Rendering with shaders

assets/shaders/ripple.fs

@@ -0,0 +1,38 @@
+// void mainImage( out vec4 fragColor, in vec2 fragCoord )
+// {
+    
+//     vec2 uv = fragCoord.xy / iResolution.xy;
+    
+//     float X = uv.x*25.+iTime;
+//     float Y = uv.y*25.+iTime;
+//     uv.y += cos(X+Y)*0.01*cos(Y);
+//     uv.x += sin(X-Y)*0.01*sin(Y);
+	
+//     fragColor = texture(iChannel0,uv);
+// }
+#version 330
+
+// Input vertex attributes (from vertex shader)
+in vec2 fragTexCoord;
+in vec4 fragColor;
+
+// Input uniform values
+uniform sampler2D texture0;
+uniform vec4 colDiffuse;
+
+// Output fragment color
+out vec4 finalColor;
+
+// NOTE: Add here your custom variables
+
+void main()
+{
+    // Texel color fetching from texture sampler
+    vec4 texelColor = texture(texture0, fragTexCoord)*colDiffuse*fragColor;
+    
+    // Convert texel color to grayscale using NTSC conversion weights
+    float gray = dot(texelColor.rgb, vec3(0.299, 0.587, 0.114));
+    
+    // Calculate final fragment color
+    finalColor = vec4(gray, gray, gray, texelColor.a);
+}

src/logic/ingame/mod.rs

@@ -154,9 +154,6 @@ impl Screen for InGameScreen {
         // Calculate DT
         let dt = draw_handle.get_time() - game_core.last_frame_time;
 
-        // Clear frame
-        draw_handle.clear_background(Color::BLACK);
-
         // Handle the pause menu being opened
         if draw_handle.is_key_pressed(KeyboardKey::KEY_ESCAPE) {
             return Some(GameState::PauseMenu);
@@ -176,38 +173,68 @@ impl Screen for InGameScreen {
 
         // Open a 2D context
         {
-            let mut context_2d = draw_handle.begin_mode2D(game_core.master_camera);
+            unsafe {
-
+                raylib::ffi::BeginTextureMode(*game_core.resources.ripple_texture);
-            // Render the world
-            self.render_world(&mut context_2d, game_core, dt);
-            if game_core.show_simple_debug_info {
-                self.render_colliders(&mut context_2d, game_core);
             }
+            {
+                let mut context_2d = draw_handle.begin_mode2D(game_core.master_camera);
 
-            // Render entities
+                // Clear frame
-            for jellyfish in game_core.world.jellyfish.iter_mut() {
+                context_2d.clear_background(Color::BLACK);
-                jellyfish.handle_logic(&mut game_core.player, dt);
-                jellyfish.render(
-                    &mut context_2d,
-                    &mut game_core.player,
-                    &mut game_core.resources,
-                    dt,
-                );
-            }
-            for octopus in game_core.world.octopus.iter_mut() {
-                octopus.handle_logic(&mut game_core.player, dt);
-                octopus.render(
-                    &mut context_2d,
-                    &mut game_core.player,
-                    &mut game_core.resources,
-                    dt,
-                );
-            }
 
-            // Render Player
+                // Render the world
-            game_core
+                self.render_world(&mut context_2d, game_core, dt);
-                .player
+                if game_core.show_simple_debug_info {
-                .render(&mut context_2d, &mut game_core.resources, dt);
+                    self.render_colliders(&mut context_2d, game_core);
+                }
+
+                // Render entities
+                for jellyfish in game_core.world.jellyfish.iter_mut() {
+                    jellyfish.handle_logic(&mut game_core.player, dt);
+                    jellyfish.render(
+                        &mut context_2d,
+                        &mut game_core.player,
+                        &mut game_core.resources,
+                        dt,
+                    );
+                }
+                for octopus in game_core.world.octopus.iter_mut() {
+                    octopus.handle_logic(&mut game_core.player, dt);
+                    octopus.render(
+                        &mut context_2d,
+                        &mut game_core.player,
+                        &mut game_core.resources,
+                        dt,
+                    );
+                }
+
+                // Render Player
+                game_core
+                    .player
+                    .render(&mut context_2d, &mut game_core.resources, dt);
+            }
+            unsafe {
+                raylib::ffi::EndTextureMode();
+            }
+        }
+
+        // Render the 2D context via the ripple shader
+        {
+            let mut shader_context =
+                draw_handle.begin_shader_mode(&game_core.resources.ripple_shader);
+
+            // Blit the texture
+            shader_context.draw_texture_rec(
+                &game_core.resources.ripple_texture,
+                Rectangle {
+                    x: 0.0,
+                    y: 0.0,
+                    width: game_core.resources.ripple_texture.width() as f32,
+                    height: (game_core.resources.ripple_texture.height() as f32) * -1.0,
+                },
+                Vector2::zero(),
+                Color::WHITE,
+            );
         }
 
         // Render the darkness layer
@@ -216,7 +243,6 @@ impl Screen for InGameScreen {
         // Render the hud
         hud::render_hud(draw_handle, game_core, window_center);
 
-
         // Handle player out of breath
         if game_core.player.breath_percent == 0.0 {
             return Some(GameState::GameEnd);

src/resources.rs

@@ -1,9 +1,5 @@
 use failure::Error;
-use raylib::{
+use raylib::{RaylibHandle, RaylibThread, math::Vector2, shaders::Shader, texture::{Image, RenderTexture2D, Texture2D}};
-    math::Vector2,
-    texture::{Image, Texture2D},
-    RaylibHandle, RaylibThread,
-};
 
 use crate::lib::wrappers::animation::FrameAnimationWrapper;
 
@@ -24,6 +20,8 @@ pub struct GlobalResources {
 
     // Cave
     pub cave_mid_layer: Texture2D,
+    pub ripple_shader: Shader,
+    pub ripple_texture: RenderTexture2D,
 
     // Enemies
     pub jellyfish_animation_regular: FrameAnimationWrapper,
@@ -106,6 +104,8 @@ impl GlobalResources {
                 &thread,
                 &Image::load_image("./assets/img/map/cave.png")?,
             )?,
+            ripple_shader: raylib.load_shader(&thread, None, Some("./assets/shaders/ripple.fs"))?,
+            ripple_texture: raylib.load_render_texture(&thread, raylib.get_screen_width() as u32, raylib.get_screen_height() as u32)?,
             jellyfish_animation_regular: FrameAnimationWrapper::new(
                 raylib.load_texture_from_image(
                     &thread,