SiandClaude Opus 5.5
ce0207c41f
Film grain's field moves to effects/grain_field.hpp so both share it; Film grain renders exactly as before. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
56 lines
2.3 KiB
C++
56 lines
2.3 KiB
C++
#include "effects/grain.hpp"
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#include <algorithm>
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#include <cstdint>
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#include <vector>
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#include "effects/grain_field.hpp"
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#include "effects/source_fill.hpp"
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namespace effector {
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const std::vector<ParamSpec>& GrainEffect::params() const {
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static const std::vector<ParamSpec> specs = {
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ParamSpec::makeDouble("grain_amount", "Amount", 0.35, 0.0, 1.0,
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"How far a grain may push a pixel, as a fraction of full scale."),
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ParamSpec::makeInt("grain_size", "Grain size", 1, 1, 32,
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"Width in pixels of one grain; larger sizes look coarser."),
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ParamSpec::makeBool("grain_colour", "Coloured grain", false,
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"Draw the channels separately instead of one grey grain per pixel."),
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ParamSpec::makeBool("grain_midtones", "Weight towards midtones", true,
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"Fade the grain out in the shadows and highlights, as film does."),
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};
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return specs;
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}
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Image GrainEffect::render(const std::vector<Image>& sources, int width, int height, Rng& rng,
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const ParamValues& values) const {
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if (width < 1 || height < 1) throw EffectError("Canvas size must be at least 1x1 pixels.");
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const double amount = std::clamp(paramDouble(values, "grain_amount", 0.35), 0.0, 1.0);
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const int size = static_cast<int>(std::max(1L, paramInt(values, "grain_size", 1)));
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const bool colour = paramBool(values, "grain_colour", false);
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const bool midtones = paramBool(values, "grain_midtones", true);
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Image canvas(width, height);
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if (!sources.empty()) {
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// Drawn before any threading, so that a seed always gives the same image.
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const std::size_t index = rng.below(sources.size() - 1);
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const Image& src = sources[index];
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const int sx = static_cast<int>(rng.inRange(0, std::max(0, src.width() - width)));
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const int sy = static_cast<int>(rng.inRange(0, std::max(0, src.height() - height)));
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fillFromSource(canvas, src, sx, sy);
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}
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if (amount <= 0.0) return canvas;
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// The whole grain field is drawn serially from the rng, exactly like the
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// scanlines plan, and only the pixel arithmetic afterwards is parallel.
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const GrainField field = drawGrain(rng, width, height, size, colour);
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applyGrain(canvas, field, amount, midtones);
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return canvas;
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}
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} // namespace effector
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