From df5ca740fa8e438e6bc67fe1ed078aa983ffeed5 Mon Sep 17 00:00:00 2001
From: Paul Duncan <pabs@pablotron.org>
Date: Sat, 19 Jan 2019 02:08:20 -0500
Subject: add fading, fix sounds

---
 src/sdl/draw.c | 30 +++++++++++++++++++++++++++++-
 src/sdl/draw.h |  3 +++
 src/sdl/main.c | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++++++----
 3 files changed, 86 insertions(+), 5 deletions(-)

diff --git a/src/sdl/draw.c b/src/sdl/draw.c
index d95e83f..e980131 100644
--- a/src/sdl/draw.c
+++ b/src/sdl/draw.c
@@ -11,6 +11,7 @@
 #define M_2_PI (2.0 * 3.1415926)
 
 #define BUMP_TIME 300
+#define FADE_TIME 200
 
 static size_t
 get_cell_size(
@@ -297,7 +298,6 @@ draw_solve_moves_text(
   draw_text(draw_ctx->renderer, draw_ctx->font, style, buf);
 }
 
-
 static void
 draw_bg(
   draw_ctx_t * const draw_ctx
@@ -320,6 +320,31 @@ draw_bg(
   SDL_RenderClear(draw_ctx->renderer);
 }
 
+static void
+draw_fade(
+  draw_ctx_t * const draw_ctx
+) {
+  // check timestamp
+  if (SDL_TICKS_PASSED(draw_ctx->ticks, draw_ctx->fade_ticks + FADE_TIME)) {
+    return;
+  }
+
+  // calculate alpha mod
+  const Uint32 delta = (draw_ctx->ticks - draw_ctx->fade_ticks);
+  const Uint8 alpha = 255 - 255.0 * delta / FADE_TIME;
+
+  // set alpha mod
+  if (SDL_SetTextureAlphaMod(draw_ctx->fade_tex, alpha)) {
+    die("SDL_TextureSetAlphaMod(): %s", SDL_GetError());
+  }
+  // SDL_Log("delta = %u, alpha = %d", delta, alpha);
+
+  // draw texture
+  if (SDL_RenderCopy(draw_ctx->renderer, draw_ctx->fade_tex, NULL, NULL)) {
+    die("SDL_RenderCopy(): %s", SDL_GetError());
+  }
+}
+
 void
 draw(
   draw_ctx_t * const draw_ctx
@@ -340,6 +365,9 @@ draw(
   draw_solve_wait_text(draw_ctx);
   draw_solve_moves_text(draw_ctx);
 
+  // draw fade overlay
+  draw_fade(draw_ctx);
+
   // flip
   SDL_RenderPresent(draw_ctx->renderer);
 }
diff --git a/src/sdl/draw.h b/src/sdl/draw.h
index 919f362..b7e6caa 100644
--- a/src/sdl/draw.h
+++ b/src/sdl/draw.h
@@ -34,6 +34,9 @@ typedef struct {
   game_state_t state;
   solve_t *solve;
   size_t solve_num_steps;
+
+  Uint32 fade_ticks;
+  SDL_Texture *fade_tex;
 } draw_ctx_t;
 
 void draw(draw_ctx_t * const);
diff --git a/src/sdl/main.c b/src/sdl/main.c
index 40896e2..0d492a5 100644
--- a/src/sdl/main.c
+++ b/src/sdl/main.c
@@ -17,6 +17,8 @@
 #include "sounds.h"
 
 #define WINDOW_TITLE "Pablotron Sokoban"
+#define WINDOW_WIDTH 800
+#define WINDOW_HEIGHT 600
 
 static TTF_Font *
 load_font(
@@ -44,12 +46,35 @@ load_font(
   return font;
 }
 
+static void
+draw_to_fade_tex(
+  draw_ctx_t * const draw_ctx
+) {
+  // set render target
+  if (SDL_SetRenderTarget(draw_ctx->renderer, draw_ctx->fade_tex)) {
+    die("SDL_SetRenderTarget(): %s", SDL_GetError());
+  }
+
+  // draw
+  draw(draw_ctx);
+
+  // clear render target
+  if (SDL_SetRenderTarget(draw_ctx->renderer, NULL)) {
+    die("SDL_SetRenderTarget(): %s", SDL_GetError());
+  }
+}
+
 static void
 set_level(
   draw_ctx_t * const draw_ctx,
   sok_ctx_t * const ctx,
   const size_t level_num
 ) {
+  if (level_num) {
+    // draw current level to fade texture
+    draw_to_fade_tex(draw_ctx);
+  }
+
   // get level data
   draw_ctx->level = levels_get_level(level_num);
 
@@ -58,6 +83,11 @@ set_level(
     die("Couldn't load level %d", (int) level_num);
   }
 
+  if (level_num) {
+    // set fade ticks
+    draw_ctx->fade_ticks = SDL_GetTicks();
+  }
+
   // log level title
   SDL_Log(
     "Loaded level \"%s: %s\" (#%d)",
@@ -167,8 +197,8 @@ int main(int argc, char *argv[]) {
     WINDOW_TITLE,
     SDL_WINDOWPOS_UNDEFINED,
     SDL_WINDOWPOS_UNDEFINED,
-    800,
-    600,
+    WINDOW_WIDTH,
+    WINDOW_HEIGHT,
     SDL_WINDOW_RESIZABLE
   );
 
@@ -198,8 +228,28 @@ int main(int argc, char *argv[]) {
     .zoom       = &zoom,
     .theme      = theme_get_default(),
     .bump_ticks = SDL_GetTicks() - 5000,
+    .fade_ticks = SDL_GetTicks() - 5000,
   };
 
+  // create fade texture
+  draw_ctx.fade_tex = SDL_CreateTexture(
+    renderer,
+    SDL_PIXELFORMAT_RGBA32,
+    SDL_TEXTUREACCESS_TARGET,
+    WINDOW_WIDTH,
+    WINDOW_HEIGHT
+  );
+
+  // set fade texture blend mode
+  if (SDL_SetTextureBlendMode(draw_ctx.fade_tex, SDL_BLENDMODE_BLEND)) {
+    die("SDl_SetTextureBlendMode(): %s", SDL_GetError());
+  }
+
+  // check for error
+  if (!draw_ctx.fade_tex) {
+    die("SDL_CreateTexture(): %s", SDL_GetError());
+  }
+
   // set level
   set_level(&draw_ctx, &ctx, level_num);
 
@@ -259,7 +309,7 @@ int main(int argc, char *argv[]) {
       case ACTION_NEXT:
         if (sok_ctx_is_done(&ctx)) {
           // play sound
-          sound_play(sounds, ASSET_SOUND_JUMP_0_WAV);
+          sound_play(sounds, ASSET_SOUND_POWERUP_1_WAV);
 
           // advance level
           level_num++;
@@ -285,7 +335,7 @@ int main(int argc, char *argv[]) {
       case ACTION_WARP:
         if (warp_buf_get(&warp_buf, &level_num)) {
           // play sound
-          sound_play(sounds, ASSET_SOUND_JUMP_0_WAV);
+          sound_play(sounds, ASSET_SOUND_POWERUP_1_WAV);
 
           // load level
           set_level(&draw_ctx, &ctx, level_num);
-- 
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