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/*
* Copyright © 2012 Intel Corporation
*
* 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.
*/
/**
* \file brw_lower_texture_gradients.cpp
*/
#include "glsl/ir.h"
#include "glsl/ir_builder.h"
#include "program/prog_instruction.h"
#include "brw_context.h"
using namespace ir_builder;
class lower_texture_grad_visitor : public ir_hierarchical_visitor {
public:
lower_texture_grad_visitor(bool has_sample_d_c)
: has_sample_d_c(has_sample_d_c)
{
progress = false;
}
ir_visitor_status visit_leave(ir_texture *ir);
bool progress;
bool has_sample_d_c;
private:
void emit(ir_variable *, ir_rvalue *);
};
/**
* Emit a variable declaration and an assignment to initialize it.
*/
void
lower_texture_grad_visitor::emit(ir_variable *var, ir_rvalue *value)
{
base_ir->insert_before(var);
base_ir->insert_before(assign(var, value));
}
static const glsl_type *
txs_type(const glsl_type *type)
{
unsigned dims;
switch (type->sampler_dimensionality) {
case GLSL_SAMPLER_DIM_1D:
dims = 1;
break;
case GLSL_SAMPLER_DIM_2D:
case GLSL_SAMPLER_DIM_RECT:
case GLSL_SAMPLER_DIM_CUBE:
dims = 2;
break;
case GLSL_SAMPLER_DIM_3D:
dims = 3;
break;
default:
assert(!"Should not get here: invalid sampler dimensionality");
dims = 2;
}
if (type->sampler_array)
dims++;
return glsl_type::get_instance(GLSL_TYPE_INT, dims, 1);
}
ir_visitor_status
lower_texture_grad_visitor::visit_leave(ir_texture *ir)
{
/* Only lower textureGrad with shadow samplers */
if (ir->op != ir_txd || !ir->shadow_comparitor)
return visit_continue;
/* Lower textureGrad() with samplerCubeShadow even if we have the sample_d_c
* message. GLSL provides gradients for the 'r' coordinate. Unfortunately:
*
* From the Ivybridge PRM, Volume 4, Part 1, sample_d message description:
* "The r coordinate contains the faceid, and the r gradients are ignored
* by hardware."
*
* We likely need to do a similar treatment for samplerCube and
* samplerCubeArray, but we have insufficient testing for that at the moment.
*/
bool need_lowering = !has_sample_d_c ||
ir->sampler->type->sampler_dimensionality == GLSL_SAMPLER_DIM_CUBE;
if (!need_lowering)
return visit_continue;
void *mem_ctx = ralloc_parent(ir);
const glsl_type *grad_type = ir->lod_info.grad.dPdx->type;
/* Use textureSize() to get the width and height of LOD 0; swizzle away
* the depth/number of array slices.
*/
ir_texture *txs = new(mem_ctx) ir_texture(ir_txs);
txs->set_sampler(ir->sampler->clone(mem_ctx, NULL),
txs_type(ir->sampler->type));
txs->lod_info.lod = new(mem_ctx) ir_constant(0);
ir_variable *size =
new(mem_ctx) ir_variable(grad_type, "size", ir_var_temporary);
if (ir->sampler->type->sampler_dimensionality == GLSL_SAMPLER_DIM_CUBE) {
base_ir->insert_before(size);
base_ir->insert_before(assign(size, expr(ir_unop_i2f, txs), WRITEMASK_XY));
base_ir->insert_before(assign(size, new(mem_ctx) ir_constant(1.0f), WRITEMASK_Z));
} else {
emit(size, expr(ir_unop_i2f,
swizzle_for_size(txs, grad_type->vector_elements)));
}
/* Scale the gradients by width and height. Effectively, the incoming
* gradients are s'(x,y), t'(x,y), and r'(x,y) from equation 3.19 in the
* GL 3.0 spec; we want u'(x,y), which is w_t * s'(x,y).
*/
ir_variable *dPdx =
new(mem_ctx) ir_variable(grad_type, "dPdx", ir_var_temporary);
emit(dPdx, mul(size, ir->lod_info.grad.dPdx));
ir_variable *dPdy =
new(mem_ctx) ir_variable(grad_type, "dPdy", ir_var_temporary);
emit(dPdy, mul(size, ir->lod_info.grad.dPdy));
/* Calculate rho from equation 3.20 of the GL 3.0 specification. */
ir_rvalue *rho;
if (dPdx->type->is_scalar()) {
rho = expr(ir_binop_max, expr(ir_unop_abs, dPdx),
expr(ir_unop_abs, dPdy));
} else {
rho = expr(ir_binop_max, expr(ir_unop_sqrt, dot(dPdx, dPdx)),
expr(ir_unop_sqrt, dot(dPdy, dPdy)));
}
/* lambda_base = log2(rho). We're ignoring GL state biases for now. */
ir->op = ir_txl;
ir->lod_info.lod = expr(ir_unop_log2, rho);
progress = true;
return visit_continue;
}
extern "C" {
bool
brw_lower_texture_gradients(struct brw_context *brw,
struct exec_list *instructions)
{
bool has_sample_d_c = brw->gen >= 8 || brw->is_haswell;
lower_texture_grad_visitor v(has_sample_d_c);
visit_list_elements(&v, instructions);
return v.progress;
}
}
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