Initial commit

.gitignore

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+/.zig-cache
+/.idea
+/zig-out

build.zig

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+const std = @import("std");
+
+// Although this function looks imperative, it does not perform the build
+// directly and instead it mutates the build graph (`b`) that will be then
+// executed by an external runner. The functions in `std.Build` implement a DSL
+// for defining build steps and express dependencies between them, allowing the
+// build runner to parallelize the build automatically (and the cache system to
+// know when a step doesn't need to be re-run).
+pub fn build(b: *std.Build) void {
+    // Standard target options allow the person running `zig build` to choose
+    // what target to build for. Here we do not override the defaults, which
+    // means any target is allowed, and the default is native. Other options
+    // for restricting supported target set are available.
+    const target = b.standardTargetOptions(.{});
+    // Standard optimization options allow the person running `zig build` to select
+    // between Debug, ReleaseSafe, ReleaseFast, and ReleaseSmall. Here we do not
+    // set a preferred release mode, allowing the user to decide how to optimize.
+    const optimize = b.standardOptimizeOption(.{});
+    // It's also possible to define more custom flags to toggle optional features
+    // of this build script using `b.option()`. All defined flags (including
+    // target and optimize options) will be listed when running `zig build --help`
+    // in this directory.
+
+    // This creates a module, which represents a collection of source files alongside
+    // some compilation options, such as optimization mode and linked system libraries.
+    // Zig modules are the preferred way of making Zig code available to consumers.
+    // addModule defines a module that we intend to make available for importing
+    // to our consumers. We must give it a name because a Zig package can expose
+    // multiple modules and consumers will need to be able to specify which
+    // module they want to access.
+    // const mod = b.addModule("rasteriser", .{
+    //     // The root source file is the "entry point" of this module. Users of
+    //     // this module will only be able to access public declarations contained
+    //     // in this file, which means that if you have declarations that you
+    //     // intend to expose to consumers that were defined in other files part
+    //     // of this module, you will have to make sure to re-export them from
+    //     // the root file.
+    //     .root_source_file = b.path("src/root.zig"),
+    //     // Later on we'll use this module as the root module of a test executable
+    //     // which requires us to specify a target.
+    //     .target = target,
+    // });
+
+    const raylib_dep = b.dependency("raylib_zig", .{
+        .target = target,
+        .optimize = optimize,
+    });
+
+    const raylib = raylib_dep.module("raylib");
+    const raylib_artifact = raylib_dep.artifact("raylib");
+
+    // Here we define an executable. An executable needs to have a root module
+    // which needs to expose a `main` function. While we could add a main function
+    // to the module defined above, it's sometimes preferable to split business
+    // logic and the CLI into two separate modules.
+    //
+    // If your goal is to create a Zig library for others to use, consider if
+    // it might benefit from also exposing a CLI tool. A parser library for a
+    // data serialization format could also bundle a CLI syntax checker, for example.
+    //
+    // If instead your goal is to create an executable, consider if users might
+    // be interested in also being able to embed the core functionality of your
+    // program in their own executable in order to avoid the overhead involved in
+    // subprocessing your CLI tool.
+    //
+    // If neither case applies to you, feel free to delete the declaration you
+    // don't need and to put everything under a single module.
+    const exe = b.addExecutable(.{
+        .name = "rasteriser",
+        .root_module = b.createModule(.{
+            // b.createModule defines a new module just like b.addModule but,
+            // unlike b.addModule, it does not expose the module to consumers of
+            // this package, which is why in this case we don't have to give it a name.
+            .root_source_file = b.path("src/main.zig"),
+            // Target and optimization levels must be explicitly wired in when
+            // defining an executable or library (in the root module), and you
+            // can also hardcode a specific target for an executable or library
+            // definition if desireable (e.g. firmware for embedded devices).
+            .target = target,
+            .optimize = optimize,
+            // List of modules available for import in source files part of the
+            // root module.
+            .imports = &.{
+                // Here "rasteriser" is the name you will use in your source code to
+                // import this module (e.g. `@import("rasteriser")`). The name is
+                // repeated because you are allowed to rename your imports, which
+                // can be extremely useful in case of collisions (which can happen
+                // importing modules from different packages).
+                // .{ .name = "rasteriser", .module = mod },
+
+                .{ .name = "raylib", .module = raylib},
+            },
+        }),
+    });
+
+    exe.linkLibrary(raylib_artifact);
+
+    // This declares intent for the executable to be installed into the
+    // install prefix when running `zig build` (i.e. when executing the default
+    // step). By default the install prefix is `zig-out/` but can be overridden
+    // by passing `--prefix` or `-p`.
+    b.installArtifact(exe);
+
+    // This creates a top level step. Top level steps have a name and can be
+    // invoked by name when running `zig build` (e.g. `zig build run`).
+    // This will evaluate the `run` step rather than the default step.
+    // For a top level step to actually do something, it must depend on other
+    // steps (e.g. a Run step, as we will see in a moment).
+    const run_step = b.step("run", "Run the app");
+
+    // This creates a RunArtifact step in the build graph. A RunArtifact step
+    // invokes an executable compiled by Zig. Steps will only be executed by the
+    // runner if invoked directly by the user (in the case of top level steps)
+    // or if another step depends on it, so it's up to you to define when and
+    // how this Run step will be executed. In our case we want to run it when
+    // the user runs `zig build run`, so we create a dependency link.
+    const run_cmd = b.addRunArtifact(exe);
+    run_step.dependOn(&run_cmd.step);
+
+    // By making the run step depend on the default step, it will be run from the
+    // installation directory rather than directly from within the cache directory.
+    run_cmd.step.dependOn(b.getInstallStep());
+
+    // This allows the user to pass arguments to the application in the build
+    // command itself, like this: `zig build run -- arg1 arg2 etc`
+    if (b.args) |args| {
+        run_cmd.addArgs(args);
+    }
+
+    // Creates an executable that will run `test` blocks from the provided module.
+    // Here `mod` needs to define a target, which is why earlier we made sure to
+    // set the releative field.
+    // const mod_tests = b.addTest(.{
+    //     .root_module = mod,
+    // });
+
+    // A run step that will run the test executable.
+    // const run_mod_tests = b.addRunArtifact(mod_tests);
+
+    // Creates an executable that will run `test` blocks from the executable's
+    // root module. Note that test executables only test one module at a time,
+    // hence why we have to create two separate ones.
+    const exe_tests = b.addTest(.{
+        .root_module = exe.root_module,
+    });
+
+    // A run step that will run the second test executable.
+    const run_exe_tests = b.addRunArtifact(exe_tests);
+
+    // A top level step for running all tests. dependOn can be called multiple
+    // times and since the two run steps do not depend on one another, this will
+    // make the two of them run in parallel.
+    const test_step = b.step("test", "Run tests");
+    // test_step.dependOn(&run_mod_tests.step);
+    test_step.dependOn(&run_exe_tests.step);
+
+    // Just like flags, top level steps are also listed in the `--help` menu.
+    //
+    // The Zig build system is entirely implemented in userland, which means
+    // that it cannot hook into private compiler APIs. All compilation work
+    // orchestrated by the build system will result in other Zig compiler
+    // subcommands being invoked with the right flags defined. You can observe
+    // these invocations when one fails (or you pass a flag to increase
+    // verbosity) to validate assumptions and diagnose problems.
+    //
+    // Lastly, the Zig build system is relatively simple and self-contained,
+    // and reading its source code will allow you to master it.
+}

