Increase FOV when moving fast (Issue#716)

src/game.zig

@@ -332,6 +332,7 @@ pub const Player = struct { // MARK: Player
 	pub var eyeVel: Vec3d = .{0, 0, 0};
 	pub var eyeCoyote: f64 = 0;
 	pub var eyeStep: @Vector(3, bool) = .{false, false, false};
+	pub var speedMod: f32 = 0.0;
 	pub var id: u32 = 0;
 	pub var gamemode: Atomic(Gamemode) = .init(.creative);
 	pub var isFlying: Atomic(bool) = .init(false);
@@ -401,6 +402,12 @@ pub const Player = struct { // MARK: Player
 		return eyeCoyote;
 	}
 
+	pub fn getSpeedModifierBlocking() f32 {
+		mutex.lock();
+		defer mutex.unlock();
+		return speedMod;
+	}
+
 	pub fn setGamemode(newGamemode: Gamemode) void {
 		gamemode.store(newGamemode, .monotonic);
 
@@ -894,6 +901,20 @@ pub fn update(deltaTime: f64) void { // MARK: update()
 			Player.eyeVel[i] = firstTerm.mul(c_3.negate().subScalar(frictionCoefficient).mulScalar(0.5)).add(secondTerm.mul((c_3.subScalar(frictionCoefficient)).mulScalar(0.5))).val[0];
 			Player.eyePos[i] += firstTerm.add(secondTerm).addScalar(a/k).val[0];
 		}
+
+		// Calculate our FOV modifier based on our current speed.
+		{
+			const x : f32 = @as(f32, @floatCast(movementSpeed));
+			const speedModGoal : f32 =  @max(@log10((x*x)-15)/1.8, 0);
+			const speedModDir: f32 = if(Player.speedMod < speedModGoal) 1 else -1;
+			const speedModNext: f32 = Player.speedMod + (speedModDir * @as(f32, @floatCast(deltaTime)) * 5.0);
+
+			if((Player.speedMod < speedModGoal and speedModNext < speedModGoal) or (Player.speedMod > speedModGoal and speedModNext > speedModGoal)) {
+				Player.speedMod = speedModNext;
+			} else {
+				Player.speedMod = speedModGoal;	
+			}
+		} 
 	}
 
 	const time = std.time.milliTimestamp();

src/graphics/Window.zig

@@ -472,7 +472,8 @@ pub const GLFWCallbacks = struct { // MARK: GLFWCallbacks
 		std.log.info("Framebuffer: {}, {}", .{newWidth, newHeight});
 		width = @intCast(newWidth);
 		height = @intCast(newHeight);
-		main.renderer.updateViewport(width, height, main.settings.fov);
+		main.renderer.updateViewport(width, height);
+		main.renderer.updateFOV(main.settings.fov);
 		main.gui.updateGuiScale();
 		main.gui.updateWindowPositions();
 	}

src/renderer.zig

@@ -112,15 +112,18 @@ var worldFrameBuffer: graphics.FrameBuffer = undefined;
 var lastWidth: u31 = 0;
 var lastHeight: u31 = 0;
 var lastFov: f32 = 0;
-pub fn updateViewport(width: u31, height: u31, fov: f32) void {
+pub fn updateViewport(width: u31, height: u31) void {
 	lastWidth = @intFromFloat(@as(f32, @floatFromInt(width))*main.settings.resolutionScale);
 	lastHeight = @intFromFloat(@as(f32, @floatFromInt(height))*main.settings.resolutionScale);
-	lastFov = fov;
-	game.projectionMatrix = Mat4f.perspective(std.math.degreesToRadians(fov), @as(f32, @floatFromInt(lastWidth))/@as(f32, @floatFromInt(lastHeight)), zNear, zFar);
 	worldFrameBuffer.updateSize(lastWidth, lastHeight, c.GL_RGB16F);
 	worldFrameBuffer.unbind();
 }
 
+pub fn updateFOV(fov: f32) void {
+	lastFov = fov;
+	game.projectionMatrix = Mat4f.perspective(std.math.degreesToRadians(fov), @as(f32, @floatFromInt(lastWidth))/@as(f32, @floatFromInt(lastHeight)), zNear, zFar);
+}
+
 pub fn render(playerPosition: Vec3d) void {
 	// TODO: player bobbing
 	if(game.world) |world| {
@@ -132,6 +135,9 @@ pub fn render(playerPosition: Vec3d) void {
 		const skyColor = vec.xyz(world.clearColor);
 		game.fog.skyColor = skyColor;
 
+		const fov: f32 = settings.fov + (game.Player.getSpeedModifierBlocking() * 20);
+		updateFOV(fov);
+
 		renderWorld(world, ambient, skyColor, playerPosition);
 		const startTime = std.time.milliTimestamp();
 		mesh_storage.updateMeshes(startTime + maximumMeshTime);
@@ -507,7 +513,8 @@ pub const MenuBackGround = struct {
 		lastTime = newTime;
 		const viewMatrix = Mat4f.rotationZ(angle);
 		shader.bind();
-		updateViewport(main.Window.width, main.Window.height, 70.0);
+		updateViewport(main.Window.width, main.Window.height);
+		updateFOV(70.0);
 
 		c.glUniformMatrix4fv(uniforms.viewMatrix, 1, c.GL_TRUE, @ptrCast(&viewMatrix));
 		c.glUniformMatrix4fv(uniforms.projectionMatrix, 1, c.GL_TRUE, @ptrCast(&game.projectionMatrix));
@@ -527,9 +534,11 @@ pub const MenuBackGround = struct {
 
 		const oldResolutionScale = main.settings.resolutionScale;
 		main.settings.resolutionScale = 1;
-		updateViewport(size, size, 90.0);
+		updateViewport(size, size);
+		updateFOV(90.0);
 		main.settings.resolutionScale = oldResolutionScale;
-		defer updateViewport(Window.width, Window.height, settings.fov);
+		defer updateViewport(Window.width, Window.height);
+		defer updateFOV(settings.fov);
 
 		var buffer: graphics.FrameBuffer = undefined;
 		buffer.init(true, c.GL_NEAREST, c.GL_REPEAT);