Package org.lwjgl.opengl

Class ARBTessellationShader

java.lang.Object
org.lwjgl.opengl.ARBTessellationShader
public class ARBTessellationShader extends Object
Native bindings to the ARB_tessellation_shader extension.

This extension introduces new tessellation stages and two new shader types to the OpenGL primitive processing pipeline. These pipeline stages operate on a new basic primitive type, called a patch. A patch consists of a fixed-size collection of vertices, each with per-vertex attributes, plus a number of associated per-patch attributes. Tessellation control shaders transform an input patch specified by the application, computing per-vertex and per-patch attributes for a new output patch. A fixed-function tessellation primitive generator subdivides the patch, and tessellation evaluation shaders are used to compute the position and attributes of each vertex produced by the tessellator.

When tessellation is active, it begins by running the optional tessellation control shader. This shader consumes an input patch and produces a new fixed-size output patch. The output patch consists of an array of vertices, and a set of per-patch attributes. The per-patch attributes include tessellation levels that control how finely the patch will be tessellated. For each patch processed, multiple tessellation control shader invocations are performed -- one per output patch vertex. Each tessellation control shader invocation writes all the attributes of its corresponding output patch vertex. A tessellation control shader may also read the per-vertex outputs of other tessellation control shader invocations, as well as read and write shared per-patch outputs. The tessellation control shader invocations for a single patch effectively run as a group. A built-in barrier() function is provided to allow synchronization points where no shader invocation will continue until all shader invocations have reached the barrier.

The tessellation primitive generator then decomposes a patch into a new set of primitives using the tessellation levels to determine how finely tessellated the output should be. The primitive generator begins with either a triangle or a quad, and splits each outer edge of the primitive into a number of segments approximately equal to the corresponding element of the outer tessellation level array. The interior of the primitive is tessellated according to elements of the inner tessellation level array. The primitive generator has three modes: "triangles" and "quads" split a triangular or quad-shaped patch into a set of triangles that cover the original patch; "isolines" splits a quad-shaped patch into a set of line strips running across the patch horizontally. Each vertex generated by the tessellation primitive generator is assigned a (u,v) or (u,v,w) coordinate indicating its relative location in the subdivided triangle or quad.

For each vertex produced by the tessellation primitive generator, the tessellation evaluation shader is run to compute its position and other attributes of the vertex, using its (u,v) or (u,v,w) coordinate. When computing final vertex attributes, the tessellation evaluation shader can also read the attributes of any of the vertices of the patch written by the tessellation control shader. Tessellation evaluation shader invocations are completely independent, although all invocations for a single patch share the same collection of input vertices and per-patch attributes.

The tessellator operates on vertices after they have been transformed by a vertex shader. The primitives generated by the tessellator are passed further down the OpenGL pipeline, where they can be used as inputs to geometry shaders, transform feedback, and the rasterizer.

The tessellation control and evaluation shaders are both optional. If neither shader type is present, the tessellation stage has no effect. If no tessellation control shader is present, the input patch provided by the application is passed directly to the tessellation primitive generator, and a set of default tessellation level parameters is used to control primitive generation. In this extension, patches may not be passed beyond the tessellation evaluation shader, and an error is generated if an application provides patches and the current program object contains no tessellation evaluation shader.

Requires GL32 and GLSL 1.50. Promoted to core in OpenGL 4.0.

  • Field Details

    • GL_PATCHES

      public static final int GL_PATCHES
      Accepted by the mode parameter of Begin and all vertex array functions that implicitly call Begin.
      See Also:

    • GL_PATCH_VERTICES

      public static final int GL_PATCH_VERTICES
      Accepted by the pname parameter of PatchParameteri, GetBooleanv, GetDoublev, GetFloatv, GetIntegerv, and GetInteger64v.
      See Also:

    • GL_PATCH_DEFAULT_INNER_LEVEL

      public static final int GL_PATCH_DEFAULT_INNER_LEVEL
      Accepted by the pname parameter of PatchParameterfv, GetBooleanv, GetDoublev, GetFloatv, and GetIntegerv, and GetInteger64v.
      See Also:

    • GL_PATCH_DEFAULT_OUTER_LEVEL

      public static final int GL_PATCH_DEFAULT_OUTER_LEVEL
      Accepted by the pname parameter of PatchParameterfv, GetBooleanv, GetDoublev, GetFloatv, and GetIntegerv, and GetInteger64v.
      See Also:

