[pingpong] Game with moving ball

Author: scopeInfinity

include/fuzzy/kernel/syscall/keyboard.h

@@ -0,0 +1,3 @@
+#pragma once
+
+int syscall_0_keyboard(int operation,int a1,int a2,int a3, int user_ds);

src/drivers/keyboard/keyboard.c

@@ -174,6 +174,13 @@ char keyboard_get_key_pressed_poll() {
     return c;
 }
 
+int keyboard_get_kbhit() {
+    for (int i = 0; !keyboard_scanner_ascii_is_available() && i < 100; i++) {
+        keyboard_scanner_step();
+    }
+    return keyboard_scanner_ascii_is_available()>0;
+}
+
 void keyboard_init() {
     unsigned char original_colors =  get_color_fgbg();
     sleep_mini(3000000);

src/drivers/keyboard/keyboard.h

@@ -4,3 +4,4 @@ void keyboard_init();
 
 char keyboard_get_key_pressed_blocking();
 char keyboard_get_key_pressed_poll();
+int keyboard_get_kbhit();

src/kernel/syscall/keyboard.c

@@ -0,0 +1,21 @@
+#include <fuzzy/kernel/syscall/keyboard.h>
+
+#include <conio.h>
+
+static int _keyboard_getch() {
+    return keyboard_get_key_pressed_poll();
+}
+
+static int _keyboard_kbhit() {
+    return keyboard_get_kbhit();
+}
+
+int syscall_0_keyboard(int operation,int a1,int a2,int a3, int user_ds) {
+    switch (operation) {
+        case SYSCALL_KEYBOARD_SUB_GETCH:
+            return _keyboard_getch();
+        case SYSCALL_KEYBOARD_SUB_KBHIT:
+            return _keyboard_kbhit();
+    }
+    return -1;
+}

src/kernel/syscall/syscall.c

@@ -3,6 +3,7 @@
 #include <fuzzy/kernel/syscall/file_handler.h>
 #include <fuzzy/kernel/syscall/console.h>
 #include <fuzzy/kernel/syscall/graphics.h>
+#include <fuzzy/kernel/syscall/keyboard.h>
 #include <fuzzy/kernel/syscall/syscall.h>
 
 #include <sys/syscall.h>
@@ -14,16 +15,12 @@
 
 int SYSCALL_TABLE[SYSCALL_SIZE];
 
-int syscall_0_keyboard_getch(int a0,int a1,int a2,int a3, int user_ds) {
-    return keyboard_get_key_pressed_poll();
-}
-
 extern int interrupt_handler_0x32_syscall_handler();
 
 void interrupt_register_0x32_syscall() {
     print_log("Registering syscalls.");
     populate_idt_entry_32bit(IDT_SYSCALL, (unsigned int)interrupt_handler_0x32_syscall_handler, 0, 1);
-    SYSCALL_TABLE[SYSCALL_KEYBOARD]=syscall_0_keyboard_getch;
+    SYSCALL_TABLE[SYSCALL_KEYBOARD]=syscall_0_keyboard;
     SYSCALL_TABLE[SYSCALL_PROCESS]=syscall_1_process;
     SYSCALL_TABLE[SYSCALL_FILE_OP]=syscall_2_file_handler;
     SYSCALL_TABLE[SYSCALL_CONSOLE]=syscall_3_console;

src/usr/include/conio.h

@@ -1,5 +1,9 @@
 #pragma once
 
-char getch();
+#define SYSCALL_KEYBOARD_SUB_GETCH       0
+#define SYSCALL_KEYBOARD_SUB_KBHIT       1
+
+int getch();
+int kbhit();
 
 void clrscr();

src/usr/include/graphics.h

@@ -43,3 +43,8 @@ int getbkcolor();
 
 void putpixel_noflush(int x, int y, int color);
 void putpixel(int x, int y, int color);
+
+void line(int x1, int y1, int x2, int y2);
+void rectangle(int left, int top, int right, int bottom);
+void bar(int left, int top, int right, int bottom);
+void fillellipse(int xcenter, int ycenter, int x_radius, int y_radius);

src/usr/lib/conio.c

@@ -1,16 +1,21 @@
 #include <sys/syscall.h>
 #include <stdio.h>
+#include <conio.h>
 
