void brw_copy_indirect_to_indirect(struct brw_codegen *p,
struct brw_indirect dst_ptr,
struct brw_indirect src_ptr,
unsigned count)
{
unsigned i;
for (i = 0; i < count; i++)
{
unsigned delta = i*32;
brw_MOV(p, deref_4f(dst_ptr, delta), deref_4f(src_ptr, delta));
brw_MOV(p, deref_4f(dst_ptr, delta+16), deref_4f(src_ptr, delta+16));
}
}
/* Interpolate between two vertices and put the result into a0.0.
* Increment a0.0 accordingly.
*/
void brw_clip_interp_vertex( struct brw_clip_compile *c,
struct brw_indirect dest_ptr,
struct brw_indirect v0_ptr, /* from */
struct brw_indirect v1_ptr, /* to */
struct brw_reg t0,
GLboolean force_edgeflag)
{
struct brw_compile *p = &c->func;
struct brw_reg tmp = get_tmp(c);
GLuint i;
/* Just copy the vertex header:
*/
brw_copy_indirect_to_indirect(p, dest_ptr, v0_ptr, 1);
/* Iterate over each attribute (could be done in pairs?)
*/
for (i = 0; i < c->nr_attrs; i++) {
GLuint delta = i*16 + 32;
if (delta == c->offset[VERT_RESULT_EDGE]) {
if (force_edgeflag)
brw_MOV(p, deref_4f(dest_ptr, delta), brw_imm_f(1));
else
brw_MOV(p, deref_4f(dest_ptr, delta), deref_4f(v0_ptr, delta));
}
else {
/* Interpolate:
*
* New = attr0 + t*attr1 - t*attr0
*/
brw_MUL(p,
vec4(brw_null_reg()),
deref_4f(v1_ptr, delta),
t0);
brw_MAC(p,
tmp,
negate(deref_4f(v0_ptr, delta)),
t0);
brw_ADD(p,
deref_4f(dest_ptr, delta),
deref_4f(v0_ptr, delta),
tmp);
}
}
if (i & 1) {
GLuint delta = i*16 + 32;
brw_MOV(p, deref_4f(dest_ptr, delta), brw_imm_f(0));
}
release_tmp(c, tmp);
/* Recreate the projected (NDC) coordinate in the new vertex
* header:
*/
brw_clip_project_vertex(c, dest_ptr );
}
void brw_copy_indirect_to_indirect(struct brw_compile *p,
struct brw_indirect dst_ptr,
struct brw_indirect src_ptr,
GLuint count)
{
GLuint i;
for (i = 0; i < count; i++)
{
GLuint delta = i*32;
brw_MOV(p, deref_4f(dst_ptr, delta), deref_4f(src_ptr, delta));
brw_MOV(p, deref_4f(dst_ptr, delta+16), deref_4f(src_ptr, delta+16));
}
}
static void brw_clip_project_vertex( struct brw_clip_compile *c,
struct brw_indirect vert_addr )
{
struct brw_compile *p = &c->func;
struct brw_reg tmp = get_tmp(c);
/* Fixup position. Extract from the original vertex and re-project
* to screen space:
*/
brw_MOV(p, tmp, deref_4f(vert_addr, c->offset[VERT_RESULT_HPOS]));
brw_clip_project_position(c, tmp);
brw_MOV(p, deref_4f(vert_addr, c->header_position_offset), tmp);
release_tmp(c, tmp);
}
void brw_copy_from_indirect(struct brw_compile *p,
struct brw_reg dst,
struct brw_indirect ptr,
GLuint count)
{
GLuint i;
dst = vec4(dst);
for (i = 0; i < count; i++)
{
GLuint delta = i*32;
brw_MOV(p, byte_offset(dst, delta), deref_4f(ptr, delta));
brw_MOV(p, byte_offset(dst, delta+16), deref_4f(ptr, delta+16));
}
}
void brw_copy_from_indirect(struct brw_codegen *p,
struct brw_reg dst,
struct brw_indirect ptr,
unsigned count)
{
unsigned i;
dst = vec4(dst);
for (i = 0; i < count; i++)
{
unsigned delta = i*32;
brw_MOV(p, byte_offset(dst, delta), deref_4f(ptr, delta));
brw_MOV(p, byte_offset(dst, delta+16), deref_4f(ptr, delta+16));
}
}
static void brw_clip_project_vertex( struct brw_clip_compile *c,
struct brw_indirect vert_addr )
{
struct brw_codegen *p = &c->func;
struct brw_reg tmp = get_tmp(c);
GLuint hpos_offset = brw_varying_to_offset(&c->vue_map, VARYING_SLOT_POS);
GLuint ndc_offset = brw_varying_to_offset(&c->vue_map,
BRW_VARYING_SLOT_NDC);
/* Fixup position. Extract from the original vertex and re-project
* to screen space:
*/
brw_MOV(p, tmp, deref_4f(vert_addr, hpos_offset));
brw_clip_project_position(c, tmp);
brw_MOV(p, deref_4f(vert_addr, ndc_offset), tmp);
release_tmp(c, tmp);
}
static void apply_one_offset( struct brw_clip_compile *c,
struct brw_indirect vert )
{
struct brw_compile *p = &c->func;
struct brw_reg pos = deref_4f(vert, c->offset[VERT_RESULT_HPOS]);
struct brw_reg z = get_element(pos, 2);
brw_ADD(p, z, z, vec1(c->reg.offset));
}
/**
* Loads the clip distance for a vertex into `dst`, and ends with
* a comparison of it to zero with the condition `cond`.
*
* - If using a fixed plane, the distance is dot(hpos, plane).
* - If using a user clip plane, the distance is directly available in the vertex.
