[Mesa-dev] [PATCH v3] mesa: readpixels add support for GL_HALF_FLOAT

[Eric Anholt]

Lin Johnson <johnson.lin at intel.com> writes:

> Ext_color_buffer_half_float is using type GL_HALF_FLOAT
> and data_type GL_FLOAT. This fix Android CTS test
> android.view.cts.PixelCopyTest
> v2: remove commtens of Ext_color_buffer_half_float.
> As Ext_color_buffer__float can use type GL_HALF_FLOAT
>
> Reviewed-by:   Palli, Tapani <tapani.palli at intel.com>
> Signed-off-by: Lin Johnson <johnson.lin at intel.com>

I've been looking into CTS issues on VC5, and I think this patch should
be reverted.

The issue is that the text above that in the spec disallows this case.
From GLES 3.0.2:

    Only two combinations of format and type are accepted in most
    cases. The first varies depending on the format of the currently
    bound rendering surface. For normalized fixed-point rendering
    surfaces, the combination format RGBA and type UNSIGNED_BYTE is
    accepted. For signed integer rendering surfaces, the combina- tion
    format RGBA_INTEGER and type INT is accepted. For unsigned integer
    rendering surfaces, the combination format RGBA_INTEGER and type
    UNSIGNED_INT is accepted.

    [...]

    ReadPixels generates an INVALID_OPERATION error if the combination
    of format and type is unsupported.

and this spec adds on to that first paragraph:

    For floating-point rendering surfaces, the combination
    format RGBA and type FLOAT is accepted.

The second allowed combo is:

    The second is an implementation-chosen format from among those
    defined in table 3.2, excluding formats DEPTH_COMPONENT and
    DEPTH_STENCIL . The values of format and type for this format may be
    determined by calling Get- Integerv with the symbolic constants
    IMPLEMENTATION_COLOR_READ_FORMAT and IMPLEMENTATION_COLOR_READ_TYPE
    , respectively.

The failing cases are in the CTS's packed_pixels testsuite, such as:

KHR-GLES3.packed_pixels.pbo_rectangle.r11f_g11f_b10f
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