feat: render stars!

4 files changed, 66 insertions, 9 deletions

diff --git a/src/constants.h b/src/constants.h
index ecd5b1f..d1ca7f4 100644
--- a/src/constants.h
+++ b/src/constants.h
@@ -1 +1,3 @@
 #define STAR_AMOUNT 1000
+#define STAR_START_POS_Z 20.0
+#define SPACE_SIZE 35.0
diff --git a/src/main.c b/src/main.c
index 01678b9..3710ae1 100644
--- a/src/main.c
+++ b/src/main.c
@@ -3,17 +3,17 @@
 #include "star.h"
 
 int main(int argc, char *argv[]) {
+  InitWindow(800, 600, "hyperspace (demo)");
+
+  SetTargetFPS(60);
+
   Star *stars[STAR_AMOUNT] = {};
 
   for (int i = 0; i < STAR_AMOUNT; i++) {
-    Star star = {{0, 0, 0}, {20, 20}, 1.0, BLACK};
-    stars[i] = &star;
+    Star s = StarCreate();
+    stars[i] = &s;
   }
 
-  InitWindow(800, 600, "hyperspace (demo)");
-
-  SetTargetFPS(60);
-
   while (!WindowShouldClose()) {
     BeginDrawing();
     ClearBackground(WHITE);
@@ -22,9 +22,16 @@ int main(int argc, char *argv[]) {
 
     for (int i = 0; i < sizeof(stars) / sizeof(stars[0]); i++) {
       Star *star = stars[i];
+      star->position.z -= star->velocity;
+
+      if (star->position.z < 1.0) {
+        star->position = Generate3DPosition();
+      }
+
+      StarUpdate(star);
 
-      DrawRectangle(star->position.x, star->position.y, star->size.x,
-                    star->size.y, star->color);
+      DrawRectangle(star->renderPosition.x, star->renderPosition.y,
+                    star->size.x, star->size.y, star->color);
     }
 
     EndDrawing();
diff --git a/src/star.c b/src/star.c
new file mode 100644
index 0000000..6251e03
--- /dev/null
+++ b/src/star.c
@@ -0,0 +1,43 @@
+#include "star.h"
+
+#include <math.h>
+#include <stdlib.h>
+#include <time.h>
+
+#include "constants.h"
+#include "raylib.h"
+
+Vector3 Generate3DPosition() {
+  srand(time(0));
+  double random = (double)rand() / RAND_MAX;
+
+  double angle = random * 2.0 * M_PI;
+  double radius =
+      (GetScreenHeight() / SPACE_SIZE) + (random * GetScreenHeight());
+
+  float x = radius * sin(angle);
+  float y = radius * cos(angle);
+
+  Vector3 v = {x, y, STAR_START_POS_Z};
+  return v;
+}
+
+Star StarCreate() {
+  return (Star){Generate3DPosition(), {1, 1}, {0, 0}, 0.25f, BLACK};
+}
+
+void StarUpdate(Star *star) {
+  float screen_center_x = GetScreenWidth() / 2.0;
+  float screen_center_y = GetScreenHeight() / 2.0;
+
+  float x = star->position.x / star->position.z + screen_center_x;
+  float y = star->position.y / star->position.z + screen_center_y;
+
+  star->renderPosition.x = x;
+  star->renderPosition.y = y;
+
+  float size = (STAR_START_POS_Z - star->position.z) / (0.2 * star->position.z);
+
+  star->size.x = size;
+  star->size.y = size;
+}
diff --git a/src/star.h b/src/star.h
index bc215ee..db34db6 100644
--- a/src/star.h
+++ b/src/star.h
@@ -2,7 +2,12 @@
 
 typedef struct Star {
     Vector3 position;
-    Vector2 size;
+    Vector2 size, renderPosition;
     float velocity;
     Color color;
 } Star;
+
+Star StarCreate();
+void StarUpdate(Star *star);
+
+Vector3 Generate3DPosition();