*/
static inline void
load_clip_distance(struct brw_clip_compile *c, struct brw_indirect vtx,
struct brw_reg dst, GLuint hpos_offset, int cond)
{
struct brw_codegen *p = &c->func;
dst = vec4(dst);
brw_AND(p, vec1(brw_null_reg()), c->reg.vertex_src_mask, brw_imm_ud(1));
brw_inst_set_cond_modifier(p->devinfo, brw_last_inst, BRW_CONDITIONAL_NZ);
brw_IF(p, BRW_EXECUTE_1);
{
struct brw_indirect temp_ptr = brw_indirect(7, 0);
brw_ADD(p, get_addr_reg(temp_ptr), get_addr_reg(vtx), c->reg.clipdistance_offset);
brw_MOV(p, vec1(dst), deref_1f(temp_ptr, 0));
}
brw_ELSE(p);
{
brw_MOV(p, dst, deref_4f(vtx, hpos_offset));
brw_DP4(p, dst, dst, c->reg.plane_equation);
}
brw_ENDIF(p);
brw_CMP(p, brw_null_reg(), cond, vec1(dst), brw_imm_f(0.0f));
}
static void brw_clip_test( struct brw_clip_compile *c )
{
struct brw_reg t = retype(get_tmp(c), BRW_REGISTER_TYPE_UD);
struct brw_reg t1 = retype(get_tmp(c), BRW_REGISTER_TYPE_UD);
struct brw_reg t2 = retype(get_tmp(c), BRW_REGISTER_TYPE_UD);
struct brw_reg t3 = retype(get_tmp(c), BRW_REGISTER_TYPE_UD);
struct brw_reg v0 = get_tmp(c);
struct brw_reg v1 = get_tmp(c);
struct brw_reg v2 = get_tmp(c);
struct brw_indirect vt0 = brw_indirect(0, 0);
struct brw_indirect vt1 = brw_indirect(1, 0);
struct brw_indirect vt2 = brw_indirect(2, 0);
struct brw_compile *p = &c->func;
struct brw_instruction *is_outside;
struct brw_reg tmp0 = c->reg.loopcount; /* handy temporary */
brw_MOV(p, get_addr_reg(vt0), brw_address(c->reg.vertex[0]));
brw_MOV(p, get_addr_reg(vt1), brw_address(c->reg.vertex[1]));
brw_MOV(p, get_addr_reg(vt2), brw_address(c->reg.vertex[2]));
brw_MOV(p, v0, deref_4f(vt0, c->offset_hpos));
brw_MOV(p, v1, deref_4f(vt1, c->offset_hpos));
brw_MOV(p, v2, deref_4f(vt2, c->offset_hpos));
brw_AND(p, c->reg.planemask, c->reg.planemask, brw_imm_ud(~0x3f));
/* test nearz, xmin, ymin plane */
/* clip.xyz < -clip.w */
brw_CMP(p, t1, BRW_CONDITIONAL_L, v0, negate(get_element(v0, 3)));
brw_set_predicate_control(p, BRW_PREDICATE_NONE);
brw_CMP(p, t2, BRW_CONDITIONAL_L, v1, negate(get_element(v1, 3)));
brw_set_predicate_control(p, BRW_PREDICATE_NONE);
brw_CMP(p, t3, BRW_CONDITIONAL_L, v2, negate(get_element(v2, 3)));
brw_set_predicate_control(p, BRW_PREDICATE_NONE);
/* All vertices are outside of a plane, rejected */
brw_AND(p, t, t1, t2);
brw_AND(p, t, t, t3);
brw_OR(p, tmp0, get_element(t, 0), get_element(t, 1));
brw_OR(p, tmp0, tmp0, get_element(t, 2));
brw_set_conditionalmod(p, BRW_CONDITIONAL_NZ);
brw_AND(p, brw_null_reg(), tmp0, brw_imm_ud(0x1));
is_outside = brw_IF(p, BRW_EXECUTE_1);
{
brw_clip_kill_thread(c);
}
brw_ENDIF(p, is_outside);
brw_set_predicate_control(p, BRW_PREDICATE_NONE);
/* some vertices are inside a plane, some are outside,need to clip */
brw_XOR(p, t, t1, t2);
brw_XOR(p, t1, t2, t3);
brw_OR(p, t, t, t1);
brw_AND(p, t, t, brw_imm_ud(0x1));
brw_CMP(p, brw_null_reg(), BRW_CONDITIONAL_NZ,
get_element(t, 0), brw_imm_ud(0));
brw_OR(p, c->reg.planemask, c->reg.planemask, brw_imm_ud((1<<5)));
brw_set_predicate_control(p, BRW_PREDICATE_NONE);
brw_CMP(p, brw_null_reg(), BRW_CONDITIONAL_NZ,
get_element(t, 1), brw_imm_ud(0));
brw_OR(p, c->reg.planemask, c->reg.planemask, brw_imm_ud((1<<3)));
brw_set_predicate_control(p, BRW_PREDICATE_NONE);
brw_CMP(p, brw_null_reg(), BRW_CONDITIONAL_NZ,
get_element(t, 2), brw_imm_ud(0));
brw_OR(p, c->reg.planemask, c->reg.planemask, brw_imm_ud((1<<1)));
brw_set_predicate_control(p, BRW_PREDICATE_NONE);
/* test farz, xmax, ymax plane */
/* clip.xyz > clip.w */
brw_CMP(p, t1, BRW_CONDITIONAL_G, v0, get_element(v0, 3));
brw_set_predicate_control(p, BRW_PREDICATE_NONE);
brw_CMP(p, t2, BRW_CONDITIONAL_G, v1, get_element(v1, 3));
brw_set_predicate_control(p, BRW_PREDICATE_NONE);
brw_CMP(p, t3, BRW_CONDITIONAL_G, v2, get_element(v2, 3));
brw_set_predicate_control(p, BRW_PREDICATE_NONE);
/* All vertices are outside of a plane, rejected */
brw_AND(p, t, t1, t2);
brw_AND(p, t, t, t3);
brw_OR(p, tmp0, get_element(t, 0), get_element(t, 1));
brw_OR(p, tmp0, tmp0, get_element(t, 2));
brw_set_conditionalmod(p, BRW_CONDITIONAL_NZ);
brw_AND(p, brw_null_reg(), tmp0, brw_imm_ud(0x1));
is_outside = brw_IF(p, BRW_EXECUTE_1);
{
brw_clip_kill_thread(c);
}
brw_ENDIF(p, is_outside);
brw_set_predicate_control(p, BRW_PREDICATE_NONE);
/* some vertices are inside a plane, some are outside,need to clip */
brw_XOR(p, t, t1, t2);
brw_XOR(p, t1, t2, t3);
brw_OR(p, t, t, t1);
brw_AND(p, t, t, brw_imm_ud(0x1));
brw_CMP(p, brw_null_reg(), BRW_CONDITIONAL_NZ,
get_element(t, 0), brw_imm_ud(0));
brw_OR(p, c->reg.planemask, c->reg.planemask, brw_imm_ud((1<<4)));
brw_set_predicate_control(p, BRW_PREDICATE_NONE);
brw_CMP(p, brw_null_reg(), BRW_CONDITIONAL_NZ,
get_element(t, 1), brw_imm_ud(0));
brw_OR(p, c->reg.planemask, c->reg.planemask, brw_imm_ud((1<<2)));
brw_set_predicate_control(p, BRW_PREDICATE_NONE);
brw_CMP(p, brw_null_reg(), BRW_CONDITIONAL_NZ,
get_element(t, 2), brw_imm_ud(0));
brw_OR(p, c->reg.planemask, c->reg.planemask, brw_imm_ud((1<<0)));
brw_set_predicate_control(p, BRW_PREDICATE_NONE);
release_tmps(c);
}
/* Use mesa's clipping algorithms, translated to GEN4 assembly.
