Update set pixel to use integers instead of floats

include/window/window.h

@@ -13,19 +13,21 @@ typedef struct {
 } colour_t;
 
 typedef struct {
-  u64 width;
-  u64 height;
+  u32 width;
+  u32 height;
+  u32 half_width;
+  u32 half_height;
   const char *title;
   SDL_Window *window;
   SDL_Surface *front_buffer;
   SDL_Surface *back_buffer;
 } window_t;
 
-bool init_window(window_t *wnd, u64 width, u64 height, const char *title);
+bool init_window(window_t *wnd, u32 width, u32 height, const char *title);
 void close_window(window_t *wnd);
 
 void clear_window(window_t *wnd, colour_t colour);
-void set_pixel(window_t *wnd, f32 x, f32 y, colour_t colour);
+void set_pixel(window_t *wnd, i32 x, i32 y, colour_t colour);
 void swap_buffers(window_t *wnd);
 
 #endif // !WINDOW_H

src/window/window.c

@@ -7,21 +7,26 @@
 #include <stdbool.h>
 #include <stdio.h>
 
-#define NORMALISED_MIN -1.0f
-#define NORMALISED_MAX 1.0f
-
 u32 colour_to_u32(colour_t colour);
 u32 index_from_coordinates(window_t *wnd, u32 x, u32 y);
-i32 denormalise(f32 value, u32 max);
+i32 denormalise(i32 value, u32 max, u32 abs_normalised);
 void set_screen_pixel(window_t *wnd, u32 x, u32 y, colour_t colour);
 
-bool init_window(window_t *wnd, u64 width, u64 height, const char *title) {
+bool init_window(window_t *wnd, u32 width, u32 height, const char *title) {
   if (SDL_Init(SDL_INIT_EVERYTHING) != 0) {
     printf("Failed to initialise SDL: %s\n", SDL_GetError());
 
     return false;
   }
 
+  if (width % 2 != 0) {
+    ++width;
+  }
+
+  if (height % 2 != 0) {
+    ++height;
+  }
+
   wnd->window = SDL_CreateWindow(title, SDL_WINDOWPOS_CENTERED,
                                  SDL_WINDOWPOS_CENTERED, width, height, 0);
   if (!(wnd->window)) {
@@ -53,6 +58,8 @@ bool init_window(window_t *wnd, u64 width, u64 height, const char *title) {
 
   wnd->width = width;
   wnd->height = height;
+  wnd->half_width = width / 2;
+  wnd->half_height = height / 2;
   wnd->title = title;
 
   return true;
@@ -95,9 +102,9 @@ void clear_window(window_t *wnd, colour_t colour) {
   SDL_UnlockSurface(wnd->back_buffer);
 }
 
-void set_pixel(window_t *wnd, f32 x, f32 y, colour_t colour) {
-  i32 screen_x = denormalise(x, wnd->width);
-  i32 screen_y = denormalise(-y, wnd->height);
+void set_pixel(window_t *wnd, i32 x, i32 y, colour_t colour) {
+  i32 screen_x = denormalise(x, wnd->width, wnd->half_width);
+  i32 screen_y = denormalise(-y, wnd->height, wnd->half_height);
 
   if (screen_x < 0 || screen_y < 0) {
     return;
@@ -125,13 +132,22 @@ u32 index_from_coordinates(window_t *wnd, u32 x, u32 y) {
   return y * wnd->width + x;
 }
 
-i32 denormalise(f32 value, u32 max) {
-  if (max == 0 || value < NORMALISED_MIN || value >= NORMALISED_MAX) {
+i32 denormalise(i32 value, u32 max, u32 abs_normalised) {
+  i32 normalised_min = -abs_normalised;
+  i32 normalised_max = abs_normalised;
+
+  if (max == 0) {
     return -1;
   }
 
-  return (i32)(((value - NORMALISED_MIN) * max) /
-               (NORMALISED_MAX - NORMALISED_MIN));
+  i32 denormalised = (i32)(((value - normalised_min) * max) /
+                           (normalised_max - normalised_min));
+
+  if (denormalised < 0 || denormalised >= max) {
+    return -1;
+  }
+
+  return denormalised;
 }
 
 void set_screen_pixel(window_t *wnd, u32 x, u32 y, colour_t colour) {