Draw first line

include/rasteriser/rasteriser.h

@@ -0,0 +1,9 @@
+#ifndef RASTERISER_H
+#define RASTERISER_H
+
+#include "vector/vec.h"
+#include "window/window.h"
+
+void draw_line(window_t *wnd, vec2i_t p0, vec2i_t p1, colour_t colour);
+
+#endif // !RASTERISER_H

include/vector/vec.h

@@ -33,6 +33,12 @@ typedef struct {
 #define vec_dot(T, v1, v2) vec_dot_##T(v1, v2)
 #define vec_magnitude(T, v) vec_magnitude_##T(v)
 #define vec_unit(T, v) vec_unit_##T(v)
+#define vec_swap(T, v1, v2)                                                    \
+  {                                                                            \
+    T tmp = v1;                                                                \
+    v1 = v2;                                                                   \
+    v2 = tmp;                                                                  \
+  }
 
 vec2i_t vec_add_vec2i_t(vec2i_t v1, vec2i_t v2);
 vec2i_t vec_sub_vec2i_t(vec2i_t v1, vec2i_t v2);

src/rasteriser/main.c

@@ -1,7 +1,47 @@
-#include <stdio.h>
+#include "rasteriser/rasteriser.h"
+#include "vector/vec.h"
+#include "window/window.h"
+#include <SDL2/SDL_events.h>
+#include <SDL2/SDL_keycode.h>
 #include <stdlib.h>
 
 int main(void) {
-  printf("RASTERISER\n");
+  colour_t bg =
+      (colour_t){.rgba.r = 27, .rgba.g = 38, .rgba.b = 79, .rgba.a = 255};
+  window_t window = {0};
+
+  if (!init_window(&window, 800, 800, "CG From Scratch Rasteriser")) {
+    return EXIT_FAILURE;
+  }
+
+  bool running = true;
+  SDL_Event event = {0};
+
+  // i32 w_min = ((i32)window.half_width) * -1;
+  // i32 w_max = (i32)window.half_width;
+  // i32 h_min = ((i32)window.half_height) * -1;
+  // i32 h_max = (i32)window.half_height;
+
+  vec2i_t a = {.x = -300, .y = 0};
+  vec2i_t b = {.x = 300, .y = 250};
+
+  while (running) {
+    while (SDL_PollEvent(&event)) {
+      switch (event.type) {
+      case SDL_QUIT:
+        running = false;
+        break;
+      }
+    }
+
+    clear_window(&window, bg);
+
+    draw_line(&window, a, b, (colour_t){.colour = 0xffffffff});
+
+    swap_buffers(&window);
+  }
+
+  close_window(&window);
+
   return EXIT_SUCCESS;
 }

src/rasteriser/rasteriser.c

@@ -0,0 +1,22 @@
+#include "c_cpp_aliases/aliases.h"
+#include "vector/vec.h"
+#include "window/window.h"
+
+void draw_line(window_t *wnd, vec2i_t p0, vec2i_t p1, colour_t colour) {
+  if (p1.x < p0.x) {
+    vec_swap(vec2i_t, p0, p1);
+  }
+
+  i32 x0 = p0.x;
+  i32 y0 = p0.y;
+  i32 x1 = p1.x;
+  i32 y1 = p1.y;
+
+  f32 a = ((f32)y1 - y0) / ((f32)x1 - x0);
+  f32 y = y0;
+
+  for (i32 x = x0; x <= x1; ++x) {
+    set_pixel(wnd, x, (i32)y, colour);
+    y += a;
+  }
+}