*/
void brw_clip_tri( struct brw_clip_compile *c )
{
struct brw_compile *p = &c->func;
struct brw_indirect vtx = brw_indirect(0, 0);
struct brw_indirect vtxPrev = brw_indirect(1, 0);
struct brw_indirect vtxOut = brw_indirect(2, 0);
struct brw_indirect plane_ptr = brw_indirect(3, 0);
struct brw_indirect inlist_ptr = brw_indirect(4, 0);
struct brw_indirect outlist_ptr = brw_indirect(5, 0);
struct brw_indirect freelist_ptr = brw_indirect(6, 0);
struct brw_instruction *plane_loop;
struct brw_instruction *plane_active;
struct brw_instruction *vertex_loop;
struct brw_instruction *next_test;
struct brw_instruction *prev_test;
brw_MOV(p, get_addr_reg(vtxPrev), brw_address(c->reg.vertex[2]) );
brw_MOV(p, get_addr_reg(plane_ptr), brw_clip_plane0_address(c));
brw_MOV(p, get_addr_reg(inlist_ptr), brw_address(c->reg.inlist));
brw_MOV(p, get_addr_reg(outlist_ptr), brw_address(c->reg.outlist));
brw_MOV(p, get_addr_reg(freelist_ptr), brw_address(c->reg.vertex[3]) );
plane_loop = brw_DO(p, BRW_EXECUTE_1);
{
/* if (planemask & 1)
*/
brw_set_conditionalmod(p, BRW_CONDITIONAL_NZ);
brw_AND(p, vec1(brw_null_reg()), c->reg.planemask, brw_imm_ud(1));
plane_active = brw_IF(p, BRW_EXECUTE_1);
{
/* vtxOut = freelist_ptr++
*/
brw_MOV(p, get_addr_reg(vtxOut), get_addr_reg(freelist_ptr) );
brw_ADD(p, get_addr_reg(freelist_ptr), get_addr_reg(freelist_ptr), brw_imm_uw(c->nr_regs * REG_SIZE));
if (c->key.nr_userclip)
brw_MOV(p, c->reg.plane_equation, deref_4f(plane_ptr, 0));
else
brw_MOV(p, c->reg.plane_equation, deref_4b(plane_ptr, 0));
brw_MOV(p, c->reg.loopcount, c->reg.nr_verts);
brw_MOV(p, c->reg.nr_verts, brw_imm_ud(0));
vertex_loop = brw_DO(p, BRW_EXECUTE_1);
{
/* vtx = *input_ptr;
*/
brw_MOV(p, get_addr_reg(vtx), deref_1uw(inlist_ptr, 0));
/* IS_NEGATIVE(prev) */
brw_set_conditionalmod(p, BRW_CONDITIONAL_L);
brw_DP4(p, vec4(c->reg.dpPrev), deref_4f(vtxPrev, c->offset_hpos), c->reg.plane_equation);
prev_test = brw_IF(p, BRW_EXECUTE_1);
{
/* IS_POSITIVE(next)
*/
brw_set_conditionalmod(p, BRW_CONDITIONAL_GE);
brw_DP4(p, vec4(c->reg.dp), deref_4f(vtx, c->offset_hpos), c->reg.plane_equation);
next_test = brw_IF(p, BRW_EXECUTE_1);
{
/* Coming back in.
*/
brw_ADD(p, c->reg.t, c->reg.dpPrev, negate(c->reg.dp));
brw_math_invert(p, c->reg.t, c->reg.t);
brw_MUL(p, c->reg.t, c->reg.t, c->reg.dpPrev);
/* If (vtxOut == 0) vtxOut = vtxPrev
*/
brw_CMP(p, vec1(brw_null_reg()), BRW_CONDITIONAL_EQ, get_addr_reg(vtxOut), brw_imm_uw(0) );
brw_MOV(p, get_addr_reg(vtxOut), get_addr_reg(vtxPrev) );
brw_set_predicate_control(p, BRW_PREDICATE_NONE);
brw_clip_interp_vertex(c, vtxOut, vtxPrev, vtx, c->reg.t, GL_FALSE);
/* *outlist_ptr++ = vtxOut;
* nr_verts++;
* vtxOut = 0;
*/
brw_MOV(p, deref_1uw(outlist_ptr, 0), get_addr_reg(vtxOut));
brw_ADD(p, get_addr_reg(outlist_ptr), get_addr_reg(outlist_ptr), brw_imm_uw(sizeof(short)));
brw_ADD(p, c->reg.nr_verts, c->reg.nr_verts, brw_imm_ud(1));
brw_MOV(p, get_addr_reg(vtxOut), brw_imm_uw(0) );
}
brw_ENDIF(p, next_test);
}
prev_test = brw_ELSE(p, prev_test);
{
/* *outlist_ptr++ = vtxPrev;
* nr_verts++;
*/
brw_MOV(p, deref_1uw(outlist_ptr, 0), get_addr_reg(vtxPrev));
brw_ADD(p, get_addr_reg(outlist_ptr), get_addr_reg(outlist_ptr), brw_imm_uw(sizeof(short)));
brw_ADD(p, c->reg.nr_verts, c->reg.nr_verts, brw_imm_ud(1));
/* IS_NEGATIVE(next)
*/
brw_set_conditionalmod(p, BRW_CONDITIONAL_L);
brw_DP4(p, vec4(c->reg.dp), deref_4f(vtx, c->offset_hpos), c->reg.plane_equation);
next_test = brw_IF(p, BRW_EXECUTE_1);
{
/* Going out of bounds. Avoid division by zero as we
* know dp != dpPrev from DIFFERENT_SIGNS, above.
