blender/intern/cycles/render/constant_fold.cpp
Alexander Gavrilov 40eedd5df9 Cycles: implement partial constant folding for exponentiation.
This is also an important mathematical operation that can be folded
if it is known that one argument is a certain constant. For colors
the operation is provided as a Gamma node.

The SVM Gamma node needs a small fix to make it follow the 0 ^ 0 == 1
rule, same as the Power node, or the Gamma node itself in OSL mode.

Reviewers: #cycles

Differential Revision: https://developer.blender.org/D2263
2016-10-01 14:37:03 +03:00

385 lines
9.1 KiB
C++

/*
* Copyright 2011-2013 Blender Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "constant_fold.h"
#include "graph.h"
#include "util_foreach.h"
#include "util_logging.h"
CCL_NAMESPACE_BEGIN
ConstantFolder::ConstantFolder(ShaderGraph *graph, ShaderNode *node, ShaderOutput *output)
: graph(graph), node(node), output(output)
{
}
bool ConstantFolder::all_inputs_constant() const
{
foreach(ShaderInput *input, node->inputs) {
if(input->link) {
return false;
}
}
return true;
}
void ConstantFolder::make_constant(float value) const
{
VLOG(1) << "Folding " << node->name << "::" << output->name() << " to constant (" << value << ").";
foreach(ShaderInput *sock, output->links) {
sock->set(value);
}
graph->disconnect(output);
}
void ConstantFolder::make_constant(float3 value) const
{
VLOG(1) << "Folding " << node->name << "::" << output->name() << " to constant " << value << ".";
foreach(ShaderInput *sock, output->links) {
sock->set(value);
}
graph->disconnect(output);
}
void ConstantFolder::make_constant_clamp(float value, bool clamp) const
{
make_constant(clamp ? saturate(value) : value);
}
void ConstantFolder::make_constant_clamp(float3 value, bool clamp) const
{
if(clamp) {
value.x = saturate(value.x);
value.y = saturate(value.y);
value.z = saturate(value.z);
}
make_constant(value);
}
void ConstantFolder::make_zero() const
{
if(output->type() == SocketType::FLOAT) {
make_constant(0.0f);
}
else if(SocketType::is_float3(output->type())) {
make_constant(make_float3(0.0f, 0.0f, 0.0f));
}
else {
assert(0);
}
}
void ConstantFolder::make_one() const
{
if(output->type() == SocketType::FLOAT) {
make_constant(1.0f);
}
else if(SocketType::is_float3(output->type())) {
make_constant(make_float3(1.0f, 1.0f, 1.0f));
}
else {
assert(0);
}
}
void ConstantFolder::bypass(ShaderOutput *new_output) const
{
assert(new_output);
VLOG(1) << "Folding " << node->name << "::" << output->name() << " to socket " << new_output->parent->name << "::" << new_output->name() << ".";
/* Remove all outgoing links from socket and connect them to new_output instead.
* The graph->relink method affects node inputs, so it's not safe to use in constant
* folding if the node has multiple outputs and will thus be folded multiple times. */
vector<ShaderInput*> outputs = output->links;
graph->disconnect(output);
foreach(ShaderInput *sock, outputs) {
graph->connect(new_output, sock);
}
}
void ConstantFolder::discard() const
{
assert(output->type() == SocketType::CLOSURE);
VLOG(1) << "Discarding closure " << node->name << ".";
graph->disconnect(output);
}
void ConstantFolder::bypass_or_discard(ShaderInput *input) const
{
assert(input->type() == SocketType::CLOSURE);
if(input->link) {
bypass(input->link);
}
else {
discard();
}
}
bool ConstantFolder::try_bypass_or_make_constant(ShaderInput *input, bool clamp) const
{
if(input->type() != output->type()) {
return false;
}
else if(!input->link) {
if(input->type() == SocketType::FLOAT) {
make_constant_clamp(node->get_float(input->socket_type), clamp);
return true;
}
else if(SocketType::is_float3(input->type())) {
make_constant_clamp(node->get_float3(input->socket_type), clamp);
return true;
}
}
else if(!clamp) {
bypass(input->link);
return true;
}
return false;
}
bool ConstantFolder::is_zero(ShaderInput *input) const
{
if(!input->link) {
if(input->type() == SocketType::FLOAT) {
return node->get_float(input->socket_type) == 0.0f;
}
else if(SocketType::is_float3(input->type())) {
return node->get_float3(input->socket_type) ==
make_float3(0.0f, 0.0f, 0.0f);
}
}
return false;
}
bool ConstantFolder::is_one(ShaderInput *input) const
{
if(!input->link) {
if(input->type() == SocketType::FLOAT) {
return node->get_float(input->socket_type) == 1.0f;
}
else if(SocketType::is_float3(input->type())) {
return node->get_float3(input->socket_type) ==
