blender/intern/cycles/kernel/svm/gradient.h
Brecht Van Lommel 7ee94c067c Refactor: Cycles: Replace uint4 SVM packing with structs
* Pass socket links and values in structs for each SVM node.
* Always pass default values along with stack offset, encoded in
  SVMInputFloat and SVMInputFloat3. For slightly more efficient
  memory access the stack offset is encoded in a NaN float.
* Simplify SVMCompiler API to use input_float, input_float3
  input_link and output functions, instead of manual stack
  assignment.

This was a leftover from early CUDA versions and old GPUs, where data
was stored in textures as there was no L1/L2 cache for global memory.

Assisted-by: Claude Opus 4.6
Co-authored-by: Sergey Sharybin <sergey@blender.org>
Pull Request: https://projects.blender.org/blender/blender/pulls/156612
2026-04-09 11:24:32 +02:00

75 lines
1.7 KiB
C

/* SPDX-FileCopyrightText: 2011-2022 Blender Foundation
*
* SPDX-License-Identifier: Apache-2.0 */
#pragma once
#include "kernel/svm/node_types.h"
#include "kernel/svm/util.h"
CCL_NAMESPACE_BEGIN
/* Gradient */
ccl_device float svm_gradient(const float3 p, NodeGradientType type)
{
float x;
float y;
float z;
x = p.x;
y = p.y;
z = p.z;
if (type == NODE_BLEND_LINEAR) {
return x;
}
if (type == NODE_BLEND_QUADRATIC) {
const float r = fmaxf(x, 0.0f);
return r * r;
}
if (type == NODE_BLEND_EASING) {
const float r = fminf(fmaxf(x, 0.0f), 1.0f);
const float t = r * r;
return (3.0f * t - 2.0f * t * r);
}
if (type == NODE_BLEND_DIAGONAL) {
return (x + y) * 0.5f;
}
if (type == NODE_BLEND_RADIAL) {
return atan2f(y, x) / M_2PI_F + 0.5f;
}
/* Bias a little bit for the case where p is a unit length vector,
* to get exactly zero instead of a small random value depending
* on float precision. */
const float r = fmaxf(0.999999f - sqrtf(x * x + y * y + z * z), 0.0f);
if (type == NODE_BLEND_QUADRATIC_SPHERE) {
return r * r;
}
if (type == NODE_BLEND_SPHERICAL) {
return r;
}
return 0.0f;
}
ccl_device_noinline void svm_node_tex_gradient(
ccl_private float *ccl_restrict stack, const ccl_global SVMNodeTexGradient &ccl_restrict node)
{
const float3 co = stack_load_float3(stack, node.co);
float f = svm_gradient(co, node.gradient_type);
f = saturatef(f);
if (stack_valid(node.fac_offset)) {
stack_store_float(stack, node.fac_offset, f);
}
if (stack_valid(node.color_offset)) {
stack_store_float3(stack, node.color_offset, make_float3(f, f, f));
}
}
CCL_NAMESPACE_END