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i965/clip: Add support for gl_ClipVertex

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When clipping triangles against a user clip plane, and gl_ClipVertex
is provided in the vertex, use it instead of hpos.

TODO: A similar change should be made at some point for line clipping.

Signed-off-by: Chris Forbes <chrisf@ijw.co.nz>
Reviewed-by: Paul Berry <stereotype441@gmail.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
This commit is contained in:
Chris Forbes 2013-05-20 21:51:43 +12:00
parent 9b34a7f29a
commit 3615949990
3 changed files with 55 additions and 4 deletions
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9
src/mesa/drivers/dri/i965/brw_clip.h
View file

@ -100,6 +100,15 @@ struct brw_clip_compile {
struct brw_reg plane_equation;
struct brw_reg ff_sync;
/* Bitmask indicating which coordinate attribute should be used for
* comparison to each clipping plane. A 0 indicates that VARYING_SLOT_POS
* should be used, because it's one of the fixed +/- x/y/z planes that
* constitute the bounds of the view volume. A 1 indicates that
* VARYING_SLOT_CLIP_VERTEX should be used (if available) since it's a user-
* defined clipping plane.
*/
struct brw_reg vertex_src_mask;
} reg;
/* Number of registers storing VUE data */

2
src/mesa/drivers/dri/i965/brw_clip_line.c
View file

@ -125,6 +125,8 @@ static void brw_clip_line_alloc_regs( struct brw_clip_compile *c )
*/
static void clip_and_emit_line( struct brw_clip_compile *c )
{
/* FIXME: use VARYING_SLOT_CLIP_VERTEX if available for user clip planes. */
struct brw_compile *p = &c->func;
struct brw_context *brw = p->brw;
struct brw_indirect vtx0 = brw_indirect(0, 0);

48
src/mesa/drivers/dri/i965/brw_clip_tri.c
View file

@ -119,6 +119,9 @@ void brw_clip_tri_alloc_regs( struct brw_clip_compile *c,
i++;
}
c->reg.vertex_src_mask = retype(brw_vec1_grf(i, 0), BRW_REGISTER_TYPE_UD);
i++;
if (intel->needs_ff_sync) {
c->reg.ff_sync = retype(brw_vec1_grf(i, 0), BRW_REGISTER_TYPE_UD);
i++;
@ -219,6 +222,31 @@ void brw_clip_tri_flat_shade( struct brw_clip_compile *c )
}
static inline void
load_vertex_pos(struct brw_clip_compile *c, struct brw_indirect vtx,
struct brw_reg dst,
GLuint hpos_offset, GLuint clip_offset)
{
struct brw_compile *p = &c->func;
/*
* Roughly:
* dst = (vertex_src_mask & 1) ? src.hpos : src.clipvertex;
*/
brw_set_conditionalmod(p, BRW_CONDITIONAL_NZ);
brw_AND(p, vec1(brw_null_reg()), c->reg.vertex_src_mask, brw_imm_ud(1));
brw_IF(p, BRW_EXECUTE_1);
{
brw_MOV(p, dst, deref_4f(vtx, clip_offset));
}
brw_ELSE(p);
{
brw_MOV(p, dst, deref_4f(vtx, hpos_offset));
}
brw_ENDIF(p);
}
/* Use mesa's clipping algorithms, translated to GEN4 assembly.
*/
@ -233,7 +261,10 @@ void brw_clip_tri( struct brw_clip_compile *c )
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);
GLuint clipvert_offset = brw_clip_have_varying(c, VARYING_SLOT_CLIP_VERTEX)
? brw_varying_to_offset(&c->vue_map, VARYING_SLOT_CLIP_VERTEX)
: hpos_offset;
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));
@ -241,6 +272,11 @@ void brw_clip_tri( struct brw_clip_compile *c )
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 6 planes are the user clipping planes.
*/
brw_MOV(p, c->reg.vertex_src_mask, brw_imm_ud(0xfc0));
brw_DO(p, BRW_EXECUTE_1);
{
/* if (planemask & 1)
@ -269,15 +305,17 @@ void brw_clip_tri( struct brw_clip_compile *c )
*/
brw_MOV(p, get_addr_reg(vtx), deref_1uw(inlist_ptr, 0));
load_vertex_pos(c, vtxPrev, vec4(c->reg.dpPrev), hpos_offset, clipvert_offset);
/* IS_NEGATIVE(prev) */
brw_set_conditionalmod(p, BRW_CONDITIONAL_L);
brw_DP4(p, vec4(c->reg.dpPrev), deref_4f(vtxPrev, hpos_offset), c->reg.plane_equation);
brw_DP4(p, vec4(c->reg.dpPrev), vec4(c->reg.dpPrev), c->reg.plane_equation);
brw_IF(p, BRW_EXECUTE_1);
{
load_vertex_pos(c, vtx, vec4(c->reg.dp), hpos_offset, clipvert_offset);
/* IS_POSITIVE(next)
*/
brw_set_conditionalmod(p, BRW_CONDITIONAL_GE);
brw_DP4(p, vec4(c->reg.dp), deref_4f(vtx, hpos_offset), c->reg.plane_equation);
brw_DP4(p, vec4(c->reg.dp), vec4(c->reg.dp), c->reg.plane_equation);
brw_IF(p, BRW_EXECUTE_1);
{
@ -316,10 +354,11 @@ void brw_clip_tri( struct brw_clip_compile *c )
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_vertex_pos(c, vtx, vec4(c->reg.dp), hpos_offset, clipvert_offset);
/* IS_NEGATIVE(next)
*/
brw_set_conditionalmod(p, BRW_CONDITIONAL_L);
brw_DP4(p, vec4(c->reg.dp), deref_4f(vtx, hpos_offset), c->reg.plane_equation);
brw_DP4(p, vec4(c->reg.dp), vec4(c->reg.dp), c->reg.plane_equation);
brw_IF(p, BRW_EXECUTE_1);
{
/* Going out of bounds. Avoid division by zero as we
@ -392,6 +431,7 @@ void brw_clip_tri( struct brw_clip_compile *c )
*/
brw_set_conditionalmod(p, BRW_CONDITIONAL_NZ);
brw_SHR(p, c->reg.planemask, c->reg.planemask, brw_imm_ud(1));
brw_SHR(p, c->reg.vertex_src_mask, c->reg.vertex_src_mask, brw_imm_ud(1));
}
brw_WHILE(p);
}