build.zig.zon

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+.{
+    // This is the default name used by packages depending on this one. For
+    // example, when a user runs `zig fetch --save <url>`, this field is used
+    // as the key in the `dependencies` table. Although the user can choose a
+    // different name, most users will stick with this provided value.
+    //
+    // It is redundant to include "zig" in this name because it is already
+    // within the Zig package namespace.
+    .name = .rasteriser,
+    // This is a [Semantic Version](https://semver.org/).
+    // In a future version of Zig it will be used for package deduplication.
+    .version = "0.0.0",
+    // Together with name, this represents a globally unique package
+    // identifier. This field is generated by the Zig toolchain when the
+    // package is first created, and then *never changes*. This allows
+    // unambiguous detection of one package being an updated version of
+    // another.
+    //
+    // When forking a Zig project, this id should be regenerated (delete the
+    // field and run `zig build`) if the upstream project is still maintained.
+    // Otherwise, the fork is *hostile*, attempting to take control over the
+    // original project's identity. Thus it is recommended to leave the comment
+    // on the following line intact, so that it shows up in code reviews that
+    // modify the field.
+    .fingerprint = 0xde5064b97e2d76b, // Changing this has security and trust implications.
+    // Tracks the earliest Zig version that the package considers to be a
+    // supported use case.
+    .minimum_zig_version = "0.15.2",
+    // This field is optional.
+    // Each dependency must either provide a `url` and `hash`, or a `path`.
+    // `zig build --fetch` can be used to fetch all dependencies of a package, recursively.
+    // Once all dependencies are fetched, `zig build` no longer requires
+    // internet connectivity.
+    .dependencies = .{
+        .raylib_zig = .{
+            .url = "git+https://github.com/raylib-zig/raylib-zig?ref=devel#7d4761b878f43671024ce197f721827b5355a67e",
+            .hash = "raylib_zig-5.6.0-dev-KE8REGlNBQDR7NML06VBtT7gP3VZNY70E5WohAxzqrNn",
+        },
+    },
+    .paths = .{
+        "build.zig",
+        "build.zig.zon",
+        "src",
+        // For example...
+        //"LICENSE",
+        //"README.md",
+    },
+}

