feat(shaders): sistema de shaders runtime amb presets externs

- Afegir GpuShaderPreset i ShaderManager per carregar shaders des de data/shaders/
- Implementar preset ntsc-md-rainbows (2 passos: encode + decode MAME NTSC)
- Render loop multi-pass per shaders externs (targets intermedis R16G16B16A16_FLOAT)
- cycleShader(): cicla OFF→PostFX natius→shaders externs amb tecla X
- --shader <nom> per arrancar directament amb un preset extern
- CMake auto-descubreix i compila data/shaders/**/*.vert/.frag → .spv
- HUD F1 mostra 'Shader: <nom>' quan hi ha shader extern actiu

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
This commit is contained in:
2026-03-20 13:37:22 +01:00
parent e3f29c864b
commit f272bab296
19 changed files with 1004 additions and 23 deletions

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#include "gpu_shader_preset.hpp"
#include "gpu_texture.hpp"
#include <SDL3/SDL_log.h>
#include <fstream>
#include <sstream>
#include <algorithm>
#include <memory>
// ============================================================================
// Helpers
// ============================================================================
static std::vector<uint8_t> readFile(const std::string& path) {
std::ifstream f(path, std::ios::binary | std::ios::ate);
if (!f) return {};
std::streamsize sz = f.tellg();
f.seekg(0, std::ios::beg);
std::vector<uint8_t> buf(static_cast<size_t>(sz));
if (!f.read(reinterpret_cast<char*>(buf.data()), sz)) return {};
return buf;
}
static std::string trim(const std::string& s) {
size_t a = s.find_first_not_of(" \t\r\n");
if (a == std::string::npos) return {};
size_t b = s.find_last_not_of(" \t\r\n");
return s.substr(a, b - a + 1);
}
// ============================================================================
// GpuShaderPreset
// ============================================================================
bool GpuShaderPreset::parseIni(const std::string& ini_path) {
std::ifstream f(ini_path);
if (!f) {
SDL_Log("GpuShaderPreset: cannot open %s", ini_path.c_str());
return false;
}
int num_passes = 0;
std::string line;
while (std::getline(f, line)) {
// Strip comments
auto comment = line.find(';');
if (comment != std::string::npos) line = line.substr(0, comment);
line = trim(line);
if (line.empty()) continue;
auto eq = line.find('=');
if (eq == std::string::npos) continue;
std::string key = trim(line.substr(0, eq));
std::string value = trim(line.substr(eq + 1));
if (key.empty() || value.empty()) continue;
if (key == "name") {
name_ = value;
} else if (key == "passes") {
num_passes = std::stoi(value);
} else {
// Try to parse as float parameter
try {
params_[key] = std::stof(value);
} catch (...) {
// Non-float values stored separately (pass0_vert etc.)
}
}
}
if (num_passes <= 0) {
SDL_Log("GpuShaderPreset: no passes defined in %s", ini_path.c_str());
return false;
}
// Second pass: read per-pass file names
f.clear();
f.seekg(0, std::ios::beg);
descs_.resize(num_passes);
while (std::getline(f, line)) {
auto comment = line.find(';');
if (comment != std::string::npos) line = line.substr(0, comment);
line = trim(line);
if (line.empty()) continue;
auto eq = line.find('=');
if (eq == std::string::npos) continue;
std::string key = trim(line.substr(0, eq));
std::string value = trim(line.substr(eq + 1));
for (int i = 0; i < num_passes; ++i) {
std::string vi = "pass" + std::to_string(i) + "_vert";
std::string fi = "pass" + std::to_string(i) + "_frag";
if (key == vi) descs_[i].vert_name = value;
if (key == fi) descs_[i].frag_name = value;
}
}
// Validate
for (int i = 0; i < num_passes; ++i) {
if (descs_[i].vert_name.empty() || descs_[i].frag_name.empty()) {
SDL_Log("GpuShaderPreset: pass %d missing vert or frag in %s", i, ini_path.c_str());
return false;
}
}
return true;
}
