[Mesa-dev] [PATCH V5 1/2] i965/blorp: Add bilinear filtering of samples for multisample scaled blits
Paul Berry
stereotype441 at gmail.com
Mon Jul 1 10:51:41 PDT 2013
On 28 June 2013 16:59, Anuj Phogat <anuj.phogat at gmail.com> wrote:
> Current implementation of ext_framebuffer_multisample_blit_scaled in
> i965/blorp uses nearest filtering for multisample scaled blits. Using
> nearest filtering produces blocky artifacts and negates the benefits
> of MSAA. That is the reason why extension was not enabled on i965.
>
> This patch implements the bilinear filtering of samples in blorp engine.
> Images generated with this patch are free from blocky artifacts and show
> big improvement in visual quality.
>
> Observed no piglit and gles3 regressions.
>
> V3:
> - Algorithm used for filtering assumes a rectangular grid of samples
> roughly corresponding to sample locations.
> - Test the boundary conditions on the edges of texture.
>
> V4:
> - Clip texcoords and use conditional MOVs.
> - Send texture dimensions as push constants.
> - Remove the optimization in case of scaled multisample blits.
>
> V5:
> - Move mcs_fetch() inside the 'for' loop after computing pixel coordinates.
>
> Signed-off-by: Anuj Phogat <anuj.phogat at gmail.com>
> ---
>
> src/mesa/drivers/dri/i965/brw_blorp.h | 16 ++
> src/mesa/drivers/dri/i965/brw_blorp_blit.cpp | 278
> +++++++++++++++++++++++++--
> 2 files changed, 273 insertions(+), 21 deletions(-)
>
> diff --git a/src/mesa/drivers/dri/i965/brw_blorp.h
> b/src/mesa/drivers/dri/i965/brw_blorp.h
> index ffc27cc..9277d09 100644
> --- a/src/mesa/drivers/dri/i965/brw_blorp.h
> +++ b/src/mesa/drivers/dri/i965/brw_blorp.h
> @@ -178,8 +178,15 @@ struct brw_blorp_wm_push_constants
> uint32_t dst_x1;
> uint32_t dst_y0;
> uint32_t dst_y1;
> + /* Top right coordinates of the rectangular sample grid used for
> + * multisample scaled blitting.
> + */
> + float sample_grid_x1;
> + float sample_grid_y1;
> brw_blorp_coord_transform_params x_transform;
> brw_blorp_coord_transform_params y_transform;
> + /* Pad out to an integral number of registers */
> + uint32_t pad[6];
> };
>
> /* Every 32 bytes of push constant data constitutes one GEN register. */
> @@ -319,6 +326,15 @@ struct brw_blorp_blit_prog_key
> * than one sample per pixel.
> */
> bool persample_msaa_dispatch;
> +
> + /* True for scaled blitting. */
> + bool blit_scaled;
> +
> + /* Scale factors between the pixel grid and the grid of samples. We're
> + * using grid of samples for bilinear filetring in multisample scaled
> blits.
> + */
> + float x_scale;
> + float y_scale;
> };
>
> class brw_blorp_blit_params : public brw_blorp_params
> diff --git a/src/mesa/drivers/dri/i965/brw_blorp_blit.cpp
> b/src/mesa/drivers/dri/i965/brw_blorp_blit.cpp
> index 8694128..d39bae1 100644
> --- a/src/mesa/drivers/dri/i965/brw_blorp_blit.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_blorp_blit.cpp
> @@ -622,7 +622,8 @@ private:
> void kill_if_outside_dst_rect();
> void translate_dst_to_src();
> void single_to_blend();
> - void manual_blend(unsigned num_samples);
> + void manual_blend_average(unsigned num_samples);
> + void manual_blend_bilinear(unsigned num_samples);
> void sample(struct brw_reg dst);
> void texel_fetch(struct brw_reg dst);
> void mcs_fetch();
> @@ -651,6 +652,11 @@ private:
> struct brw_reg dst_x1;
> struct brw_reg dst_y0;
> struct brw_reg dst_y1;
> + /* Top right coordinates of the rectangular sample grid used for
> + * multisample scaled blitting.