    • GL_TESS_CONTROL_OUTPUT_VERTICES

      public static final int GL_TESS_CONTROL_OUTPUT_VERTICES
      Accepted by the pname parameter of GetProgramiv.
      See Also:

    • GL_TESS_GEN_MODE

      public static final int GL_TESS_GEN_MODE
      Accepted by the pname parameter of GetProgramiv.
      See Also:

    • GL_TESS_GEN_SPACING

      public static final int GL_TESS_GEN_SPACING
      Accepted by the pname parameter of GetProgramiv.
      See Also:

    • GL_TESS_GEN_VERTEX_ORDER

      public static final int GL_TESS_GEN_VERTEX_ORDER
      Accepted by the pname parameter of GetProgramiv.
      See Also:

    • GL_TESS_GEN_POINT_MODE

      public static final int GL_TESS_GEN_POINT_MODE
      Accepted by the pname parameter of GetProgramiv.
      See Also:

    • GL_ISOLINES

      public static final int GL_ISOLINES
      Returned by GetProgramiv when pname is TESS_GEN_MODE.
      See Also:

    • GL_FRACTIONAL_ODD

      public static final int GL_FRACTIONAL_ODD
      Returned by GetProgramiv when pname is TESS_GEN_SPACING.
      See Also:

    • GL_FRACTIONAL_EVEN

      public static final int GL_FRACTIONAL_EVEN
      Returned by GetProgramiv when pname is TESS_GEN_SPACING.
      See Also:

    • GL_MAX_PATCH_VERTICES

      public static final int GL_MAX_PATCH_VERTICES
      Accepted by the pname parameter of GetBooleanv, GetDoublev, GetFloatv, GetIntegerv, and GetInteger64v.
      See Also:

    • GL_MAX_TESS_GEN_LEVEL

      public static final int GL_MAX_TESS_GEN_LEVEL
      Accepted by the pname parameter of GetBooleanv, GetDoublev, GetFloatv, GetIntegerv, and GetInteger64v.
      See Also:

    • GL_MAX_TESS_CONTROL_UNIFORM_COMPONENTS

      public static final int GL_MAX_TESS_CONTROL_UNIFORM_COMPONENTS
      Accepted by the pname parameter of GetBooleanv, GetDoublev, GetFloatv, GetIntegerv, and GetInteger64v.
      See Also:

    • GL_MAX_TESS_EVALUATION_UNIFORM_COMPONENTS

      public static final int GL_MAX_TESS_EVALUATION_UNIFORM_COMPONENTS
      Accepted by the pname parameter of GetBooleanv, GetDoublev, GetFloatv, GetIntegerv, and GetInteger64v.
      See Also:

    • GL_MAX_TESS_CONTROL_TEXTURE_IMAGE_UNITS

      public static final int GL_MAX_TESS_CONTROL_TEXTURE_IMAGE_UNITS
      Accepted by the pname parameter of GetBooleanv, GetDoublev, GetFloatv, GetIntegerv, and GetInteger64v.
      See Also:

    • GL_MAX_TESS_EVALUATION_TEXTURE_IMAGE_UNITS

      public static final int GL_MAX_TESS_EVALUATION_TEXTURE_IMAGE_UNITS
      Accepted by the pname parameter of GetBooleanv, GetDoublev, GetFloatv, GetIntegerv, and GetInteger64v.
      See Also:

    • GL_MAX_TESS_CONTROL_OUTPUT_COMPONENTS

      public static final int GL_MAX_TESS_CONTROL_OUTPUT_COMPONENTS
      Accepted by the pname parameter of GetBooleanv, GetDoublev, GetFloatv, GetIntegerv, and GetInteger64v.
      See Also:

    • GL_MAX_TESS_PATCH_COMPONENTS

      public static final int GL_MAX_TESS_PATCH_COMPONENTS
      Accepted by the pname parameter of GetBooleanv, GetDoublev, GetFloatv, GetIntegerv, and GetInteger64v.
      See Also:

    • GL_MAX_TESS_CONTROL_TOTAL_OUTPUT_COMPONENTS

      public static final int GL_MAX_TESS_CONTROL_TOTAL_OUTPUT_COMPONENTS
      Accepted by the pname parameter of GetBooleanv, GetDoublev, GetFloatv, GetIntegerv, and GetInteger64v.
      See Also:

    • GL_MAX_TESS_EVALUATION_OUTPUT_COMPONENTS

      public static final int GL_MAX_TESS_EVALUATION_OUTPUT_COMPONENTS
      Accepted by the pname parameter of GetBooleanv, GetDoublev, GetFloatv, GetIntegerv, and GetInteger64v.
      See Also:

    • GL_MAX_TESS_CONTROL_UNIFORM_BLOCKS

      public static final int GL_MAX_TESS_CONTROL_UNIFORM_BLOCKS
      Accepted by the pname parameter of GetBooleanv, GetDoublev, GetFloatv, GetIntegerv, and GetInteger64v.
      See Also:

    • GL_MAX_TESS_EVALUATION_UNIFORM_BLOCKS

      public static final int GL_MAX_TESS_EVALUATION_UNIFORM_BLOCKS
      Accepted by the pname parameter of GetBooleanv, GetDoublev, GetFloatv, GetIntegerv, and GetInteger64v.
      See Also:

    • GL_MAX_TESS_CONTROL_INPUT_COMPONENTS

      public static final int GL_MAX_TESS_CONTROL_INPUT_COMPONENTS
      Accepted by the pname parameter of GetBooleanv, GetDoublev, GetFloatv, GetIntegerv, and GetInteger64v.
      See Also:

    • GL_MAX_TESS_EVALUATION_INPUT_COMPONENTS

      public static final int GL_MAX_TESS_EVALUATION_INPUT_COMPONENTS
      Accepted by the pname parameter of GetBooleanv, GetDoublev, GetFloatv, GetIntegerv, and GetInteger64v.
      See Also:

    • GL_MAX_COMBINED_TESS_CONTROL_UNIFORM_COMPONENTS

      public static final int GL_MAX_COMBINED_TESS_CONTROL_UNIFORM_COMPONENTS
      Accepted by the pname parameter of GetBooleanv, GetDoublev, GetFloatv, GetIntegerv, and GetInteger64v.
      See Also:

    • GL_MAX_COMBINED_TESS_EVALUATION_UNIFORM_COMPONENTS

      public static final int GL_MAX_COMBINED_TESS_EVALUATION_UNIFORM_COMPONENTS
      Accepted by the pname parameter of GetBooleanv, GetDoublev, GetFloatv, GetIntegerv, and GetInteger64v.
      See Also:

    • GL_UNIFORM_BLOCK_REFERENCED_BY_TESS_CONTROL_SHADER

      public static final int GL_UNIFORM_BLOCK_REFERENCED_BY_TESS_CONTROL_SHADER
      Accepted by the pname parameter of GetActiveUniformBlockiv.
      See Also:

    • GL_UNIFORM_BLOCK_REFERENCED_BY_TESS_EVALUATION_SHADER

      public static final int GL_UNIFORM_BLOCK_REFERENCED_BY_TESS_EVALUATION_SHADER
      Accepted by the pname parameter of GetActiveUniformBlockiv.
      See Also:

    • GL_TESS_EVALUATION_SHADER

      public static final int GL_TESS_EVALUATION_SHADER
      Accepted by the type parameter of CreateShader and returned by the params parameter of GetShaderiv.
      See Also:

    • GL_TESS_CONTROL_SHADER

      public static final int GL_TESS_CONTROL_SHADER
      Accepted by the type parameter of CreateShader and returned by the params parameter of GetShaderiv.
      See Also:

  • Method Details

    • glPatchParameteri

      public static void glPatchParameteri(int pname, int value)
      Specifies the integer value of the specified parameter for patch primitives.
      Parameters:
      pname - the name of the parameter to set. Must be:
      PATCH_VERTICES
      value - the new value for the parameter given by pname

    • nglPatchParameterfv

      public static void nglPatchParameterfv(int pname, long values)
      Unsafe version of: PatchParameterfv

    • glPatchParameterfv

      public static void glPatchParameterfv(int pname, FloatBuffer values)
      Specifies an array of float values for the specified parameter for patch primitives.
      Parameters:
      pname - the name of the parameter to set. One of:
      PATCH_DEFAULT_OUTER_LEVELPATCH_DEFAULT_INNER_LEVEL
      values - an array containing the new values for the parameter given by pname

    • glPatchParameterfv

      public static void glPatchParameterfv(int pname, float[] values)
      Array version of: PatchParameterfv