SDL_GPUGraphicsPipeline* GpuShaderPreset::buildPassPipeline(SDL_GPUDevice* device,
const std::string& vert_spv_path,
const std::string& frag_spv_path,
SDL_GPUTextureFormat target_fmt) {
auto vert_spv = readFile(vert_spv_path);
auto frag_spv = readFile(frag_spv_path);
if (vert_spv.empty()) {
SDL_Log("GpuShaderPreset: cannot read %s", vert_spv_path.c_str());
return nullptr;
}
if (frag_spv.empty()) {
SDL_Log("GpuShaderPreset: cannot read %s", frag_spv_path.c_str());
return nullptr;
}
SDL_GPUShaderCreateInfo vert_info = {};
vert_info.code = vert_spv.data();
vert_info.code_size = vert_spv.size();
vert_info.entrypoint = "main";
vert_info.format = SDL_GPU_SHADERFORMAT_SPIRV;
vert_info.stage = SDL_GPU_SHADERSTAGE_VERTEX;
vert_info.num_samplers = 0;
vert_info.num_uniform_buffers = 0;
SDL_GPUShaderCreateInfo frag_info = {};
frag_info.code = frag_spv.data();
frag_info.code_size = frag_spv.size();
frag_info.entrypoint = "main";
frag_info.format = SDL_GPU_SHADERFORMAT_SPIRV;
frag_info.stage = SDL_GPU_SHADERSTAGE_FRAGMENT;
frag_info.num_samplers = 1;
frag_info.num_uniform_buffers = 1;
SDL_GPUShader* vert_shader = SDL_CreateGPUShader(device, &vert_info);
SDL_GPUShader* frag_shader = SDL_CreateGPUShader(device, &frag_info);
if (!vert_shader || !frag_shader) {
SDL_Log("GpuShaderPreset: shader creation failed for %s / %s: %s",
vert_spv_path.c_str(), frag_spv_path.c_str(), SDL_GetError());
if (vert_shader) SDL_ReleaseGPUShader(device, vert_shader);
if (frag_shader) SDL_ReleaseGPUShader(device, frag_shader);
return nullptr;
}
// Full-screen triangle: no vertex input, no blend
SDL_GPUColorTargetBlendState no_blend = {};
no_blend.enable_blend = false;
no_blend.enable_color_write_mask = false;
SDL_GPUColorTargetDescription ct_desc = {};
ct_desc.format = target_fmt;
ct_desc.blend_state = no_blend;
SDL_GPUVertexInputState no_input = {};
SDL_GPUGraphicsPipelineCreateInfo pipe_info = {};
pipe_info.vertex_shader = vert_shader;
pipe_info.fragment_shader = frag_shader;
pipe_info.vertex_input_state = no_input;
pipe_info.primitive_type = SDL_GPU_PRIMITIVETYPE_TRIANGLELIST;
pipe_info.target_info.num_color_targets = 1;
pipe_info.target_info.color_target_descriptions = &ct_desc;
SDL_GPUGraphicsPipeline* pipeline = SDL_CreateGPUGraphicsPipeline(device, &pipe_info);
SDL_ReleaseGPUShader(device, vert_shader);
SDL_ReleaseGPUShader(device, frag_shader);
if (!pipeline)
SDL_Log("GpuShaderPreset: pipeline creation failed: %s", SDL_GetError());
return pipeline;
}
bool GpuShaderPreset::load(SDL_GPUDevice* device,
const std::string& dir,
SDL_GPUTextureFormat swapchain_fmt,
int w, int h) {
dir_ = dir;
swapchain_fmt_ = swapchain_fmt;
// Parse ini
if (!parseIni(dir + "/preset.ini"))
return false;
int n = static_cast<int>(descs_.size());
passes_.resize(n);
// Intermediate render target format (signed float to handle NTSC signal range)
SDL_GPUTextureFormat inter_fmt = SDL_GPU_TEXTUREFORMAT_R16G16B16A16_FLOAT;
for (int i = 0; i < n; ++i) {
bool is_last = (i == n - 1);
SDL_GPUTextureFormat target_fmt = is_last ? swapchain_fmt : inter_fmt;
std::string vert_spv = dir + "/" + descs_[i].vert_name + ".spv";
std::string frag_spv = dir + "/" + descs_[i].frag_name + ".spv";
passes_[i].pipeline = buildPassPipeline(device, vert_spv, frag_spv, target_fmt);
if (!passes_[i].pipeline) {
SDL_Log("GpuShaderPreset: failed to build pipeline for pass %d", i);
return false;
}
if (!is_last) {
// Create intermediate render target
auto tex = std::make_unique<GpuTexture>();
if (!tex->createRenderTarget(device, w, h, inter_fmt)) {
SDL_Log("GpuShaderPreset: failed to create intermediate target for pass %d", i);
return false;
}
passes_[i].target = tex.get();
targets_.push_back(std::move(tex));
}
// Last pass: target = null (caller binds swapchain)
}
SDL_Log("GpuShaderPreset: loaded '%s' (%d passes)", name_.c_str(), n);
return true;
}
