Add shapes to grammar

.gitignore

@@ -1,5 +1,6 @@
-/fart
 *.bmp
 *.png
+/.propane*
 /.rscons*
 /build/
+/fart

Rsconscript

@@ -3,10 +3,25 @@ configure do
   check_cfg package: "libpng"
 end
 
-env do |env|
-  env["CCFLAGS"] += %w[-Wall -O2 -std=c++23]
-  env["CPPPATH"] += %w[src]
+class Propane < Builder
+  def run(options)
+    @sources += ["propane"] unless @sources.include?("propane")
+    if @command
+      finalize_command
+    else
+      command = %W[./propane -w --log #{@target}.log #{@sources.first} #{@target}]
+      standard_command("Propane <target>#{@target}<reset>", command, options)
+    end
+  end
+end
 
-  sources = glob("src/**/*.cpp")
+env do |env|
+  env.add_builder(Propane)
+  env["CCFLAGS"] += %w[-Wall -O2 -std=c++23 -include fart/common.h]
+  env["CPPPATH"] += %W[src #{env.build_root}/src]
+
+  env.Propane("^/src/fart/propane.cpp", "src/fart.propane")
+  env.barrier
+  sources = glob("src/**/*.cpp") + ["#{env.build_root}/src/fart/propane.cpp"]
   env.Program("fart", sources)
 end

propane

@@ -0,0 +1,45 @@
+#!/usr/bin/env ruby
+
+# The MIT License (MIT)
+#
+# Copyright (c) 2010-2026 Josh Holtrop
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+
+
+script = File.join(File.dirname(__FILE__), ".propane-5.2.0-58c963344c9bc893689cbae5e4c49b1b.rb")
+unless File.exist?(script)
+  if File.read(__FILE__, mode: "rb") =~ /^#==>(.*)/
+    require "zlib"
+    require "base64"
+    encoded_compressed = $1
+    unescaped_compressed = Base64.decode64(encoded_compressed)
+    inflated = Zlib::Inflate.inflate(unescaped_compressed)
+    File.open(script, "wb") do |fh|
+      fh.write(inflated)
+    end
+  else
+    raise "Could not decompress."
+  end
+end
+load script
+if __FILE__ == $0
+  Propane::CLI.new.run(ARGV)
+end
+#==>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 truncated

src/fart.propane

@@ -0,0 +1,134 @@
+tree;
+tree_prefix P;
+ptype double;
+
+<<header
+/* User terminate codes. */
+#define PARSER_TERMINATE_NUMBER_RANGE 1u
+>>
+
+<<
+#include <charconv>
+
+/* Store the numeric value of the matched text in *out. Returns false if the
+ * value cannot be represented. */
+static bool parse_number(uint8_t const * match_text, size_t match_length, double * out)
+{
+    const char * first = (const char *)match_text;
+    const char * last = first + match_length;
+    std::from_chars_result r = std::from_chars(first, last, *out);
+    return (r.ec == std::errc()) && (r.ptr == last);
+}
+>>
+
+drop /\s+/;
+drop /#.*/;
+
+token background;
+token box;
+token camera;
+token color;
+token comma /,/;
+token cyl;
+token gt />/;
+token height;
+token intersect;
+token lcurly /\{/;
+token lt /</;
+token material;
+token options;
+token plane;
+token position;
+token rcurly /\}/;
+token rotate;
+token scale;
+token size;
+token sphere;
+token subtract;
+token target;
+token translate;
+token union;
+token up;
+token width;
+
+token uint /\d+/ <<
+    if (!parse_number(match_text, match_length, &$$))
+    {
+        $terminate(PARSER_TERMINATE_NUMBER_RANGE);
+    }
+>>
+token number /-?\d+(\.\d+)?/ <<
+    if (!parse_number(match_text, match_length, &$$))
+    {
+        $terminate(PARSER_TERMINATE_NUMBER_RANGE);
+    }
+>>
+
+start Scene;
+
+Background -> background Vector;
+
+Color -> color Vector;
+
+Height -> height uint;
+
+Number -> uint;
+Number -> number;
+
+Options -> options lcurly OptionsItems rcurly;
+
+OptionsItems -> ;
+OptionsItems -> OptionsItem OptionsItems;
+
+OptionsItem -> Background;
+OptionsItem -> Height;
+OptionsItem -> Width;
+
+Position -> position Vector;
+
+Rotate -> rotate Number comma Vector;
+Rotate -> rotate Number comma Vector lcurly SceneItems rcurly;
+
+Scale -> scale Number;
+Scale -> scale Number lcurly SceneItems rcurly;
+Scale -> scale Vector;
+Scale -> scale Vector lcurly SceneItems rcurly;
+
+SceneItemBlock -> SceneItemName lcurly SceneItems rcurly;
+
+Scene -> Options? SceneItems;
+
+SceneItems -> ;
+SceneItems -> SceneItem SceneItems;
+
+SceneItem -> Color;
+SceneItem -> Position;
+SceneItem -> Rotate;
+SceneItem -> Scale;
+SceneItem -> SceneItemBlock;
+SceneItem -> Size;
+SceneItem -> Target;
+SceneItem -> Translate;
+SceneItem -> Up;
+
+SceneItemName -> box;
+SceneItemName -> camera;
+SceneItemName -> cyl;
+SceneItemName -> material;
+SceneItemName -> plane;
+SceneItemName -> sphere;
+
+Size -> size Number;
+Size -> size Vector;
+
+Target -> target Vector;
+
+Translate -> translate Vector;
+Translate -> translate Vector lcurly SceneItems rcurly;
+
+Up -> up Vector;
+
+Vector -> lt Number comma Number comma Number gt;
+Vector -> lt Number comma Number comma Number comma Number gt;
+
+Width -> width uint;