> + */
> + struct brw_reg sample_grid_x1;
> + struct brw_reg sample_grid_y1;
> struct {
> struct brw_reg multiplier;
> struct brw_reg offset;
> @@ -676,6 +682,16 @@ private:
> */
> struct brw_reg y_coords[2];
>
> + /* X, Y coordinates of the pixel from which we need to fetch the
> specific
> + * sample. These are used for multisample scaled blitting.
> + */
> + struct brw_reg x_sample_coords;
> + struct brw_reg y_sample_coords;
> +
> + /* Fractional parts of the x and y coordinates, used as bilinear
> interpolation coefficients */
> + struct brw_reg x_frac;
> + struct brw_reg y_frac;
> +
> /* Which element of x_coords and y_coords is currently in use.
> */
> int xy_coord_index;
> @@ -814,15 +830,17 @@ brw_blorp_blit_program::compile(struct brw_context
> *brw,
> * that we want to texture from. Exception: if we are blending, then
> S is
> * irrelevant, because we are going to fetch all samples.
> */
> - if (key->blend) {
> + if (key->blend && !key->blit_scaled) {
> if (brw->intel.gen == 6) {
> /* Gen6 hardware an automatically blend using the SAMPLE message
> */
> single_to_blend();
> sample(texture_data[0]);
> } else {
> /* Gen7+ hardware doesn't automaticaly blend. */
> - manual_blend(key->src_samples);
> + manual_blend_average(key->src_samples);
> }
> + } else if(key->blend && key->blit_scaled) {
> + manual_blend_bilinear(key->src_samples);
> } else {
> /* We aren't blending, which means we just want to fetch a single
> sample
> * from the source surface. The address that we want to fetch from
> is
> @@ -872,18 +890,21 @@ void
> brw_blorp_blit_program::alloc_push_const_regs(int base_reg)
> {
> #define CONST_LOC(name) offsetof(brw_blorp_wm_push_constants, name)
> -#define ALLOC_REG(name) \
> +#define ALLOC_REG(name, offset) \
> this->name = \
> - brw_vec1_reg(BRW_GENERAL_REGISTER_FILE, base_reg, CONST_LOC(name) /
> 4)
> -
> - ALLOC_REG(dst_x0);
> - ALLOC_REG(dst_x1);
> - ALLOC_REG(dst_y0);
> - ALLOC_REG(dst_y1);
> - ALLOC_REG(x_transform.multiplier);
> - ALLOC_REG(x_transform.offset);
> - ALLOC_REG(y_transform.multiplier);
> - ALLOC_REG(y_transform.offset);
> + brw_vec1_reg(BRW_GENERAL_REGISTER_FILE, base_reg + offset / 32, \
> + offset >= 32 ? (offset - 32) / 4 : offset / 4)
>
I don't understand why it's necessary to add "offset" as a parameter to the
ALLOC_REG macro. Also, I see that you're trying to generalize ALLOC_REG to
work when the offset is >= 32, which is great, but as long as we're
generalizing it we should generalize it fully--what you've written doesn't
work for offsets >= 64. How about this instead:
#define ALLOC_REG(name) \
this->name = \
brw_vec1_reg(BRW_GENERAL_REGISTER_FILE, \
base_reg + CONST_LOC(name) / 32, \
(CONST_LOC(name) % 32) / 4)
With that fixed, this patch is:
Reviewed-by: Paul Berry <stereotype441 at gmail.com>
Thanks for all your hard work on this, Anuj.
