external/openglcts/docs/specs/CTS_EXT_texture_filter_anisotropic.txt

Conformance Test

    CTS_EXT_texture_filter_anisotropic

Contributors

    Adam Czupryna, Mobica

Contacts

    Adam Czupryna, Mobica (adam.czupryna 'at' mobica.com)

Status

    In review

Version

    April 24, 2017 (version 1)

Dependencies

    OpenGL 1.2 is required.

    EXT_texture_filter_anisotropic extension is required.

    This specification is written against:
      - EXT_texture_filter_anisotropic specification,
      - OpenGL 1.2 specification.

Overview

    This tests verifies if functionality provided by EXT_texture_filter_anisotropic
    works as expected:

      * Verify if TexParameter*, GetTexParameter* queries works correctly for
        TEXTURE_MAX_ANISOTROPY_EXT token and Get* queries for
        MAX_TEXTURE_MAX_ANISOTROPY_EXT token respectively.

      * Verify if there is difference between polygon rendered with different
        degree of anisotropy.

New Tests

    New State Queries Test

      * Test TexParameter{i f}{v}, GetTexParameter{i f} queries for <pname>:

          - TEXTURE_MAX_ANISOTROPY_EXT

        Check default values and set manually. Test if setting value lower
          than 1.0 would generate INVALID_VALUE error.

      * Test GetBooleanv, GetDoublev, GetFloatv and GetIntegerv queries for <pname>"

          - MAX_TEXTURE_MAX_ANISOTROPY_EXT

        Check if no error is generated.

    Anisotropic Filtering Test

      * Iterate through all supported targets and texture formats.
            Generate high contrast texture (vertical strips) with at least two
              mipmap levels.
                Set min filtering to GL_LINEAR_MIPMAP_LINEAR and render polygon with
                  top vertices set far away from camera and bottom vertices set near
                  camera. Do it for 3 different degrees of anisotropy:
                  - 1.0 (disabled anisotropic filtering)
                  - 2.0
                  - MAX_TEXTURE_MAX_ANISOTROPY_EXT
                Expect that for higher degrees of anisotropy top part of rendered
                  strips will be smoother. It means that total sum of absolute
                  derivatives of color in x direction will be less than for lower
                  degree of anisotropy.

Revision History

    Revision 1, 24 April, 2017 (Adam Czupryna)
      - Intial version;

    Revision 2, 2 June, 2017 (Adam Czupryna)
      - Added description of anisotropy verification method to
        Anisotropic Filtering Test section;