src/fart/Cli.cpp

@@ -1,5 +1,226 @@
 #include <fart/Cli.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+#include <stdint.h>
 
-Cli::Cli()
+#define FLAGS \
+    FLAG(height, "h", true) \
+    FLAG(height_l, "height", true) \
+    FLAG(help, "help", false) \
+    FLAG(output, "o", true) \
+    FLAG(output_l, "output", true) \
+    FLAG(threads, "t", true) \
+    FLAG(threads_l, "threads", true) \
+    FLAG(version, "version", false) \
+    FLAG(width, "w", true) \
+    FLAG(width_l, "width", true) \
+
+#define FLAG(name, flag, arg) flag_##name,
+typedef enum
 {
+    FLAGS
+    flag__count
+} flag_id_t;
+#undef FLAG
+
+#define FLAG(name, flag, arg) static const char flag_##name##_str[] = flag;
+FLAGS
+#undef FLAG
+
+typedef struct
+{
+    const char * flag;
+    size_t flag_length;
+    bool arg;
+} flag_def_t;
+
+#define FLAG(name, flag, arg) { \
+    flag_##name##_str, \
+    sizeof(flag_##name##_str) - 1u, \
+    arg},
+static const flag_def_t flag_defs[] = {
+    FLAGS
+};
+#undef FLAG
+
+int Cli::run(int argc, char * argv[])
+{
+    for (size_t i = 1; i < argc; i++)
+    {
+        size_t dashes = 0u;
+        if (strncmp(argv[i], "--", 2) == 0)
+        {
+            dashes = 2u;
+        }
+        else if (strncmp(argv[i], "-", 1) == 0)
+        {
+            dashes = 1u;
+        }
+        if (dashes > 0u)
+        {
+            const char * flag = &argv[i][dashes];
+            size_t flag_idx;
+            for (flag_idx = 0u; flag_idx < flag__count; flag_idx++)
+            {
+                size_t flag_length = flag_defs[flag_idx].flag_length;
+                size_t flag_dashes = flag_length == 1u ? 1u : 2u;
+                if (flag_dashes != dashes)
+                {
+                    continue;
+                }
+                if (strncmp(flag, flag_defs[flag_idx].flag, flag_length) != 0)
+                {
+                    continue;
+                }
+                if (dashes == 2 && flag[flag_length] != '\0' && flag[flag_length] != '=')
+                {
+                    continue;
+                }
+                bool arg = flag_defs[flag_idx].arg;
+                const char * arg_value = nullptr;
+                if (arg)
+                {
+                    if (flag[flag_length] == '\0')
+                    {
+                        if (i >= (argc - 1))
+                        {
+                            fprintf(stderr, "Error: option %s requires an argument\n", flag_defs[flag_idx].flag);
+                            return 2;
+                        }
+                        i++;
+                        arg_value = argv[i];
+                    }
+                    else if (dashes == 1u)
+                    {
+                        arg_value = &flag[flag_length];
+                    }
+                    else if (flag[flag_length + 1] != '\0')
+                    {
+                        arg_value = &flag[flag_length + 1];
+                    }
+                    else
+                    {
+                        fprintf(stderr, "Error: option %s requires an argument\n", flag_defs[flag_idx].flag);
+                        return 2;
+                    }
+                }
+                else if (dashes == 2u && flag[flag_length] == '=')
+                {
+                    fprintf(stderr, "Error: option %s does not take an argument\n", flag_defs[flag_idx].flag);
+                    return 2;
+                }
+                else
+                {
+                    /* TODO: support combining short flags, e.g. -cofoo */