> +
> + ALLOC_REG(dst_x0, CONST_LOC(dst_x0));
> + ALLOC_REG(dst_x1, CONST_LOC(dst_x1));
> + ALLOC_REG(dst_y0, CONST_LOC(dst_y0));
> + ALLOC_REG(dst_y1, CONST_LOC(dst_y1));
> + ALLOC_REG(sample_grid_x1, CONST_LOC(sample_grid_x1));
> + ALLOC_REG(sample_grid_y1, CONST_LOC(sample_grid_y1));
> + ALLOC_REG(x_transform.multiplier, CONST_LOC(x_transform.multiplier));
> + ALLOC_REG(x_transform.offset, CONST_LOC(x_transform.offset));
> + ALLOC_REG(y_transform.multiplier, CONST_LOC(y_transform.multiplier));
> + ALLOC_REG(y_transform.offset, CONST_LOC(y_transform.offset));
> #undef CONST_LOC
> #undef ALLOC_REG
> }
> @@ -913,6 +934,18 @@ brw_blorp_blit_program::alloc_regs()
> = retype(brw_vec8_grf(reg, 0), BRW_REGISTER_TYPE_UD);
> reg += 2;
> }
> +
> + if (key->blit_scaled && key->blend) {
> + this->x_sample_coords = brw_vec8_grf(reg, 0);
> + reg += 2;
> + this->y_sample_coords = brw_vec8_grf(reg, 0);
> + reg += 2;
> + this->x_frac = brw_vec8_grf(reg, 0);
> + reg += 2;
> + this->y_frac = brw_vec8_grf(reg, 0);
> + reg += 2;
> + }
> +
> this->xy_coord_index = 0;
> this->sample_index
> = retype(brw_vec8_grf(reg, 0), BRW_REGISTER_TYPE_UD);
> @@ -1368,11 +1401,59 @@ brw_blorp_blit_program::translate_dst_to_src()
> brw_MUL(&func, Y_f, Yp_f, y_transform.multiplier);
> brw_ADD(&func, X_f, X_f, x_transform.offset);
> brw_ADD(&func, Y_f, Y_f, y_transform.offset);
> - /* Round the float coordinates down to nearest integer by moving to
> - * UD registers.
> - */
> - brw_MOV(&func, Xp, X_f);
> - brw_MOV(&func, Yp, Y_f);
> + if (key->blit_scaled && key->blend) {
> + /* Translate coordinates to lay out the samples in a rectangular
> grid
> + * roughly corresponding to sample locations.
> + */
> + brw_MUL(&func, X_f, X_f, brw_imm_f(key->x_scale));
> + brw_MUL(&func, Y_f, Y_f, brw_imm_f(key->y_scale));
> + /* Adjust coordinates so that integers represent pixel centers rather
> + * than pixel edges.
> + */
> + brw_ADD(&func, X_f, X_f, brw_imm_f(-0.5));
> + brw_ADD(&func, Y_f, Y_f, brw_imm_f(-0.5));
> +
> + /* Clamp the X, Y texture coordinates to properly handle the
> sampling of
> + * texels on texture edges.
> + */
> + brw_CMP(&func, vec16(brw_null_reg()), BRW_CONDITIONAL_L,
> + X_f, brw_imm_f(0.0));
> + brw_MOV(&func, X_f, brw_imm_f(0.0));
> + brw_set_predicate_control(&func, BRW_PREDICATE_NONE);
> +
> + brw_CMP(&func, vec16(brw_null_reg()), BRW_CONDITIONAL_GE,
> + X_f, sample_grid_x1);
> + brw_MOV(&func, X_f, sample_grid_x1);
> + brw_set_predicate_control(&func, BRW_PREDICATE_NONE);
> +
> + brw_CMP(&func, vec16(brw_null_reg()), BRW_CONDITIONAL_L,
> + Y_f, brw_imm_f(0.0));
> + brw_MOV(&func, Y_f, brw_imm_f(0.0));
> + brw_set_predicate_control(&func, BRW_PREDICATE_NONE);
> +
> + brw_CMP(&func, vec16(brw_null_reg()), BRW_CONDITIONAL_GE,
> + Y_f, sample_grid_y1);
> + brw_MOV(&func, Y_f, sample_grid_y1);
> + brw_set_predicate_control(&func, BRW_PREDICATE_NONE);
> +
> + /* Store the fractional parts to be used as bilinear interpolation
> + * coefficients.
