On Fri, Dec 19, 2014 at 3:50 PM, Ilia Mirkin <imir...@alum.mit.edu> wrote:
> On Fri, Dec 19, 2014 at 2:11 PM, Rob Clark <robdcl...@gmail.com> wrote:
>> From: Rob Clark <robcl...@freedesktop.org>
>>
>> This emulates alpha-test with a compare + KILL_IF. The alpha-ref value
>> is passed to the shader via constant tagged with new ALPHAREF semantic.
>> For example:
>>
>> FRAG
>> PROPERTY FS_COLOR0_WRITES_ALL_CBUFS 1
>> DCL IN[0], COLOR, COLOR
>> DCL OUT[0], COLOR
>> 0: MOV OUT[0], IN[0]
>> 1: END
>>
>> with alpha-func PIPE_FUNC_LESS, becomes:
>>
>> FRAG
>> PROPERTY FS_COLOR0_WRITES_ALL_CBUFS 1
>> DCL IN[0], COLOR, COLOR
>> DCL OUT[0], COLOR
>> IMM[0] FLT32 { 0.0000, 1.0000, 128.0000, 0.0000}
>> DCL TEMP[0]
>> DCL TEMP[1]
>> DCL CONST[0], ALPHAREF
>
> IMO this is pretty confusing. A SV makes more sense, no? Otherwise
> you'd have a situation where
>
> DCL CONST[0]
> DCL CONST[1]
> DCL CONST[2], ALPHAREF
>
> MOV TEMP[0], CONST[ADDR[0].x]
>
> Could potentially be expected to move the alpharef into the temp,
> which is... odd. Also I don't think there's any precendent for tagging
> const's with semantics.
it is a bit odd, but isn't an out of bounds access undefined anyways?
And yes, I don't think there is any precedent for tagging const's w/
semantic, it was a rather logical choice.. ie. if you are lowering
alpha-test, that means you don't have some special register/etc to
store alpharef, therefore driver is going to treat it as a normal
const. It just needs some way to know where to stuff the const val.
Treating it as something other than a const didn't seem to make much
sense from the perspective of the consumer of the resulting tgsi.
> The other thing to consider is whether each of these things should be
> semantics, or whether there should be a
>
> TGSI_SEMANTIC_DRIVER
>
> Which is then indexed in a custom way (in this case, however
> tgsi_lowering decides). Many drivers end up with driver-internal
> constbufs full of convenient values, this would be a way to represent
> that.
I thought about it.. but not like we are running out of room in
semantic namespace, and it was a very straightforward way to hook this
all up (including tgsi_dump() and tgsi_text_translate())
BR,
-R
>
>> 0: MOV TEMP[1], IN[0]
>> 1: SLT TEMP[0].x, TEMP[1].wwww, CONST[0].xxxx
>> 2: KILL_IF TEMP[0].xxxx
>> 3: MOV OUT[0], TEMP[1]
>> 4: END
>>
>> Signed-off-by: Rob Clark <robcl...@freedesktop.org>
>> ---
>> src/gallium/auxiliary/tgsi/tgsi_lowering.c | 170
>> ++++++++++++++++++++++++++++-
>> src/gallium/auxiliary/tgsi/tgsi_lowering.h | 7 ++
>> src/gallium/auxiliary/tgsi/tgsi_strings.c | 1 +
>> src/gallium/include/pipe/p_shader_tokens.h | 3 +-
>> 4 files changed, 177 insertions(+), 4 deletions(-)
>>
>> diff --git a/src/gallium/auxiliary/tgsi/tgsi_lowering.c
>> b/src/gallium/auxiliary/tgsi/tgsi_lowering.c
>> index dee6c41..4f1da29 100644
>> --- a/src/gallium/auxiliary/tgsi/tgsi_lowering.c
>> +++ b/src/gallium/auxiliary/tgsi/tgsi_lowering.c
>> @@ -37,15 +37,22 @@ struct tgsi_lowering_context {
>> struct tgsi_transform_context base;
>> const struct tgsi_lowering_config *config;
>> struct tgsi_shader_info *info;
>> +
>> + bool alpha_test;
>> + unsigned colorout;
