vibe4_shaders/source/backends/sdl_renderer.cpp

#include "sdl_renderer.h"
#include <SDL3/SDL_render.h>
#include <SDL3/SDL_error.h>
#include <iostream>
#include <cmath>

namespace vibe4 {

SDLRenderer::SDLRenderer() = default;

SDLRenderer::~SDLRenderer() {
    shutdown();
}

bool SDLRenderer::initialize(SDL_Window* window, int width, int height) {
    window_ = window;
    screen_width_ = width;
    screen_height_ = height;

    // Crear renderer SDL con aceleración por hardware
    renderer_ = SDL_CreateRenderer(window, nullptr);
    if (!renderer_) {
        std::cout << "¡No se pudo crear el renderer SDL! Error: " << SDL_GetError() << std::endl;
        return false;
    }

    // Configurar el renderer
    SDL_SetRenderLogicalPresentation(renderer_, width, height,
                                   SDL_LOGICAL_PRESENTATION_LETTERBOX);

    // Reservar espacio para el batch rendering
    batch_vertices_.reserve(50000 * 4); // 4 vértices por sprite
    batch_indices_.reserve(50000 * 6);  // 6 índices por sprite

    std::cout << "SDLRenderer inicializado exitosamente" << std::endl;
    return true;
}

void SDLRenderer::shutdown() {
    if (sprite_texture_) {
        SDL_DestroyTexture(sprite_texture_);
        sprite_texture_ = nullptr;
    }

    if (renderer_) {
        SDL_DestroyRenderer(renderer_);
        renderer_ = nullptr;
    }
}

bool SDLRenderer::beginFrame() {
    if (!renderer_) return false;

    // Limpiar el frame
    SDL_SetRenderDrawColor(renderer_, 0, 0, 0, 255);
    SDL_RenderClear(renderer_);

    // Limpiar batch de la frame anterior
    clearBatch();

    return true;
}

void SDLRenderer::endFrame() {
    // Renderizar todo el batch acumulado
    renderBatch();
}

void SDLRenderer::present() {
    if (renderer_) {
        SDL_RenderPresent(renderer_);
    }
}

void SDLRenderer::renderGradientBackground(
    float top_r, float top_g, float top_b,
    float bottom_r, float bottom_g, float bottom_b) {

    if (!renderer_) return;

    // Crear gradiente usando múltiples rectángulos
    const int gradient_steps = 32;
    float step_height = static_cast<float>(screen_height_) / gradient_steps;

    for (int i = 0; i < gradient_steps; ++i) {
        float t = static_cast<float>(i) / (gradient_steps - 1);

        // Interpolar colores
        float r = top_r + (bottom_r - top_r) * t;
        float g = top_g + (bottom_g - top_g) * t;
        float b = top_b + (bottom_b - top_b) * t;

        // Aplicar efectos CRT básicos si están habilitados
        if (crt_enabled_) {
            applyCRTEffectsToColor(r, g, b, 0, i * step_height);
        }

        SDL_SetRenderDrawColor(renderer_,
                             static_cast<Uint8>(r * 255),
                             static_cast<Uint8>(g * 255),
                             static_cast<Uint8>(b * 255), 255);

        SDL_FRect rect = {
            0, i * step_height,
            static_cast<float>(screen_width_), step_height + 1
        };
        SDL_RenderFillRect(renderer_, &rect);
    }
}

void SDLRenderer::renderSpriteBatch(
    const std::vector<SpriteData>& sprites,
    void* texture_data) {

    // Agregar todos los sprites al batch
    for (const auto& sprite : sprites) {
        addSpriteToBatch(sprite.x, sprite.y, sprite.w, sprite.h,
                        sprite.r, sprite.g, sprite.b);
    }
}

void SDLRenderer::addSpriteToBatch(float x, float y, float w, float h,
                                 float r, float g, float b) {
    // Aplicar efectos CRT a los colores si están habilitados
    float final_r = r, final_g = g, final_b = b;
    if (crt_enabled_) {
        applyCRTEffectsToColor(final_r, final_g, final_b, x, y);
    }

    // Normalizar colores (0-255 -> 0-1)
    final_r /= 255.0f;
    final_g /= 255.0f;
    final_b /= 255.0f;

