vertices and triangle faces.

src/ragar/ragar_main.c

@@ -9,9 +9,64 @@
 #include "base/base_inc.c"
 #include "renderer/display.c"
 
-#define POINTS (9 * 9 * 9)
+// NOTE(tijani): Vertices are points;
-Vec3F32 cube_points[POINTS];
+// Faces are the surfaces formed by connecting those points.
-Vec2F32 g_projected_points[POINTS];
+
+#define MESH_VERTICES 8
+#define MESH_FACES (6 * 2) // 6 cube faces, 2 triangles per face
+
+typedef struct Triangle2F32 Triangle2F32;
+struct Triangle2F32 {
+  Vec2F32 points[3];
+};
+
+typedef struct Face3S32 Face3S32;
+struct Face3S32 {
+  s32 a;
+  s32 b;
+  s32 c;
+};
+
+// clang-format off
+Vec3F32 mesh_vertices[MESH_VERTICES] = {
+  { .x = -1, .y = -1, .z = -1},
+  { .x = -1, .y =  1, .z = -1},
+  { .x =  1, .y =  1, .z = -1},
+  { .x =  1, .y = -1, .z = -1},
+  { .x =  1, .y =  1, .z =  1},
+  { .x =  1, .y = -1, .z =  1},
+  { .x = -1, .y =  1, .z =  1},
+  { .x = -1, .y = -1, .z =  1},
+};
+// clang-format on
+
+Face3S32 mesh_faces[MESH_FACES] = {
+    // front
+    {.a = 1, .b = 2, .c = 3},
+    {.a = 1, .b = 3, .c = 4},
+
+    // right
+    {.a = 4, .b = 3, .c = 5},
+    {.a = 4, .b = 5, .c = 6},
+
+    // back
+    {.a = 6, .b = 5, .c = 7},
+    {.a = 6, .b = 7, .c = 8},
+
+    // left
+    {.a = 8, .b = 7, .c = 2},
+    {.a = 8, .b = 2, .c = 1},
+
+    // top
+    {.a = 2, .b = 7, .c = 5},
+    {.a = 2, .b = 5, .c = 3},
+
+    // bottom
+    {.a = 6, .b = 8, .c = 1},
+    {.a = 6, .b = 1, .c = 4},
+};
+
+Triangle2F32 g_triangles_to_render[MESH_FACES];
 Vec3F32 camera_position = {.x = 0, .y = 0, .z = -5};
 Vec3F32 cube_rotation = {.x = 0, .y = 0, .z = 0};
 
@@ -38,17 +93,6 @@ 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) {
@@ -81,32 +125,52 @@ void update(void) {
   cube_rotation.y += 0.01;
   cube_rotation.z += 0.01;
 
-  for (s32 i = 0; i < POINTS; i++) {
+  // Loop through all triangle faces of the mesh
-    Vec3F32 point = cube_points[i];
+  for (s32 i = 0; i < MESH_FACES; i++) {
+    Face3S32 current_mesh_face = mesh_faces[i];
+    
+    Vec3F32 face_vertices[3];
+    face_vertices[0] = mesh_vertices[current_mesh_face.a - 1];
+    face_vertices[1] = mesh_vertices[current_mesh_face.b - 1];
+    face_vertices[2] = mesh_vertices[current_mesh_face.c - 1];
 
-    // Transform points
+    Triangle2F32 projected_triangle;
-    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);
 
-    // Translate points away from the camera
+    // Loop throug all three vertices of the current face and apply transformations
-    transformed_points.z -= camera_position.z;
+    for (s32 j = 0; j < 3; j++) {
+      Vec3F32 transformed_vertex = face_vertices[j];
 
-    // Project the transformed point
+      transformed_vertex = vec3f32_rotate_x(transformed_vertex, cube_rotation.x);
-    Vec2F32 projected_point = perspective_projection(transformed_points);
+      transformed_vertex = vec3f32_rotate_y(transformed_vertex, cube_rotation.y);
+      transformed_vertex = vec3f32_rotate_z(transformed_vertex, cube_rotation.z);
 
-    // Save the projected 2D vector in the global array of projected points
+      // Translate the vertex away from the camera
-    g_projected_points[i] = projected_point;
+      transformed_vertex.z -= camera_position.z;
+
+      // Project the current vertex
+      Vec2F32 projected_point = perspective_projection(transformed_vertex);
+
+      // Scale and translate the projected points to the middle of the screen.
+      projected_point.x += (window_width / 2);
+      projected_point.y += (window_height / 2);
+
+      projected_triangle.points[j] = projected_point;
+    }
+
+    // Save the projected triangle in the array of triangles to render
+    g_triangles_to_render[i] = projected_triangle;
   }
 }
 
 void render(void) {
-  draw_grid(0xFF000000);
+  draw_grid(0xFF444444);
 
   // Loop through all projected points and render them
-  for (u32 i = 0; i < POINTS; i++) {
+  for (u32 i = 0; i < MESH_FACES; i++) {
-    Vec2F32 projected_point = g_projected_points[i];
+    Triangle2F32 triangle = g_triangles_to_render[i];
-    draw_rect(projected_point.x + (window_width / 2), projected_point.y + (window_height / 2), 4, 4, 0xFF659F00);
+    draw_rect(triangle.points[0].x, triangle.points[0].y, 3, 3, 0xFFFFFF00);
+    draw_rect(triangle.points[1].x, triangle.points[1].y, 3, 3, 0xFFFFFF00);
+    draw_rect(triangle.points[2].x, triangle.points[2].y, 3, 3, 0xFFFFFF00);
   }
 
   render_colour_buffer();

src/renderer/display.c

@@ -58,8 +58,8 @@ void draw_dots(u32 colour) {
 }
 
 void draw_grid(u32 colour) {
-  for (s32 column = 0; column < window_height; column++) {
+  for (s32 column = 0; column < window_height; column += 10) {
-    for (s32 row = 0; row < window_width; row++) {
+    for (s32 row = 0; row < window_width; row += 10) {
       colour_buffer[(window_width * column) + row] = colour;
     }
   }