mirror of
https://github.com/raylib-zig/raylib-zig.git
synced 2026-02-21 16:54:36 +00:00
103 lines
4.3 KiB
Zig
103 lines
4.3 KiB
Zig
// raylib [core] example - delta time
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//
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// Example complexity rating: [★☆☆☆] 1/4
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//
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// Example originally created with raylib 5.5, last time updated with raylib 5.6-dev
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//
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// Example contributed by Robin (@RobinsAviary) and reviewed by Ramon Santamaria (@raysan5)
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//
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// Example licensed under an unmodified zlib/libpng license, which is an OSI-certified,
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// BSD-like license that allows static linking with closed source software
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//
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// Copyright (c) 2025 Robin (@RobinsAviary)
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//
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// Ported to Zig by Isaac de Andrade in Jan 2026
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const rl = @import("raylib");
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//------------------------------------------------------------------------------------
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// Program main entry point
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//------------------------------------------------------------------------------------
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pub fn main() anyerror!void {
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// Initialization
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//--------------------------------------------------------------------------------------
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const screenWidth = 800;
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const screenHeight = 450;
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rl.initWindow(screenWidth, screenHeight, "raylib-zig [core] example - delta time");
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defer rl.closeWindow(); // Close window and OpenGL context
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var current_fps: i32 = 60;
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// Store the position for the both of the circles
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var delta_circle = rl.Vector2{ .x = 0, .y = screenHeight / 3.0 };
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var frame_circle = rl.Vector2{ .x = 0, .y = screenHeight * (2.0 / 3.0) };
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// The speed applied to both circles
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const speed = 10.0;
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const circle_radius = 32.0;
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rl.setTargetFPS(current_fps);
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//--------------------------------------------------------------------------------------
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// Main game loop
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while (!rl.windowShouldClose()) { // Detect window close button or ESC key
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// Update
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//----------------------------------------------------------------------------------
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// Adjust the FPS target based on the mouse wheel
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const mouse_wheel = rl.getMouseWheelMove();
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if (mouse_wheel != 0) {
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current_fps += @intFromFloat(mouse_wheel);
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if (current_fps < 0) current_fps = 0;
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rl.setTargetFPS(current_fps);
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}
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// rl.getFrameTime() returns the time it took to draw the last frame, in seconds (usually called delta time)
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// Uses the delta time to make the circle look like it's moving at a "consistent" speed regardless of FPS
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// Multiply by 6.0 (an arbitrary value) in order to make the speed
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// visually closer to the other circle (at 60 fps), for comparison
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delta_circle.x += rl.getFrameTime() * 6 * speed;
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// This circle can move faster or slower visually depending on the FPS
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frame_circle.x += 0.1 * speed;
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if (delta_circle.x > screenWidth) delta_circle.x = 0;
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if (frame_circle.x > screenWidth) frame_circle.x = 0;
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// Reset both circles positions
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if (rl.isKeyPressed(rl.KeyboardKey.r)) {
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delta_circle.x = 0;
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frame_circle.x = 0;
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}
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//----------------------------------------------------------------------------------
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// Draw
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//----------------------------------------------------------------------------------
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rl.beginDrawing();
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defer rl.endDrawing();
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rl.clearBackground(rl.Color.ray_white);
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// Draw both circles to the screen
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rl.drawCircleV(delta_circle, circle_radius, rl.Color.red);
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rl.drawCircleV(frame_circle, circle_radius, rl.Color.blue);
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// Draw the help text
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// Determine what help text to show depending on the current FPS target uses the c string format syntax
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const fps_text: [:0]const u8 = if (current_fps <= 0)
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rl.textFormat("FPS: unlimited (%i)", .{rl.getFPS()}) // uses C string format syntax from raylib
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else
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rl.textFormat("FPS: %i (target: %i)", .{ rl.getFPS(), current_fps });
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rl.drawText(fps_text, 10, 10, 20, rl.Color.dark_gray);
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// uses C string format syntax
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rl.drawText(rl.textFormat("Frame time: %02.02f ms", .{rl.getFrameTime()}), 10, 30, 20, rl.Color.dark_gray);
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rl.drawText("Use the scroll wheel to change the fps limit, r to reset", 10, 50, 20, rl.Color.dark_gray);
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// Draw the text above the circles
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rl.drawText("FUNC: x += rl.getFrameTime() * speed", 10, 90, 20, rl.Color.red);
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rl.drawText("FUNC: x += speed", 10, 240, 20, rl.Color.blue);
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}
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}
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