-char getch() {
+int getch() {
     // syscall is irq blocking,
     // so try to keep them as short as possible.
     while (1) {
-        char c = SYSCALL_A0(SYSCALL_KEYBOARD);
+        char c = SYSCALL_A1(SYSCALL_KEYBOARD, SYSCALL_KEYBOARD_SUB_GETCH);
         if (c) return c;
         yield();
     }
 }
 
+int kbhit() {
+    return SYSCALL_A1(SYSCALL_KEYBOARD, SYSCALL_KEYBOARD_SUB_KBHIT);
+}
+
 void clrscr() {
     SYSCALL_A1(SYSCALL_CONSOLE, SYSCALL_CONSOLE_SUB_CLRSCR);
-}
+}

src/usr/lib/graphics.c

@@ -151,8 +151,29 @@ void ellipse(int x, int y, int x_radius, int y_radius) {
     // TODO
 }
 
-void fillellipse(int x, int y, int x_radius, int y_radius) {
-    // TODO
+void fillellipse(int xcenter, int ycenter, int x_radius, int y_radius) {
+    // x**2/a**2 + y**2/b**2 <= 1
+    // (x*b)**2 + (y*a)**2 <= (a*b)**2
+    const int color = getcolor();
+
+    int t3 = x_radius*y_radius;
+    t3 *= t3;
+    for (int y = -y_radius; y <= y_radius; y++) {
+        for (int x = -x_radius; x <= x_radius; x++) {
+            int t1 = (x*y_radius);
+            t1 *= t1;
+            int t2 = (y*x_radius);
+            t2 *= t2;
+            if (t1+t2 <= t3) {
+                int fx = xcenter + x;
+                int fy = ycenter + y;
+                if(fx>=0 && fy>=0 && fx<GRAPHICS_MAX_WIDTH && fy<GRAPHICS_MAX_HEIGHT) {
+                    BUFFER[fy][fx]=color;
+                }
+            }
+        }
+    }
+    graphflush();
 }
 
 void floodfill(int x,int y, int color) {

src/usr/local/src/pingpong.c

@@ -21,22 +21,41 @@ const int bat_maxy = (WINDOW_HEIGHT-1)-BAT_HALF_HEIGHT;
 const int p1_x = 10;
 const int p2_x = (WINDOW_WIDTH-1)-p1_x;
 
+const int BALL_SPEED = 2;
+const int BALL_RADIUS = 3;
+
 struct playerState {
     int y;
 };
 
+struct {
+    int x,y;
+    int xspeed, yspeed;
+} ball;
+
 struct {
     struct playerState p1, p2;
 } gstate;
 
+void frame_wait() {
+    // busy wait
+    volatile int counter = 1e7;
+    while (counter--);
+}
+
 void game_init() {
     gstate.p1.y = (bat_miny+bat_maxy)/2;
     gstate.p2 = gstate.p1;
+
+    ball.x = WINDOW_WIDTH/2;
+    ball.y = WINDOW_HEIGHT/2;
+    ball.xspeed = BALL_SPEED*0.8;
+    ball.yspeed = BALL_SPEED*0.6;
 }
 
 void draw_board() {
     // clear screen
-    setbkcolor(LIGHT_GREEN);
+    setbkcolor(GREEN);
     cleardevice();
 
     setcolor(BLUE);
@@ -46,6 +65,9 @@ void draw_board() {
     setcolor(RED);
     bar(p2_x-BAT_HALF_WIDTH, gstate.p2.y-BAT_HALF_HEIGHT,
         p2_x+BAT_HALF_WIDTH, gstate.p2.y+BAT_HALF_HEIGHT);
+
+    setcolor(WHITE);
+    fillellipse(ball.x, ball.y, BALL_RADIUS, BALL_RADIUS);
 }
 
 void move_bat(int player_id, int dir) {
@@ -68,11 +90,22 @@ void move_bat(int player_id, int dir) {
     p->y = max(bat_miny, min(bat_maxy, p->y));
 }
 
+void move_ball() {
+    ball.x += ball.xspeed;
+    ball.y += ball.yspeed;
+}
+
 void game() {
     game_init();
     while (1)  {
         draw_board();
 
+        move_ball();
+
+        if(!kbhit()) {
+            frame_wait();
+            continue;
+        }
         char c = getch();
         if(c=='e') {
             return;