*/
brw_ADD(p, c->reg.t, c->reg.dp, negate(c->reg.dpPrev));
brw_math_invert(p, c->reg.t, c->reg.t);
brw_MUL(p, c->reg.t, c->reg.t, c->reg.dp);
/* If (vtxOut == 0) vtxOut = vtx
*/
brw_CMP(p, vec1(brw_null_reg()), BRW_CONDITIONAL_EQ, get_addr_reg(vtxOut), brw_imm_uw(0) );
brw_MOV(p, get_addr_reg(vtxOut), get_addr_reg(vtx) );
brw_set_predicate_control(p, BRW_PREDICATE_NONE);
brw_clip_interp_vertex(c, vtxOut, vtx, vtxPrev, c->reg.t, GL_TRUE);
/* *outlist_ptr++ = vtxOut;
* nr_verts++;
* vtxOut = 0;
*/
brw_MOV(p, deref_1uw(outlist_ptr, 0), get_addr_reg(vtxOut));
brw_ADD(p, get_addr_reg(outlist_ptr), get_addr_reg(outlist_ptr), brw_imm_uw(sizeof(short)));
brw_ADD(p, c->reg.nr_verts, c->reg.nr_verts, brw_imm_ud(1));
brw_MOV(p, get_addr_reg(vtxOut), brw_imm_uw(0) );
}
brw_ENDIF(p, next_test);
}
brw_ENDIF(p, prev_test);
/* vtxPrev = vtx;
* inlist_ptr++;
*/
brw_MOV(p, get_addr_reg(vtxPrev), get_addr_reg(vtx));
brw_ADD(p, get_addr_reg(inlist_ptr), get_addr_reg(inlist_ptr), brw_imm_uw(sizeof(short)));
/* while (--loopcount != 0)
*/
brw_set_conditionalmod(p, BRW_CONDITIONAL_NZ);
brw_ADD(p, c->reg.loopcount, c->reg.loopcount, brw_imm_d(-1));
}
brw_WHILE(p, vertex_loop);
/* vtxPrev = *(outlist_ptr-1) OR: outlist[nr_verts-1]
* inlist = outlist
* inlist_ptr = &inlist[0]
* outlist_ptr = &outlist[0]
*/
brw_ADD(p, get_addr_reg(outlist_ptr), get_addr_reg(outlist_ptr), brw_imm_w(-2));
brw_MOV(p, get_addr_reg(vtxPrev), deref_1uw(outlist_ptr, 0));
brw_MOV(p, brw_vec8_grf(c->reg.inlist.nr, 0), brw_vec8_grf(c->reg.outlist.nr, 0));
brw_MOV(p, get_addr_reg(inlist_ptr), brw_address(c->reg.inlist));
brw_MOV(p, get_addr_reg(outlist_ptr), brw_address(c->reg.outlist));
}
brw_ENDIF(p, plane_active);
/* plane_ptr++;
*/
brw_ADD(p, get_addr_reg(plane_ptr), get_addr_reg(plane_ptr), brw_clip_plane_stride(c));
/* nr_verts >= 3
*/
brw_CMP(p,
vec1(brw_null_reg()),
BRW_CONDITIONAL_GE,
c->reg.nr_verts,
brw_imm_ud(3));
/* && (planemask>>=1) != 0
*/
brw_set_conditionalmod(p, BRW_CONDITIONAL_NZ);
brw_SHR(p, c->reg.planemask, c->reg.planemask, brw_imm_ud(1));
}
brw_WHILE(p, plane_loop);
}
/* Interpolate between two vertices and put the result into a0.0.
* Increment a0.0 accordingly.
*
* Beware that dest_ptr can be equal to v0_ptr!
*/
void brw_clip_interp_vertex( struct brw_clip_compile *c,
struct brw_indirect dest_ptr,
struct brw_indirect v0_ptr, /* from */
struct brw_indirect v1_ptr, /* to */
struct brw_reg t0,
bool force_edgeflag)
{
struct brw_codegen *p = &c->func;
struct brw_reg t_nopersp, v0_ndc_copy;
GLuint slot;
/* Just copy the vertex header:
*/
/*
* After CLIP stage, only first 256 bits of the VUE are read
* back on Ironlake, so needn't change it
*/
brw_copy_indirect_to_indirect(p, dest_ptr, v0_ptr, 1);
/* First handle the 3D and NDC interpolation, in case we
* need noperspective interpolation. Doing it early has no
* performance impact in any case.
*/
/* Take a copy of the v0 NDC coordinates, in case dest == v0. */
if (c->has_noperspective_shading) {
GLuint offset = brw_varying_to_offset(&c->vue_map,
BRW_VARYING_SLOT_NDC);
v0_ndc_copy = get_tmp(c);
brw_MOV(p, v0_ndc_copy, deref_4f(v0_ptr, offset));
}
/* Compute the new 3D position
*
* dest_hpos = v0_hpos * (1 - t0) + v1_hpos * t0
*/
{
GLuint delta = brw_varying_to_offset(&c->vue_map, VARYING_SLOT_POS);
struct brw_reg tmp = get_tmp(c);
brw_MUL(p, vec4(brw_null_reg()), deref_4f(v1_ptr, delta), t0);
brw_MAC(p, tmp, negate(deref_4f(v0_ptr, delta)), t0);
brw_ADD(p, deref_4f(dest_ptr, delta), deref_4f(v0_ptr, delta), tmp);
release_tmp(c, tmp);
}
/* Recreate the projected (NDC) coordinate in the new vertex header */
brw_clip_project_vertex(c, dest_ptr);
/* If we have noperspective attributes,
* we need to compute the screen-space t
*/
if (c->has_noperspective_shading) {
GLuint delta = brw_varying_to_offset(&c->vue_map,
BRW_VARYING_SLOT_NDC);
struct brw_reg tmp = get_tmp(c);
t_nopersp = get_tmp(c);
/* t_nopersp = vec4(v1.xy, dest.xy) */
brw_MOV(p, t_nopersp, deref_4f(v1_ptr, delta));
brw_MOV(p, tmp, deref_4f(dest_ptr, delta));
brw_set_default_access_mode(p, BRW_ALIGN_16);
brw_MOV(p,
brw_writemask(t_nopersp, WRITEMASK_ZW),
brw_swizzle(tmp, 0, 1, 0, 1));
/* t_nopersp = vec4(v1.xy, dest.xy) - v0.xyxy */
brw_ADD(p, t_nopersp, t_nopersp,
negate(brw_swizzle(v0_ndc_copy, 0, 1, 0, 1)));
/* Add the absolute values of the X and Y deltas so that if
* the points aren't in the same place on the screen we get
* nonzero values to divide.
