doc/testspecs/GLES31/functional.compute.shared_var.txt

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drawElements Quality Program Test Specification
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    Shader Shared Variable Tests

Tests:
 + dEQP-GLES31.functional.compute.shared_var.*

Includes:
 + All basic types, all precisions
 + Single shared variable
 + Various work group sizes
   - 2x1x3 in basic type cases
   - 1x1x1, 64x1x1, 1x64x1, 1x1x64, 256x1x1, 1x256x1, 17x5x9 for selected types
 + All built-in atomic operation functions
   + int, uint types
   + all precisions
 + Multiple work groups for atomic function cases

Excludes:
 + Multiple shared variables
 + Complex types (arrays, structures)
 + Negative tests

Description:

Basic type test cases declare a single shared variable of the appropriate
type. In addition following input/output variables are used:
 + buffer block containing an array of booleans, one for each item in work group
 + u_val[], u_ref[] uniform arrays, filled with identical values
 + u_numIters iteration count uniform, initialized with work group size

The compute shader contains a loop that is limited by the u_numIters uniform.
In each iteration one of the work items writes a value from u_val to the
shared variable. A shared memory barrier is issued, and after that all work
items read and compare shared var value to u_ref. If comparison passed for all
iterations, true is set to appropriate element of the output array. Test case
then maps the output SSBO and checks that all elements are true, meaning that
all shader invocations passed the test.


Atomic operation test cases issue multiple work groups of size 3x2x1. In each
work group first invocation initializes shared variable to a certain value.
Barrier is issued and after that each invocation issues atomic operation with
per-invocation value. Resulting values are written out into SSBO. Finally, one
invocation per work group writes out the final shared variable value.

Resulting values from SSBO are read using buffer mapping and verified. The
input values and validation logic depends on the type of the atomic operation.