Package org.lwjgl.opengl

Class ARBSampleLocations


  • public class ARBSampleLocations
extends java.lang.Object
    Native bindings to the ARB_sample_locations extension.

    This extension allows an application to modify the locations of samples within a pixel used in multisample rasterization. Additionally, it allows applications to specify different sample locations for each pixel in a group of adjacent pixels, which may increase antialiasing quality (particularly if a custom resolve shader is used that takes advantage of these different locations).

    It is common for implementations to optimize the storage of depth values by storing values that can be used to reconstruct depth at each sample location, rather than storing separate depth values for each sample. For example, the depth values from a single triangle can be represented using plane equations. When the depth value for a sample is needed, it is automatically evaluated at the sample location. Modifying the sample locations causes the reconstruction to no longer evaluate the same depth values as when the samples were originally generated. This extension provides a command to "evaluate" and store per-sample depth values using the currently programmed sample locations, which allows the application to manage this issue if/when necessary.

    The programmable sample locations are used during rasterization and for evaluation of depth functions during normal geometric rendering. The programmable locations are associated with a framebuffer object rather than an individual depth buffer, so if the depth buffer is used as a texture the texture sampling may be done at the standard sample locations. Additionally, commands that do not render geometric primitives (e.g. ReadPixels, BlitFramebuffer, CopyTexSubImage2D, etc.) may use the standard sample locations to evaluate depth functions rather than the programmable locations. If a single depth buffer is used at different times with different sample locations, the depth functions may be interpreted using the current sample locations.

    • Method Detail

      • glFramebufferSampleLocationsfvARB

        public static void glFramebufferSampleLocationsfvARB(int target,
                                                     int start,
                                                     java.nio.FloatBuffer v)
        Controls the programmable sample locations for the framebuffer bound to the specified target.

        There are N pairs of programmable sample locations values in a framebuffer, where N is the value of PROGRAMMABLE_SAMPLE_LOCATION_TABLE_SIZE_ARB. Each programmable sample location is specified as a pair of floating point values in the range [0,1], corresponding to the x and y locations respectively in GL pixel space. (0.5, 0.5) thus corresponds to the pixel center. Sample locations outside of [0,1] result in undefined behavior.

        Parameters:
        target - the framebuffer target. One of:
        FRAMEBUFFERDRAW_FRAMEBUFFERREAD_FRAMEBUFFER
        start - the first sample location to update
        v - a pair of values for each sample location to update

      • glNamedFramebufferSampleLocationsfvARB

        public static void glNamedFramebufferSampleLocationsfvARB(int framebuffer,
                                                          int start,
                                                          java.nio.FloatBuffer v)
        DSA version of FramebufferSampleLocationsfvARB.
        Parameters:
        framebuffer - the framebuffer object to update
        start - the first sample location to update
        v - a pair of values for each sample location to update

      • glEvaluateDepthValuesARB

        public static void glEvaluateDepthValuesARB()
        Evaluates depth values for all samples in the current depth buffer (subject to the pixel ownership and scissor tests) and stores each value in the depth buffer. This can be used to ensure that later accesses will use depth values consistent with the sample locations used when the samples were generated. If the current framebuffer has no depth buffer, EvaluateDepthValuesARB will have no effect.

      • glFramebufferSampleLocationsfvARB

        public static void glFramebufferSampleLocationsfvARB(int target,
                                                     int start,
                                                     float[] v)
        Array version of: FramebufferSampleLocationsfvARB

      • glNamedFramebufferSampleLocationsfvARB

        public static void glNamedFramebufferSampleLocationsfvARB(int framebuffer,
                                                          int start,
                                                          float[] v)
        Array version of: NamedFramebufferSampleLocationsfvARB