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ba82476ade
This adds the Integer Math node to shader nodes. It's the same node that can already be used in Geometry Nodes and the Compositor. While creating the regression test, I noticed that the integer math implementation was a bit broken: * The integer modulo (`%`) operator on the GPU is undefined for negative divisors (the added regression test showed that the behavior is not consistent across platforms). * Use integer power function instead of using float implementation with casts. The MaterialX implementation is omitted for now. I didn't look into it in detail yet but for the Boolean Math node (#162798) it seemed like some more work is needed there to support this type. Pull Request: https://projects.blender.org/blender/blender/pulls/163805
96 lines
2.7 KiB
Text
96 lines
2.7 KiB
Text
/* SPDX-FileCopyrightText: 2026 Blender Authors
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*
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* SPDX-License-Identifier: Apache-2.0 */
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#include "stdcycles.h"
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int integer_math_divide_floor(int a, int b)
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{
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int d = a / b;
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int r = a % b;
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return (r != 0) ? (d - int((a < 0) != (b < 0))) : d;
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}
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int integer_math_gcd(int a_in, int b_in)
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{
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int a = abs(a_in);
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int b = abs(b_in);
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while (b != 0) {
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int t = b;
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b = a % b;
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a = t;
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}
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return a;
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}
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int integer_math_power(int base_in, int exponent_in)
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{
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int base = base_in;
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int exponent = exponent_in;
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if (exponent < 0) {
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if (base == 1 || base == -1) {
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return (base < 0 && (exponent & 1) != 0) ? -1 : 1;
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}
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return 0;
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}
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int result = 1;
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while (exponent != 0) {
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if ((exponent & 1) != 0) {
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result *= base;
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}
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exponent = exponent >> 1;
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base = base * base;
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}
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return result;
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}
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shader node_integer_math(
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string math_type = "add", int Value1 = 0, int Value2 = 0, int Value3 = 0, output int Value = 0)
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{
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if (math_type == "add")
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Value = Value1 + Value2;
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else if (math_type == "subtract")
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Value = Value1 - Value2;
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else if (math_type == "multiply")
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Value = Value1 * Value2;
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else if (math_type == "divide")
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Value = (Value2 != 0) ? (Value1 / Value2) : 0;
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else if (math_type == "multiply_add")
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Value = Value1 * Value2 + Value3;
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else if (math_type == "power")
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Value = integer_math_power(Value1, Value2);
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else if (math_type == "floored_modulo")
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Value = (Value2 != 0) ? (((Value1 % Value2) + Value2) % Value2) : 0;
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else if (math_type == "absolute")
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Value = abs(Value1);
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else if (math_type == "minimum")
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Value = min(Value1, Value2);
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else if (math_type == "maximum")
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Value = max(Value1, Value2);
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else if (math_type == "gcd")
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Value = integer_math_gcd(Value1, Value2);
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else if (math_type == "lcm") {
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int gcd = integer_math_gcd(Value1, Value2);
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Value = (gcd != 0) ? abs(Value1 / gcd * Value2) : 0;
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}
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else if (math_type == "negate")
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Value = -Value1;
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else if (math_type == "sign")
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Value = int(0 < Value1) - int(Value1 < 0);
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else if (math_type == "divide_floor")
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Value = (Value2 != 0) ? integer_math_divide_floor(Value1, Value2) : 0;
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else if (math_type == "divide_ceil")
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Value = (Value2 != 0) ? -integer_math_divide_floor(Value1, -Value2) : 0;
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else if (math_type == "divide_round") {
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int abs_b = abs(Value2);
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int sign_b = int(0 < Value2) - int(Value2 < 0);
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if (Value1 >= 0)
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Value = ((abs_b != 0) ? ((2 * Value1 + abs_b) / (2 * abs_b)) : 0) * sign_b;
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else
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Value = -((abs_b != 0) ? ((2 * -Value1 + abs_b) / (2 * abs_b)) : 0) * sign_b;
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}
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else if (math_type == "modulo")
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Value = (Value2 != 0) ? (Value1 % Value2) : 0;
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else
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Value = 0;
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}
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