src/main.zig

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+const std = @import("std");
+const rl = @import("raylib");
+const structures = @import("structures/structures.zig");
+
+pub fn main() !void {
+    const screen = .{.width = 800, .height = 600};
+    rl.initWindow(screen.width, screen.height, "Rasteriser");
+    defer rl.closeWindow();
+
+    rl.setTargetFPS(60);
+
+    const point_a = rl.Vector2 {.x = 50, .y = 550};  // A
+    const point_b = rl.Vector2 {.x = 750, .y = 550}; // B
+    const point_c = rl.Vector2 {.x = 400, .y = 100}; // C
+
+    var triangle = structures.Triangle.new(point_a, point_b, point_c);
+    const range = triangle.getCoordsLimit();
+
+    while (!rl.windowShouldClose()) {
+        rl.beginDrawing();
+        defer rl.endDrawing();
+
+        rl.clearBackground(.gray);
+
+        for (range.y.min..range.y.max+1) |y| {
+            for (range.x.min..range.x.max+1) |x| {
+                const point = rl.Vector2 {
+                    .x = @floatFromInt(x),
+                    .y = @floatFromInt(y),
+                };
+
+                const colour = triangle.pixelColour(point) orelse continue;
+                rl.drawPixelV(point, colour);
+            }
+        }
+    }
+}

src/structures/internal/base_structs.zig

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+/// Tracks minimum and maximum possible x/y coordinate of the triangle (or any other object we wish to render)
+pub const MinMaxLimit = struct{
+    x: struct{min: usize, max: usize},
+    y: struct{min: usize, max: usize},
+};

src/structures/internal/triangle.zig

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+const rl = @import("raylib");
+const BaseStructures = @import("base_structs.zig");
+
+pub const Triangle = struct {
+    point_a: rl.Vector2,
+    point_b: rl.Vector2,
+    point_c: rl.Vector2,
+
+    /// Constructor
+    pub fn new(point_a: rl.Vector2, point_b: rl.Vector2, point_c: rl.Vector2) Triangle {
+        return .{
+            .point_a = point_a,
+            .point_b = point_b,
+            .point_c = point_c,
+        };
+    }
+
+    /// Calculates the pixel colour or returns null if the pixle is not within the triangle
+    pub fn pixelColour(self: *Triangle, point: rl.Vector2) ?rl.Color {
+        const acp = edgeFunction(self.point_a, self.point_c, point);
+        const cbp = edgeFunction(self.point_c, self.point_b, point);
+        const apb = edgeFunction(self.point_a, point, self.point_b);
+        if (acp < 0 or cbp < 0 or apb < 0) return null;
+
+        // normalize values
+        const abc = edgeFunction(self.point_a, self.point_c, self.point_b);
+        // a red,  b blue, c green
+        const weight_a = cbp / abc;
+        const weight_b = acp / abc;
+        const weight_c = apb / abc;
+
+        const colour_a = rl.Vector3 {
+            .x = @floatFromInt(rl.Color.red.r),
+            .y = @floatFromInt(rl.Color.red.g),
+            .z = @floatFromInt(rl.Color.red.b),
+        };
+        const colour_b = rl.Vector3 {
+            .x = @floatFromInt(rl.Color.blue.r),
+            .y = @floatFromInt(rl.Color.blue.g),
+            .z = @floatFromInt(rl.Color.blue.b),
+        };
+        const colour_c = rl.Vector3 {
+            .x = @floatFromInt(rl.Color.green.r),
+            .y = @floatFromInt(rl.Color.green.g),
+            .z = @floatFromInt(rl.Color.green.b),
+        };
+
+        // craft colours
+        const r = colour_a.x * weight_a + colour_b.x * weight_b + colour_c.x * weight_c;
+        const g = colour_a.y * weight_a + colour_b.y * weight_b + colour_c.y * weight_c;
+        const b = colour_a.z * weight_a + colour_b.z * weight_b + colour_c.z * weight_c;
+
+        return .{
+            .r = @intFromFloat(r),
+            .g = @intFromFloat(g),
+            .b = @intFromFloat(b),
+            .a = 255,
+        };
+    }
+
+    /// Calculates point's orientation
+    fn edgeFunction(a: rl.Vector2, b: rl.Vector2, c: rl.Vector2) f32 {
+        return (b.x - a.x) * (c.y - a.y) - (b.y - a.y) * (c.x - a.x);
+    }
+
+    /// Returns what the triangle's minimum and maximum x and y are
+    pub fn getCoordsLimit(self: *Triangle) BaseStructures.MinMaxLimit {
+        return .{
+            .x = .{
+                .min = @intFromFloat(@min(self.point_a.x, self.point_b.x, self.point_c.x)),
+                .max = @intFromFloat(@max(self.point_a.x, self.point_b.x, self.point_c.x)),
+            },
+            .y = .{
+                .min = @intFromFloat(@min(self.point_a.y, self.point_b.y, self.point_c.y)),
+                .max = @intFromFloat(@max(self.point_a.y, self.point_b.y, self.point_c.y)),
+            }
+        };
+    }
+};

src/structures/structures.zig

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+pub const Triangle = @import("internal/triangle.zig").Triangle;
+pub const BaseStr = @import("internal/base_structs.zig");