ps_1_3 uses Tx to pass in texture coordinates, but also as temporary
registers. ps_1_4 and ps_2_0 only use them for texture coordinates. This patch
gets rid of the Tx = fragment.texcoord[x] assign in all shader versions, and
doesn't even declare Tx in ps_1_4 and ps_2_0.
The <=ps_1_3 instructions know which kind of input they expect from the Tx
register, so the instruction handlers now know if they have to read the
tempreg Tx or the varying fragment.texcoord[x].
shader_arb_add_src_param handled DW and TXP undid it again. Remove DZ DW from
the modifiers and handle it in the instruction. DZ cannot be handled by TXP as
is, so move the .z component to .w and make it DW-like. Using SZW+TXP is
likely more efficient than the RCP, MUL, TEX we'd get if we let
shader_arb_add_src_param do the job.
Use shader_arb_get_dst_param instead of get_register_name to find the register
name. Even though this adds support for modifiers(which aren't allowed by
native), this shouldn't hurt. If an app passes in an incorrect shader it
should be caught in the frontend.
Mostly based on the code of pshader_gen_input_modifier_line. The space-adding
behavior of shader_arb_add_src_param was removed because the plurality of
instruction handlers passes an uninitialized buffer in and expects a register
name written to its start, and only map2gl and rcp_rsq use the space-adding
stuff. I'll change rcp_rsq in a later patch anyway. I changed the name to
shader_arb_get_src_param to reflect this behavior.
Use shader_arb_add_instruction_modifiers instead. This avoids calling the
fixup function from each single instruction handler to handle shifts. It does
not yet get rid of the modifier handler in each instruction because we don't
want a separate line if we can just append _SAT to the instruction name.
This is needed to raise the number of advertised constants to the GL
limit. The ARB assembler ususally does not optimize away unused
constants, so we have to do this.
This moves the GLSL and ARB specific reserved constants out of directx.c into
the get_caps methods of the shader backends. That way the number of reserved
constants remains in the backend.
GL_LIMITS({v/p}shader_constantsF) now contains the real number of constants as
advertised by GL instead of some mixture of GL info and backend implementation
specifics. This makes it easier for backends to decide how many constants to
use.