> + */
> + brw_FRC(&func, x_frac, X_f);
> + brw_FRC(&func, y_frac, Y_f);
> +
> + /* Round the float coordinates down to nearest integer */
> + brw_RNDD(&func, Xp_f, X_f);
> + brw_RNDD(&func, Yp_f, Y_f);
> + brw_MUL(&func, X_f, Xp_f, brw_imm_f(1 / key->x_scale));
> + brw_MUL(&func, Y_f, Yp_f, brw_imm_f(1 / key->y_scale));
> + } else {
> + /* Round the float coordinates down to nearest integer by moving to
> + * UD registers.
> + */
> + brw_MOV(&func, Xp, X_f);
> + brw_MOV(&func, Yp, Y_f);
> + }
> SWAP_XY_AND_XPYP();
> brw_set_compression_control(&func, BRW_COMPRESSION_NONE);
> }
> @@ -1418,7 +1499,7 @@ inline int count_trailing_one_bits(unsigned value)
>
>
> void
> -brw_blorp_blit_program::manual_blend(unsigned num_samples)
> +brw_blorp_blit_program::manual_blend_average(unsigned num_samples)
> {
> if (key->tex_layout == INTEL_MSAA_LAYOUT_CMS)
> mcs_fetch();
> @@ -1523,6 +1604,143 @@ brw_blorp_blit_program::manual_blend(unsigned
> num_samples)
> brw_ENDIF(&func);
> }
>
> +void
> +brw_blorp_blit_program::manual_blend_bilinear(unsigned num_samples)
> +{
> + /* We do this computation by performing the following operations:
> + *
> + * In case of 4x, 8x MSAA:
> + * - Compute the pixel coordinates and sample numbers (a, b, c, d)
> + * which are later used for interpolation
> + * - linearly interpolate samples a and b in X
> + * - linearly interpolate samples c and d in X
> + * - linearly interpolate the results of last two operations in Y
> + *
> + * result = lrp(lrp(a + b) + lrp(c + d))
> + */
> + struct brw_reg Xp_f = retype(Xp, BRW_REGISTER_TYPE_F);
> + struct brw_reg Yp_f = retype(Yp, BRW_REGISTER_TYPE_F);
> + struct brw_reg t1_f = retype(t1, BRW_REGISTER_TYPE_F);
> + struct brw_reg t2_f = retype(t2, BRW_REGISTER_TYPE_F);
> +
> + for (unsigned i = 0; i < 4; ++i) {
> + assert(i < ARRAY_SIZE(texture_data));
> + s_is_zero = false;
> +
> + /* Compute pixel coordinates */
> + brw_ADD(&func, vec16(x_sample_coords), Xp_f,
> + brw_imm_f((float)(i & 0x1) * (1.0 / key->x_scale)));
> + brw_ADD(&func, vec16(y_sample_coords), Yp_f,
> + brw_imm_f((float)((i >> 1) & 0x1) * (1.0 / key->y_scale)));
> + brw_MOV(&func, vec16(X), x_sample_coords);
> + brw_MOV(&func, vec16(Y), y_sample_coords);
> +
> + /* The MCS value we fetch has to match up with the pixel that we're
> + * sampling from. Since we sample from different pixels in each
> + * iteration of this "for" loop, the call to mcs_fetch() should be
> + * here inside the loop after computing the pixel coordinates.
> + */
> + if (key->tex_layout == INTEL_MSAA_LAYOUT_CMS)
> + mcs_fetch();
> +
> + /* Compute sample index and map the sample index to a sample number.
