initial commit

src/main.zig

@@ -0,0 +1,69 @@
+const rl = @import("raylib");
+const std = @import("std");
+const math = @import("math.zig");
+
+const SCREENWIDTH = 1920;
+const SCREENHEIGHT = 1080;
+
+pub fn main() !void {
+    rl.setConfigFlags(.{ .msaa_4x_hint = true });
+    rl.initWindow(SCREENWIDTH, SCREENHEIGHT, "Koordinatni sistem");
+    defer rl.closeWindow();
+
+    rl.setTargetFPS(60);
+
+    while (!rl.windowShouldClose()) {
+        rl.beginDrawing();
+        defer rl.endDrawing();
+
+        rl.clearBackground(rl.Color.white);
+        drawAxis();
+        // markAxis();
+        plotGraph(0.01);
+    }
+}
+
+fn drawAxis() void {
+    const endy_on_abscis: i32 = @divTrunc(SCREENHEIGHT, 2);
+    const endx_on_ordinat: i32 = @divTrunc(SCREENWIDTH, 2);
+    // x
+    rl.drawLine(0, endy_on_abscis, SCREENWIDTH, endy_on_abscis, rl.Color.black);
+    // y
+    rl.drawLine(endx_on_ordinat, 0, endx_on_ordinat, SCREENHEIGHT, rl.Color.black);
+}
+
+// todo in the future we will do calculations only once and just repeat displaying
+fn plotGraph(diff: f32) void {
+    // diff is currently 0.01
+    const thickness = 2.5;
+    var x_value: f32 = -SCREENWIDTH / 2;
+
+    while (x_value <= SCREENWIDTH) : (x_value += diff) {
+        const cur_pos = adjustForGridSystem(rl.Vector2{
+            .x = x_value,
+            .y = getY(x_value),
+        });
+
+        const next_pos = adjustForGridSystem(rl.Vector2{
+            .x = x_value + diff,
+            .y = getY(x_value + diff),
+        });
+
+        rl.drawLineEx(cur_pos, next_pos, thickness, rl.Color.dark_blue);
+    }
+}
+
+fn getY(x: f32) f32 {
+    const a = math.abs(x) - 2;
+    const b = 1;
+    return @divTrunc(a, b);
+}
+
+fn adjustForGridSystem(input_vector: rl.Vector2) rl.Vector2 {
+    const new_vector = rl.Vector2{
+        .x = input_vector.x + SCREENWIDTH / 2,
+        .y = -input_vector.y + SCREENHEIGHT / 2,
+    };
+
+    return new_vector;
+}

src/math.zig

@@ -0,0 +1,27 @@
+pub fn abs(a: f32) f32 {
+    if (a < 0) {
+        return -a;
+    }
+
+    return a;
+}
+
+pub fn pow(a: f32, b: i32) f32 {
+    var res: f32 = 1.0;
+    var n: usize = undefined;
+    var f: f32 = undefined;
+
+    if (b < 0) {
+        f = 1 / a;
+        n = @intCast(-b);
+    } else {
+        f = a;
+        n = @intCast(b);
+    }
+
+    for (0..n) |_| {
+        res *= f;
+    }
+
+    return res;
+}