external/openglcts/docs/specs/CTS_EXT_polygon_offset_clamp.txt

Conformance Test

    CTS_EXT_polygon_offset_clamp

Contributors

    Filip Demczewski, Mobica

Contacts

    Filip Demczewski, Mobica (filip.demczewski 'at' mobica.com)

Status

    In review

Version

    March 22, 2017 (version 1)

Dependencies

    OpenGL 3.3 (either core or compatibility profile) is required.
    OpenGL ES 3.1 is required.

    EXT_polygon_offset_clamp extension is required.

    This specification is written against:
      - EXT_polygon_offset_clamp specification
      - OpenGL 3.3 (Core Profile) specification

Overview

    Test is validating new polygon offset function that extends
    existing one with a new parameter that clamps the calculated
    offset to a minimum or maximum value.

New Tests

    Availability test

      * Check if extension is supported.

      * Check if GetBooleanv, GetIntegerv, GetInteger64v, GetFloatv
        and GetDoublev can be called with POLYGON_OFFSET_CLAMP_EXT
        passed as <pname> parameter.

      * Check if new PolygonOffsetClampEXT function is available to call.

    Clamp min/max test

      * Render primitive.
        Read depth buffer value and store it.
        Disable depth test to ensure second primitive overwrites values
        in depth buffer.
        Call PolygonOffsetClampEXT.
        Render the same primitive again.
        Read depth buffer value again and compare it with previous one.
        Check if offset is clamped correctly by validating it against
        equation described in extension's specification.

    Zero or inifinity parameter test

      * Call PolygonOffset function.
        Render primitive.
        Read depth value and store it.
        Clear depth buffer.
        Call PolygonOffsetClampEXT function with 0 or infinity value
        passed as <clamp> parameter.
        Read depth value and compare it to the stored one.
        Values should be equal as no clamping should occur.

Revision History

    Revision 1, 22 March, 2017 (Filip Demczewski)
      - Intial version;