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cell: perform triangle cull a little earlier

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In spu_tri.c:setup_sort_vertices() triangles are culled after the
vertices are sorted.  This patch moves the check a little earlier
and performs the actual check a little faster through intrinsics and
a little trickery.

Reduced code size and less work is done before a triangle is deemed
OK to skip.
This commit is contained in:
Jonathan Adamczewski
2009-05-21 08:19:00 -06:00
committed by Brian Paul
parent b4824520ec
commit 2c007517b5
1 changed files with 74 additions and 31 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/gallium/drivers/cell/spu/spu_tri.c
+74 -31
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@@ -133,7 +133,15 @@ struct setup_stage {
uint tx, ty; /**< position of current tile (x, y) */
int cliprect_minx, cliprect_maxx, cliprect_miny, cliprect_maxy;
union {
struct {
int cliprect_minx;
int cliprect_miny;
int cliprect_maxx;
int cliprect_maxy;
};
qword cliprect;
};
struct interp_coef coef[PIPE_MAX_SHADER_INPUTS];
@@ -432,6 +440,41 @@ print_vertex(const struct vertex_header *v)
}
#endif
/* Returns the minimum of each slot of two vec_float4s as qwords.
* i.e. return[n] = min(q0[n],q1[n]);
*/
static qword
minfq(qword q0, qword q1)
{
const qword q0q1m = si_fcgt(q0, q1);
return si_selb(q0, q1, q0q1m);
}
/* Returns the minimum of each slot of three vec_float4s as qwords.
* i.e. return[n] = min(q0[n],q1[n],q2[n]);
*/
static qword
min3fq(qword q0, qword q1, qword q2)
{
return minfq(minfq(q0, q1), q2);
}
/* Returns the maximum of each slot of two vec_float4s as qwords.
* i.e. return[n] = min(q0[n],q1[n],q2[n]);
*/
static qword
maxfq(qword q0, qword q1) {
const qword q0q1m = si_fcgt(q0, q1);
return si_selb(q1, q0, q0q1m);
}
/* Returns the maximum of each slot of three vec_float4s as qwords.
* i.e. return[n] = min(q0[n],q1[n],q2[n]);
*/
static qword
max3fq(qword q0, qword q1, qword q2) {
return maxfq(maxfq(q0, q1), q2);
}
/**
* Sort vertices from top to bottom.
@@ -453,8 +496,25 @@ setup_sort_vertices(const qword vs)
}
#endif
/* determine bottom to top order of vertices */
{
/* Load the float values for various processing... */
const qword f0 = (qword)(((const struct vertex_header*)si_to_ptr(vs))->data[0]);
const qword f1 = (qword)(((const struct vertex_header*)si_to_ptr(si_rotqbyi(vs, 4)))->data[0]);
const qword f2 = (qword)(((const struct vertex_header*)si_to_ptr(si_rotqbyi(vs, 8)))->data[0]);
/* Check if triangle is completely outside the tile bounds
* Find the min and max x and y positions of the three poits */
const qword minf = min3fq(f0, f1, f2);
const qword maxf = max3fq(f0, f1, f2);
/* Compare min and max against cliprect vals */
const qword maxsmins = si_shufb(maxf, minf, SHUFB4(A,B,a,b));
const qword outside = si_fcgt(maxsmins, si_csflt(setup.cliprect, 0));
/* Use a little magic to work out of the tri is visible or not */
if(si_to_uint(si_xori(si_gb(outside), 0xc))) return FALSE;
/* determine bottom to top order of vertices */
/* A table of shuffle patterns for putting vertex_header pointers into
correct order. Quite magical. */
const qword sort_order_patterns[] = {
@@ -467,43 +527,26 @@ setup_sort_vertices(const qword vs)
/* Collate y values into two vectors for comparison.