void GpuShaderPreset::recreateTargets(SDL_GPUDevice* device, int w, int h) {
SDL_GPUTextureFormat inter_fmt = SDL_GPU_TEXTUREFORMAT_R16G16B16A16_FLOAT;
for (auto& tex : targets_) {
tex->destroy(device);
tex->createRenderTarget(device, w, h, inter_fmt);
}
}
void GpuShaderPreset::destroy(SDL_GPUDevice* device) {
for (auto& pass : passes_) {
if (pass.pipeline) {
SDL_ReleaseGPUGraphicsPipeline(device, pass.pipeline);
pass.pipeline = nullptr;
}
}
for (auto& tex : targets_) {
if (tex) tex->destroy(device);
}
targets_.clear();
passes_.clear();
descs_.clear();
params_.clear();
}
float GpuShaderPreset::param(const std::string& key, float default_val) const {
auto it = params_.find(key);
return (it != params_.end()) ? it->second : default_val;
}

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#pragma once
#include <SDL3/SDL_gpu.h>
#include <memory>
#include <string>
#include <unordered_map>
#include <vector>
#include "gpu_texture.hpp"
// ============================================================================
// NTSCParams — uniform buffer for NTSC shader passes (set=3, binding=0)
// Matches the layout in pass0_encode.frag and pass1_decode.frag.
// Pushed via SDL_PushGPUFragmentUniformData(cmd, 0, &ntsc, sizeof(NTSCParams)).
// ============================================================================
struct NTSCParams {
float source_width;
float source_height;
float a_value;
float b_value;
float cc_value;
float scan_time;
float notch_width;
float y_freq;
float i_freq;
float q_freq;
float _pad[2];
};
static_assert(sizeof(NTSCParams) == 48, "NTSCParams must be 48 bytes");
// ============================================================================
// ShaderPass — one render pass in a multi-pass shader preset
// ============================================================================
struct ShaderPass {
SDL_GPUGraphicsPipeline* pipeline = nullptr;
GpuTexture* target = nullptr; // null = swapchain (last pass)
};
// ============================================================================
// GpuShaderPreset — loads and owns a multi-pass shader preset from disk.
//
// Directory layout:
// <dir>/preset.ini — descriptor
// <dir>/pass0_xxx.vert — GLSL 4.50 vertex shader source
// <dir>/pass0_xxx.frag — GLSL 4.50 fragment shader source
// <dir>/pass0_xxx.vert.spv — compiled SPIRV (by CMake/glslc at build time)
// <dir>/pass0_xxx.frag.spv — compiled SPIRV
// ...
// ============================================================================
class GpuShaderPreset {
public:
// Load preset from directory. swapchain_fmt is the target format for the
// last pass; intermediate passes use R16G16B16A16_FLOAT.
bool load(SDL_GPUDevice* device,
const std::string& dir,
SDL_GPUTextureFormat swapchain_fmt,
int w, int h);
void destroy(SDL_GPUDevice* device);
// Recreate intermediate render targets on resolution change.
void recreateTargets(SDL_GPUDevice* device, int w, int h);
int passCount() const { return static_cast<int>(passes_.size()); }
ShaderPass& pass(int i) { return passes_[i]; }
const std::string& name() const { return name_; }
// Read a float parameter parsed from preset.ini (returns default_val if absent).
float param(const std::string& key, float default_val) const;
private:
std::vector<ShaderPass> passes_;
std::vector<std::unique_ptr<GpuTexture>> targets_; // intermediate render targets
std::string name_;
std::string dir_;
std::unordered_map<std::string, float> params_;
SDL_GPUTextureFormat swapchain_fmt_ = SDL_GPU_TEXTUREFORMAT_R8G8B8A8_UNORM;
// Entries read from preset.ini for each pass
struct PassDesc {
std::string vert_name; // e.g. "pass0_encode.vert"
std::string frag_name; // e.g. "pass0_encode.frag"
};
std::vector<PassDesc> descs_;
bool parseIni(const std::string& ini_path);
// Build a full-screen-triangle pipeline from two on-disk SPV files.
