Vector transformation now in place, just fancy words for saying

sum and difference identities in trigonometry.

src/base/base_inc.c

@@ -1,3 +1,5 @@
 // clang-format off
 
+#include "base_math.c"
+
 // clang-format on

src/base/base_math.c

@@ -0,0 +1,20 @@
+Vec3F32 vec3f32_rotate_x(Vec3F32 vector, float new_angle) {
+  Vec3F32 rotated_vector = {.x = vector.x,
+                            .y = vector.y * cos(new_angle) - vector.z * sin(new_angle),
+                            .z = vector.y * sin(new_angle) + vector.z * cos(new_angle)};
+  return rotated_vector;
+}
+
+Vec3F32 vec3f32_rotate_y(Vec3F32 vector, float new_angle) {
+  Vec3F32 rotated_vector = {.x = vector.x * cos(new_angle) - vector.z * sin(new_angle),
+                            .y = vector.y,
+                            .z = vector.x * sin(new_angle) + vector.z * cos(new_angle)};
+  return rotated_vector;
+}
+
+Vec3F32 vec3f32_rotate_z(Vec3F32 vector, float new_angle) {
+  Vec3F32 rotated_vector = {.x = vector.x * cos(new_angle) - vector.y * sin(new_angle),
+                            .y = vector.x * sin(new_angle) + vector.y * cos(new_angle),
+                            .z = vector.z};
+  return rotated_vector;
+}

src/base/base_math.h

@@ -20,4 +20,8 @@ union Vec3F32 {
   f32 v[2];
 };
 
+Vec3F32 vec3f32_rotate_x(Vec3F32 vector, float angle);
+Vec3F32 vec3f32_rotate_y(Vec3F32 vector, float angle);
+Vec3F32 vec3f32_rotate_z(Vec3F32 vector, float angle);
+
 #endif // BASE_MATH_H

src/ragar/ragar_main.c

@@ -1,3 +1,4 @@
+#include <math.h>
 #include <stdbool.h>
 #include <stdint.h>
 #include <stdio.h>
@@ -5,20 +6,21 @@
 #include "base/base_inc.h"
 #include "renderer/display.h"
 
+#include "base/base_inc.c"
 #include "renderer/display.c"
 
 #define POINTS (9 * 9 * 9)
 Vec3F32 cube_points[POINTS];
 Vec2F32 g_projected_points[POINTS];
 Vec3F32 camera_position = {.x = 0, .y = 0, .z = -5};
+Vec3F32 cube_rotation = {.x = 0, .y = 0, .z = 0};
 
 int is_running;
 
-// Perspective Projection
-// Perspective divide formula
-// P'x = Px/Pz
-//
-// P'y = Py/Pz
+// Perspective Projection (perspective divide)
+// Formula
+//   P'x = Px/Pz
+//   P'y = Py/Pz
 Vec2F32 perspective_projection(Vec3F32 points) {
   Vec2F32 projected_point = {.x = (field_of_view_factor * points.x) / points.z,
                              .y = (field_of_view_factor * points.y) / points.z};
@@ -67,14 +69,23 @@ void process_input(void) {
 }
 
 void update(void) {
+  cube_rotation.x += 0.01;
+  cube_rotation.y += 0.01;
+  cube_rotation.z += 0.01;
+
   for (s32 i = 0; i < POINTS; i++) {
     Vec3F32 point = cube_points[i];
 
-    // Move things away from the camera
-    point.z -= camera_position.z;
+    // Transform points
+    Vec3F32 transformed_points = vec3f32_rotate_x(point, cube_rotation.x);
+    transformed_points = vec3f32_rotate_y(transformed_points, cube_rotation.y);
+    transformed_points = vec3f32_rotate_z(transformed_points, cube_rotation.z);
 
-    // Project the current point
-    Vec2F32 projected_point = perspective_projection(point);
+    // Translate points away from the camera
+    transformed_points.z -= camera_position.z;
+
+    // Project the transformed point
+    Vec2F32 projected_point = perspective_projection(transformed_points);
 
     // Save the projected 2D vector in the global array of projected points
     g_projected_points[i] = projected_point;
@@ -87,7 +98,7 @@ void render(void) {
   // Loop through all projected points and render them
   for (u32 i = 0; i < POINTS; i++) {
     Vec2F32 projected_point = g_projected_points[i];
-    draw_rect(projected_point.x + (window_width / 2), projected_point.y + (window_height / 2), 4, 4, 0xFFFFFF00);
+    draw_rect(projected_point.x + (window_width / 2), projected_point.y + (window_height / 2), 4, 4, 0xFF659F00);
   }
 
   render_colour_buffer();

src/renderer/display.c

@@ -4,14 +4,15 @@ int initialize_window(void) {
     return false;
   }
 
-  // NOTE(tijani): Query screen size for fullscreen
-  // SDL_DisplayMode display_mode;
-  // SDL_GetCurrentDisplayMode(0, &display_mode); // NOTE(tijani): second screen instead of main one
-  // window_width = display_mode.w;
-  // window_height = display_mode.h;
+  // NOTE(tijani): Query screen size for fullscreen, this is important as not doing so
+  // will make everything compressed and not scale properly.
+  SDL_DisplayMode display_mode;
+  SDL_GetCurrentDisplayMode(0, &display_mode); // NOTE(tijani): second screen instead of main one
+  window_width = display_mode.w;
+  window_height = display_mode.h;
 
   window = SDL_CreateWindow("Ragar: 3D Software Renderer", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, window_width,
-                            window_height, 0);
+                            window_height, SDL_WINDOW_FULLSCREEN_DESKTOP);
   if (!window) {
     fprintf(stderr, "SDL could not create a window.\n");
     return false;

src/renderer/display.h

@@ -7,8 +7,8 @@ SDL_Window *window = NULL;
 SDL_Renderer *renderer = NULL;
 SDL_Texture *colour_buffer_texture = NULL;
 
-global s32 window_width = 800;
-global s32 window_height = 600;
+global s32 window_width = 1080;
+global s32 window_height = 1920;
 global f32 field_of_view_factor = 940;
 global u32 *colour_buffer;