>> + unsigned colortmp; /* tmp register to hold original color out */
>> + unsigned alpharef; /* const slot used to hold alpharef value */
>> +
>> unsigned two_side_colors;
>> unsigned two_side_idx[PIPE_MAX_SHADER_INPUTS];
>> unsigned color_base; /* base register for chosen COLOR/BCOLOR's */
>> int face_idx;
>> +
>> unsigned numtmp;
>> struct {
>> struct tgsi_full_src_register src;
>> struct tgsi_full_dst_register dst;
>> - } tmp[2];
>> + } tmp[3];
>> #define A 0
>> #define B 1
>> struct tgsi_full_src_register imm;
>> @@ -1146,6 +1153,128 @@ transform_samp(struct tgsi_transform_context *tctx,
>> return 0;
>> }
>>
>> +/* Alpha-test emulation:
>> + * Redirects writes to COLOR output to a temporary and appends
>> + * extra instructions to do conditional kill based on output
>> + * alpha value
>> + */
>> +#define ALPHATEST_GROW ( \
>> + 3 + /* CONST[], ALPHAREF */ \
>> + NINST(2) + /* SEQ/SNE/SLE/SGT/SLT */ \
>> + NINST(1) + /* KILL_IF */ \
>> + NINST(1) /* MOV */ \
>> + )
>> +#define ALPHATEST_TMP 1
>> +
>> +static void
>> +emit_alphatest_decls(struct tgsi_transform_context *tctx)
>> +{
>> + struct tgsi_lowering_context *ctx = tgsi_lowering_context(tctx);
>> + struct tgsi_full_declaration decl;
>> +
>> + /* NOTE: the temporaries we need are handled in emit_decls() */
>> +
>> + decl = tgsi_default_full_declaration();
>> + decl.Declaration.File = TGSI_FILE_CONSTANT;
>> + decl.Declaration.Semantic = true;
>> + decl.Range.First = decl.Range.Last = ctx->alpharef;
>> + decl.Semantic.Name = TGSI_SEMANTIC_ALPHAREF;
>> + decl.Semantic.Index = 0;
>> + tctx->emit_declaration(tctx, &decl);
>> +}
>> +
>> +static void
>> +emit_alphatest_instrs(struct tgsi_transform_context *tctx)
>> +{
>> + struct tgsi_lowering_context *ctx = tgsi_lowering_context(tctx);
>> + struct tgsi_full_instruction new_inst;
>> + int c = ctx->colortmp;
>> +
>> + if (ctx->config->alpha_func == PIPE_FUNC_NEVER) {
>> + /* KILL */
>> + new_inst = tgsi_default_full_instruction();
>> + new_inst.Instruction.Opcode = TGSI_OPCODE_KILL;
>> + new_inst.Instruction.NumDstRegs = 0;
>> + new_inst.Instruction.NumSrcRegs = 0;
>> + tctx->emit_instruction(tctx, &new_inst);
>> + } else {
>> + unsigned opcode;
>> +
>> + switch (ctx->config->alpha_func) {
>> + case PIPE_FUNC_LESS:
>> + opcode = TGSI_OPCODE_SLT;
>> + break;
>> + case PIPE_FUNC_EQUAL:
>> + opcode = TGSI_OPCODE_SEQ;
>> + break;
>> + case PIPE_FUNC_LEQUAL:
>> + opcode = TGSI_OPCODE_SLE;
>> + break;
>> + case PIPE_FUNC_GREATER:
>> + opcode = TGSI_OPCODE_SGT;
>> + break;
>> + case PIPE_FUNC_NOTEQUAL:
>> + opcode = TGSI_OPCODE_SNE;
>> + break;
>> + case PIPE_FUNC_GEQUAL:
>> + opcode = TGSI_OPCODE_SGE;
>> + break;
>> + default:
>> + assert(0);
>> + return;
>> + }
>> +
>> + /* SEQ/SNE/SGE/SLE/SGT/SLT tmpA.x, tmpColor.w, alpharef.x */
>> + new_inst = tgsi_default_full_instruction();
>> + new_inst.Instruction.Opcode = opcode;
>> + new_inst.Instruction.NumDstRegs = 1;
>> + reg_dst(&new_inst.Dst[0], &ctx->tmp[A].dst, TGSI_WRITEMASK_X);
>> + new_inst.Instruction.NumSrcRegs = 2;
>> + reg_src(&new_inst.Src[0], &ctx->tmp[c].src, SWIZ(W, W, W, W));
>> + new_inst.Src[1].Register.File = TGSI_FILE_CONSTANT;
>> + new_inst.Src[1].Register.Index = ctx->alpharef;