+                }
+                int r = handle_option(flag_idx, arg_value);
+                if (r != 0)
+                {
+                    return r;
+                }
+                break;
+            }
+            if (flag_idx == flag__count)
+            {
+                fprintf(stderr, "Unknown flag: %s\n", flag);
+                return 2;
+            }
+        }
+        else
+        {
+            if (!this->input_file.empty())
+            {
+                fprintf(stderr, "Extraneous argument: %s\n", argv[i]);
+                return 2;
+            }
+            this->input_file = argv[i];
+        }
+    }
+    return 0;
+}
+
+static bool parse_size(const char * flag, const char * value, opt<size_t> * out)
+{
+    bool valid = value[0] != '\0';
+    for (const char * c = value; *c != '\0'; c++)
+    {
+        if (*c < '0' || *c > '9')
+        {
+            valid = false;
+            break;
+        }
+    }
+    if (valid)
+    {
+        errno = 0;
+        unsigned long long v = strtoull(value, nullptr, 10);
+        if (errno == 0 && v <= SIZE_MAX)
+        {
+            *out = (size_t)v;
+            return true;
+        }
+    }
+    fprintf(stderr, "Error: invalid value for option %s: '%s'\n", flag, value);
+    return false;
+}
+
+int Cli::handle_option(size_t flag_idx, const char * arg_value)
+{
+    switch (flag_idx)
+    {
+    case flag_height:
+    case flag_height_l:
+        if (!parse_size(flag_defs[flag_idx].flag, arg_value, &this->options.height))
+        {
+            return 2;
+        }
+        return 0;
+
+    case flag_help:
+        printf("Usage: fart [options] input-file\n");
+        printf("\n");
+        printf("  Options:\n");
+        printf("\n");
+        printf("  -h, --height H        Set render height to H\n");
+        printf("  --help                Show this help and exit\n");
+        printf("  -o, --output F        Write rendered image to file F\n");
+        printf("  -t, --threads N       Use N render threads (default: number of CPUs)\n");
+        printf("  -w, --width W         Set render width to W\n");
+        printf("  --version             Show fart version and exit\n");
+        return 1;
+
+    case flag_output:
+    case flag_output_l:
+        this->output_file = arg_value;
+        return 0;
+
+    case flag_threads:
+    case flag_threads_l:
+        if (!parse_size(flag_defs[flag_idx].flag, arg_value, &this->options.threads))
+        {
+            return 2;
+        }
+        if (*this->options.threads == 0u)
+        {
+            fprintf(stderr, "Error: option %s must be at least 1\n", flag_defs[flag_idx].flag);
+            return 2;
+        }
+        return 0;
+
+    case flag_width:
+    case flag_width_l:
+        if (!parse_size(flag_defs[flag_idx].flag, arg_value, &this->options.width))
+        {
+            return 2;
+        }
+        return 0;
+
+    case flag_version:
+        printf("fart, version 0.0.0.0.0.1\n");
+        return 1;
+    }
+    fprintf(stderr, "Internal error: unhandled flag_idx=%zu\n", flag_idx);
+    return 2;
 }

src/fart/Cli.h

@@ -1,7 +1,16 @@
 #pragma once
 
+#include <fart/Options.h>
+
 class Cli
 {
 public:
-    Cli();
+    Options options;
+    string_view input_file;
+    opt<string_view> output_file;
+
+    int run(int argc, char * argv[]);
+
+private:
+    int handle_option(size_t option_idx, const char * arg_value);
 };

src/fart/Engine.cpp

@@ -1,5 +1,84 @@
 #include <fart/Engine.h>
+#include <fart/Parser.h>
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
 
