Upcoming Cool Features

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Upcoming Cool Features

• Siggraph BOF 2006

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• Lots of new functionality coming your way!

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Programmability 1/3

• Integers are first class citizens
• bitwise operators, vertex attributes, uniforms,
  fragment shader output
• Shadow cube maps
• DEPTH_COMPONENT format now allowed for cube maps
• Vertex id
• Vertex shader knows what index number a vertex is
• Primitive id
• fragment shader and geometry shader know
  primitive index number
• Varying variable interpolation modifiers
• flat, no-perspective, centroid
• Full shader control

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Programmability 2/3

• Use buffer objects for constant storage
• Back uniform storage by a buffer object -gt hugely
  increases constant space available in shaders
• Texture lookups that return integer values from
  integer textures
• Up till now a texture lookup would always return
  floating-point values
• Texel offset lookups
• Adds an integer offset to the address used for a
  texture lookup
• Fetch a single texel using integer address
• Useful to treat a texture as a lookup table
• Query the size of a texture map
• Why not?

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Programmability Geometry shader 3/3

• A new pipeline stage
• Now this is cool!
• Operates on primitives
• Comes after vertex shader and primitive assembly
• before clipping and rasterization
• One primitive in, one or more primitives out
• Can do texture lookups
• Output primitive type does not need to match
  input type

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Texturing

• Support for texture arrays
• Collection of images of identical size and format
  arranged in layers
• True integer texture formats
• In OpenGL today, textures are normalized
  texture components represent 0,1 fp values
• New unnormalized texture internal formats
• Support for super-sized 1D textures
• Texture store is a buffer object no copy of
  data
• Can be used for very large arrays, lookup tables
• L, LA compressed formats
• Could be used to store compressed normal maps
• Compact encoded float formats
• Efficient FP encoding of 3 component vectors in
  32 bit word

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Framebuffer support

• sRGB framebuffers
• OpenGL assumes framebuffer is in linear space,
  particularly blending
• Fragments to be written to a framebuffer
  converted to sRGB first
• Blending takes framebuffer value, converts to
  linear, blends, converts to sRGB
• Floating point depth buffer
• New texture internal format
• 32 bit fp value
• Can store values outside 0,1 range

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Miscellaneous important functionality

• Record vertices of transformed primitives into
  buffer objects
• Useful for multi-pass algorithms
• Captured prior to clipping
• Conditional rendering
• Submit a set of geometry to OpenGL that is only
  rendered if a previous occlusion query passes