*
* After that, we have vert1 - vert0 in t_nopersp.x and
* vertnew - vert0 in t_nopersp.y
*
* t_nopersp = vec2(|v1.x -v0.x| + |v1.y -v0.y|,
* |dest.x-v0.x| + |dest.y-v0.y|)
*/
brw_ADD(p,
brw_writemask(t_nopersp, WRITEMASK_XY),
brw_abs(brw_swizzle(t_nopersp, 0, 2, 0, 0)),
brw_abs(brw_swizzle(t_nopersp, 1, 3, 0, 0)));
brw_set_default_access_mode(p, BRW_ALIGN_1);
/* If the points are in the same place, just substitute a
* value to avoid divide-by-zero
*/
brw_CMP(p, vec1(brw_null_reg()), BRW_CONDITIONAL_EQ,
vec1(t_nopersp),
brw_imm_f(0));
brw_IF(p, BRW_EXECUTE_1);
brw_MOV(p, t_nopersp, brw_imm_vf4(brw_float_to_vf(1.0),
brw_float_to_vf(0.0),
brw_float_to_vf(0.0),
brw_float_to_vf(0.0)));
brw_ENDIF(p);
/* Now compute t_nopersp = t_nopersp.y/t_nopersp.x and broadcast it. */
brw_math_invert(p, get_element(t_nopersp, 0), get_element(t_nopersp, 0));
brw_MUL(p, vec1(t_nopersp), vec1(t_nopersp),
vec1(suboffset(t_nopersp, 1)));
brw_set_default_access_mode(p, BRW_ALIGN_16);
brw_MOV(p, t_nopersp, brw_swizzle(t_nopersp, 0, 0, 0, 0));
brw_set_default_access_mode(p, BRW_ALIGN_1);
release_tmp(c, tmp);
release_tmp(c, v0_ndc_copy);
}
/* Now we can iterate over each attribute
* (could be done in pairs?)
*/
for (slot = 0; slot < c->vue_map.num_slots; slot++) {
int varying = c->vue_map.slot_to_varying[slot];
GLuint delta = brw_vue_slot_to_offset(slot);
/* HPOS, NDC already handled above */
if (varying == VARYING_SLOT_POS || varying == BRW_VARYING_SLOT_NDC)
continue;
if (varying == VARYING_SLOT_EDGE) {
if (force_edgeflag)
brw_MOV(p, deref_4f(dest_ptr, delta), brw_imm_f(1));
else
brw_MOV(p, deref_4f(dest_ptr, delta), deref_4f(v0_ptr, delta));
} else if (varying == VARYING_SLOT_PSIZ) {
/* PSIZ doesn't need interpolation because it isn't used by the
* fragment shader.
*/
} else if (varying < VARYING_SLOT_MAX) {
/* This is a true vertex result (and not a special value for the VUE
* header), so interpolate:
*
* New = attr0 + t*attr1 - t*attr0
*
* Unless the attribute is flat shaded -- in which case just copy
* from one of the sources (doesn't matter which; already copied from pv)
*/
GLuint interp = c->key.interpolation_mode.mode[slot];
if (interp != INTERP_QUALIFIER_FLAT) {
struct brw_reg tmp = get_tmp(c);
struct brw_reg t =
interp == INTERP_QUALIFIER_NOPERSPECTIVE ? t_nopersp : t0;
brw_MUL(p,
vec4(brw_null_reg()),
deref_4f(v1_ptr, delta),
t);
brw_MAC(p,
tmp,
negate(deref_4f(v0_ptr, delta)),
t);
brw_ADD(p,
deref_4f(dest_ptr, delta),
deref_4f(v0_ptr, delta),
tmp);
release_tmp(c, tmp);
}
else {
brw_MOV(p,
deref_4f(dest_ptr, delta),
deref_4f(v0_ptr, delta));
}
}
}
if (c->vue_map.num_slots % 2) {
GLuint delta = brw_vue_slot_to_offset(c->vue_map.num_slots);
brw_MOV(p, deref_4f(dest_ptr, delta), brw_imm_f(0));
}
if (c->has_noperspective_shading)
release_tmp(c, t_nopersp);
}
/* Line clipping, more or less following the following algorithm:
*
* for (p=0;p<MAX_PLANES;p++) {
* if (clipmask & (1 << p)) {
* GLfloat dp0 = DOTPROD( vtx0, plane[p] );
* GLfloat dp1 = DOTPROD( vtx1, plane[p] );
*
* if (dp1 < 0.0f) {
* GLfloat t = dp1 / (dp1 - dp0);
* if (t > t1) t1 = t;
* } else {
* GLfloat t = dp0 / (dp0 - dp1);
* if (t > t0) t0 = t;
* }
*
* if (t0 + t1 >= 1.0)
* return;
* }
* }
*
* interp( ctx, newvtx0, vtx0, vtx1, t0 );
* interp( ctx, newvtx1, vtx1, vtx0, t1 );
*
*/
static void clip_and_emit_line( struct brw_clip_compile *c )
{
struct brw_codegen *p = &c->func;
struct brw_indirect vtx0 = brw_indirect(0, 0);
struct brw_indirect vtx1 = brw_indirect(1, 0);
struct brw_indirect newvtx0 = brw_indirect(2, 0);
struct brw_indirect newvtx1 = brw_indirect(3, 0);
struct brw_indirect plane_ptr = brw_indirect(4, 0);
struct brw_reg v1_null_ud = retype(vec1(brw_null_reg()), BRW_REGISTER_TYPE_UD);
GLuint hpos_offset = brw_varying_to_offset(&c->vue_map, VARYING_SLOT_POS);
GLint clipdist0_offset = c->key.nr_userclip
? brw_varying_to_offset(&c->vue_map, VARYING_SLOT_CLIP_DIST0)
: 0;
brw_MOV(p, get_addr_reg(vtx0), brw_address(c->reg.vertex[0]));
brw_MOV(p, get_addr_reg(vtx1), brw_address(c->reg.vertex[1]));
brw_MOV(p, get_addr_reg(newvtx0), brw_address(c->reg.vertex[2]));
brw_MOV(p, get_addr_reg(newvtx1), brw_address(c->reg.vertex[3]));
brw_MOV(p, get_addr_reg(plane_ptr), brw_clip_plane0_address(c));
/* Note: init t0, t1 together:
*/
brw_MOV(p, vec2(c->reg.t0), brw_imm_f(0));
brw_clip_init_planes(c);
brw_clip_init_clipmask(c);
/* -ve rhw workaround */
if (p->devinfo->has_negative_rhw_bug) {
brw_AND(p, brw_null_reg(), get_element_ud(c->reg.R0, 2),
brw_imm_ud(1<<20));
brw_inst_set_cond_modifier(p->devinfo, brw_last_inst, BRW_CONDITIONAL_NZ);
brw_OR(p, c->reg.planemask, c->reg.planemask, brw_imm_ud(0x3f));
brw_inst_set_pred_control(p->devinfo, brw_last_inst, BRW_PREDICATE_NORMAL);
}
/* Set the initial vertex source mask: The first 6 planes are the bounds
* of the view volume; the next 8 planes are the user clipping planes.
