235 lines
11 KiB
C++
235 lines
11 KiB
C++
#include "core/rendering/lighting.hpp"
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#include <SDL3/SDL.h>
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#include <algorithm>
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#include <cmath>
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#include <cstddef>
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#include <numbers>
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#include <vector>
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#include "core/resources/resource_helper.hpp"
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#include "external/fkyaml_node.hpp"
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#include "utils/defaults.hpp"
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#include "utils/log.hpp"
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namespace Lighting {
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namespace {
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// Buffer de luminància compartit entre frames. Es redimensiona
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// només si canvia la mida del canvas (mai en un run normal: el
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// canvas del joc és 320×240 fix). El reusem perquè una `apply`
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// allotjant cada frame seria un cost evitable.
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auto luminanceBuffer() -> std::vector<std::uint8_t>& {
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static std::vector<std::uint8_t> buf_;
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return buf_;
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}
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// Configuració global, inicialitzada amb els defaults compilats.
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// loadConfig() la reemplaça si troba el fitxer.
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auto activeConfig() -> GradientConfig& {
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static GradientConfig cfg_{
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.inner_ratio = Defaults::Lighting::INNER_RATIO,
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.mid_ratio = Defaults::Lighting::MID_RATIO,
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.inner_intensity = Defaults::Lighting::INNER_INTENSITY,
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.mid_intensity = Defaults::Lighting::MID_INTENSITY,
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.outer_intensity = Defaults::Lighting::OUTER_INTENSITY,
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};
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return cfg_;
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}
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auto activeFlicker() -> FlickerConfig& {
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static FlickerConfig fc_{
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.wave_amplitude_px = Defaults::Lighting::FLICKER_WAVE_AMPLITUDE_PX,
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.wave_frequency_hz = Defaults::Lighting::FLICKER_WAVE_FREQUENCY_HZ,
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.noise_amplitude_px = Defaults::Lighting::FLICKER_NOISE_AMPLITUDE_PX,
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.noise_frequency_hz = Defaults::Lighting::FLICKER_NOISE_FREQUENCY_HZ,
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};
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return fc_;
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}
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// Modula el radi base d'un emissor amb la suma de dues sinusoides
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// (`wave` + `noise`) i una fase derivada de `seed`. La seed és un
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// identificador estable de l'emissor (no canvia amb la posició) —
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// així el patró no "deriva" quan l'emissor es mou. El factor
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// ~φ (golden ratio) dispersa les fases per a seeds consecutives.
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auto computeFlickerRadius(int base_radius, int seed, float t_s, const FlickerConfig& fc) -> int {
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constexpr float TWO_PI = 2.0F * std::numbers::pi_v<float>;
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constexpr float GOLDEN_FRACTION = 0.6180339F;
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const float PHASE = static_cast<float>(seed) * GOLDEN_FRACTION;
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const float W1 = std::sin((TWO_PI * fc.wave_frequency_hz * t_s) + PHASE);
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const float W2 = std::sin((TWO_PI * fc.noise_frequency_hz * t_s) + (PHASE * 2.7F));
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const float DELTA = (fc.wave_amplitude_px * W1) + (fc.noise_amplitude_px * W2);
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const int R = base_radius + static_cast<int>(std::lround(DELTA));
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return std::max(1, R);
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}
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// Quantitza un factor 0..1 a 0..255. `clamp` per defensar-nos de
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// YAMLs que entreguen valors fora de rang sense forçar la mà.
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auto toByte(float v) -> std::uint8_t {
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const float CLAMPED = std::clamp(v, 0.0F, 1.0F);
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return static_cast<std::uint8_t>(std::lround(CLAMPED * 255.0F));
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}
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void readField(const fkyaml::node& node, const char* key, float& dst) {
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if (node.contains(key)) { dst = node[key].get_value<float>(); }
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}
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// Pre-calcula els 3 quadrats de radi i les intensitats que farem
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// servir dins del bucle per píxel. Es resol una sola vegada per
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// emissor i s'evita arrastrar 6 paràmetres a `rasterizeEmitter`.
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struct EmitterRings {
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int radius_sq{0};
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int mid_sq{0};
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int inner_sq{0};
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std::uint8_t inner{0};
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std::uint8_t mid{0};
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std::uint8_t outer{0};
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};
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auto computeRings(int radius, const GradientConfig& cfg) -> EmitterRings {
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const auto R_F = static_cast<float>(radius);
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const float R_INNER = R_F * cfg.inner_ratio;
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const float R_MID = R_F * cfg.mid_ratio;
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return EmitterRings{
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.radius_sq = radius * radius,
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.mid_sq = static_cast<int>(R_MID * R_MID),
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.inner_sq = static_cast<int>(R_INNER * R_INNER),
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.inner = toByte(cfg.inner_intensity),
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.mid = toByte(cfg.mid_intensity),
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.outer = toByte(cfg.outer_intensity),
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};
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}
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// Itera la bounding box de l'emissor clipada al canvas i actualitza
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// la fila de luminància corresponent amb `max(actual, ring)`. Es
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// crida un cop per emissor, així extreure-la deixa `apply` simple.