-Engine::Engine()
+Engine::Engine(const Options & options)
+    : options(options)
 {
 }
+
+Engine::~Engine()
+{
+    delete scene;
+}
+
+int Engine::run(string_view input_file, opt<string_view> output_file)
+{
+    string output_path;
+    if (output_file)
+    {
+        output_path = *output_file;
+    }
+    else
+    {
+        string_view base = input_file;
+        if (base.ends_with(".fart"))
+        {
+            base.remove_suffix(5u);
+        }
+        output_path = string(base) + ".png";
+    }
+
+    image_writer.reset(ImageWriter::build(output_path));
+    if (!image_writer)
+    {
+        return 1;
+    }
+
+    /* Verify the output file can be written before rendering. */
+    FILE * fh = fopen(output_path.c_str(), "wb");
+    if (fh == nullptr)
+    {
+        fprintf(stderr, "Error opening output file '%s': %s\n", output_path.c_str(), strerror(errno));
+        return 1;
+    }
+    if (fclose(fh) != 0)
+    {
+        fprintf(stderr, "Error closing output file '%s': %s\n", output_path.c_str(), strerror(errno));
+        return 1;
+    }
+    if (remove(output_path.c_str()) != 0)
+    {
+        fprintf(stderr, "Error removing output file '%s': %s\n", output_path.c_str(), strerror(errno));
+        return 1;
+    }
+
+    delete scene;
+    scene = Parser::load_scene(input_file);
+    if (!scene)
+    {
+        return 1;
+    }
+
+    /* CLI options take precedence over scene options; defaults fill the rest. */
+    options.merge(scene->options);
+    options.apply_defaults();
+
+    Image image(*options.width, *options.height);
+    for (size_t y = 0u; y < *options.height; y++)
+    {
+        for (size_t x = 0u; x < *options.width; x++)
+        {
+            image[x, y] = *options.background;
+        }
+    }
+
+    if (!image_writer->write(image))
+    {
+        return 1;
+    }
+
+    return 0;
+}

src/fart/Engine.h

@@ -1,7 +1,19 @@
 #pragma once
 
+#include <fart/ImageWriter.h>
+#include <fart/Options.h>
+#include <fart/Scene.h>
+#include <memory>
+
 class Engine
 {
 public:
-    Engine();
+    Engine(const Options & options);
+    ~Engine();
+    int run(string_view input_file, opt<string_view> output_file);
+
+protected:
+    Options options;
+    std::unique_ptr<ImageWriter> image_writer;
+    Scene * scene = nullptr;
 };

src/fart/Image.h

@@ -2,13 +2,12 @@
 
 #include <fart/Color.h>
 #include <stddef.h>
-#include <vector>
 
 struct Image
 {
     size_t width;
     size_t height;
-    std::vector<Color> pixels;
+    vector<Color> pixels;
     Image(size_t width, size_t height);
 
     Color & operator[](size_t x, size_t y)

src/fart/ImageWriter.cpp

@@ -3,9 +3,9 @@
 #include <stdio.h>
 #include <filesystem>
 
-ImageWriter * ImageWriter::build(const std::string & fname)
+ImageWriter * ImageWriter::build(const string & fname)
 {
-    std::string ext = std::filesystem::path(fname).extension().string();
+    string ext = std::filesystem::path(fname).extension().string();
     if (ext == ".png")
     {
         return new PngImageWriter(fname);

src/fart/ImageWriter.h

@@ -6,11 +6,11 @@
 class ImageWriter
 {
 public:
-    static ImageWriter * build(const std::string & fname);
+    static ImageWriter * build(const string & fname);
     virtual ~ImageWriter() = default;
     virtual bool write(const Image & image) = 0;
 
 protected:
-    ImageWriter(const std::string & fname) : fname(fname) {}
-    std::string fname;
+    ImageWriter(const string & fname) : fname(fname) {}
+    string fname;
 };

src/fart/Options.cpp

@@ -0,0 +1,44 @@
+#include <fart/Options.h>
+#include <thread>
+
+void Options::merge(const Options & other)
+{
+    if (!width)
+    {
+        width = other.width;
+    }
+    if (!height)
+    {
+        height = other.height;
+    }
+    if (!threads)
+    {
+        threads = other.threads;
+    }
+    if (!background)
+    {
+        background = other.background;
+    }
+}
+
+void Options::apply_defaults()
+{
+    if (!width)
+    {
+        width = 800u;
+    }
+    if (!height)
+    {
+        height = 600u;
+    }
+    if (!threads)
+    {
+        /* hardware_concurrency() may return 0 if it cannot be determined. */
+        size_t n = std::thread::hardware_concurrency();
+        threads = n > 0u ? n : 1u;
+    }
+    if (!background)
+    {
+        background = Color{0.0, 0.0, 0.0, 1.0};
+    }
+}