*/
brw_MOV(p, c->reg.vertex_src_mask, brw_imm_ud(0x3fc0));
/* Set the initial clipdistance offset to be 6 floats before gl_ClipDistance[0].
* We'll increment 6 times before we start hitting actual user clipping. */
brw_MOV(p, c->reg.clipdistance_offset, brw_imm_d(clipdist0_offset - 6*sizeof(float)));
brw_DO(p, BRW_EXECUTE_1);
{
/* if (planemask & 1)
*/
brw_AND(p, v1_null_ud, c->reg.planemask, brw_imm_ud(1));
brw_inst_set_cond_modifier(p->devinfo, brw_last_inst, BRW_CONDITIONAL_NZ);
brw_IF(p, BRW_EXECUTE_1);
{
brw_AND(p, v1_null_ud, c->reg.vertex_src_mask, brw_imm_ud(1));
brw_inst_set_cond_modifier(p->devinfo, brw_last_inst, BRW_CONDITIONAL_NZ);
brw_IF(p, BRW_EXECUTE_1);
{
/* user clip distance: just fetch the correct float from each vertex */
struct brw_indirect temp_ptr = brw_indirect(7, 0);
brw_ADD(p, get_addr_reg(temp_ptr), get_addr_reg(vtx0), c->reg.clipdistance_offset);
brw_MOV(p, c->reg.dp0, deref_1f(temp_ptr, 0));
brw_ADD(p, get_addr_reg(temp_ptr), get_addr_reg(vtx1), c->reg.clipdistance_offset);
brw_MOV(p, c->reg.dp1, deref_1f(temp_ptr, 0));
}
brw_ELSE(p);
{
/* fixed plane: fetch the hpos, dp4 against the plane. */
if (c->key.nr_userclip)
brw_MOV(p, c->reg.plane_equation, deref_4f(plane_ptr, 0));
else
brw_MOV(p, c->reg.plane_equation, deref_4b(plane_ptr, 0));
brw_DP4(p, vec4(c->reg.dp0), deref_4f(vtx0, hpos_offset), c->reg.plane_equation);
brw_DP4(p, vec4(c->reg.dp1), deref_4f(vtx1, hpos_offset), c->reg.plane_equation);
}
brw_ENDIF(p);
brw_CMP(p, brw_null_reg(), BRW_CONDITIONAL_L, vec1(c->reg.dp1), brw_imm_f(0.0f));
brw_IF(p, BRW_EXECUTE_1);
{
/*
* Both can be negative on GM965/G965 due to RHW workaround
* if so, this object should be rejected.
*/
if (p->devinfo->has_negative_rhw_bug) {
brw_CMP(p, vec1(brw_null_reg()), BRW_CONDITIONAL_LE, c->reg.dp0, brw_imm_f(0.0));
brw_IF(p, BRW_EXECUTE_1);
{
brw_clip_kill_thread(c);
}
brw_ENDIF(p);
}
brw_ADD(p, c->reg.t, c->reg.dp1, negate(c->reg.dp0));
brw_math_invert(p, c->reg.t, c->reg.t);
brw_MUL(p, c->reg.t, c->reg.t, c->reg.dp1);
brw_CMP(p, vec1(brw_null_reg()), BRW_CONDITIONAL_G, c->reg.t, c->reg.t1 );
brw_MOV(p, c->reg.t1, c->reg.t);
brw_inst_set_pred_control(p->devinfo, brw_last_inst,
BRW_PREDICATE_NORMAL);
}
brw_ELSE(p);
{
/* Coming back in. We know that both cannot be negative
* because the line would have been culled in that case.
*/
/* If both are positive, do nothing */
/* Only on GM965/G965 */
if (p->devinfo->has_negative_rhw_bug) {
brw_CMP(p, vec1(brw_null_reg()), BRW_CONDITIONAL_L, c->reg.dp0, brw_imm_f(0.0));
brw_IF(p, BRW_EXECUTE_1);
}
{
brw_ADD(p, c->reg.t, c->reg.dp0, negate(c->reg.dp1));
brw_math_invert(p, c->reg.t, c->reg.t);
brw_MUL(p, c->reg.t, c->reg.t, c->reg.dp0);
brw_CMP(p, vec1(brw_null_reg()), BRW_CONDITIONAL_G, c->reg.t, c->reg.t0 );
brw_MOV(p, c->reg.t0, c->reg.t);
brw_inst_set_pred_control(p->devinfo, brw_last_inst,
BRW_PREDICATE_NORMAL);
}
if (p->devinfo->has_negative_rhw_bug) {
brw_ENDIF(p);
}
}
brw_ENDIF(p);
}
brw_ENDIF(p);
/* plane_ptr++;
*/
brw_ADD(p, get_addr_reg(plane_ptr), get_addr_reg(plane_ptr), brw_clip_plane_stride(c));
/* while (planemask>>=1) != 0
*/
brw_SHR(p, c->reg.planemask, c->reg.planemask, brw_imm_ud(1));
brw_inst_set_cond_modifier(p->devinfo, brw_last_inst, BRW_CONDITIONAL_NZ);
brw_SHR(p, c->reg.vertex_src_mask, c->reg.vertex_src_mask, brw_imm_ud(1));
brw_inst_set_pred_control(p->devinfo, brw_last_inst, BRW_PREDICATE_NORMAL);
brw_ADD(p, c->reg.clipdistance_offset, c->reg.clipdistance_offset, brw_imm_w(sizeof(float)));
brw_inst_set_pred_control(p->devinfo, brw_last_inst, BRW_PREDICATE_NORMAL);
}
brw_WHILE(p);
brw_inst_set_pred_control(p->devinfo, brw_last_inst, BRW_PREDICATE_NORMAL);
brw_ADD(p, c->reg.t, c->reg.t0, c->reg.t1);
brw_CMP(p, vec1(brw_null_reg()), BRW_CONDITIONAL_L, c->reg.t, brw_imm_f(1.0));
brw_IF(p, BRW_EXECUTE_1);
{
brw_clip_interp_vertex(c, newvtx0, vtx0, vtx1, c->reg.t0, false);
brw_clip_interp_vertex(c, newvtx1, vtx1, vtx0, c->reg.t1, false);
brw_clip_emit_vue(c, newvtx0, BRW_URB_WRITE_ALLOCATE_COMPLETE,
(_3DPRIM_LINESTRIP << URB_WRITE_PRIM_TYPE_SHIFT)
| URB_WRITE_PRIM_START);
brw_clip_emit_vue(c, newvtx1, BRW_URB_WRITE_EOT_COMPLETE,
(_3DPRIM_LINESTRIP << URB_WRITE_PRIM_TYPE_SHIFT)
| URB_WRITE_PRIM_END);
}
brw_ENDIF(p);
brw_clip_kill_thread(c);
}
/* Use mesa's clipping algorithms, translated to GEN4 assembly.
