Class EXTTextureInteger

  • public class EXTTextureInteger
    extends java.lang.Object
    Native bindings to the EXT_texture_integer extension.

    Fixed-point textures in unextended OpenGL have integer components, but those values are taken to represent floating-point values in the range [0,1]. These integer components are considered "normalized" integers. When such a texture is accessed by a shader or by fixed-function fragment processing, floating-point values are returned.

    This extension provides a set of new "unnormalized" integer texture formats. Formats with both signed and unsigned integers are provided. In these formats, the components are treated as true integers. When such textures are accessed by a shader, actual integer values are returned.

    Pixel operations that read from or write to a texture or color buffer with unnormalized integer components follow a path similar to that used for color index pixel operations, except that more than one component may be provided at once. Integer values flow through the pixel processing pipe, and no pixel transfer operations are performed. Integer format enumerants used for such operations indicate unnormalized integer data.

    Textures or render buffers with unnormalized integer formats may also be attached to framebuffer objects to receive fragment color values written by a fragment shader. Per-fragment operations that require floating-point color components, including multisample alpha operations, alpha test, blending, and dithering, have no effect when the corresponding colors are written to an integer color buffer. The NV_gpu_program4 and EXT_gpu_shader4 extensions add the capability to fragment programs and fragment shaders to write signed and unsigned integer output values.

    This extension does not enforce type consistency for texture accesses or between fragment shaders and the corresponding framebuffer attachments. The results of a texture lookup from an integer texture are undefined:

    • for fixed-function fragment processing, or
    • for shader texture accesses expecting floating-point return values.

    The color components used for per-fragment operations and written into a color buffer are undefined:

    • for fixed-function fragment processing with an integer color buffer,
    • for fragment shaders that write floating-point color components to an integer color buffer, or
    • for fragment shaders that write integer color components to a color buffer with floating point or normalized integer components.

    Requires OpenGL 2.0 and NV_gpu_program4 or EXT_gpu_shader4. Promoted to core in OpenGL 3.0.