Graphics Reference
In-Depth Information
• Instance and vertex ID—The vertex index is now accessible in the
vertex shader as well as the instance ID if using instance rendering.
• Fragment depth—The fragment shader can explicitly control the
depth value for the current fragment rather than relying on the
interpolation of its depth value.
• New built-in functions—ESSL 3.00 introduces many new built-in
functions to support new texture features, fragment derivatives, half-
float data conversion, and matrix and math operations.
• Relaxed limitations—ESSL 3.0 greatly relaxes the restrictions on
shaders. Shaders are no longer limited in terms of instruction length,
fully support looping and branching on variables, and support
indexing on arrays.
OpenGL ES 3.0 introduces several new features related to geometry
specification and control of primitive rendering:
• Transform feedback—Allows the output of the vertex shader to
be captured in a buffer object. This is useful for a wide range of
techniques that perform animation on the GPU without any CPU
intervention—for example, particle animation or physics simulation
using render-to-vertex-buffer.
• Boolean occlusion queries—Enable the application to query whether
any pixels of a draw call (or a set of draw calls) passes the depth
test. This feature can be used within a variety of techniques, such as
visibility determination for a lens flare effect as well as optimization
to avoid performing geometry processing on objects whose bounding
volume is obscured.
• Instanced rendering—Efficiently renders objects that contain similar
geometry but differ by attributes (such as transformation matrix, color,
or size). This feature is useful in rendering large quantities of similar
objects, such as for crowd rendering.
• Primitive restart—When using triangle strips in OpenGL ES 2.0 for a
new primitive, the application would have to insert indices into the
index buffer to represent a degenerate triangle. In OpenGL ES 3.0, a
special index value can be used that indicates the beginning of a new
primitive. This obviates the need for generating degenerate triangles
when using triangle strips.
