+++ /dev/null
-/*
- * 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 "compiler/glsl/ir.h"
-#include "compiler/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 *);
- ir_variable *temp(void *ctx, const glsl_type *type, const char *name);
-};
-
-/**
- * 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));
-}
-
-/**
- * Emit a temporary variable declaration
- */
-ir_variable *
-lower_texture_grad_visitor::temp(void *ctx, const glsl_type *type, const char *name)
-{
- ir_variable *var = new(ctx) ir_variable(type, name, ir_var_temporary);
- base_ir->insert_before(var);
- return var;
-}
-
-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:
- unreachable("Should not get here: invalid sampler dimensionality");
- }
-
- 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 cube maps or shadow samplers */
- if (ir->op != ir_txd ||
- (ir->sampler->type->sampler_dimensionality != GLSL_SAMPLER_DIM_CUBE &&
- !ir->shadow_comparator))
- return visit_continue;
-
- /* Lower textureGrad() with samplerCube* 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."
- */
- 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,
- swizzle_for_size(expr(ir_unop_i2f, txs), 2),
- 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));
-
- ir->op = ir_txl;
- if (ir->sampler->type->sampler_dimensionality == GLSL_SAMPLER_DIM_CUBE) {
- /* Cubemap texture lookups first generate a texture coordinate normalized
- * to [-1, 1] on the appropiate face. The appropiate face is determined
- * by which component has largest magnitude and its sign. The texture
- * coordinate is the quotient of the remaining texture coordinates against
- * that absolute value of the component of largest magnitude. This
- * division requires that the computing of the derivative of the texel
- * coordinate must use the quotient rule. The high level GLSL code is as
- * follows:
- *
- * Step 1: selection
- *
- * vec3 abs_p, Q, dQdx, dQdy;
- * abs_p = abs(ir->coordinate);
- * if (abs_p.x >= max(abs_p.y, abs_p.z)) {
- * Q = ir->coordinate.yzx;
- * dQdx = ir->lod_info.grad.dPdx.yzx;
- * dQdy = ir->lod_info.grad.dPdy.yzx;
- * }
- * if (abs_p.y >= max(abs_p.x, abs_p.z)) {
- * Q = ir->coordinate.xzy;
- * dQdx = ir->lod_info.grad.dPdx.xzy;
- * dQdy = ir->lod_info.grad.dPdy.xzy;
- * }
- * if (abs_p.z >= max(abs_p.x, abs_p.y)) {
- * Q = ir->coordinate;
- * dQdx = ir->lod_info.grad.dPdx;
- * dQdy = ir->lod_info.grad.dPdy;
- * }
- *
- * Step 2: use quotient rule to compute derivative. The normalized to
- * [-1, 1] texel coordinate is given by Q.xy / (sign(Q.z) * Q.z). We are
- * only concerned with the magnitudes of the derivatives whose values are
- * not affected by the sign. We drop the sign from the computation.
- *
- * vec2 dx, dy;
- * float recip;
- *
- * recip = 1.0 / Q.z;
- * dx = recip * ( dQdx.xy - Q.xy * (dQdx.z * recip) );
- * dy = recip * ( dQdy.xy - Q.xy * (dQdy.z * recip) );
- *
- * Step 3: compute LOD. At this point we have the derivatives of the
- * texture coordinates normalized to [-1,1]. We take the LOD to be
- * result = log2(max(sqrt(dot(dx, dx)), sqrt(dy, dy)) * 0.5 * L)
- * = -1.0 + log2(max(sqrt(dot(dx, dx)), sqrt(dy, dy)) * L)
- * = -1.0 + log2(sqrt(max(dot(dx, dx), dot(dy,dy))) * L)
- * = -1.0 + log2(sqrt(L * L * max(dot(dx, dx), dot(dy,dy))))
- * = -1.0 + 0.5 * log2(L * L * max(dot(dx, dx), dot(dy,dy)))
- * where L is the dimension of the cubemap. The code is:
- *
- * float M, result;
- * M = max(dot(dx, dx), dot(dy, dy));
- * L = textureSize(sampler, 0).x;
- * result = -1.0 + 0.5 * log2(L * L * M);
- */
-
-/* Helpers to make code more human readable. */
-#define EMIT(instr) base_ir->insert_before(instr)