src/fart/Options.h

@@ -0,0 +1,18 @@
+#pragma once
+
+#include <fart/Color.h>
+#include <stddef.h>
+
+struct Options
+{
+    opt<size_t> width;
+    opt<size_t> height;
+    opt<size_t> threads;
+    opt<Color> background;
+
+    /* Set each field that is not already set to the value from other. */
+    void merge(const Options & other);
+
+    /* Fill in any unset fields with default values. */
+    void apply_defaults();
+};

src/fart/Parser.cpp

@@ -0,0 +1,147 @@
+#include <fart/Parser.h>
+#include <fart/propane.h>
+#include <fart/read_file.h>
+#include <stdint.h>
+#include <stdio.h>
+
+Scene * Parser::load_scene(const string_view & input_file)
+{
+    opt<vector<uint8_t>> input = read_file(input_file);
+    if (!input)
+    {
+        return nullptr;
+    }
+
+    p_context_t * context = p_context_new(input->data(), input->size());
+    size_t result = p_parse(context);
+    p_position_t pos = p_position(context);
+    int fname_len = (int)input_file.size();
+    const char * fname = input_file.data();
+    bool success = false;
+    switch (result)
+    {
+    case P_SUCCESS:
+        success = true;
+        break;
+
+    case P_DECODE_ERROR:
+        fprintf(stderr, "%.*s:%u:%u: error: invalid UTF-8 encoding\n",
+            fname_len, fname, pos.row, pos.col);
+        break;
+
+    case P_UNEXPECTED_INPUT:
+        fprintf(stderr, "%.*s:%u:%u: error: unexpected input\n",
+            fname_len, fname, pos.row, pos.col);
+        break;
+
+    case P_UNEXPECTED_TOKEN:
+    {
+        p_token_t token = p_token(context);
+        if (token == TOKEN___EOF)
+        {
+            fprintf(stderr, "%.*s:%u:%u: error: unexpected end of input\n",
+                fname_len, fname, pos.row, pos.col);
+        }
+        else
+        {
+            fprintf(stderr, "%.*s:%u:%u: error: unexpected token '%s'\n",
+                fname_len, fname, pos.row, pos.col, p_token_names[token]);
+        }
+        break;
+    }
+
+    case P_USER_TERMINATED:
+        if (p_user_terminate_code(context) == PARSER_TERMINATE_NUMBER_RANGE)
+        {
+            fprintf(stderr, "%.*s:%u:%u: error: number out of range\n",
+                fname_len, fname, pos.row, pos.col);
+        }
+        else
+        {
+            fprintf(stderr, "%.*s:%u:%u: internal error: unknown terminate code %zu\n",
+                fname_len, fname, pos.row, pos.col, p_user_terminate_code(context));
+        }
+        break;
+
+    default:
+        fprintf(stderr, "%.*s:%u:%u: internal error: unknown parser result %zu\n",
+            fname_len, fname, pos.row, pos.col, result);
+        break;
+    }
+
+    if (!success)
+    {
+        p_context_delete(context);
+        return nullptr;
+    }
+
+    Scene * scene = build_scene(input_file, p_result(context));
+    p_context_delete(context);
+    return scene;
+}
+
+/* Convert a uint token value to a size_t, reporting an error if it does not
+ * fit. */
+static bool token_to_size(const string_view & input_file, PToken token, opt<size_t> * out)
+{
+    /* SIZE_MAX + 1, computed so that it is exactly representable as a double. */
+    const double size_limit = (double)(SIZE_MAX / 2u + 1u) * 2.0;
+    double value = token.pvalue();
+    if (value >= size_limit)
+    {
+        p_position_t pos = token.position();
+        fprintf(stderr, "%.*s:%u:%u: error: value out of range\n",
+            (int)input_file.size(), input_file.data(), pos.row, pos.col);
+        return false;
+    }
+    *out = (size_t)value;
+    return true;
+}
+
+static Color vector_to_color(PVector vector)
+{
+    Color color{
+        vector.pNumber2().pToken().pvalue(),
+        vector.pNumber4().pToken().pvalue(),
+        vector.pNumber6().pToken().pvalue(),
+    };
+    if (PNumber a = vector.pNumber8(); p_node_valid(a))
+    {
+        color.a = a.pToken().pvalue();
+    }
+    return color;
+}
+
+Scene * Parser::build_scene(const string_view & input_file, PScene pscene)
+{
+    Scene * scene = new Scene();
+
+    /* If the options block is absent, pOptions() returns a null node and so
+     * does pOptionsItems() on it, so the loop body is skipped. */
+    for (POptionsItems items = pscene.pOptions().pOptionsItems();
+         p_node_valid(items);
+         items = items.pOptionsItems())
+    {
+        POptionsItem item = items.pOptionsItem();
+        bool ok = true;
+        if (PBackground background = item.pBackground(); p_node_valid(background))
+        {
+            scene->options.background = vector_to_color(background.pVector());
+        }
+        else if (PHeight height = item.pHeight(); p_node_valid(height))
+        {
+            ok = token_to_size(input_file, height.pToken2(), &scene->options.height);
+        }
+        else if (PWidth width = item.pWidth(); p_node_valid(width))
+        {
+            ok = token_to_size(input_file, width.pToken2(), &scene->options.width);
+        }
+        if (!ok)
+        {
+            delete scene;
+            return nullptr;
+        }
+    }
+
+    return scene;
+}

