polygon lines

★★☆☆by Matthew Roush (@MatthewRoush)

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Is it the same as C?

Desktop:verified The Zig version renders a final frame that is byte-identical to the C example.
Browser:verified In headless Chrome, the Zig version gives a final frame byte-identical to the C example built for the web.

ZigC (original)

//! raylib [shapes] example - polygon lines
//!
//! Zig-API translation of examples/shapes/shapes_polygon_lines.c (raylib 6.2).
//! Example licensed under an unmodified zlib/libpng license.
//! Copyright (c) 2026 Matthew Roush (@MatthewRoush)

const std = @import("std");
const rl = @import("raylib");

pub fn main() void {
    // Initialization
    const screen_width = 800;
    const screen_height = 450;

    rl.initWindow(screen_width, screen_height, "raylib [shapes] example - polygon lines");
    defer rl.closeWindow(); // Close window and OpenGL context

    var thick: i32 = 2;
    var rotation: f32 = 0.0;

    rl.setTargetFPS(60);

    // Main game loop
    while (!rl.windowShouldClose()) { // Detect window close button or ESC key
        // Update
        if (rl.isKeyPressed(.up)) thick += 1;
        if (rl.isKeyPressed(.down)) thick -= 1;

        thick = std.math.clamp(thick, 1, 60);

        rotation += (360.0 / 10.0) * rl.getFrameTime();

        // Draw
        rl.beginDrawing();
        defer rl.endDrawing();

        rl.clearBackground(.ray_white);

        rl.drawText(rl.textFormat("thick = {d}", .{thick}), 10, 280, 20, .lime);

        // The square and circle outlines in the top left should match
        // The fist pair of outlines are drawn using `DrawRectangleLinesEx()` and `DrawCircleLinesEx()`
        // The second pair are drawn using `DrawPolyLinesEx()` with parameters that should visually match the first pair

        rl.drawText("These should look identical!", 10, 10, 20, .maroon);

        const line_thick: f32 = @floatFromInt(thick);

        // Outline pair 1
        rl.drawRectangle(10, 40, 50, 50, .light_gray);
        rl.drawRectangleLinesEx(.{ .x = 10, .y = 40, .width = 50, .height = 50 }, line_thick, .red);

        rl.drawCircle(95, 65, 25, .light_gray);
        rl.drawCircleLinesEx(.{ .x = 95, .y = 65 }, 25, line_thick, .red);

        rl.drawText("DrawRectangleLinesEx() and DrawCircleLinesEx()", 130, 60, 10, .black);

        // Outline pair 2
        rl.drawPoly(.{ .x = 35, .y = 125 }, 4, 35.355, 45, .light_gray);
        rl.drawPolyLinesEx(.{ .x = 35, .y = 125 }, 4, 35.355, 45, line_thick, .red);

        rl.drawPoly(.{ .x = 95, .y = 125 }, 36, 25, 0, .light_gray);
        rl.drawPolyLinesEx(.{ .x = 95, .y = 125 }, 36, 25, 0, line_thick, .red);

        rl.drawText("DrawPolyLinesEx()", 130, 120, 10, .black);

        // Some other shapes, all of these outlines should have the same looking thickness
        const centers = [_]rl.Vector2{
            .{ .x = 290, .y = 220 }, .{ .x = 430, .y = 220 }, .{ .x = 570, .y = 220 }, .{ .x = 710, .y = 220 },
            .{ .x = 290, .y = 360 }, .{ .x = 430, .y = 360 }, .{ .x = 570, .y = 360 }, .{ .x = 710, .y = 360 },
        };
        for (centers, 3..) |center, sides| {
            rl.drawPoly(center, @intCast(sides), 60, rotation, .light_gray);
            rl.drawPolyLinesEx(center, @intCast(sides), 60, rotation, line_thick, .blue);
        }
    }
}

/*******************************************************************************************
*
*   raylib [shapes] example - polygon lines
*
*   Example complexity rating: [★★☆☆] 2/4
*
*   Example originally created with raylib 6.1, last time updated with raylib 6.1
*
*   Example contributed by Matthew Roush (@MatthewRoush) and reviewed by Ramon Santamaria (@raysan5)
*
*   Example licensed under an unmodified zlib/libpng license, which is an OSI-certified,
*   BSD-like license that allows static linking with closed source software
*
*   Copyright (c) 2026 Matthew Roush (@MatthewRoush)
*
********************************************************************************************/

#include "raylib.h"

//------------------------------------------------------------------------------------
// Program main entry point
//------------------------------------------------------------------------------------
int main(void)
{
    // Initialization
    //--------------------------------------------------------------------------------------
    const int screenWidth = 800;
    const int screenHeight = 450;

