Added explanation for Fixed-point usage, + a useful macro

3 files changed, 23 insertions, 4 deletions

diff --git a/src/config.h b/src/config.h
index 5099409..18dc414 100644
--- a/src/config.h
+++ b/src/config.h
@@ -9,12 +9,28 @@ typedef unsigned long long u64;
 typedef float f32;
 typedef double f64;
 
+/*
+You may be wondering "why fixed point values???", and that's simple
+Floating Point was a mistake and has caused great suffering to countless.
+Time-keeping is specially burdened. Nobody should ever keep track of time
+with float values. Variable precision can and WILL throw off calculations
+no matter how much of a NERD you are.
+
+What I did was to just leverage the support for floats in order to make most
+things simply take them (that's what everyone expects) then convert them to
+fixed point for precise operations.
+
+They can still be happily used for other things, specially inside shaders.
+But don't @ me.
+*/
+
 // 24.8 format
 typedef i32 fx32;
 #define FIXED_POINT_BITS 8
 #define FIXED_POINT_ONE (1 << FIXED_POINT_BITS)
 #define TO_FIXED(x) ((fx32)(x) << FIXED_POINT_BITS)
 #define FROM_FIXED(x) ((x) >> FIXED_POINT_BITS)
+#define FP_TO_FIXED(x) (fx32)((x) * FIXED_POINT_BITS)
 
 typedef struct{
 	fx32 x, y;
diff --git a/src/controller.c b/src/controller.c
index cacada3..aa8d4d9 100644
--- a/src/controller.c
+++ b/src/controller.c
@@ -19,8 +19,8 @@ b32 is_button_released(i32 btn)
 
 vec2 get_dir_input(void)
 {
-	fx32 cont_x = (fx32)(FIXED_POINT_ONE * GetGamepadAxisMovement(0, 0));
-	fx32 cont_y = (fx32)(FIXED_POINT_ONE * GetGamepadAxisMovement(0, 1));
+	fx32 cont_x = FP_TO_FIXED(GetGamepadAxisMovement(0, 0));
+	fx32 cont_y = FP_TO_FIXED(GetGamepadAxisMovement(0, 1));
 	
 	fx32 key_w = is_button_held(KEY_W) ? FIXED_POINT_ONE : 0;
 	fx32 key_s = is_button_held(KEY_S) ? FIXED_POINT_ONE : 0;
diff --git a/src/rumble.c b/src/rumble.c
index 2313d68..2212761 100644
--- a/src/rumble.c
+++ b/src/rumble.c
@@ -2,6 +2,8 @@
 I made this a separate source file because Raylib has some quirks
 regarding Windows compilation. And I also suppose because it has
 some state of its own.
+
+NOTE FOR SPELUNKERS: this requires linking to xinput1_4 AFAIK
 */
 
 #include "controller.h"
@@ -23,16 +25,17 @@ void set_rumble(f32 duration, f32 strength)
     state.wRightMotorSpeed = (unsigned)(strength * 65535.0f);
 
     if (XInputSetState(0, &state) == 0){
-        timer = FIXED_POINT_ONE * duration;
+        timer = FP_TO_FIXED(duration);
     }
 }
 
 void poll_rumble(f32 dt)
 {
+	// Early return
 	if(timer <= 0)
 		return;
 		
-	fx32 delta = FIXED_POINT_ONE * dt;
+	fx32 delta = FP_TO_FIXED(dt);
 	
 	timer -= delta;
 	if(timer <= 0){