> + * Sample index layout shows the numbering of slots in a rectangular
> + * grid of samples with in a pixel. Sample number layout shows the
> + * rectangular grid of samples roughly corresponding to the real
> sample
> + * locations with in a pixel.
> + * In case of 4x MSAA, layout of sample indices matches the layout of
> + * sample numbers:
> + * ---------
> + * | 0 | 1 |
> + * ---------
> + * | 2 | 3 |
> + * ---------
> + *
> + * In case of 8x MSAA the two layouts don't match.
> + * sample index layout : --------- sample number layout :
> ---------
> + * | 0 | 1 | | 5 |
> 2 |
> + * ---------
> ---------
> + * | 2 | 3 | | 4 |
> 6 |
> + * ---------
> ---------
> + * | 4 | 5 | | 0 |
> 3 |
> + * ---------
> ---------
> + * | 6 | 7 | | 7 |
> 1 |
> + * ---------
> ---------
> + */
> + brw_FRC(&func, vec16(t1_f), x_sample_coords);
> + brw_FRC(&func, vec16(t2_f), y_sample_coords);
> + brw_MUL(&func, vec16(t1_f), t1_f, brw_imm_f(key->x_scale));
> + brw_MUL(&func, vec16(t2_f), t2_f, brw_imm_f(key->x_scale *
> key->y_scale));
> + brw_ADD(&func, vec16(t1_f), t1_f, t2_f);
> + brw_MOV(&func, vec16(S), t1_f);
> +
> + if (num_samples == 8) {
> + /* Map the sample index to a sample number */
> + brw_CMP(&func, vec16(brw_null_reg()), BRW_CONDITIONAL_L,
> + S, brw_imm_d(4));
> + brw_IF(&func, BRW_EXECUTE_16);
> + {
> + brw_MOV(&func, vec16(t2), brw_imm_d(5));
> + brw_CMP(&func, vec16(brw_null_reg()), BRW_CONDITIONAL_EQ,
> + S, brw_imm_d(1));
> + brw_MOV(&func, vec16(t2), brw_imm_d(2));
> + brw_set_predicate_control(&func, BRW_PREDICATE_NONE);
> + brw_CMP(&func, vec16(brw_null_reg()), BRW_CONDITIONAL_EQ,
> + S, brw_imm_d(2));
> + brw_MOV(&func, vec16(t2), brw_imm_d(4));
> + brw_set_predicate_control(&func, BRW_PREDICATE_NONE);
> + brw_CMP(&func, vec16(brw_null_reg()), BRW_CONDITIONAL_EQ,
> + S, brw_imm_d(3));
> + brw_MOV(&func, vec16(t2), brw_imm_d(6));
> + brw_set_predicate_control(&func, BRW_PREDICATE_NONE);
> + }
> + brw_ELSE(&func);
> + {
> + brw_MOV(&func, vec16(t2), brw_imm_d(0));
> + brw_CMP(&func, vec16(brw_null_reg()), BRW_CONDITIONAL_EQ,
> + S, brw_imm_d(5));
> + brw_MOV(&func, vec16(t2), brw_imm_d(3));
> + brw_set_predicate_control(&func, BRW_PREDICATE_NONE);
> + brw_CMP(&func, vec16(brw_null_reg()), BRW_CONDITIONAL_EQ,
> + S, brw_imm_d(6));
> + brw_MOV(&func, vec16(t2), brw_imm_d(7));
> + brw_set_predicate_control(&func, BRW_PREDICATE_NONE);
> + brw_CMP(&func, vec16(brw_null_reg()), BRW_CONDITIONAL_EQ,
> + S, brw_imm_d(7));
> + brw_MOV(&func, vec16(t2), brw_imm_d(1));
> + brw_set_predicate_control(&func, BRW_PREDICATE_NONE);
> + }
> + brw_ENDIF(&func);
> + brw_MOV(&func, vec16(S), t2);
> + }
> + texel_fetch(texture_data[i]);
> + }
> +
> +#define SAMPLE(x, y) offset(texture_data[x], y)
> + brw_set_access_mode(&func, BRW_ALIGN_16);
> + for (int index = 3; index > 0; ) {
> + /* Since we're doing SIMD16, 4 color channels fits in to 8
> registers.