    InitWindow(screenWidth, screenHeight, "raylib [shapes] example - polygon lines");

    int thick = 2;
    float rotation = 0.0f;

    SetTargetFPS(60);
    //--------------------------------------------------------------------------------------

    // Main game loop
    while (!WindowShouldClose())    // Detect window close button or ESC key
    {
        // Update
        //----------------------------------------------------------------------------------
        if (IsKeyPressed(KEY_UP))   thick = thick + 1;
        if (IsKeyPressed(KEY_DOWN)) thick = thick - 1;

        thick = (thick < 1) ? 1 : (thick > 60) ? 60 : thick;

        rotation += (360.0f/10.0f)*GetFrameTime();
        //----------------------------------------------------------------------------------

        // Draw
        //----------------------------------------------------------------------------------
        BeginDrawing();

            ClearBackground(RAYWHITE);

            DrawText(TextFormat("thick = %d", thick), 10, 280, 20, LIME);

            // The square and circle outlines in the top left should match
            // The fist pair of outlines are drawn using `DrawRectangleLinesEx()` and `DrawCircleLinesEx()`
            // The second pair are drawn using `DrawPolyLinesEx()` with parameters that should visually match the first pair

            DrawText("These should look identical!", 10, 10, 20, MAROON);

            // Outline pair 1
            DrawRectangle(10, 40, 50, 50, LIGHTGRAY);
            DrawRectangleLinesEx((Rectangle){ 10, 40, 50, 50 }, (float)thick, RED);

            DrawCircle(95, 65, 25, LIGHTGRAY);
            DrawCircleLinesEx((Vector2){ 95, 65 }, 25, (float)thick, RED);

            DrawText("DrawRectangleLinesEx() and DrawCircleLinesEx()", 130, 60, 10, BLACK);

            // Outline pair 2
            DrawPoly((Vector2){ 35, 125 }, 4, 35.355f, 45, LIGHTGRAY);
            DrawPolyLinesEx((Vector2){ 35, 125 }, 4, 35.355f, 45, (float)thick, RED);

            DrawPoly((Vector2){ 95, 125 }, 36, 25, 0, LIGHTGRAY);
            DrawPolyLinesEx((Vector2){ 95, 125 }, 36, 25, 0, (float)thick, RED);

            DrawText("DrawPolyLinesEx()", 130, 120, 10, BLACK);

            // Some other shapes, all of these outlines should have the same looking thickness
            DrawPoly((Vector2){ 290, 220 }, 3, 60, rotation, LIGHTGRAY);
            DrawPolyLinesEx((Vector2){ 290, 220 }, 3, 60, rotation, (float)thick, BLUE);

            DrawPoly((Vector2){ 430, 220 }, 4, 60, rotation, LIGHTGRAY);
            DrawPolyLinesEx((Vector2){ 430, 220 }, 4, 60, rotation, (float)thick, BLUE);

            DrawPoly((Vector2){ 570, 220 }, 5, 60, rotation, LIGHTGRAY);
            DrawPolyLinesEx((Vector2){ 570, 220 }, 5, 60, rotation, (float)thick, BLUE);

            DrawPoly((Vector2){ 710, 220 }, 6, 60, rotation, LIGHTGRAY);
            DrawPolyLinesEx((Vector2){ 710, 220 }, 6, 60, rotation, (float)thick, BLUE);

            DrawPoly((Vector2){ 290, 360 }, 7, 60, rotation, LIGHTGRAY);
            DrawPolyLinesEx((Vector2){ 290, 360 }, 7, 60, rotation, (float)thick, BLUE);

            DrawPoly((Vector2){ 430, 360 }, 8, 60, rotation, LIGHTGRAY);
            DrawPolyLinesEx((Vector2){ 430, 360 }, 8, 60, rotation, (float)thick, BLUE);

            DrawPoly((Vector2){ 570, 360 }, 9, 60, rotation, LIGHTGRAY);
            DrawPolyLinesEx((Vector2){ 570, 360 }, 9, 60, rotation, (float)thick, BLUE);

            DrawPoly((Vector2){ 710, 360 }, 10, 60, rotation, LIGHTGRAY);
            DrawPolyLinesEx((Vector2){ 710, 360 }, 10, 60, rotation, (float)thick, BLUE);

        EndDrawing();
        //----------------------------------------------------------------------------------
    }

    // De-Initialization
    //--------------------------------------------------------------------------------------
    CloseWindow();        // Close window and OpenGL context
    //--------------------------------------------------------------------------------------

    return 0;
}

From raylib 6.2. The original on GitHub.