>> + new_inst.Src[1].Register.SwizzleX = TGSI_SWIZZLE_X;
>> + new_inst.Src[1].Register.SwizzleY = TGSI_SWIZZLE_X;
>> + new_inst.Src[1].Register.SwizzleZ = TGSI_SWIZZLE_X;
>> + new_inst.Src[1].Register.SwizzleW = TGSI_SWIZZLE_X;
>> + tctx->emit_instruction(tctx, &new_inst);
>> +
>> + /* KILL_IF tmpA.x */
>> + new_inst = tgsi_default_full_instruction();
>> + new_inst.Instruction.Opcode = TGSI_OPCODE_KILL_IF;
>> + new_inst.Instruction.NumDstRegs = 0;
>> + new_inst.Instruction.NumSrcRegs = 1;
>> + reg_src(&new_inst.Src[0], &ctx->tmp[A].src, SWIZ(X, _, _, _));
>> + tctx->emit_instruction(tctx, &new_inst);
>> + }
>> +
>> + /* MOV OUT[color], tmpColor */
>> + /* (would be nice if we could create_mov() here..) */
>> + new_inst = tgsi_default_full_instruction();
>> + new_inst.Instruction.Opcode = TGSI_OPCODE_MOV;
>> + new_inst.Instruction.NumDstRegs = 1;
>> + new_inst.Dst[0].Register.File = TGSI_FILE_OUTPUT;
>> + new_inst.Dst[0].Register.Index = ctx->colorout;
>> + new_inst.Dst[0].Register.WriteMask = TGSI_WRITEMASK_XYZW;
>> + new_inst.Instruction.NumSrcRegs = 1;
>> + reg_src(&new_inst.Src[0], &ctx->tmp[c].src, SWIZ(X, Y, Z, W));
>> + tctx->emit_instruction(tctx, &new_inst);
>> +}
>> +
>> +static void
>> +rename_color_outputs(struct tgsi_lowering_context *ctx,
>> + struct tgsi_full_instruction *inst)
>> +{
>> + unsigned i;
>> + for (i = 0; i < inst->Instruction.NumDstRegs; i++) {
>> + struct tgsi_dst_register *dst = &inst->Dst[i].Register;
>> + if ((dst->File == TGSI_FILE_OUTPUT) &&
>> + (dst->Index == ctx->colorout)) {
>> + *dst = ctx->tmp[ctx->colortmp].dst.Register;
>> + }
>> + }
>> +}
>> +
>> /* Two-sided color emulation:
>> * For each COLOR input, create a corresponding BCOLOR input, plus
>> * CMP instruction to select front or back color based on FACE
>> @@ -1288,6 +1417,9 @@ emit_decls(struct tgsi_transform_context *tctx)
>>
>> if (ctx->two_side_colors)
>> emit_twoside(tctx);
>> +
>> + if (ctx->alpha_test)
>> + emit_alphatest_decls(tctx);
>> }
>>
>> static void
>> @@ -1307,7 +1439,6 @@ rename_color_inputs(struct tgsi_lowering_context *ctx,
>> }
>> }
>> }
>> -
>> }
>>
>> static void
>> @@ -1327,6 +1458,12 @@ transform_instr(struct tgsi_transform_context *tctx,
>> if (ctx->two_side_colors)
>> rename_color_inputs(ctx, inst);
>>
>> + /* if emulating alpha-test, we need to re-write some dst
>> + * registers:
>> + */
>> + if (ctx->alpha_test)
>> + rename_color_outputs(ctx, inst);
>> +
>> switch (inst->Instruction.Opcode) {
>> case TGSI_OPCODE_DST:
>> if (!ctx->config->lower_DST)
>> @@ -1406,6 +1543,10 @@ transform_instr(struct tgsi_transform_context *tctx,
>> if (transform_samp(tctx, inst))
>> goto skip;
>> break;
>> + case TGSI_OPCODE_END:
>> + if (ctx->alpha_test)
>> + emit_alphatest_instrs(tctx);
>> + goto skip; /* emit the actual END instruction itself */
>> default:
>> skip:
>> tctx->emit_instruction(tctx, inst);
>> @@ -1452,6 +1593,20 @@ tgsi_transform_lowering(const struct
>> tgsi_lowering_config *config,
>> }
>> }
>>
>> + if ((info->processor == TGSI_PROCESSOR_FRAGMENT) &&
>> + config->lower_alpha_test &&
>> + (config->alpha_func != PIPE_FUNC_ALWAYS)) {
>> + int i;
>> + ctx.alpha_test = true;
>> + for (i = 0; i < info->file_max[TGSI_FILE_OUTPUT]; i++) {