make_float3(1.0f, 1.0f, 1.0f);
}
}
return false;
}
/* Specific nodes */
void ConstantFolder::fold_mix(NodeMix type, bool clamp) const
{
ShaderInput *fac_in = node->input("Fac");
ShaderInput *color1_in = node->input("Color1");
ShaderInput *color2_in = node->input("Color2");
float fac = saturate(node->get_float(fac_in->socket_type));
bool fac_is_zero = !fac_in->link && fac == 0.0f;
bool fac_is_one = !fac_in->link && fac == 1.0f;
/* remove no-op node when factor is 0.0 */
if(fac_is_zero) {
/* note that some of the modes will clamp out of bounds values even without use_clamp */
if(!(type == NODE_MIX_LIGHT || type == NODE_MIX_DODGE || type == NODE_MIX_BURN)) {
if(try_bypass_or_make_constant(color1_in, clamp)) {
return;
}
}
}
switch(type) {
case NODE_MIX_BLEND:
/* remove useless mix colors nodes */
if(color1_in->link && color2_in->link) {
if(color1_in->link == color2_in->link) {
try_bypass_or_make_constant(color1_in, clamp);
break;
}
}
else if(!color1_in->link && !color2_in->link) {
float3 color1 = node->get_float3(color1_in->socket_type);
float3 color2 = node->get_float3(color2_in->socket_type);
if(color1 == color2) {
try_bypass_or_make_constant(color1_in, clamp);
break;
}
}
/* remove no-op mix color node when factor is 1.0 */
if(fac_is_one) {
try_bypass_or_make_constant(color2_in, clamp);
break;
}
break;
case NODE_MIX_ADD:
/* 0 + X (fac 1) == X */
if(is_zero(color1_in) && fac_is_one) {
try_bypass_or_make_constant(color2_in, clamp);
}
/* X + 0 (fac ?) == X */
else if(is_zero(color2_in)) {
try_bypass_or_make_constant(color1_in, clamp);
}
break;
case NODE_MIX_SUB:
/* X - 0 (fac ?) == X */
if(is_zero(color2_in)) {
try_bypass_or_make_constant(color1_in, clamp);
}
/* X - X (fac 1) == 0 */
else if(color1_in->link && color1_in->link == color2_in->link && fac_is_one) {
make_zero();
}
break;
case NODE_MIX_MUL:
/* X * 1 (fac ?) == X, 1 * X (fac 1) == X */
if(is_one(color1_in) && fac_is_one) {
try_bypass_or_make_constant(color2_in, clamp);
}
else if(is_one(color2_in)) {
try_bypass_or_make_constant(color1_in, clamp);
}
/* 0 * ? (fac ?) == 0, ? * 0 (fac 1) == 0 */
else if(is_zero(color1_in)) {
make_zero();
}
else if(is_zero(color2_in) && fac_is_one) {
make_zero();
}
break;
case NODE_MIX_DIV:
/* X / 1 (fac ?) == X */
if(is_one(color2_in)) {
try_bypass_or_make_constant(color1_in, clamp);
}
/* 0 / ? (fac ?) == 0 */
else if(is_zero(color1_in)) {
make_zero();
}
break;
default:
break;
}
}
void ConstantFolder::fold_math(NodeMath type, bool clamp) const
{
ShaderInput *value1_in = node->input("Value1");
ShaderInput *value2_in = node->input("Value2");
switch(type) {
case NODE_MATH_ADD:
/* X + 0 == 0 + X == X */
if(is_zero(value1_in)) {
try_bypass_or_make_constant(value2_in, clamp);
}
else if(is_zero(value2_in)) {
try_bypass_or_make_constant(value1_in, clamp);
}
break;
case NODE_MATH_SUBTRACT:
/* X - 0 == X */
if(is_zero(value2_in)) {
try_bypass_or_make_constant(value1_in, clamp);
}
break;
case NODE_MATH_MULTIPLY:
/* X * 1 == 1 * X == X */
if(is_one(value1_in)) {
try_bypass_or_make_constant(value2_in, clamp);
}
else if(is_one(value2_in)) {
try_bypass_or_make_constant(value1_in, clamp);
}
/* X * 0 == 0 * X == 0 */
else if(is_zero(value1_in) || is_zero(value2_in)) {
make_zero();
}
break;
case NODE_MATH_DIVIDE:
/* X / 1 == X */
if(is_one(value2_in)) {
try_bypass_or_make_constant(value1_in, clamp);
}
/* 0 / X == 0 */
else if(is_zero(value1_in)) {
make_zero();
}
break;
case NODE_MATH_POWER:
/* 1 ^ X == X ^ 0 == 1 */
if(is_one(value1_in) || is_zero(value2_in)) {
make_one();
}
/* X ^ 1 == X */
else if(is_one(value2_in)) {
try_bypass_or_make_constant(value1_in, clamp);
}
default:
break;
}
}
void ConstantFolder::fold_vector_math(NodeVectorMath type) const
{
ShaderInput *vector1_in = node->input("Vector1");
ShaderInput *vector2_in = node->input("Vector2");
switch(type) {
case NODE_VECTOR_MATH_ADD:
/* X + 0 == 0 + X == X */
if(is_zero(vector1_in)) {
try_bypass_or_make_constant(vector2_in);
}
else if(is_zero(vector2_in)) {
try_bypass_or_make_constant(vector1_in);
}
break;
case NODE_VECTOR_MATH_SUBTRACT:
/* X - 0 == X */
if(is_zero(vector2_in)) {
try_bypass_or_make_constant(vector1_in);
}
break;
case NODE_VECTOR_MATH_DOT_PRODUCT:
case NODE_VECTOR_MATH_CROSS_PRODUCT:
/* X * 0 == 0 * X == 0 */
if(is_zero(vector1_in) || is_zero(vector2_in)) {
make_zero();
}
break;
default:
break;
}
}
CCL_NAMESPACE_END