From 5299fa66afc9cf6c9ee01a7de821bbbb43683be8 Mon Sep 17 00:00:00 2001
From: Zack Buhman <zack@buhman.org>
Date: Fri, 5 Dec 2025 13:14:33 -0600
Subject: [PATCH] multiple balls

---
 include/state.h    | 15 ++++++---
 include/update.hpp |  1 +
 src/main.c         | 20 +++++++++++-
 src/render.cpp     |  9 ++++--
 src/update.cpp     | 78 +++++++++++++++++++++++++++++-----------------
 5 files changed, 86 insertions(+), 37 deletions(-)

diff --git a/include/state.h b/include/state.h
index 720c367..4d51e21 100644
--- a/include/state.h
+++ b/include/state.h
@@ -10,6 +10,15 @@ extern "C" {
     double destroyed_time;
   };
 
+  struct ball_state {
+    float ball_x;
+    float ball_y;
+    float ball_dx;
+    float ball_dy;
+  };
+
+  #define MAX_BALLS 20
+
   struct game_state {
     struct block_state blocks[28 * 13];
     const uint8_t * level;
@@ -18,10 +27,8 @@ extern "C" {
     float paddle_x;
     float paddle_y;
 
-    float ball_x;
-    float ball_y;
-    float ball_dx;
-    float ball_dy;
+    struct ball_state balls[MAX_BALLS];
+    int balls_launched;
 
     double start_time;
     double time;
diff --git a/include/update.hpp b/include/update.hpp
index 547e465..757802e 100644
--- a/include/update.hpp
+++ b/include/update.hpp
@@ -6,6 +6,7 @@
 extern "C" {
 #endif
 
+  void launch_ball(struct game_state * state);
   void reset_level(struct game_state * state);
   void update(struct game_state * state, double time);
 
diff --git a/src/main.c b/src/main.c
index a83e6f0..b863263 100644
--- a/src/main.c
+++ b/src/main.c
@@ -163,7 +163,7 @@ int main()
   double frames = 1;
   const char * last_gamepad_name = NULL;
 
-  struct game_state state;
+  struct game_state state = {0};
   reset_level(&state);
   state.start_time = glfwGetTime();
 
@@ -179,14 +179,27 @@ int main()
 
     float paddle_dx = 0.0;
     //float paddle_dy = 0.0;
+    static bool last_x_press = false;
+    bool x_press = false;
 
     for (int i = 0; i < 16; i++) {
       int present = glfwJoystickPresent(GLFW_JOYSTICK_1 + i);
       int is_gamepad = glfwJoystickIsGamepad(GLFW_JOYSTICK_1 + i);
       int count;
       const float * axes = glfwGetJoystickAxes(GLFW_JOYSTICK_1 + i, &count);
+
       //printf("present, %d %d %s %d\n", i, count, name, is_gamepad);
       if (present && is_gamepad && count == 6) {
+        const unsigned char * buttons = glfwGetJoystickButtons(GLFW_JOYSTICK_1 + i, &count);
+        /*
+        printf("buttons count %d\n", count);
+        for (int i = 0; i < count; i++) {
+          printf("[% 2d % 2d] ", i, buttons[i]);
+        }
+        printf("\n");
+        */
+        x_press = buttons[0] != 0;
+
         const char * name = glfwGetJoystickName(GLFW_JOYSTICK_1 + i);
         if (name != last_gamepad_name) {
           printf("active gamepad: `%s`; axes: %d\n", name, count);
@@ -204,6 +217,11 @@ int main()
       }
     }
 
+    if (!last_x_press && x_press) {
+      launch_ball(&state);
+    }
+    last_x_press = x_press;
+
     float extent = 0.25;
     state.paddle_x += paddle_dx;
     if (state.paddle_x < extent)
diff --git a/src/render.cpp b/src/render.cpp
index ed72215..092564a 100644
--- a/src/render.cpp
+++ b/src/render.cpp
@@ -222,12 +222,15 @@ void render(mesh paddle_mesh,
   }
 
   //////////////////////////////////////////////////////////////////////
-  // render ball
+  // render balls
   //////////////////////////////////////////////////////////////////////
 
-  {
+  for (int i = 0; i < state->balls_launched; i++) {
+    struct ball_state& ball = state->balls[i];
+
     mat4x4 rx = rotate_y(PI / 2.0f);
-    mat4x4 t = translate(vec3(state->ball_x * 4.0f, -state->ball_y * 2.0f, 0.0));
+    vec3 ball_position = vec3(ball.ball_x * 4.0f, -ball.ball_y * 2.0f, 0.0);
+    mat4x4 t = translate(ball_position);
 
     mat4x4 trans = a * t * rx;
     mat3x3 normal_trans = submatrix(rx, 3, 3);
diff --git a/src/update.cpp b/src/update.cpp
index dcd067a..af6f761 100644
--- a/src/update.cpp
+++ b/src/update.cpp
@@ -12,16 +12,26 @@
 #include "math/float_types.hpp"
 #include "math/transform.hpp"
 
