From 66ae83793e07554e4dfaed4fb4e7e1666419c62e Mon Sep 17 00:00:00 2001
From: Thomas Perl <thp@perli.net>
Date: Thu, 7 Feb 2008 11:10:24 +0100
Subject: [PATCH] Smoothen player racket movement (accelerate)

Add an "acceleration" effect to the player racket
movement, so that keyboard control is a bit more
fine-grained and easier to use (hopefully).

Thanks To Enrico Zini <enricozini.org> for suggesting
this change and providing the feature request.
---
 game.c | 18 ++++++++++--------
 game.h |  5 ++++-
 2 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/game.c b/game.c
index 826bea5..51e5d7f 100644
--- a/game.c
+++ b/game.c
@@ -34,8 +34,8 @@ void game( bool singleplayer) {
     GameState s = {
         { 0, 0, 0.0, 0.0, 0.0 },
         { 0, 0, 0, 0, 0 },
-        { GAME_X_MIN-RACKET_X_MID*2, GAME_Y_MID, 0, 0, 1, DESIRE_NORMAL, PLAYER_TYPE_HUMAN, false, 0, 0 },
-        { GAME_X_MAX+RACKET_X_MID*2, GAME_Y_MID, 0, 0, 0, DESIRE_NORMAL, PLAYER_TYPE_HUMAN, false, 0, 0 },
+        { GAME_X_MIN-RACKET_X_MID*2, GAME_Y_MID, 0, 0, 1, DESIRE_NORMAL, PLAYER_TYPE_HUMAN, false, 0, 0, PLAYER_ACCEL_DEFAULT },
+        { GAME_X_MAX+RACKET_X_MID*2, GAME_Y_MID, 0, 0, 0, DESIRE_NORMAL, PLAYER_TYPE_HUMAN, false, 0, 0, PLAYER_ACCEL_DEFAULT },
         0,
         0,
         0,
@@ -483,12 +483,14 @@ void input_human( Player* player, bool up, bool down, bool hit, bool use_mouse,
         }
     }
 
-    if( up) {
-        player->y -= diff;
-    }
-
-    if( down) {
-        player->y += diff;
+    if (up) {
+        player->y -= fminf(diff, diff*player->accelerate);
+        player->accelerate *= PLAYER_ACCEL_INCREASE;
+    } else if (down) {
+        player->y += fminf(diff, diff*player->accelerate);
+        player->accelerate *= PLAYER_ACCEL_INCREASE;
+    } else {
+        player->accelerate = PLAYER_ACCEL_DEFAULT;
     }
 
     if( hit) {
diff --git a/game.h b/game.h
index fcaddb8..a538400 100644
--- a/game.h
+++ b/game.h
@@ -73,6 +73,7 @@ typedef struct {
     int sets[SETS_TO_WIN*2]; /* score for each set */
     int mouse_x; /* x position of mouse */
     int mouse_y; /* y position of mouse */
+    float accelerate; /* a value [0..1] how fast the user accelerates */
 } Player;
 
 enum {
@@ -158,7 +159,9 @@ typedef struct {
 #define IS_NEAR_X(px,bx) (fabsf(px-bx)<PLAYER_AREA_X)
 #define IS_NEAR_X_AI(px,bx) (fabsf(px-bx)<PLAYER_AREA_X*2)
 
-#define PLAYER_MOVE_Y 6.0
+#define PLAYER_MOVE_Y 5.0
+#define PLAYER_ACCEL_DEFAULT 0.2
+#define PLAYER_ACCEL_INCREASE 1.2
 #define PLAYER_STATE_MAX 7
 #define PLAYER_POWERSHOT 6.2
 
-- 
2.11.4.GIT