>> + /* TODO not sure what to do in case of MRT */
>> + if (info->output_semantic_name[i] == TGSI_SEMANTIC_COLOR) {
>> + ctx.colorout = i;
>> + break;
>> + }
>> + }
>> + }
>> +
>> ctx.saturate = config->saturate_r | config->saturate_s |
>> config->saturate_t;
>>
>> #define OPCS(x) ((config->lower_ ## x) ? info->opcode_count[TGSI_OPCODE_ ##
>> x] : 0)
>> @@ -1472,7 +1627,8 @@ tgsi_transform_lowering(const struct
>> tgsi_lowering_config *config,
>> OPCS(DP2A) ||
>> OPCS(TXP) ||
>> ctx.two_side_colors ||
>> - ctx.saturate))
>> + ctx.saturate ||
>> + ctx.alpha_test))
>> return NULL;
>>
>> #if 0 /* debug */
>> @@ -1555,6 +1711,14 @@ tgsi_transform_lowering(const struct
>> tgsi_lowering_config *config,
>> numtmp = MAX2(numtmp, SAMP_TMP);
>> }
>>
>> + if (ctx.alpha_test) {
>> + newlen += ALPHATEST_GROW;
>> + numtmp = MAX2(numtmp, ALPHATEST_TMP);
>> + /* and one more tmp to hold temporary color output: */
>> + ctx.colortmp = numtmp++;
>> + ctx.alpharef = info->file_max[TGSI_FILE_CONSTANT] + 1;
>> + }
>> +
>> /* specifically don't include two_side_colors temps in the count: */
>> ctx.numtmp = numtmp;
>>
>> diff --git a/src/gallium/auxiliary/tgsi/tgsi_lowering.h
>> b/src/gallium/auxiliary/tgsi/tgsi_lowering.h
>> index 52c204f..3a95c82 100644
>> --- a/src/gallium/auxiliary/tgsi/tgsi_lowering.h
>> +++ b/src/gallium/auxiliary/tgsi/tgsi_lowering.h
>> @@ -69,6 +69,13 @@ struct tgsi_lowering_config
>> unsigned lower_DP2:1;
>> unsigned lower_DP2A:1;
>>
>> + /* If lowering alpha-test, a constant w/ the semantic
>> + * ALPHAREF is inserted. The driver should pass in the
>> + * actual alpha-ref value via this constant (.x coord)
>> + */
>> + unsigned lower_alpha_test:1;
>> + unsigned alpha_func:3; /* PIPE_FUNC_x */
>> +
>> /* bitmask of (1 << TGSI_TEXTURE_type): */
>> unsigned lower_TXP;
>>
>> diff --git a/src/gallium/auxiliary/tgsi/tgsi_strings.c
>> b/src/gallium/auxiliary/tgsi/tgsi_strings.c
>> index bd97544..b696838 100644
>> --- a/src/gallium/auxiliary/tgsi/tgsi_strings.c
>> +++ b/src/gallium/auxiliary/tgsi/tgsi_strings.c
>> @@ -88,6 +88,7 @@ const char *tgsi_semantic_names[TGSI_SEMANTIC_COUNT] =
>> "INVOCATIONID",
>> "VERTEXID_NOBASE",
>> "BASEVERTEX",
>> + "ALPHAREF",
>> };
>>
>> const char *tgsi_texture_names[TGSI_TEXTURE_COUNT] =
>> diff --git a/src/gallium/include/pipe/p_shader_tokens.h
>> b/src/gallium/include/pipe/p_shader_tokens.h
>> index 442b67b..bf54c3e 100644
>> --- a/src/gallium/include/pipe/p_shader_tokens.h
>> +++ b/src/gallium/include/pipe/p_shader_tokens.h
>> @@ -178,7 +178,8 @@ struct tgsi_declaration_interp
>> #define TGSI_SEMANTIC_INVOCATIONID 27
>> #define TGSI_SEMANTIC_VERTEXID_NOBASE 28
>> #define TGSI_SEMANTIC_BASEVERTEX 29
>> -#define TGSI_SEMANTIC_COUNT 30 /**< number of semantic values */
>> +#define TGSI_SEMANTIC_ALPHAREF 30
>> +#define TGSI_SEMANTIC_COUNT 31 /**< number of semantic values */
>>
>> struct tgsi_declaration_semantic
>> {
>> --
>> 2.1.0
>>
>> _______________________________________________
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>> mesa-dev@lists.freedesktop.org
>> http://lists.freedesktop.org/mailman/listinfo/mesa-dev
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