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/*
* © Copyright 2018 Alyssa Rosenzweig
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
*/
#include <stdio.h>
#include "pan_blend_shaders.h"
#include "pan_util.h"
#include "midgard/midgard_compile.h"
#include "compiler/nir/nir_builder.h"
#include "nir/nir_lower_blend.h"
#include "panfrost/util/pan_lower_framebuffer.h"
#include "gallium/auxiliary/util/u_blend.h"
#include "util/u_memory.h"
/*
* Implements the command stream portion of programmatic blend shaders.
*
* On Midgard, common blending operations are accelerated by the fixed-function
* blending pipeline. Panfrost supports this fast path via the code in
* pan_blending.c. Nevertheless, uncommon blend modes (including some seemingly
* simple modes present in ES2) require "blend shaders", a special internal
* shader type used for programmable blending.
*
* Blend shaders operate during the normal blending time, but they bypass the
* fixed-function blending pipeline and instead go straight to the Midgard
* shader cores. The shaders themselves are essentially just fragment shaders,
* making heavy use of uint8 arithmetic to manipulate RGB values for the
* framebuffer.
*
* As is typical with Midgard, shader binaries must be accompanied by
* information about the first tag (ORed with the bottom nibble of address,
* like usual) and work registers. Work register count is assumed to be less
* than or equal to the coresponding fragment shader's work count. This
* suggests that blend shader invocation is tied to fragment shader
* execution.
*
* The shaders themselves use the standard ISA. The source pixel colour,
* including alpha, is preloaded into r0 as a vec4 of float32. The destination
* pixel colour must be loaded explicitly via load/store ops, possibly
* performing conversions in software. The blended colour must be stored with a
* fragment writeout in the correct framebuffer format, either in software or
* via conversion opcodes on the load/store pipe.
*
* Blend shaders hardcode constants. Naively, this requires recompilation each
* time the blend color changes, which is a performance risk. Accordingly, we
* 'cheat' a bit: instead of loading the constant, we compile a shader with a
* dummy constant, exporting the offset to the immediate in the shader binary,
* storing this generic binary and metadata in the CSO itself at CSO create
* time.
*
* We then hot patch in the color into this shader at attachment / color change
* time, allowing for CSO create to be the only expensive operation
* (compilation).
*/
static nir_lower_blend_options
nir_make_options(const struct pipe_blend_state *blend, unsigned i)
{
nir_lower_blend_options options = { 0 };
if (blend->logicop_enable) {
options.logicop_enable = true;
options.logicop_func = blend->logicop_func;
return options;
}
options.logicop_enable = false;
if (!blend->independent_blend_enable)
i = 0;
/* If blend is disabled, we just use replace mode */
nir_lower_blend_channel rgb = {
.func = BLEND_FUNC_ADD,
.src_factor = BLEND_FACTOR_ZERO,
.invert_src_factor = true,
.dst_factor = BLEND_FACTOR_ZERO,
.invert_dst_factor = false
};
nir_lower_blend_channel alpha = rgb;
if (blend->rt[i].blend_enable) {
rgb.func = util_blend_func_to_shader(blend->rt[i].rgb_func);
rgb.src_factor = util_blend_factor_to_shader(blend->rt[i].rgb_src_factor);
rgb.dst_factor = util_blend_factor_to_shader(blend->rt[i].rgb_dst_factor);
rgb.invert_src_factor = util_blend_factor_is_inverted(blend->rt[i].rgb_src_factor);
rgb.invert_dst_factor = util_blend_factor_is_inverted(blend->rt[i].rgb_dst_factor);
alpha.func = util_blend_func_to_shader(blend->rt[i].alpha_func);
