-------------------------------------------------------------------------
drawElements Quality Program Test Specification
-----------------------------------------------

Copyright 2014 The Android Open Source Project

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

     http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
-------------------------------------------------------------------------
    Title

Tests:
 + dEQP-GLES31.functional.fbo.no_attachments.*
 + dEQP-GLES31.functional.fbo.completeness.no_attachments

Includes:
 + Framebuffer completeness
 + Rendering
   - Multiple sizes
   - Multisampled
 + Limits

Excludes:
 + Most usefull forms of output
   - Atomic counter use (none guaranteed in fragment shader)
   - Image read/write (no image units guaranteed in fragment shader)
 + Fixed sample locations (no way to verify)

Description:

Framebuffer completenss is tested trivially

Rendering is verified to happen with occlusion queries. This rather limited
method has been chosen since there is a general shortage of guaranteed valid
ways of outputting data from a fragment shader without a color/depth/stencil
buffer. Namely all relevant minimum maximums (atomic counters, atomic counter
buffers, shader storage blocks and image uniforms) are zero.

Basic functioning of the framebuffer is tested by rendering a full buffer quad
and verifying its presence with an occlusion query. Size of the framebuffer
is verified by running a shader that discard all fragments that are not within
a given pixel's boundaries with several pixels placed around the edge of the
framebuffer and checking for that these fragments were (not) rendered with
an occlusion query. Each tested pixel has its own render call and occlusion
query.

Basic functionality tests iterate a number of size & sampling parameters,
including the required maximum and implementation reported limits

The completeness test verifies that a framebuffer with both widht and height
set is considered complete.