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void rasterizeEmitter(const Emitter& e, const EmitterRings& rings, std::uint8_t* lum, int width, int height) {
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const int R = e.radius;
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const int CX = static_cast<int>(e.cx);
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const int CY = static_cast<int>(e.cy);
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const int X0 = std::max(0, CX - R);
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const int Y0 = std::max(0, CY - R);
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const int X1 = std::min(width - 1, CX + R);
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const int Y1 = std::min(height - 1, CY + R);
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for (int y = Y0; y <= Y1; ++y) {
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const int DY = y - CY;
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const int DY_SQ = DY * DY;
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if (DY_SQ > rings.radius_sq) { continue; }
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std::uint8_t* row = lum + (static_cast<std::ptrdiff_t>(y) * width);
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for (int x = X0; x <= X1; ++x) {
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const int DX = x - CX;
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const int DIST_SQ = (DX * DX) + DY_SQ;
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if (DIST_SQ > rings.radius_sq) { continue; }
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std::uint8_t intensity = rings.outer;
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if (DIST_SQ <= rings.inner_sq) {
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intensity = rings.inner;
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} else if (DIST_SQ <= rings.mid_sq) {
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intensity = rings.mid;
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}
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row[x] = std::max(intensity, row[x]);
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}
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}
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}
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// Pasada final: pixel = pixel * lum / 255 per canal. El canal alpha
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// es preserva (la resta del pipeline assumeix opacitat total al
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// canvas; veure Rendering::OPAQUE_ALPHA).
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void modulateCanvas(std::uint32_t* canvas, const std::uint8_t* lum, int width, int height) {
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for (int y = 0; y < height; ++y) {
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std::uint32_t* px = canvas + (static_cast<std::ptrdiff_t>(y) * width);
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const std::uint8_t* lrow = lum + (static_cast<std::ptrdiff_t>(y) * width);
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for (int x = 0; x < width; ++x) {
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const std::uint8_t L = lrow[x];
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if (L == 255) { continue; } // píxel intacte.
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const std::uint32_t SRC = px[x];
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const std::uint8_t SR = (SRC >> 16) & 0xFF;
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const std::uint8_t SG = (SRC >> 8) & 0xFF;
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const std::uint8_t SB = SRC & 0xFF;
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const auto R = static_cast<std::uint8_t>((SR * L) / 255);
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const auto G = static_cast<std::uint8_t>((SG * L) / 255);
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const auto B = static_cast<std::uint8_t>((SB * L) / 255);
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px[x] = (SRC & 0xFF000000U) |
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(static_cast<std::uint32_t>(R) << 16) |
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(static_cast<std::uint32_t>(G) << 8) |
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static_cast<std::uint32_t>(B);
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}
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}
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}
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} // namespace
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auto config() -> const GradientConfig& {
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return activeConfig();
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}
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void loadConfig(const std::string& yaml_path) {
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auto bytes = Resource::Helper::loadFile(yaml_path);
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if (bytes.empty()) {
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Log::warn("Lighting", "no s'ha pogut obrir {} — s'usaran els defaults compilats", yaml_path);
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return;
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}
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try {
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const auto* begin = reinterpret_cast<const char*>(bytes.data());
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const auto* end = begin + bytes.size();
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auto yaml = fkyaml::node::deserialize(begin, end);
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if (yaml.contains("gradient")) {
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const auto& g = yaml["gradient"];
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auto& cfg = activeConfig();
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readField(g, "inner_ratio", cfg.inner_ratio);
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readField(g, "mid_ratio", cfg.mid_ratio);
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readField(g, "inner_intensity", cfg.inner_intensity);
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readField(g, "mid_intensity", cfg.mid_intensity);
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readField(g, "outer_intensity", cfg.outer_intensity);
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}
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if (yaml.contains("flicker")) {
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const auto& f = yaml["flicker"];
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auto& fc = activeFlicker();
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readField(f, "wave_amplitude_px", fc.wave_amplitude_px);
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readField(f, "wave_frequency_hz", fc.wave_frequency_hz);
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readField(f, "noise_amplitude_px", fc.noise_amplitude_px);
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readField(f, "noise_frequency_hz", fc.noise_frequency_hz);
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}
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} catch (const std::exception& ex) {
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Log::warn("Lighting", "error parsejant {}: {} — s'usaran els defaults compilats", yaml_path, ex.what());
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}
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}
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void apply(std::uint32_t* canvas, int width, int height, float room_light, std::span<const Emitter> emitters) {
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if (canvas == nullptr || width <= 0 || height <= 0) { return; }
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// Atajo: si la sala està totalment il·luminada i no hi ha
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// emissors, la pasada seria un `pixel * 1.0` global — no cal
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// tocar res. És el camí curt habitual mentre no posem
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// `light_level` a les sales.
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const std::uint8_t ROOM = toByte(room_light);
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if (ROOM == 255 && emitters.empty()) { return; }
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auto& lum = luminanceBuffer();
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const std::size_t TOTAL = static_cast<std::size_t>(width) * static_cast<std::size_t>(height);
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if (lum.size() != TOTAL) { lum.resize(TOTAL); }
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std::ranges::fill(lum, ROOM);
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const auto& cfg = activeConfig();
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const auto& fc = activeFlicker();
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const float T_S = static_cast<float>(SDL_GetTicks()) / 1000.0F;
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for (const auto& e : emitters) {
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if (e.radius <= 0) { continue; }
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const int R_EFF = e.flicker
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? computeFlickerRadius(e.radius, e.seed, T_S, fc)
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: e.radius;
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const auto RINGS = computeRings(R_EFF, cfg);
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// El rasteritzador llegeix el radi de l'`Emitter` per al
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// càlcul de la bounding box, així que li passem un emissor
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// "patxat" amb el radi efectiu d'aquest frame. Mantenim el
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// valor original al `Emitter` del caller intacte.
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const Emitter EFF{.cx = e.cx, .cy = e.cy, .radius = R_EFF, .seed = e.seed, .flicker = e.flicker};
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rasterizeEmitter(EFF, RINGS, lum.data(), width, height);
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}
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modulateCanvas(canvas, lum.data(), width, height);
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}
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} // namespace Lighting
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