SDL_GPUGraphicsPipeline* buildPassPipeline(SDL_GPUDevice* device,
const std::string& vert_spv_path,
const std::string& frag_spv_path,
SDL_GPUTextureFormat target_fmt);
};

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#include "shader_manager.hpp"
#include <SDL3/SDL_log.h>
#include <filesystem>
#include <algorithm>
namespace fs = std::filesystem;
void ShaderManager::scan(const std::string& root_dir) {
root_dir_ = root_dir;
names_.clear();
dirs_.clear();
std::error_code ec;
for (const auto& entry : fs::directory_iterator(root_dir, ec)) {
if (!entry.is_directory()) continue;
fs::path ini = entry.path() / "preset.ini";
if (!fs::exists(ini)) continue;
std::string preset_name = entry.path().filename().string();
names_.push_back(preset_name);
dirs_[preset_name] = entry.path().string();
}
if (ec) {
SDL_Log("ShaderManager: scan error on %s: %s", root_dir.c_str(), ec.message().c_str());
}
std::sort(names_.begin(), names_.end());
SDL_Log("ShaderManager: found %d preset(s) in %s", (int)names_.size(), root_dir.c_str());
}
GpuShaderPreset* ShaderManager::load(SDL_GPUDevice* device,
const std::string& name,
SDL_GPUTextureFormat swapchain_fmt,
int w, int h) {
auto it = loaded_.find(name);
if (it != loaded_.end()) return it->second.get();
auto dir_it = dirs_.find(name);
if (dir_it == dirs_.end()) {
SDL_Log("ShaderManager: preset '%s' not found", name.c_str());
return nullptr;
}
auto preset = std::make_unique<GpuShaderPreset>();
if (!preset->load(device, dir_it->second, swapchain_fmt, w, h)) {
SDL_Log("ShaderManager: failed to load preset '%s'", name.c_str());
return nullptr;
}
GpuShaderPreset* raw = preset.get();
loaded_[name] = std::move(preset);
return raw;
}
void ShaderManager::onResize(SDL_GPUDevice* device, SDL_GPUTextureFormat /*swapchain_fmt*/, int w, int h) {
for (auto& [name, preset] : loaded_) {
preset->recreateTargets(device, w, h);
}
}
void ShaderManager::destroyAll(SDL_GPUDevice* device) {
for (auto& [name, preset] : loaded_) {
preset->destroy(device);
}
loaded_.clear();
}

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#pragma once
#include <SDL3/SDL_gpu.h>
#include <map>
#include <memory>
#include <string>
#include <vector>
#include "gpu_shader_preset.hpp"
// ============================================================================
// ShaderManager — discovers and manages runtime shader presets under
// a root directory (e.g., data/shaders/).
//
// Each subdirectory with a preset.ini is treated as a shader preset.
// ============================================================================
class ShaderManager {
public:
// Scan root_dir for preset subdirectories (each must contain preset.ini).
void scan(const std::string& root_dir);
// Available preset names (e.g. {"ntsc-md-rainbows"}).
const std::vector<std::string>& names() const { return names_; }
// Load and return a preset (cached). Returns null on failure.
GpuShaderPreset* load(SDL_GPUDevice* device,
const std::string& name,
SDL_GPUTextureFormat swapchain_fmt,
int w, int h);
// Recreate intermediate render targets on resolution change.
void onResize(SDL_GPUDevice* device, SDL_GPUTextureFormat swapchain_fmt, int w, int h);
void destroyAll(SDL_GPUDevice* device);
private:
std::string root_dir_;
std::vector<std::string> names_;
std::map<std::string, std::string> dirs_;
std::map<std::string, std::unique_ptr<GpuShaderPreset>> loaded_;
};