xref: /third_party/vk-gl-cts/doc/testspecs/GLES2/functional.vertex_arrays.single_attribute.txt

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drawElements Quality Program Test Specification
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	Single vertex attribute vertex array tests

Tests:
 + dEQP-GLES2.functional.vertex_arrays.single_attribute.*

Includes:
 + Rendering with different strides from buffer and user pointer.
 + Attribute normalization with different types and component counts.
 + Passing attributes to vec2, vec3 and vec4.
 + Using buffers with different usage.
 + Buffer attributes with different offsets.

Excludes:
 + Buffer data modifications
 + Stride less than types own size
 + Robustness with nan or inf
 + Index buffers or glDrawElements
 + Different first values for glDrawArrays

Description:

Testcases generate data that defines quads in testcase specifig format.
This takes account stride, offsets and other parameters. Input types must
have two or more components to form distinct coordinates. First two components
are coordinates and six subsequent attributes form two triangles which define a
quad. Third and fourth component are same for each vertex in quad.
This data is uploaded to buffer or used from user pointer while rendering.
Rendering uses simple shader that takes first two components and adds
first to third component and second to fourth component if more than
two components are used. First and third component are used as x coordinate
and second and fourth as y. These values are also scaled to range from -1.0 to 1.0.
Test renders only once and result is checked against reference implementations result.

Stride tests render different input type and component count combinations from buffer
and user pointer. Stride testcases test npot and pot strides and types real size as stride.
Data is passed to shader as vec4.

Normalization is tested with different input types and component counts. User
pointers are used as source for data and vec4 is used in shaders.

Output type tests pass different input types to different vector types in shader.
Also different input type and output type component counts are tested. Data is used
from user pointer.

Usage testcases test buffers with different usage parameters with different strides
and different sized types. The data is used as vec2 in shaders.