> + * Counter value of 8 in 'for' loop below is used to interpolate all
> + * the color components.
> + */
> + for (int k = 0; k < 8; ++k)
> + brw_LRP(&func,
> + vec8(SAMPLE(index - 1, k)),
> + offset(x_frac, k & 1),
> + SAMPLE(index, k),
> + SAMPLE(index - 1, k));
> + index -= 2;
> + }
> + for (int k = 0; k < 8; ++k)
> + brw_LRP(&func,
> + vec8(SAMPLE(0, k)),
> + offset(y_frac, k & 1),
> + vec8(SAMPLE(2, k)),
> + vec8(SAMPLE(0, k)));
> + brw_set_access_mode(&func, BRW_ALIGN_1);
> +#undef SAMPLE
> +}
> +
> /**
> * Emit code to look up a value in the texture using the SAMPLE message
> (which
> * does blending of MSAA surfaces).
> @@ -1535,7 +1753,8 @@ brw_blorp_blit_program::sample(struct brw_reg dst)
> SAMPLER_MESSAGE_ARG_V_FLOAT
> };
>
> - texture_lookup(dst, GEN5_SAMPLER_MESSAGE_SAMPLE, args,
> ARRAY_SIZE(args));
> + texture_lookup(dst, GEN5_SAMPLER_MESSAGE_SAMPLE, args,
> + ARRAY_SIZE(args));
> }
>
> /**
> @@ -1809,6 +2028,9 @@ brw_blorp_blit_params::brw_blorp_blit_params(struct
> brw_context *brw,
> GLfloat dst_x1, GLfloat
> dst_y1,
> bool mirror_x, bool mirror_y)
> {
> + struct gl_context *ctx = &brw->intel.ctx;
> + const struct gl_framebuffer *read_fb = ctx->ReadBuffer;
> +
> src.set(brw, src_mt, src_level, src_layer);
> dst.set(brw, dst_mt, dst_level, dst_layer);
>
> @@ -1872,6 +2094,17 @@ brw_blorp_blit_params::brw_blorp_blit_params(struct
> brw_context *brw,
> wm_prog_key.persample_msaa_dispatch = true;
> }
>
> + /* Scaled blitting or not. */
> + wm_prog_key.blit_scaled =
> + ((dst_x1 - dst_x0) == (src_x1 - src_x0) &&
> + (dst_y1 - dst_y0) == (src_y1 - src_y0)) ? false : true;
> +
> + /* Scaling factors used for bilinear filtering in multisample scaled
> + * blits.
> + */
> + wm_prog_key.x_scale = 2.0;
> + wm_prog_key.y_scale = src_mt->num_samples / 2.0;
> +
> /* The render path must be configured to use the same number of
> samples as
> * the destination buffer.
> */
> @@ -1915,6 +2148,9 @@ brw_blorp_blit_params::brw_blorp_blit_params(struct
> brw_context *brw,
> y0 = wm_push_consts.dst_y0 = dst_y0;
> x1 = wm_push_consts.dst_x1 = dst_x1;
> y1 = wm_push_consts.dst_y1 = dst_y1;
> + wm_push_consts.sample_grid_x1 = read_fb->Width * wm_prog_key.x_scale -
> 1.0;
> + wm_push_consts.sample_grid_y1 = read_fb->Height * wm_prog_key.y_scale
> - 1.0;
> +
> wm_push_consts.x_transform.setup(src_x0, src_x1, dst_x0, dst_x1,
> mirror_x);
> wm_push_consts.y_transform.setup(src_y0, src_y1, dst_y0, dst_y1,
> mirror_y);
>
> --
> 1.8.1.4
>
>
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