    // Crear índice base para este sprite
    int base_index = static_cast<int>(batch_vertices_.size());

    // Añadir 4 vértices (quad) - SDL_Vertex usa RGB sin alpha
    SDL_Vertex v1, v2, v3, v4;

    v1.position = {x, y};
    v1.tex_coord = {0, 0};
    v1.color = {final_r, final_g, final_b};

    v2.position = {x + w, y};
    v2.tex_coord = {1, 0};
    v2.color = {final_r, final_g, final_b};

    v3.position = {x + w, y + h};
    v3.tex_coord = {1, 1};
    v3.color = {final_r, final_g, final_b};

    v4.position = {x, y + h};
    v4.tex_coord = {0, 1};
    v4.color = {final_r, final_g, final_b};

    batch_vertices_.push_back(v1);
    batch_vertices_.push_back(v2);
    batch_vertices_.push_back(v3);
    batch_vertices_.push_back(v4);

    // Añadir 6 índices (2 triángulos)
    batch_indices_.insert(batch_indices_.end(), {
        base_index, base_index + 1, base_index + 2,  // Primer triángulo
        base_index, base_index + 2, base_index + 3   // Segundo triángulo
    });
}

void SDLRenderer::clearBatch() {
    batch_vertices_.clear();
    batch_indices_.clear();
}

void SDLRenderer::renderBatch() {
    if (batch_vertices_.empty() || !renderer_) return;

    // Renderizar todo el batch en una sola llamada
    SDL_RenderGeometry(renderer_, nullptr,
                      batch_vertices_.data(), static_cast<int>(batch_vertices_.size()),
                      batch_indices_.data(), static_cast<int>(batch_indices_.size()));
}

void SDLRenderer::applyCRTEffectsToColor(float& r, float& g, float& b, float x, float y) {
    // Simulación básica de efectos CRT sin shaders reales

    // Scanlines básicos
    if (crt_params_.enable_scanlines) {
        float scanline = std::sin(y * 3.14159f * 2.0f / 2.0f); // 2 píxeles por scanline
        float scanline_factor = crt_params_.scanline_intensity +
                               (1.0f - crt_params_.scanline_intensity) * (scanline * 0.5f + 0.5f);
        r *= scanline_factor;
        g *= scanline_factor;
        b *= scanline_factor;
    }

    // Efecto de máscara básico (simulando píxeles RGB)
    if (crt_params_.mask_brightness < 1.0f) {
        int pixel_x = static_cast<int>(x) % 3;
        float mask_factor = crt_params_.mask_brightness;

        switch (pixel_x) {
            case 0: g *= mask_factor; b *= mask_factor; break; // Pixel rojo
            case 1: r *= mask_factor; b *= mask_factor; break; // Pixel verde
            case 2: r *= mask_factor; g *= mask_factor; break; // Pixel azul
        }
    }

    // Bloom básico (intensificar colores brillantes)
    if (crt_params_.enable_bloom && crt_params_.bloom_factor > 1.0f) {
        float brightness = (r + g + b) / 3.0f;
        if (brightness > 0.7f) {
            float bloom_strength = (brightness - 0.7f) * (crt_params_.bloom_factor - 1.0f);
            r += bloom_strength;
            g += bloom_strength;
            b += bloom_strength;
        }
    }

    // Clamp valores
    r = std::min(255.0f, std::max(0.0f, r));
    g = std::min(255.0f, std::max(0.0f, g));
    b = std::min(255.0f, std::max(0.0f, b));
}

void SDLRenderer::setCRTParams(const CRTParams& params) {
    crt_params_ = params;
}

void SDLRenderer::enableCRT(bool enable) {
    crt_enabled_ = enable;
}

void SDLRenderer::setVSync(bool enable) {
    vsync_enabled_ = enable;
    if (renderer_) {
        SDL_SetRenderVSync(renderer_, enable ? 1 : 0);
    }
}

void SDLRenderer::resize(int width, int height) {
    screen_width_ = width;
    screen_height_ = height;

    if (renderer_) {
        SDL_SetRenderLogicalPresentation(renderer_, width, height,
                                       SDL_LOGICAL_PRESENTATION_LETTERBOX);
    }
}

} // namespace vibe4