IR_LOOP's BranchNode ptr is the head of a linked list of CONT and BRK nodes.
After emitting loop, walk over the linked list, filling in the CONT/BRK
instruction's BranchTarget field (location of the ENDLOOP instruction, or
one past).
BRK's BranchTarget field actually points to the top of the loop, not the
bottom, since we don't know the later's location yet. In the interpreter,
basically do an indirect jump to update the PC.
This allows us to back-patch the IF/ELSE instruction's BranchTarget field
to point to the location of the ELSE/ENDIF instructions. No longer have to
search for ELSE/ENDIF in the interpreter. Also makes it trivial to translate
IF/ELSE instructions into conditional/unconditional BRA instructions.
IF/ELSE/ENDIF and BEGIN_LOOP/END_LOOP/BREAK instructions seem to work.
Disabled by default though until better tested.
Implemented IR_NOT, but needs optimization.
ARB_vp requires vertex transformation to be invariant to fixed function tnl
if the position_invariant option is used. So the same function needs to be
used, otherwise z-fighting artifacts may happen with applications which rely
on the results being really the same due to precision issues when dealing with
floating point values (may not be a problem when using a non-optimizing
compiler strictly following IEEE rules).
The old code suffered from a number of issues, the most severe being that
with the Mesa VBO merge even swtcl used the driver's bufferobj interface.
On most VBO types (or non-AGP cards) the buffer ended up in vram, and
killed swtcl performance greatly. All bufferobj's start in system memory
now, until they get referenced as a "real" VBO.
The other big change is that only potentially "damaged" areas are
uploaded/downloaded to/from the hardware.
Used to track the number of components in a float/int/bool literal.
Helps with some typechecking things.
Fixes problems with calls such as "distance(v2, vec2(1.0, 2.0))"
