Merge pull request #35 from Ewpratten/shaders

Use a pixel shader

assets/shaders/pixel.fs

@@ -0,0 +1,32 @@
+#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;
+
+// Viewport dimensions
+const float renderWidth = 1080;
+const float renderHeight = 720;
+
+// Pixel scaling
+uniform float pixelWidth = 2.0;
+uniform float pixelHeight = 2.0;
+
+void main()
+{
+    float dx = pixelWidth * (1.0 / renderWidth);
+    float dy = pixelHeight * (1.0 / renderHeight);
+
+    vec2 coord = vec2(dx * floor(fragTexCoord.x / dx), dy * floor(fragTexCoord.y / dy));
+
+    vec3 tc = texture(texture0, coord).rgb;
+
+    finalColor = vec4(tc, 1.0);
+}

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);
@@ -175,9 +172,16 @@ impl Screen for InGameScreen {
         playerlogic::update_player_movement(draw_handle, game_core, window_center);
 
         // Open a 2D context
+        {
+            unsafe {
+                raylib::ffi::BeginTextureMode(*game_core.resources.shader_texture);
+            }
             {
                 let mut context_2d = draw_handle.begin_mode2D(game_core.master_camera);
 
+                // Clear frame
+                context_2d.clear_background(Color::BLACK);
+
                 // Render the world
                 self.render_world(&mut context_2d, game_core, dt);
                 if game_core.show_simple_debug_info {
@@ -209,6 +213,29 @@ impl Screen for InGameScreen {
                     .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.pixel_shader);
+
+            // Blit the texture
+            shader_context.draw_texture_rec(
+                &game_core.resources.shader_texture,
+                Rectangle {
+                    x: 0.0,
+                    y: 0.0,
+                    width: game_core.resources.shader_texture.width() as f32,
+                    height: (game_core.resources.shader_texture.height() as f32) * -1.0,
+                },
+                Vector2::zero(),
+                Color::WHITE,
+            );
+        }
 
         // Render the darkness layer
         self.render_darkness(draw_handle, game_core);
@@ -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 pixel_shader: Shader,
+    pub shader_texture: RenderTexture2D,
 
     // Enemies
     pub jellyfish_animation_regular: FrameAnimationWrapper,
@@ -106,6 +104,8 @@ impl GlobalResources {
                 &thread,
                 &Image::load_image("./assets/img/map/cave.png")?,
             )?,
+            pixel_shader: raylib.load_shader(&thread, None, Some("./assets/shaders/pixel.fs"))?,
+            shader_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,