On Thu, Jul 12, 2012 at 10:43 AM, Paul Berry <stereotype...@gmail.com> wrote:
> When downsampling an integer-format buffer on Gen7, we need to use the
> "avg" instruction rather than the "add" instruction, to ensure that we
> don't overflow the range of 32-bit integers. Also, we need to use the
> proper register type (BRW_REGISTER_TYPE_D or BRW_REGISTER_TYPE_UD) for
> intermediate color data and for writing to the render target.
>
> Note: this patch causes blorp to use the proper register type for all
> operations (downsampling, upsampling, and ordinary blits). Strictly
> speaking, this is only necessary for downsampling, because the other
> operations exclusively use MOV instructions on the color data. But
> it's simpler to use the proper register type in all cases.
> ---
> src/mesa/drivers/dri/i965/brw_blorp.h | 5 ++
> src/mesa/drivers/dri/i965/brw_blorp_blit.cpp | 61
> +++++++++++++++++++++-----
> 2 files changed, 55 insertions(+), 11 deletions(-)
>
> diff --git a/src/mesa/drivers/dri/i965/brw_blorp.h
> b/src/mesa/drivers/dri/i965/brw_blorp.h
> index 053eef7..9af492d 100644
> --- a/src/mesa/drivers/dri/i965/brw_blorp.h
> +++ b/src/mesa/drivers/dri/i965/brw_blorp.h
> @@ -223,6 +223,11 @@ struct brw_blorp_blit_prog_key
> /* Actual MSAA layout used by the destination image. */
> intel_msaa_layout dst_layout;
>
> + /* Type of the data to be read from the texture (one of
> + * BRW_REGISTER_TYPE_{UD,D,F}).
> + */
> + unsigned texture_data_type;
> +
> /* True if the source image is W tiled. If true, the surface state for
> the
> * source image must be configured as Y tiled, and tex_samples must be 0.
> */
> diff --git a/src/mesa/drivers/dri/i965/brw_blorp_blit.cpp
> b/src/mesa/drivers/dri/i965/brw_blorp_blit.cpp
> index 74ae52d..32fd48e 100644
> --- a/src/mesa/drivers/dri/i965/brw_blorp_blit.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_blorp_blit.cpp
> @@ -696,7 +696,9 @@ brw_blorp_blit_program::alloc_regs()
> alloc_push_const_regs(reg);
> reg += BRW_BLORP_NUM_PUSH_CONST_REGS;
> for (unsigned i = 0; i < ARRAY_SIZE(texture_data); ++i) {
> - this->texture_data[i] = vec16(brw_vec8_grf(reg, 0)); reg += 8;
> + this->texture_data[i] =
> + retype(vec16(brw_vec8_grf(reg, 0)), key->texture_data_type);
> + reg += 8;
> }
> this->mcs_data =
> retype(brw_vec8_grf(reg, 0), BRW_REGISTER_TYPE_UD); reg += 8;
> @@ -1117,7 +1119,16 @@ brw_blorp_blit_program::manual_blend()
> * operations we do is equal to the number of trailing 1 bits in i. This
> * works provided the total number of samples is a power of two, which it
> * always is for i965.
> + *
> + * For integer formats, we replace the add operations with average
> + * operations and skip the final division.
> */
> + typedef struct brw_instruction *(*brw_op2_ptr)(struct brw_compile *,
> + struct brw_reg,
> + struct brw_reg,
> + struct brw_reg);
> + brw_op2_ptr combine_op =
> + key->texture_data_type == BRW_REGISTER_TYPE_F ? brw_ADD : brw_AVG;
> unsigned stack_depth = 0;
> for (int i = 0; i < num_samples; ++i) {
> assert(stack_depth == _mesa_bitcount(i)); /* Loop invariant */
> @@ -1139,9 +1150,9 @@ brw_blorp_blit_program::manual_blend()
>
> /* TODO: should use a smaller loop bound for non_RGBA formats */
> for (int k = 0; k < 4; ++k) {
> - brw_ADD(&func, offset(texture_data[stack_depth - 1], 2*k),
> - offset(vec8(texture_data[stack_depth - 1]), 2*k),
> - offset(vec8(texture_data[stack_depth]), 2*k));
> + combine_op(&func, offset(texture_data[stack_depth - 1], 2*k),
> + offset(vec8(texture_data[stack_depth - 1]), 2*k),
> + offset(vec8(texture_data[stack_depth]), 2*k));
> }
> }
> }
> @@ -1149,12 +1160,14 @@ brw_blorp_blit_program::manual_blend()
> /* We should have just 1 sample on the stack now. */
> assert(stack_depth == 1);
>
> - /* Scale the result down by a factor of num_samples */
> - /* TODO: should use a smaller loop bound for non-RGBA formats */
> - for (int j = 0; j < 4; ++j) {
> - brw_MUL(&func, offset(texture_data[0], 2*j),
> - offset(vec8(texture_data[0]), 2*j),
> - brw_imm_f(1.0/num_samples));
> + if (key->texture_data_type == BRW_REGISTER_TYPE_F) {
> + /* Scale the result down by a factor of num_samples */
> + /* TODO: should use a smaller loop bound for non-RGBA formats */
> + for (int j = 0; j < 4; ++j) {
> + brw_MUL(&func, offset(texture_data[0], 2*j),
> + offset(vec8(texture_data[0]), 2*j),
> + brw_imm_f(1.0/num_samples));
> + }
> }
> }
>
> @@ -1319,7 +1332,8 @@ brw_blorp_blit_program::texture_lookup(struct brw_reg
> dst,
> void
> brw_blorp_blit_program::render_target_write()
> {
> - struct brw_reg mrf_rt_write = vec16(brw_message_reg(base_mrf));
> + struct brw_reg mrf_rt_write =
> + retype(vec16(brw_message_reg(base_mrf)), key->texture_data_type);
> int mrf_offset = 0;
>
> /* If we may have killed pixels, then we need to send R0 and R1 in a
> header
> @@ -1427,6 +1441,31 @@ brw_blorp_blit_params::brw_blorp_blit_params(struct
> brw_context *brw,
> use_wm_prog = true;
> memset(&wm_prog_key, 0, sizeof(wm_prog_key));
>
> + /* texture_data_type indicates the register type that should be used to
> + * manipulate texture data.
> + */
> + switch (_mesa_get_format_datatype(src_mt->format)) {
> + case GL_UNSIGNED_NORMALIZED:
> + case GL_SIGNED_NORMALIZED:
> + case GL_FLOAT:
> + wm_prog_key.texture_data_type = BRW_REGISTER_TYPE_F;
> + break;
> + case GL_UNSIGNED_INT:
> + if (src_mt->format == MESA_FORMAT_S8) {
> + /* We process stencil as though it's an unsigned normalized color */
> + wm_prog_key.texture_data_type = BRW_REGISTER_TYPE_F;
> + } else {
> + wm_prog_key.texture_data_type = BRW_REGISTER_TYPE_UD;
> + }
> + break;
> + case GL_INT:
> + wm_prog_key.texture_data_type = BRW_REGISTER_TYPE_D;
> + break;
> + default:
> + assert(!"Unrecognized blorp format");
> + break;
> + }
> +
> if (brw->intel.gen > 6) {
> /* Gen7's texturing hardware only supports the IMS layout with the
> * ld2dms instruction (which blorp doesn't use). So if the source is
> --
> 1.7.7.6
>
looks good to me:
Reviewed-by: Anuj Phogat <anuj.pho...@gmail.com>
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