Update ScanLine effect to remove jump and scale the same for differen…

…t screen sizes

src/Asteroids.zig

@@ -78,7 +78,7 @@ pub inline fn main() void {
     var view = Shared.View.ViewLocator.Build(current_view);
     view.init();
 
-    var scanlinePosition: f32 = 0;
+    var scanlinePosition: f32 = -10;
 
     Shared.Log.Info("Begin Game Loop");
     while (!raylib.windowShouldClose()) {
@@ -90,13 +90,16 @@ pub inline fn main() void {
         defer current_view = new_view;
 
         // Draw scan lines
+        const screenHeight: f32 = @floatFromInt(raylib.getScreenHeight());
+        const screenTick = screenHeight / 240;
         scanlinePosition += raylib.getFrameTime() * 5;
-        if (scanlinePosition > 10) scanlinePosition = 0;
+        if (scanlinePosition > 0) scanlinePosition -= 10;
+        //raylib.drawLine(0, @intFromFloat(screenTick * (scanlinePosition + 10)), raylib.getScreenWidth(), @intFromFloat(screenTick * (scanlinePosition + 10)), Shared.Color.Red.Base);
         Shared.Shader.DrawTexture(.ScanLine, .ScanLines, raylib.Rectangle.init(
             0,
-            -10 + scanlinePosition,
+            screenTick * scanlinePosition,
             @as(f32, @floatFromInt(raylib.getScreenWidth())),
-            @as(f32, @floatFromInt(raylib.getScreenHeight() + 20)),
+            screenHeight + (screenTick * 20),
         ));
 
         if (Shared.Settings.GetSettings().Debug) {

src/Shaders/ScanLines.fs

@@ -8,14 +8,15 @@ varying vec2 fragTexCoord;
 // Input uniform values
 uniform sampler2D texture0;
 
-// NOTE: Add here your custom variables
 
-float frequency = 120.0;
+uniform float screenHeight;
+
+float frequency = 4.0;
 
 void main()
 {
     // Scanlines method 2
-    float globalPos = (fragTexCoord.y) * frequency;
+    float globalPos = (fragTexCoord.y) * (screenHeight / frequency);
     float wavePos = cos((fract(globalPos) - 0.5)*3.14);
 
     vec4 color = texture2D(texture0, fragTexCoord);

src/Shared.zig

@@ -229,6 +229,12 @@ pub const Shared = struct {
                     loaded_settings.?.CurrentResolution.Width,
                     loaded_settings.?.CurrentResolution.Height,
                 );
+
+                // Update shader scanlines
+                const shader = Shared.Shader.Get(.ScanLines);
+                const screenHeight: f32 = @floatFromInt(raylib.getScreenHeight());
+                const screenHeightLoc = raylib.getShaderLocation(shader, "screenHeight");
+                raylib.setShaderValue(shader, screenHeightLoc, &screenHeight, @intFromEnum(raylib.ShaderUniformDataType.shader_uniform_float));
             }
 
             if (original_settings.UserLocale != loaded_settings.?.UserLocale) {