*/
void brw_clip_tri( struct brw_clip_compile *c )
{
struct brw_codegen *p = &c->func;
struct brw_indirect vtx = brw_indirect(0, 0);
struct brw_indirect vtxPrev = brw_indirect(1, 0);
struct brw_indirect vtxOut = brw_indirect(2, 0);
struct brw_indirect plane_ptr = brw_indirect(3, 0);
struct brw_indirect inlist_ptr = brw_indirect(4, 0);
struct brw_indirect outlist_ptr = brw_indirect(5, 0);
struct brw_indirect freelist_ptr = brw_indirect(6, 0);
GLuint hpos_offset = brw_varying_to_offset(&c->vue_map, VARYING_SLOT_POS);
GLint clipdist0_offset = c->key.nr_userclip
? brw_varying_to_offset(&c->vue_map, VARYING_SLOT_CLIP_DIST0)
: 0;
brw_MOV(p, get_addr_reg(vtxPrev), brw_address(c->reg.vertex[2]) );
brw_MOV(p, get_addr_reg(plane_ptr), brw_clip_plane0_address(c));
brw_MOV(p, get_addr_reg(inlist_ptr), brw_address(c->reg.inlist));
brw_MOV(p, get_addr_reg(outlist_ptr), brw_address(c->reg.outlist));
brw_MOV(p, get_addr_reg(freelist_ptr), brw_address(c->reg.vertex[3]) );
/* Set the initial vertex source mask: The first 6 planes are the bounds
* of the view volume; the next 8 planes are the user clipping planes.
*/
brw_MOV(p, c->reg.vertex_src_mask, brw_imm_ud(0x3fc0));
/* Set the initial clipdistance offset to be 6 floats before gl_ClipDistance[0].
* We'll increment 6 times before we start hitting actual user clipping. */
brw_MOV(p, c->reg.clipdistance_offset, brw_imm_d(clipdist0_offset - 6*sizeof(float)));
brw_DO(p, BRW_EXECUTE_1);
{
/* if (planemask & 1)
*/
brw_AND(p, vec1(brw_null_reg()), c->reg.planemask, brw_imm_ud(1));
brw_inst_set_cond_modifier(p->devinfo, brw_last_inst, BRW_CONDITIONAL_NZ);
brw_IF(p, BRW_EXECUTE_1);
{
/* vtxOut = freelist_ptr++
*/
brw_MOV(p, get_addr_reg(vtxOut), get_addr_reg(freelist_ptr) );
brw_ADD(p, get_addr_reg(freelist_ptr), get_addr_reg(freelist_ptr), brw_imm_uw(c->nr_regs * REG_SIZE));
if (c->key.nr_userclip)
brw_MOV(p, c->reg.plane_equation, deref_4f(plane_ptr, 0));
else
brw_MOV(p, c->reg.plane_equation, deref_4b(plane_ptr, 0));
brw_MOV(p, c->reg.loopcount, c->reg.nr_verts);
brw_MOV(p, c->reg.nr_verts, brw_imm_ud(0));
brw_DO(p, BRW_EXECUTE_1);
{
/* vtx = *input_ptr;
*/
brw_MOV(p, get_addr_reg(vtx), deref_1uw(inlist_ptr, 0));
load_clip_distance(c, vtxPrev, c->reg.dpPrev, hpos_offset, BRW_CONDITIONAL_L);
/* (prev < 0.0f) */
brw_IF(p, BRW_EXECUTE_1);
{
load_clip_distance(c, vtx, c->reg.dp, hpos_offset, BRW_CONDITIONAL_GE);
/* IS_POSITIVE(next)
*/
brw_IF(p, BRW_EXECUTE_1);
{
/* Coming back in.
*/
brw_ADD(p, c->reg.t, c->reg.dpPrev, negate(c->reg.dp));
brw_math_invert(p, c->reg.t, c->reg.t);
brw_MUL(p, c->reg.t, c->reg.t, c->reg.dpPrev);
/* If (vtxOut == 0) vtxOut = vtxPrev
*/
brw_CMP(p, vec1(brw_null_reg()), BRW_CONDITIONAL_EQ, get_addr_reg(vtxOut), brw_imm_uw(0) );
brw_MOV(p, get_addr_reg(vtxOut), get_addr_reg(vtxPrev));
brw_inst_set_pred_control(p->devinfo, brw_last_inst,
BRW_PREDICATE_NORMAL);
brw_clip_interp_vertex(c, vtxOut, vtxPrev, vtx, c->reg.t, false);
/* *outlist_ptr++ = vtxOut;
* nr_verts++;
* vtxOut = 0;
*/
brw_MOV(p, deref_1uw(outlist_ptr, 0), get_addr_reg(vtxOut));
brw_ADD(p, get_addr_reg(outlist_ptr), get_addr_reg(outlist_ptr), brw_imm_uw(sizeof(short)));
brw_ADD(p, c->reg.nr_verts, c->reg.nr_verts, brw_imm_ud(1));
brw_MOV(p, get_addr_reg(vtxOut), brw_imm_uw(0) );
}
brw_ENDIF(p);
}
brw_ELSE(p);
{
/* *outlist_ptr++ = vtxPrev;
* nr_verts++;
*/
brw_MOV(p, deref_1uw(outlist_ptr, 0), get_addr_reg(vtxPrev));
brw_ADD(p, get_addr_reg(outlist_ptr), get_addr_reg(outlist_ptr), brw_imm_uw(sizeof(short)));
brw_ADD(p, c->reg.nr_verts, c->reg.nr_verts, brw_imm_ud(1));
load_clip_distance(c, vtx, c->reg.dp, hpos_offset, BRW_CONDITIONAL_L);
/* (next < 0.0f)
*/
brw_IF(p, BRW_EXECUTE_1);
{
/* Going out of bounds. Avoid division by zero as we
* know dp != dpPrev from DIFFERENT_SIGNS, above.