-#define THEN(irif, instr) irif->then_instructions.push_tail(instr)
-#define CLONE(x) x->clone(mem_ctx, NULL)
-
- ir_variable *abs_p = temp(mem_ctx, glsl_type::vec3_type, "abs_p");
-
- EMIT(assign(abs_p, swizzle_for_size(abs(CLONE(ir->coordinate)), 3)));
-
- ir_variable *Q = temp(mem_ctx, glsl_type::vec3_type, "Q");
- ir_variable *dQdx = temp(mem_ctx, glsl_type::vec3_type, "dQdx");
- ir_variable *dQdy = temp(mem_ctx, glsl_type::vec3_type, "dQdy");
-
- /* unmodified dPdx, dPdy values */
- ir_rvalue *dPdx = ir->lod_info.grad.dPdx;
- ir_rvalue *dPdy = ir->lod_info.grad.dPdy;
-
- /* 1. compute selector */
-
- /* if (abs_p.x >= max(abs_p.y, abs_p.z)) ... */
- ir_if *branch_x =
- new(mem_ctx) ir_if(gequal(swizzle_x(abs_p),
- max2(swizzle_y(abs_p), swizzle_z(abs_p))));
-
- /* Q = p.yzx;
- * dQdx = dPdx.yzx;
- * dQdy = dPdy.yzx;
- */
- int yzx = MAKE_SWIZZLE4(SWIZZLE_Y, SWIZZLE_Z, SWIZZLE_X, 0);
- THEN(branch_x, assign(Q, swizzle(CLONE(ir->coordinate), yzx, 3)));
- THEN(branch_x, assign(dQdx, swizzle(CLONE(dPdx), yzx, 3)));
- THEN(branch_x, assign(dQdy, swizzle(CLONE(dPdy), yzx, 3)));
- EMIT(branch_x);
-
- /* if (abs_p.y >= max(abs_p.x, abs_p.z)) */
- ir_if *branch_y =
- new(mem_ctx) ir_if(gequal(swizzle_y(abs_p),
- max2(swizzle_x(abs_p), swizzle_z(abs_p))));
-
- /* Q = p.xzy;
- * dQdx = dPdx.xzy;
- * dQdy = dPdy.xzy;
- */
- int xzy = MAKE_SWIZZLE4(SWIZZLE_X, SWIZZLE_Z, SWIZZLE_Y, 0);
- THEN(branch_y, assign(Q, swizzle(CLONE(ir->coordinate), xzy, 3)));
- THEN(branch_y, assign(dQdx, swizzle(CLONE(dPdx), xzy, 3)));
- THEN(branch_y, assign(dQdy, swizzle(CLONE(dPdy), xzy, 3)));
- EMIT(branch_y);
-
- /* if (abs_p.z >= max(abs_p.x, abs_p.y)) */
- ir_if *branch_z =
- new(mem_ctx) ir_if(gequal(swizzle_z(abs_p),
- max2(swizzle_x(abs_p), swizzle_y(abs_p))));
-
- /* Q = p;
- * dQdx = dPdx;
- * dQdy = dPdy;
- */
- THEN(branch_z, assign(Q, swizzle_for_size(CLONE(ir->coordinate), 3)));
- THEN(branch_z, assign(dQdx, CLONE(dPdx)));
- THEN(branch_z, assign(dQdy, CLONE(dPdy)));
- EMIT(branch_z);
-
- /* 2. quotient rule */
- ir_variable *recip = temp(mem_ctx, glsl_type::float_type, "recip");
- EMIT(assign(recip, expr(ir_unop_rcp, swizzle_z(Q))));
-
- ir_variable *dx = temp(mem_ctx, glsl_type::vec2_type, "dx");
- ir_variable *dy = temp(mem_ctx, glsl_type::vec2_type, "dy");
-
- /* tmp = Q.xy * recip;
- * dx = recip * ( dQdx.xy - (tmp * dQdx.z) );
- * dy = recip * ( dQdy.xy - (tmp * dQdy.z) );
- */
- ir_variable *tmp = temp(mem_ctx, glsl_type::vec2_type, "tmp");
- EMIT(assign(tmp, mul(swizzle_xy(Q), recip)));
- EMIT(assign(dx, mul(recip, sub(swizzle_xy(dQdx),
- mul(tmp, swizzle_z(dQdx))))));
- EMIT(assign(dy, mul(recip, sub(swizzle_xy(dQdy),
- mul(tmp, swizzle_z(dQdy))))));
-
- /* M = max(dot(dx, dx), dot(dy, dy)); */
- ir_variable *M = temp(mem_ctx, glsl_type::float_type, "M");
- EMIT(assign(M, max2(dot(dx, dx), dot(dy, dy))));
-
- /* size has textureSize() of LOD 0 */
- ir_variable *L = temp(mem_ctx, glsl_type::float_type, "L");
- EMIT(assign(L, swizzle_x(size)));
-
- ir_variable *result = temp(mem_ctx, glsl_type::float_type, "result");
-
- /* result = -1.0 + 0.5 * log2(L * L * M); */
- EMIT(assign(result,
- add(new(mem_ctx)ir_constant(-1.0f),
- mul(new(mem_ctx)ir_constant(0.5f),
- expr(ir_unop_log2, mul(mul(L, L), M))))));
-
- /* 3. final assignment of parameters to textureLod call */
- ir->lod_info.lod = new (mem_ctx) ir_dereference_variable(result);
-
-#undef THEN
-#undef EMIT
-
- } else {
- /* 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->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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