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etnaviv: tgsi: Fix gl_FrontFacing support 

The GPU presents the state of the hardware front_face in internal
register 0 (i0), the range of which is 0.0f..1.0f.

This patch assigns the fragment shader input to this internal register.
Moreover, based on the internal front_ccw state, the value of the i0
register is inverted accordingly using SET.EQ/SEQ.NE instruction before
being further processed in the shader. This mimics the operation of the
NIR compiler.

Signed-off-by: Marek Vasut <marex@denx.de>
Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Reviewed-by: Jonathan Marek <jonathan@marek.ca>
Tested-by: Marge Bot <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/2868>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/2868>
This commit is contained in:
Marek Vasut 2019-11-17 14:53:54 +01:00
parent 63b33120b7
commit 45e1443fd8
1 changed files with 53 additions and 10 deletions
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63
src/gallium/drivers/etnaviv/etnaviv_compiler_tgsi.c
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@ -222,6 +222,16 @@ etna_native_temp(unsigned reg)
};
}
static struct etna_native_reg
etna_native_internal(unsigned reg)
{
return (struct etna_native_reg) {
.valid = 1,
.rgroup = INST_RGROUP_INTERNAL,
.id = reg
};
}
/** Register allocation **/
enum reg_sort_order {
FIRST_USE_ASC,
@ -622,12 +632,19 @@ assign_special_inputs(struct etna_compile *c)
/* never assign t0 as it is the position output, start assigning at t1 */
c->next_free_native = 1;
/* hardwire TGSI_SEMANTIC_POSITION (input and output) to t0 */
for (int idx = 0; idx < c->total_decls; ++idx) {
struct etna_reg_desc *reg = &c->decl[idx];
if (reg->active && reg->semantic.Name == TGSI_SEMANTIC_POSITION)
if (!reg->active)
continue;
/* hardwire TGSI_SEMANTIC_POSITION (input and output) to t0 */
if (reg->semantic.Name == TGSI_SEMANTIC_POSITION)
reg->native = etna_native_temp(0);
/* hardwire TGSI_SEMANTIC_FACE to i0 */
if (reg->semantic.Name == TGSI_SEMANTIC_FACE)
reg->native = etna_native_internal(0);
}
}
}
@ -824,7 +841,34 @@ emit_inst(struct etna_compile *c, struct etna_inst *inst)
unsigned uni_reg = -1;
for (int src = 0; src < ETNA_NUM_SRC; ++src) {
if (etna_rgroup_is_uniform(inst->src[src].rgroup)) {
if (inst->src[src].rgroup == INST_RGROUP_INTERNAL &&
c->info.processor == PIPE_SHADER_FRAGMENT &&
c->key->front_ccw) {
struct etna_native_reg inner_temp = etna_compile_get_inner_temp(c);
/*
* Set temporary register to 0.0 or 1.0 based on the gl_FrontFacing
* configuration (CW or CCW).
*/
etna_assemble(&c->code[c->inst_ptr * 4], &(struct etna_inst) {
.opcode = INST_OPCODE_SET,
.cond = INST_CONDITION_NE,
.dst = etna_native_to_dst(inner_temp, INST_COMPS_X | INST_COMPS_Y |
INST_COMPS_Z | INST_COMPS_W),
.src[0] = inst->src[src],
.src[1] = alloc_imm_f32(c, 1.0f)
});
c->inst_ptr++;
/* Modify instruction to use temp register instead of uniform */
inst->src[src].use = 1;
inst->src[src].rgroup = INST_RGROUP_TEMP;
inst->src[src].reg = inner_temp.id;
inst->src[src].swiz = INST_SWIZ_IDENTITY; /* swizzling happens on MOV */
inst->src[src].neg = 0; /* negation happens on MOV */
inst->src[src].abs = 0; /* abs happens on MOV */
inst->src[src].amode = 0; /* amode effects happen on MOV */
} else if (etna_rgroup_is_uniform(inst->src[src].rgroup)) {
if (uni_reg == -1) { /* first unique uniform used */
uni_rgroup = inst->src[src].rgroup;
uni_reg = inst->src[src].reg;
@ -2037,8 +2081,9 @@ static void
permute_ps_inputs(struct etna_compile *c)
{
/* Special inputs:
* gl_FragCoord VARYING_SLOT_POS TGSI_SEMANTIC_POSITION
* gl_PointCoord VARYING_SLOT_PNTC TGSI_SEMANTIC_PCOORD
* gl_FragCoord VARYING_SLOT_POS TGSI_SEMANTIC_POSITION
* gl_FrontFacing VARYING_SLOT_FACE TGSI_SEMANTIC_FACE
* gl_PointCoord VARYING_SLOT_PNTC TGSI_SEMANTIC_PCOORD
*/
uint native_idx = 1;
@ -2047,7 +2092,9 @@ permute_ps_inputs(struct etna_compile *c)
uint input_id;
assert(reg->has_semantic);
if (!reg->active || reg->semantic.Name == TGSI_SEMANTIC_POSITION)
if (!reg->active ||
reg->semantic.Name == TGSI_SEMANTIC_POSITION ||
reg->semantic.Name == TGSI_SEMANTIC_FACE)
continue;
input_id = native_idx++;
@ -2347,10 +2394,6 @@ etna_compile_shader(struct etna_shader_variant *v)
/* optimize outputs */
etna_compile_pass_optimize_outputs(c);
/* XXX assign special inputs: gl_FrontFacing (VARYING_SLOT_FACE)
* this is part of RGROUP_INTERNAL
*/
/* assign inputs: last usage of input should be <= first usage of temp */
/* potential optimization case:
* if single MOV TEMP[y], IN[x] before which temp y is not used, and