*/
brw_ADD(p, c->reg.t, c->reg.dp, negate(c->reg.dpPrev));
brw_math_invert(p, c->reg.t, c->reg.t);
brw_MUL(p, c->reg.t, c->reg.t, c->reg.dp);
/* If (vtxOut == 0) vtxOut = vtx
*/
brw_CMP(p, vec1(brw_null_reg()), BRW_CONDITIONAL_EQ, get_addr_reg(vtxOut), brw_imm_uw(0) );
brw_MOV(p, get_addr_reg(vtxOut), get_addr_reg(vtx));
brw_inst_set_pred_control(p->devinfo, brw_last_inst,
BRW_PREDICATE_NORMAL);
brw_clip_interp_vertex(c, vtxOut, vtx, vtxPrev, c->reg.t, true);
/* *outlist_ptr++ = vtxOut;
* nr_verts++;
* vtxOut = 0;
*/
brw_MOV(p, deref_1uw(outlist_ptr, 0), get_addr_reg(vtxOut));
brw_ADD(p, get_addr_reg(outlist_ptr), get_addr_reg(outlist_ptr), brw_imm_uw(sizeof(short)));
brw_ADD(p, c->reg.nr_verts, c->reg.nr_verts, brw_imm_ud(1));
brw_MOV(p, get_addr_reg(vtxOut), brw_imm_uw(0) );
}
brw_ENDIF(p);
}
brw_ENDIF(p);
/* vtxPrev = vtx;
* inlist_ptr++;
*/
brw_MOV(p, get_addr_reg(vtxPrev), get_addr_reg(vtx));
brw_ADD(p, get_addr_reg(inlist_ptr), get_addr_reg(inlist_ptr), brw_imm_uw(sizeof(short)));
/* while (--loopcount != 0)
*/
brw_ADD(p, c->reg.loopcount, c->reg.loopcount, brw_imm_d(-1));
brw_inst_set_cond_modifier(p->devinfo, brw_last_inst, BRW_CONDITIONAL_NZ);
}
brw_WHILE(p);
brw_inst_set_pred_control(p->devinfo, brw_last_inst, BRW_PREDICATE_NORMAL);
/* vtxPrev = *(outlist_ptr-1) OR: outlist[nr_verts-1]
* inlist = outlist
* inlist_ptr = &inlist[0]
* outlist_ptr = &outlist[0]
*/
brw_ADD(p, get_addr_reg(outlist_ptr), get_addr_reg(outlist_ptr), brw_imm_w(-2));
brw_MOV(p, get_addr_reg(vtxPrev), deref_1uw(outlist_ptr, 0));
brw_MOV(p, brw_vec8_grf(c->reg.inlist.nr, 0), brw_vec8_grf(c->reg.outlist.nr, 0));
brw_MOV(p, get_addr_reg(inlist_ptr), brw_address(c->reg.inlist));
brw_MOV(p, get_addr_reg(outlist_ptr), brw_address(c->reg.outlist));
}
brw_ENDIF(p);
/* plane_ptr++;
*/
brw_ADD(p, get_addr_reg(plane_ptr), get_addr_reg(plane_ptr), brw_clip_plane_stride(c));
/* nr_verts >= 3
*/
brw_CMP(p,
vec1(brw_null_reg()),
BRW_CONDITIONAL_GE,
c->reg.nr_verts,
brw_imm_ud(3));
brw_set_default_predicate_control(p, BRW_PREDICATE_NORMAL);
/* && (planemask>>=1) != 0
*/
brw_SHR(p, c->reg.planemask, c->reg.planemask, brw_imm_ud(1));
brw_inst_set_cond_modifier(p->devinfo, brw_last_inst, BRW_CONDITIONAL_NZ);
brw_SHR(p, c->reg.vertex_src_mask, c->reg.vertex_src_mask, brw_imm_ud(1));
brw_ADD(p, c->reg.clipdistance_offset, c->reg.clipdistance_offset, brw_imm_w(sizeof(float)));
}
brw_WHILE(p);
brw_set_default_predicate_control(p, BRW_PREDICATE_NONE);
}
/* Interpolate between two vertices and put the result into a0.0.
* Increment a0.0 accordingly.
*/
void brw_clip_interp_vertex( struct brw_clip_compile *c,
struct brw_indirect dest_ptr,
struct brw_indirect v0_ptr, /* from */
struct brw_indirect v1_ptr, /* to */
struct brw_reg t0,
bool force_edgeflag)
{
struct brw_compile *p = &c->func;
struct brw_reg tmp = get_tmp(c);
GLuint slot;
/* Just copy the vertex header:
*/
/*
* After CLIP stage, only first 256 bits of the VUE are read
* back on Ironlake, so needn't change it
*/
brw_copy_indirect_to_indirect(p, dest_ptr, v0_ptr, 1);
/* Iterate over each attribute (could be done in pairs?)
*/
for (slot = 0; slot < c->vue_map.num_slots; slot++) {
int varying = c->vue_map.slot_to_varying[slot];
GLuint delta = brw_vue_slot_to_offset(slot);
if (varying == VARYING_SLOT_EDGE) {
if (force_edgeflag)
brw_MOV(p, deref_4f(dest_ptr, delta), brw_imm_f(1));
else
brw_MOV(p, deref_4f(dest_ptr, delta), deref_4f(v0_ptr, delta));
} else if (varying == VARYING_SLOT_PSIZ ||
varying == VARYING_SLOT_CLIP_DIST0 ||
varying == VARYING_SLOT_CLIP_DIST1) {
/* PSIZ doesn't need interpolation because it isn't used by the
* fragment shader. CLIP_DIST0 and CLIP_DIST1 don't need
* intepolation because on pre-GEN6, these are just placeholder VUE
* slots that don't perform any action.
*/
} else if (varying < VARYING_SLOT_MAX) {
/* This is a true vertex result (and not a special value for the VUE
* header), so interpolate:
*
* New = attr0 + t*attr1 - t*attr0
*/
brw_MUL(p,
vec4(brw_null_reg()),
deref_4f(v1_ptr, delta),
t0);
brw_MAC(p,
tmp,
negate(deref_4f(v0_ptr, delta)),
t0);
brw_ADD(p,
deref_4f(dest_ptr, delta),
deref_4f(v0_ptr, delta),
tmp);
}
}
if (c->vue_map.num_slots % 2) {
GLuint delta = brw_vue_slot_to_offset(c->vue_map.num_slots);
brw_MOV(p, deref_4f(dest_ptr, delta), brw_imm_f(0));
}
release_tmp(c, tmp);
/* Recreate the projected (NDC) coordinate in the new vertex
* header:
*/
brw_clip_project_vertex(c, dest_ptr );
}