Using only one shuffle constant! ;) */
const vector float f0 = ((const struct vertex_header*)si_to_ptr(vs))->data[0];
const vector float f1 = ((const struct vertex_header*)si_to_ptr(si_rotqbyi(vs, 4)))->data[0];
const vector float f2 = ((const struct vertex_header*)si_to_ptr(si_rotqbyi(vs, 8)))->data[0];
const vec_float4 y_02_ = spu_shuffle(f0, f2, SHUFFLE4(0,B,b,C));
const vec_float4 y_10_ = spu_shuffle(f1, f0, SHUFFLE4(0,B,b,C));
const vec_float4 y_012 = spu_shuffle(y_02_, f1, SHUFFLE4(0,B,b,C));
const vec_float4 y_120 = spu_shuffle(y_10_, f2, SHUFFLE4(0,B,b,C));
const qword y_02_ = si_shufb(f0, f2, SHUFB4(0,B,b,C));
const qword y_10_ = si_shufb(f1, f0, SHUFB4(0,B,b,C));
const qword y_012 = si_shufb(y_02_, f1, SHUFB4(0,B,b,C));
const qword y_120 = si_shufb(y_10_, f2, SHUFB4(0,B,b,C));
/* Perform comparison: {y0,y1,y2} > {y1,y2,y0} */
const vec_uint4 compare = spu_cmpgt(y_012, y_120);
const qword compare = si_fcgt(y_012, y_120);
/* Compress the result of the comparison into 4 bits */
const vec_uint4 gather = spu_gather(compare);
const qword gather = si_gb(compare);
/* Subtract one to attain the index into the LUT. Magical. */
const unsigned int index = spu_extract(gather, 0) - 1;
const unsigned int index = si_to_uint(gather) - 1;
/* Load the appropriate pattern and construct the desired vector. */
setup.vertex_headers = si_shufb(vs, vs, sort_order_patterns[index]);
/* Using the result of the comparison, set sign.
Very magical. */
sign = ((si_to_uint(si_cntb((qword)gather)) == 2) ? 1.0f : -1.0f);
sign = ((si_to_uint(si_cntb(gather)) == 2) ? 1.0f : -1.0f);
}
/* Check if triangle is completely outside the tile bounds */
if (spu_extract(setup.vmin->data[0], 1) > setup.cliprect_maxy)
return FALSE;
if (spu_extract(setup.vmax->data[0], 1) < setup.cliprect_miny)
return FALSE;
if (spu_extract(setup.vmin->data[0], 0) < setup.cliprect_minx &&
spu_extract(setup.vmid->data[0], 0) < setup.cliprect_minx &&
spu_extract(setup.vmax->data[0], 0) < setup.cliprect_minx)
return FALSE;
if (spu_extract(setup.vmin->data[0], 0) > setup.cliprect_maxx &&
spu_extract(setup.vmid->data[0], 0) > setup.cliprect_maxx &&
spu_extract(setup.vmax->data[0], 0) > setup.cliprect_maxx)
return FALSE;
setup.ebot.ds = spu_sub(setup.vmid->data[0], setup.vmin->data[0]);
setup.emaj.ds = spu_sub(setup.vmax->data[0], setup.vmin->data[0]);
setup.etop.ds = spu_sub(setup.vmax->data[0], setup.vmid->data[0]);
@@ -766,10 +809,10 @@ tri_draw(const qword vs,
setup.ty = ty;
/* set clipping bounds to tile bounds */
setup.cliprect_minx = tx * TILE_SIZE;
setup.cliprect_miny = ty * TILE_SIZE;
setup.cliprect_maxx = (tx + 1) * TILE_SIZE;
setup.cliprect_maxy = (ty + 1) * TILE_SIZE;
const qword clipbase = (qword)((vec_uint4){tx, ty});
const qword clipmin = si_mpyui(clipbase, TILE_SIZE);
const qword clipmax = si_ai(clipmin, TILE_SIZE);
setup.cliprect = si_shufb(clipmin, clipmax, SHUFB4(A,B,a,b));
if(!setup_sort_vertices(vs)) {
return FALSE; /* totally clipped */