Add a CRT shader effect over the game.

src/game.odin

@@ -26,6 +26,7 @@ RESOLUTIONS := [?]Resolution{
 Game :: struct {
     viewport:     rl.RenderTexture2D,
     bg_texture:   rl.Texture2D, 
+    crt_shader:   rl.Shader,
     scene_stack:  [dynamic]Scene,
     should_close: bool,
     audio:        Audio_Manager,
@@ -65,8 +66,8 @@ game_init :: proc(game: ^Game) {
     game.scene_stack = make([dynamic]Scene, 0, 8)
     game.viewport = rl.LoadRenderTexture(VIEWPORT_W, VIEWPORT_H)
 
-    // Force nearest neighbor point filtering on the viewport texture
-    rl.SetTextureFilter(game.viewport.texture, .POINT)
+    // Look into texture filters
+    rl.SetTextureFilter(game.viewport.texture, .BILINEAR)
 
     // Generate soft CRT background radial texture once on startup
     bg_center := rl.Color{22, 28, 36, 255}
@@ -74,7 +75,8 @@ game_init :: proc(game: ^Game) {
     bg_img    := rl.GenImageGradientRadial(VIEWPORT_W, VIEWPORT_H, 0.3, bg_center, bg_corner)
     game.bg_texture = rl.LoadTextureFromImage(bg_img)
     rl.UnloadImage(bg_img) // Free CPU memory
-    // rl.SetTextureFilter(game.bg_texture, .BILINEAR)
+
+    game.crt_shader = rl.LoadShader(nil, "assets/shaders/crt.fs")
 
     game.should_close = false
     set_root_scene(game, make_main_menu()) 
@@ -121,6 +123,7 @@ game_render :: proc(game: ^Game) {
 game_quit :: proc(game: ^Game) {
     audio_manager_quit(&game.audio)
 
+    rl.UnloadShader(game.crt_shader)
     rl.UnloadTexture(game.bg_texture)
     rl.UnloadRenderTexture(game.viewport)
     delete(GLOBAL_EVENTS)
@@ -156,6 +159,7 @@ game_set_resolution :: proc(game: ^Game, res_index: int) {
 render_game_to_window :: proc(game: ^Game) {
     texture := game.viewport.texture
 
+    rl.BeginShaderMode(game.crt_shader)
         rl.DrawTexturePro(
             texture, 
             // src: inverted y coordinate flips opengl texture buffer correctly
@@ -166,5 +170,5 @@ render_game_to_window :: proc(game: ^Game) {
             0,
             rl.WHITE,
         ) 
-
+    rl.EndShaderMode()
 }