src/fart/Parser.h

@@ -0,0 +1,14 @@
+#pragma once
+
+#include <fart/Scene.h>
+
+struct PScene;
+
+class Parser
+{
+public:
+    static Scene * load_scene(const string_view & input_file);
+
+private:
+    static Scene * build_scene(const string_view & input_file, PScene pscene);
+};

src/fart/PngImageWriter.cpp

@@ -4,7 +4,6 @@
 #include <stdio.h>
 #include <algorithm>
 #include <cmath>
-#include <vector>
 
 static uint8_t to_byte(double v)
 {
@@ -13,7 +12,7 @@ static uint8_t to_byte(double v)
 
 bool PngImageWriter::write(const Image & image)
 {
-    std::vector<uint8_t> buffer(image.width * image.height * 4u);
+    vector<uint8_t> buffer(image.width * image.height * 4u);
     for (size_t i = 0u; i < image.pixels.size(); i++)
     {
         const Color & c = image.pixels[i];

src/fart/PngImageWriter.h

@@ -5,6 +5,6 @@
 class PngImageWriter : public ImageWriter
 {
 public:
-    PngImageWriter(const std::string & fname) : ImageWriter(fname) {}
+    PngImageWriter(const string & fname) : ImageWriter(fname) {}
     bool write(const Image & image) override;
 };

src/fart/Scene.h

@@ -0,0 +1,9 @@
+#pragma once
+
+#include <fart/Options.h>
+
+class Scene
+{
+public:
+    Options options;
+};

src/fart/common.h

@@ -0,0 +1,11 @@
+#pragma once
+
+#include <optional>
+#include <string>
+#include <string_view>
+#include <vector>
+
+using string = std::string;
+using string_view = std::string_view;
+template <typename T> using opt = std::optional<T>;
+template <typename T> using vector = std::vector<T>;

src/fart/main.cpp

@@ -5,7 +5,16 @@
 int main(int argc, char * argv[])
 {
     Cli cli;
-    Engine engine;
-    printf("Hello\n");
-    return 0;
+    int rc = cli.run(argc, argv);
+    if (rc > 0)
+    {
+        return rc - 1;
+    }
+    if (cli.input_file.empty())
+    {
+        fprintf(stderr, "Error: no input file specified\n");
+        return 1;
+    }
+    Engine engine(cli.options);
+    return engine.run(cli.input_file, cli.output_file);
 }

src/fart/read_file.cpp

@@ -0,0 +1,32 @@
+#include <fart/read_file.h>
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+
+opt<vector<uint8_t>> read_file(string_view fname)
+{
+    string path(fname);
+    FILE * fh = fopen(path.c_str(), "rb");
+    if (fh == nullptr)
+    {
+        fprintf(stderr, "Error opening input file '%s': %s\n", path.c_str(), strerror(errno));
+        return std::nullopt;
+    }
+
+    vector<uint8_t> buffer;
+    uint8_t chunk[4096];
+    size_t n;
+    while ((n = fread(chunk, 1u, sizeof(chunk), fh)) > 0u)
+    {
+        buffer.insert(buffer.end(), chunk, chunk + n);
+    }
+    if (ferror(fh))
+    {
+        fprintf(stderr, "Error reading input file '%s': %s\n", path.c_str(), strerror(errno));
+        fclose(fh);
+        return std::nullopt;
+    }
+    fclose(fh);
+
+    return buffer;
+}

src/fart/read_file.h

@@ -0,0 +1,5 @@
+#pragma once
+
+#include <stdint.h>
+
+opt<vector<uint8_t>> read_file(string_view fname);