(0, 0, QOpenGLTexture::CubeMapPositiveY,
                        QOpenGLTexture::RGBA, QOpenGLTexture::UInt8,
                        (const void*)posy.constBits(), 0);
d->environment->setData(0, 0, QOpenGLTexture::CubeMapPositiveZ,
                        QOpenGLTexture::RGBA, QOpenGLTexture::UInt8,
                        (const void*)posz.constBits(), 0);
d->environment->setData(0, 0, QOpenGLTexture::CubeMapNegativeX,
                        QOpenGLTexture::RGBA, QOpenGLTexture::UInt8,
                        (const void*)negx.constBits(), 0);
d->environment->setData(0, 0, QOpenGLTexture::CubeMapNegativeY,
                        QOpenGLTexture::RGBA, QOpenGLTexture::UInt8,
                        (const void*)negy.constBits(), 0);
d->environment->setData(0, 0, QOpenGLTexture::CubeMapNegativeZ,
                        QOpenGLTexture::RGBA, QOpenGLTexture::UInt8,
                        (const void*)negz.constBits(), 0);
d->environment->setWrapMode(QOpenGLTexture::ClampToEdge);
d->environment->setMinificationFilter(QOpenGLTexture::LinearMipMapLinear);
d->environment->setMagnificationFilter(QOpenGLTexture::LinearMipMapLinear);

I then bind the environment texture during paintGL() as follows

.....
d->environment->bind(0);
d->shader->setUniformValue("qt_Environment", 0);

const int nrIndicies = d->torusResolution * d->tubeResolution * 6;
glDrawElements(GL_TRIANGLES, nrIndicies, GL_UNSIGNED_INT, (void*)0);
.....

Vertex shader snippet is as follows

....
varying vec3 v_TexCoord;
....

void main(void)
{
    ....
    v_TexCoord = normalize(v_Normal + v_Position);
    ....
}

The fragment shader snippet is as follows

.....
varying vec3 v_TexCoord;
uniform samplerCube qt_Environment;
.....

vec4 evaluateColor(in vec3 normal, in vec3 texCoord)
{
    vec3 finalColor ....
    .....
    .....

    finalColor += textureCube(qt_Environment, texCoord).rgb;    
    return vec4( finalColor, c_one );
}

void main(void)
{
    gl_FragColor = evaluateColor(v_Normal, v_TexCoord);
}

I also have another part of the code which renders the cubemap on a skybox. While I am able to project the 6 images on the skybox and render it properly, I am unable to render the reflection on a torus object in the scene.

I am getting a well lit torus, with no reflection.

Can somebody help with this please?

Answer 1

EDIT: This issue is now SOLVED. http://lists.qt-project.org/pipermail/interest/2016-February/020788.html

I had to call generateMipMap() on the environment texture before applying it on the torus.