+void launch_ball(struct game_state * state)
+{
+  if (state->balls_launched >= MAX_BALLS)
+    return;
+
+  struct ball_state& ball = state->balls[state->balls_launched];
+  ball.ball_x = state->paddle_x;
+  ball.ball_y = 25.0;
+  ball.ball_dx = 0.1;
+  ball.ball_dy = -0.1;
+
+  state->balls_launched += 1;
+}
+
 void reset_level(struct game_state * state)
 {
   state->paddle_x = 0.0;
   state->paddle_y = 26.0;
 
-  state->ball_x = 0.0;
-  state->ball_y = 25.0;
-
-  state->ball_dx = 0.1;
-  state->ball_dy = 0.1;
+  launch_ball(state);
 
   state->start_time = 0.0;
 
@@ -36,19 +46,19 @@ void reset_level(struct game_state * state)
   }
 }
 
-static inline void ball_collision_response(struct game_state * state,
+static inline void ball_collision_response(struct ball_state& ball,
                                            struct collision_data& cd)
 {
-  state->ball_x = cd.escape_position.x / 4.0f;
-  state->ball_y = -cd.escape_position.y / 2.0f;
-  vec3 vel = reflect(vec3(state->ball_dx, state->ball_dy, 0), cd.bounds_normal);
-  state->ball_dx = vel.x;
-  state->ball_dy = vel.y;
+  ball.ball_x = cd.escape_position.x / 4.0f;
+  ball.ball_y = -cd.escape_position.y / 2.0f;
+  vec3 vel = reflect(vec3(ball.ball_dx, ball.ball_dy, 0), cd.bounds_normal);
+  ball.ball_dx = vel.x;
+  ball.ball_dy = vel.y;
 }
 
-void update(struct game_state * state, double time)
+void update_ball(struct game_state * state, struct ball_state& ball, double time)
 {
-  vec3 ball_position = vec3(state->ball_x * 4.0f, -state->ball_y * 2.0f, 0.0);
+  vec3 ball_position = vec3(ball.ball_x * 4.0f, -ball.ball_y * 2.0f, 0.0);
 
   //////////////////////////////////////////////////////////////////////
   // block collision
@@ -70,7 +80,7 @@ void update(struct game_state * state, double time)
       struct collision_data cd;
       bool collided = aabb_circle_collision(block_position, ball_position, block_bounds, &cd);
       if (collided) {
-        ball_collision_response(state, cd);
+        ball_collision_response(ball, cd);
         state->blocks[block_ix].destroyed_time = time;
       }
     }
@@ -86,31 +96,41 @@ void update(struct game_state * state, double time)
     struct collision_data cd;
     bool collided = aabb_circle_collision(paddle_position, ball_position, paddle_bounds, &cd);
     if (collided) {
-      ball_collision_response(state, cd);
+      ball_collision_response(ball, cd);
     }
   }
 
   //////////////////////////////////////////////////////////////////////
   // arena collision
   //////////////////////////////////////////////////////////////////////
-  if ((state->ball_x + state->ball_dx * 0.4) > 12.25f) {
-    state->ball_x = 12.25f;
-    state->ball_dx = -state->ball_dx;
-  } else if ((state->ball_x + state->ball_dx * 0.4) < -0.25f) {
-    state->ball_x = -0.25f;
-    state->ball_dx = -state->ball_dx;
+  if ((ball.ball_x + ball.ball_dx * 0.4) > 12.25f) {
+    ball.ball_x = 12.25f;
+    ball.ball_dx = -ball.ball_dx;
+  } else if ((ball.ball_x + ball.ball_dx * 0.4) < -0.25f) {
+    ball.ball_x = -0.25f;
+    ball.ball_dx = -ball.ball_dx;
   }
 
-  if ((state->ball_y + state->ball_dy * 0.4) > 27.0f) {
-    //state->ball_y = 27.0f;
-    //state->ball_dy = -state->ball_dy;
-  } else if ((state->ball_y + state->ball_dy * 0.4) < 0.0f) {
-    state->ball_y = 0.0f;
-    state->ball_dy = -state->ball_dy;
+  if ((ball.ball_y + ball.ball_dy * 0.4) > 27.0f) {
+    //ball.ball_y = 27.0f;
+    //ball.ball_dy = -ball.ball_dy;
+  } else if ((ball.ball_y + ball.ball_dy * 0.4) < 0.0f) {
+    ball.ball_y = 0.0f;
+    ball.ball_dy = -ball.ball_dy;
   }
 
-  state->ball_x += state->ball_dx;
-  state->ball_y += state->ball_dy;
+  ball.ball_x += ball.ball_dx;
+  ball.ball_y += ball.ball_dy;
+}
+
+void update(struct game_state * state, double time)
+{
+  for (int i = 0; i < state->balls_launched; i++) {
+    if (state->balls[i].ball_y > 30.0f)
+      continue;
+
+    update_ball(state, state->balls[i], time);
+  }
 
   state->time = time;
   state->remaining = 20.0 - (time - state->start_time);