Implemented CRT shader

game/assets/configs/final_shader.json

@@ -0,0 +1,5 @@
+{
+    "pixel_scale": 1.0,
+    "warp_factor": 0.35,
+    "scanline_darkness": 0.15
+}

game/assets/shaders/pixelart.fs

@@ -1,3 +1,7 @@
+/**
+ * This shader is the last piece of the graphics pipeline. EVERYTHING is passed through it.
+ */
+
 #version 330
 
 // Fragment texture UV coordinate
@@ -13,22 +17,41 @@ uniform vec2 viewport;
 out vec4 finalColor;
 
 // Pixel scaling factor (pixels per pixel)
-const vec2 pixelScale = vec2(1.0, 1.0);
+uniform vec2 pixelScale;
+
+// CRT effect parameters
+uniform float warpFactor;
+uniform float scanlineDarkness;
 
 void main() {
   // Calculate the distance to merge pixels
   float dx = pixelScale.x * (1.0 / viewport.x);
   float dy = pixelScale.y * (1.0 / viewport.y);
 
+  // Calculate the squared distance from the center
+  vec2 dist_center_sq = abs(0.5 - fragTexCoord);
+  dist_center_sq *= dist_center_sq;
+
   // Get the base UV coordinate of the pixel
   vec2 baseUV = fragTexCoord;
 
   // Calculate a UV for this new blocky pixel
   vec2 pixelatedUV = vec2(dx * floor(baseUV.x / dx), dy * floor(baseUV.y / dy));
 
-  // Rebuild the texture with the new UVs
-  vec3 tc = texture(texture0, pixelatedUV).rgb;
+  // Warp the UVs of the pixelated texture
+  vec2 warpedUV = pixelatedUV;
+  warpedUV.x -= 0.5; warpedUV.x *= 1.0+(dist_center_sq.y * (0.3 * warpFactor)); warpedUV.x += 0.5;
+  warpedUV.y -= 0.5; warpedUV.y *= 1.0+(dist_center_sq.x * (0.4 * warpFactor)); warpedUV.y += 0.5;
+
+  // If the UV is outside the texture, return black
+  if (warpedUV.x < 0.0 || warpedUV.x > 1.0 || warpedUV.y < 0.0 || warpedUV.y > 1.0) {
+    finalColor = vec4(0.0, 0.0, 0.0, 1.0);
+    return;
+  }
+
+  // Determine factor of if we are rendering on a scanline
+  float scanlineFactor = abs(sin(fragTexCoord.y * viewport.y) * 0.5 * scanlineDarkness);
 
   // Build the final pixel
-  finalColor = vec4(tc, 1.0);
-}
+  finalColor = vec4(mix(texture(texture0, warpedUV).rgb, vec3(0.0), scanlineFactor), 1.0);
+}

game/src/lib.rs

@@ -80,9 +80,12 @@ use crate::{
     context::GameContext,
     discord_rpc::{maybe_set_discord_presence, try_connect_to_local_discord},
     scenes::{build_screen_state_machine, Scenes},
-    utilities::shaders::{
-        shader::ShaderWrapper,
-        util::{dynamic_screen_texture::DynScreenTexture, render_texture::render_to_texture},
+    utilities::{
+        game_config::FinalShaderConfig,
+        shaders::{
+            shader::ShaderWrapper,
+            util::{dynamic_screen_texture::DynScreenTexture, render_texture::render_to_texture},
+        },
     },
 };
 
@@ -166,16 +169,20 @@ pub async fn game_begin(game_config: &GameConfig) -> Result<(), Box<dyn std::err
         .unwrap();
 
     // Create a dynamic texture to draw to for processing by shaders
-    info!("Allocating a SNOWZ7Zresizable texture for the screen");
+    info!("Allocating a resizable texture for the screen");
     let mut dynamic_texture =
         DynScreenTexture::new(&mut context.renderer.borrow_mut(), &raylib_thread)?;
 
     // Load the pixel art shader
     info!("Loading the pixel art shader");
+    let pixel_shader_config = FinalShaderConfig::load(
+        StaticGameData::get("configs/final_shader.json").expect("Failed to load final_shader.json"),
+    )
+    .unwrap();
     let mut pixel_shader = ShaderWrapper::new(
         None,
         Some(StaticGameData::get("shaders/pixelart.fs")).expect("Failed to load pixelart.fs"),
-        vec!["viewport"],
+        vec!["viewport", "pixelScale", "warpFactor", "scanlineDarkness"],
         &mut context.renderer.borrow_mut(),
         &raylib_thread,
     )?;
@@ -202,6 +209,15 @@ pub async fn game_begin(game_config: &GameConfig) -> Result<(), Box<dyn std::err
 
         // Update the pixel shader to correctly handle the screen size
         pixel_shader.set_variable("viewport", screen_size)?;
+        pixel_shader.set_variable(
+            "pixelScale",
+            Vector2::new(
+                pixel_shader_config.pixel_scale,
+                pixel_shader_config.pixel_scale,
+            ),
+        )?;
+        pixel_shader.set_variable("warpFactor", pixel_shader_config.warp_factor)?;
+        pixel_shader.set_variable("scanlineDarkness", pixel_shader_config.scanline_darkness)?;
 
         // Render the game via the pixel shader
         render_to_texture(&mut dynamic_texture, || {

game/src/utilities/game_config.rs

@@ -8,7 +8,7 @@ use rust_embed::EmbeddedFile;
 pub struct Author {
     pub name: String,
     pub url: Option<String>,
-    pub roles: Vec<String>
+    pub roles: Vec<String>,
 }
 
 #[derive(Debug, Clone, Deserialize)]
@@ -16,7 +16,7 @@ pub struct GameConfig {
     pub name: String,
     // pub authors: Vec<Author>,
     pub base_window_size: (i32, i32),
-    pub sentry_dsn: String
+    pub sentry_dsn: String,
 }
 
 impl GameConfig {
@@ -25,3 +25,17 @@ impl GameConfig {
         serde_json::from_slice(&file.data)
     }
 }
+
+#[derive(Debug, Clone, Deserialize)]
+pub struct FinalShaderConfig {
+    pub pixel_scale: f32,
+    pub warp_factor: f32,
+    pub scanline_darkness: f32,
+}
+
+impl FinalShaderConfig {
+    /// Load from a file
+    pub fn load(file: EmbeddedFile) -> Result<Self, serde_json::Error> {
+        serde_json::from_slice(&file.data)
+    }
+}