Cubemap texture with bitmap in OpenGL ES 2.0/3.0

Question

When I create a cubemap texture with simple colors, this works well:

@JvmStatic
fun createSimpleTextureCubemap() {
    val textureId = IntArray(1)
    val cubeFace0 = byteArrayOf(127, 127, 127) 
    val cubeFace1 = byteArrayOf(0, 127, 0) 
    ... // create other cube faces with simple color

    val cubeFaces = ByteBuffer.allocateDirect(3)
    glGenTextures(1, textureId, 0)
    glBindTexture(GL_TEXTURE_CUBE_MAP, textureId[0])

    cubeFaces.put(cubeFace0).position(0)
    glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X, 0, GL_RGB, 
        1, 1, 0, GL_RGB, GL_UNSIGNED_BYTE, cubeFaces)

    cubeFaces.put(cubeFace1).position(0)
    glTexImage2D(GL_TEXTURE_CUBE_MAP_NEGATIVE_X, 0, GL_RGB, 
        1, 1, 0, GL_RGB, GL_UNSIGNED_BYTE, cubeFaces)
    ...
    return textureId[0]
}

But when I try to create a cubemap texture with bitmap:

@JvmStatic
fun createTextureCubemap(context: Context, rowID: Int) {
    val input = context.resources.openRawResource(rowID)
    val bitmap = BitmapFactory.decodeStream(input)

    val textureId = IntArray(1)
    glGenTextures(1, textureId, 0)
    glBindTexture(GL_TEXTURE_CUBE_MAP, textureId[0])

    GLUtils.texImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X, 0, bitmap, 0)
    GLUtils.texImage2D(GL_TEXTURE_CUBE_MAP_NEGATIVE_X, 0, bitmap, 0)
    GLUtils.texImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_Y, 0, bitmap, 0)
    GLUtils.texImage2D(GL_TEXTURE_CUBE_MAP_NEGATIVE_Y, 0, bitmap, 0)
    GLUtils.texImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_Z, 0, bitmap, 0)
    GLUtils.texImage2D(GL_TEXTURE_CUBE_MAP_NEGATIVE_Z, 0, bitmap, 0)

    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_NEAREST)
    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_NEAREST)
    return textureId[0]
}

Then the object turns black. Someone may suggest why the cubemap with the bitmap does not work (black color)?

Thanks for any comment/answer.

Are the dimensions of your bitmap square and a power-of-two? — Columbo, May 14 '20 at 23:11
@Columbo It was not a square). Thank You!!! You really helped me. — alexrnov, May 15 '20 at 01:19

score 1 · Accepted Answer · answered May 15 '20 at 08:54

Textures for Cubemaps need to be square. As mentioned in the comments, the bitmap used was not square.

From glTexImage2D reference (GLUtils.texImage2D is a convenience wrapper around glTexImage2D)

GL_INVALID_VALUE is generated if target is one of the six cube map 2D image targets and the width and height parameters are not equal.

Cubemap texture with bitmap in OpenGL ES 2.0/3.0

1 Answers1