From 7e65bd9ab6bf0d01e63ca2b2e477495c7e37f761 Mon Sep 17 00:00:00 2001
From: tijani <tijani@tijanilawal.com>
Date: Sat, 31 Aug 2024 15:31:33 -0500
Subject: [PATCH] orthographic projection.

---
 src/base/base_inc.c    |  1 -
 src/ragar/ragar_main.c | 41 ++++++++++++++++++++++++++++++++++++-----
 src/renderer/display.c | 24 +++++++++++-------------
 src/renderer/display.h | 11 ++++++-----
 4 files changed, 53 insertions(+), 24 deletions(-)

diff --git a/src/base/base_inc.c b/src/base/base_inc.c
index 2d2667c..71f2db1 100644
--- a/src/base/base_inc.c
+++ b/src/base/base_inc.c
@@ -1,4 +1,3 @@
 // clang-format off
 
-
 // clang-format on
diff --git a/src/ragar/ragar_main.c b/src/ragar/ragar_main.c
index bb615a7..eb983c3 100644
--- a/src/ragar/ragar_main.c
+++ b/src/ragar/ragar_main.c
@@ -7,14 +7,34 @@
 
 #include "renderer/display.c"
 
+#define POINTS (9 * 9 * 9)
+Vec3F32 cube_points[POINTS];
+Vec2F32 g_projected_points[POINTS];
+
 int is_running;
 
+// Orthographic Projection - convert 3D points into a 2D projected point
+Vec2F32 orthographic_projection(Vec3F32 points) {
+  Vec2F32 projected_point = {.x = (field_of_view_factor * points.x), .y = (field_of_view_factor * points.y)};
+  return projected_point;
+}
+
 void setup(void) {
   colour_buffer = (u32 *)malloc(sizeof(u32) * window_width * window_height);
   colour_buffer_texture =
       SDL_CreateTexture(renderer, SDL_PIXELFORMAT_ARGB8888, SDL_TEXTUREACCESS_STREAMING, window_width, window_height);
-}
 
+  int point_count = 0;
+  // Load array of vectors, from -1 to 1 in the 9*9*9 cube
+  for (f32 x = -1; x <= 1; x += 0.25) {
+    for (f32 y = -1; y <= 1; y += 0.25) {
+      for (f32 z = -1; z <= 1; z += 0.25) {
+        Vec3F32 new_points = {.x = x, .y = y, .z = z};
+        cube_points[point_count++] = new_points;
+      }
+    }
+  }
+}
 
 void process_input(void) {
   SDL_Event event;
@@ -35,16 +55,27 @@ void process_input(void) {
 }
 
 void update(void) {
+  for (s32 i = 0; i < POINTS; i++) {
+    Vec3F32 point = cube_points[i];
+
+    // Project the current point
+    Vec2F32 projected_point = orthographic_projection(point);
+
+    // Save the projected 2D vector in the global array of projected points
+    g_projected_points[i] = projected_point;
+  }
 }
 
 void render(void) {
-  draw_dots(0xFFFFFFFF);
+  draw_grid(0xFF000000);
 
-  SDL_SetRenderDrawColor(renderer, 28, 450, 560, 255);
-  SDL_RenderClear(renderer);
+  // 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);
+  }
 
   render_colour_buffer();
-  clear_colour_buffer(0xFF384893);
   clear_colour_buffer(0xFF000000);
 
   SDL_RenderPresent(renderer);
diff --git a/src/renderer/display.c b/src/renderer/display.c
index 3f77f95..d960f40 100644
--- a/src/renderer/display.c
+++ b/src/renderer/display.c
@@ -10,8 +10,8 @@ int initialize_window(void) {
   // 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 = SDL_CreateWindow("Ragar: 3D Software Renderer", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,
+                            window_width, window_height, 0);
   if (!window) {
     fprintf(stderr, "SDL could not create a window.\n");
     return false;
@@ -36,9 +36,9 @@ void destroy_window(void) {
 }
 
 void clear_colour_buffer(u32 colour) {
-  for (int i = 0; i < window_height; i++) {
-    for (int j = 0; j < window_width; j++) {
-      colour_buffer[(window_width * i) + j] = colour;
+  for (int y = 0; y < window_height; y++) {
+    for (int x = 0; x < window_width; x++) {
+      colour_buffer[(window_width * y) + x] = colour;
     }
   }
 }
@@ -59,26 +59,24 @@ void draw_dots(u32 colour) {
 void draw_grid(u32 colour) {
   for (s32 column = 0; column < window_height; column++) {
     for (s32 row = 0; row < window_width; row++) {
-      if ((row % 10) == 0 || (column % 100) == 0) {
-        colour_buffer[(window_width * column) + row] = colour;
-      }
+      colour_buffer[(window_width * column) + row] = colour;
     }
   }
 }
 
-void draw_rect(s32 x, s32 y, s32 width, s32 height, s32 colour) {
+void draw_rect(s32 x, s32 y, s32 width, s32 height, u32 colour) {
   for (int row = 0; row < width; row++) {
     for (int column = 0; column < height; column++) {
       s32 l_row = row + x;
       s32 l_column = column + y;
 
       draw_pixel(l_row, l_column, colour);
-
-      // colour_buffer[(window_width * l_column) + l_row] = colour;
     }
   }
 }
 
-void draw_pixel(u32 x, u32 y, u32 colour) {
-  colour_buffer[(window_width * y) + x] = colour;
+void draw_pixel(s32 x, s32 y, u32 colour) {
+  if (((x >= 0) && (x < window_width)) && ((y >= 0) && (y < window_height))) {
+    colour_buffer[(window_width * y) + x] = colour;
+  }
 }
diff --git a/src/renderer/display.h b/src/renderer/display.h
index 7256960..bf7eb3a 100644
--- a/src/renderer/display.h
+++ b/src/renderer/display.h
@@ -7,19 +7,20 @@ SDL_Window *window = NULL;
 SDL_Renderer *renderer = NULL;
 SDL_Texture *colour_buffer_texture = NULL;
 
-u32 *colour_buffer;
-s32 window_width = 800;
-s32 window_height = 600;
+global s32 window_width = 800;
+global s32 window_height = 600;
+global f32 field_of_view_factor = 128;
+global u32 *colour_buffer;
 
 int initialize_window(void);
 void destroy_window(void);
 void clear_colour_buffer(u32 colour);
 void render_colour_buffer(void);
 
-void draw_pixel(u32 x, u32 y, u32 colour);
+void draw_pixel(s32 x, s32 y, u32 colour);
 
 void draw_grid(u32 colour);
 void draw_dots(u32 colour);
-void draw_rect(s32 x, s32 y, s32 width, s32 height, s32 colour);
+void draw_rect(s32 x, s32 y, s32 width, s32 height, u32 colour);
 
 #endif // RAGAR_DISPLAY_H