cell: implement basic TXP instruction in fragment shaders
Lots of restrictions for now (one 2D texture, no mipmaps, etc.) for now
but basic texture demos work.
TEX, TXD, TXP do the same thing for the time being.
cell: implement function calls from shader code. fslight demo runs now.
Used for SIN, COS, EXP2, LOG2, POW instructions. TEX next.
Fixed some bugs in MIN, MAX, DP3, DP4, DPH instructions.
In rtasm code:
Special-case spe_lqd(), spe_stqd() functions so they take byte offsets but
low-order 4 bits are shifted out. This makes things consistant with SPU
assembly language conventions.
Added spe_get_registers_used() function.
This set of code changes are for stencil code generation
support. Both one-sided and two-sided stenciling are supported.
In addition to the raw code generation changes, these changes had
to be made elsewhere in the system:
- Added new "register set" feature to the SPE assembly generation.
A "register set" is a way to allocate multiple registers and free
them all at the same time, delegating register allocation management
to the spe_function unit. It's quite useful in complex register
allocation schemes (like stenciling).
- Added and improved SPE macro calculations.
These are operations between registers and unsigned integer
immediates. In many cases, the calculation can be performed
with a single instruction; the macros will generate the
single instruction if possible, or generate a register load
and register-to-register operation if not. These macro
functions are: spe_load_uint() (which has new ways to
load a value in a single instruction), spe_and_uint(),
spe_xor_uint(), spe_compare_equal_uint(), and spe_compare_greater_uint().
- Added facing to fragment generation. While rendering, the rasterizer
needs to be able to determine front- and back-facing fragments, in order
to correctly apply two-sided stencil. That requires these changes:
- Added front_winding field to the cell_command_render block, so that
the state tracker could communicate to the rasterizer what it
considered to be the front-facing direction.
- Added fragment facing as an input to the fragment function.
- Calculated facing is passed during emit_quad().