alpha.src_factor = util_blend_factor_to_shader(blend->rt[i].alpha_src_factor);
alpha.dst_factor = util_blend_factor_to_shader(blend->rt[i].alpha_dst_factor);
alpha.invert_src_factor = util_blend_factor_is_inverted(blend->rt[i].alpha_src_factor);
alpha.invert_dst_factor = util_blend_factor_is_inverted(blend->rt[i].alpha_dst_factor);
}
options.rgb = rgb;
options.alpha = alpha;
options.colormask = blend->rt[i].colormask;
return options;
}
static nir_ssa_def *
nir_iclamp(nir_builder *b, nir_ssa_def *v, int32_t lo, int32_t hi)
{
return nir_imin(b, nir_imax(b, v, nir_imm_int(b, lo)), nir_imm_int(b, hi));
}
struct panfrost_blend_shader
panfrost_compile_blend_shader(
struct panfrost_context *ctx,
struct pipe_blend_state *cso,
enum pipe_format format,
unsigned rt)
{
struct panfrost_device *dev = pan_device(ctx->base.screen);
struct panfrost_blend_shader res;
res.ctx = ctx;
/* Build the shader */
nir_shader *shader = nir_shader_create(NULL, MESA_SHADER_FRAGMENT, &midgard_nir_options, NULL);
nir_function *fn = nir_function_create(shader, "main");
nir_function_impl *impl = nir_function_impl_create(fn);
const struct util_format_description *format_desc =
util_format_description(format);
nir_alu_type T = pan_unpacked_type_for_format(format_desc);
enum glsl_base_type g =
(T == nir_type_float16) ? GLSL_TYPE_FLOAT16 :
(T == nir_type_float32) ? GLSL_TYPE_FLOAT :
(T == nir_type_int8) ? GLSL_TYPE_INT8 :
(T == nir_type_int16) ? GLSL_TYPE_INT16 :
(T == nir_type_int32) ? GLSL_TYPE_INT :
(T == nir_type_uint8) ? GLSL_TYPE_UINT8 :
(T == nir_type_uint16) ? GLSL_TYPE_UINT16 :
(T == nir_type_uint32) ? GLSL_TYPE_UINT :
GLSL_TYPE_FLOAT;
/* Create the blend variables */
nir_variable *c_src = nir_variable_create(shader, nir_var_shader_in, glsl_vector_type(GLSL_TYPE_FLOAT, 4), "gl_Color");
nir_variable *c_src1 = nir_variable_create(shader, nir_var_shader_in, glsl_vector_type(GLSL_TYPE_FLOAT, 4), "gl_Color1");
nir_variable *c_out = nir_variable_create(shader, nir_var_shader_out, glsl_vector_type(g, 4), "gl_FragColor");
c_src->data.location = VARYING_SLOT_COL0;
c_src1->data.location = VARYING_SLOT_VAR0;
c_out->data.location = FRAG_RESULT_COLOR;
c_src1->data.driver_location = 1;
/* Setup nir_builder */
nir_builder _b;
nir_builder *b = &_b;
nir_builder_init(b, impl);
b->cursor = nir_before_block(nir_start_block(impl));
/* Setup inputs */
nir_ssa_def *s_src[] = {nir_load_var(b, c_src), nir_load_var(b, c_src1)};
for (int i = 0; i < ARRAY_SIZE(s_src); ++i) {
if (T == nir_type_float16)
s_src[i] = nir_f2f16(b, s_src[i]);
else if (T == nir_type_int16)
s_src[i] = nir_i2i16(b, nir_iclamp(b, s_src[i], -32768, 32767));
else if (T == nir_type_uint16)
s_src[i] = nir_u2u16(b, nir_umin(b, s_src[i], nir_imm_int(b, 65535)));
else if (T == nir_type_int8)
s_src[i] = nir_i2i8(b, nir_iclamp(b, s_src[i], -128, 127));
else if (T == nir_type_uint8)
s_src[i] = nir_u2u8(b, nir_umin(b, s_src[i], nir_imm_int(b, 255)));
}
/* Build a trivial blend shader */
nir_store_var(b, c_out, s_src[0], 0xFF);
nir_lower_blend_options options =
nir_make_options(cso, rt);
options.format = format;
options.src1 = s_src[1];
if (T == nir_type_float16)
options.half = true;
NIR_PASS_V(shader, nir_lower_blend, options);
/* Compile the built shader */
panfrost_program program = {
.rt_formats = {format}
};
midgard_compile_shader_nir(shader, &program, true, rt, dev->gpu_id, false);
/* Allow us to patch later */
res.patch_index = program.blend_patch_offset;
res.first_tag = program.first_tag;
res.size = program.compiled.size;
res.buffer = program.compiled.data;
res.work_count = program.work_register_count;
return res;
}
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