Add actor engine

.vscode/c_cpp_properties.json

@@ -0,0 +1,13 @@
+{
+    "version": 4,
+    "configurations": [
+        {
+            "name": "Default",
+            "includePath": [
+                "${default}",
+                "${workspaceFolder}/gbsdk/inc",
+                "${workspaceFolder}/include"
+            ]
+        }
+    ]
+}

.vscode/settings.json

@@ -0,0 +1,6 @@
+{
+    "files.associations": {
+        "hardware.h": "c",
+        "util.h": "c"
+    }
+}

src/actor.c

@@ -0,0 +1,119 @@
+#include "actor.h"
+
+#include <stddef.h>
+
+#include "sdk/oam.h"
+#include "util.h"
+
+#define MAX_UNIQUE_MOBS 3
+#define MAX_ACTORS 5
+#define NUM_OAM_ENTRIES 40
+#define TILE_WIDTH 8
+
+static uint8_t mob_ids[MAX_UNIQUE_MOBS];
+static sprite16_mob mob_anim_data[MAX_UNIQUE_MOBS];
+static sprite16_player player_anim_data;
+static actor_t all_actors[MAX_ACTORS];
+
+static uint8_t actor_load_mob_anim_data(uint8_t mob_id);
+
+void actor_reset(void) {
+    for (uint8_t i = 0; i < ARRSIZE(mob_ids); ++i) {
+        mob_ids[i] = 0xff;
+    }
+
+    for (uint8_t i = 0; i < ARRSIZE(all_actors); ++i) {
+        all_actors[i].active = 0;
+    }
+}
+
+actor_t *actor_create_mob(uint8_t id) {
+    uint8_t mob_anim_idx = actor_load_mob_anim_data(id);
+    if (mob_anim_idx == 0xff) {
+        return NULL;
+    }
+
+    actor_t *a = NULL;
+    for (uint8_t i = 0; i < ARRSIZE(all_actors); ++i) {
+        if (all_actors[i].active) {
+            continue;
+        }
+
+        a = &all_actors[i];
+        a->active = 1;
+        a->mob_anim_idx = mob_anim_idx;
+        a->anim = ANIM_STAND;
+        a->frame_idx = 0;
+        a->frame_counter = 0;
+
+        break;
+    }
+
+    return a;
+}
+
+void actor_remove(actor_t *a) { a->active = 0; }
+
+void actor_flush_oam(void) {
+    struct oam_entry *oam_ptr = &shadow_oam[0];
+    actor_t *a = &all_actors[0];
+
+    for (uint8_t i = 0; i < ARRSIZE(all_actors); ++i) {
+        if (!a->active) {
+            continue;
+        }
+
+        uint8_t *anim_ptr = mob_anim_data[a->mob_anim_idx].anims[a->anim];
+        anim_ptr += a->frame_idx * 4;
+
+        oam_ptr->y = a->y;
+        oam_ptr->x = a->x;
+        oam_ptr->tile = *anim_ptr++;
+        oam_ptr->attr = 0;
+        oam_ptr++;
+
+        oam_ptr->y = a->y;
+        oam_ptr->x = a->x + TILE_WIDTH;
+        oam_ptr->tile = *anim_ptr++;
+        oam_ptr->attr = 0;
+        oam_ptr++;
+
+        oam_ptr->y = a->y + TILE_WIDTH;
+        oam_ptr->x = a->x;
+        oam_ptr->tile = *anim_ptr++;
+        oam_ptr->attr = 0;
+        oam_ptr++;
+
+        oam_ptr->y = a->y + TILE_WIDTH;
+        oam_ptr->x = a->x + TILE_WIDTH;
+        oam_ptr->tile = *anim_ptr++;
+        oam_ptr->attr = 0;
+        oam_ptr++;
+
+        a++;
+    }
+}
+
+static uint8_t actor_load_mob_anim_data(uint8_t mob_id) {
+    uint8_t mob_anim_idx = 0xff;
+
+    for (uint8_t i = 0; i < ARRSIZE(mob_ids); ++i) {
+        if (mob_ids[i] == mob_id) {
+            mob_anim_idx = i;
+            break;
+        }
+    }
+
+    if (mob_anim_idx == 0xff) {
+        for (uint8_t i = 0; i < ARRSIZE(mob_ids); ++i) {
+            if (mob_ids[i] == 0xff) {
+                mob_ids[i] = mob_id;
+                // TODO: Load data into mob_anim_data[i]
+                mob_anim_idx = i;
+                break;
+            }
+        }
+    }
+
+    return mob_anim_idx;
+}

src/actor.h

@@ -0,0 +1,60 @@
+#ifndef IS_ACTOR_H_
+#define IS_ACTOR_H_
+
+#include <stdint.h>
+
+typedef enum {
+    ANIM_STAND,
+    ANIM_WALK,
+    ANIM_JUMP,
+    ANIM_ATTACK,
+    ANIM_HURT,
+    ANIM_CLIMB,
+} actor_anim_state_t;
+
+typedef struct {
+    uint8_t active;
+    uint8_t mob_anim_idx;
+    actor_anim_state_t anim;
+    uint8_t frame_idx;
+    uint8_t frame_counter;
+    uint8_t x;
+    uint8_t y;
+} actor_t;
+
+typedef struct {
+    uint8_t *tiles;
+    uint16_t num_tiles;
+    uint8_t *anims[ANIM_HURT + 1];
+} sprite16_mob;
+
+typedef struct {
+    uint8_t *tiles;
+    uint16_t num_tiles;
+    uint8_t *anims[ANIM_CLIMB + 1];
+} sprite16_player;
+
+/**
+ * @brief Clear all actor data.
+ */
+void actor_reset(void);
+
+/**
+ * @brief Register an actor for a mob.
+ * @param id The ID of the mob to create
+ * @return A pointer to the new actor or NULL if one could not be created
+ */
+actor_t *actor_create_mob(uint8_t id);
+
+/**
+ * @brief Remove an actor from the screen.
+ * @param a The actor to remove
+ */
+void actor_remove(actor_t *a);
+
+/**
+ * @brief Flush actor sprite data to OAM.
+ */
+void actor_flush_oam(void);
+
+#endif

src/main.c

@@ -1,29 +1,31 @@
-#include "sdk/hardware.h"
-#include "sdk/video.h"
-#include "sdk/oam.h"
+#include <string.h>
+
+#include "actor.h"
 #include "sdk/assets.h"
+#include "sdk/hardware.h"
 #include "sdk/joypad.h"
-#include <string.h>
+#include "sdk/oam.h"
+#include "sdk/video.h"
 
 ASSET(tiles, "tiles.2bpp");
 
 uint8_t cursor_x = 0;
 uint8_t cursor_y = 0;
 
-
 void main() {
-    //Load our initial vram (this is slow, but always works, even outside of vblank)
+    // Load our initial vram (this is slow, but always works, even outside of
+    // vblank)
     vram_memcpy(0x8000, tiles, tiles_end - tiles);
     vram_memcpy(0x9000, tiles, tiles_end - tiles);
-    //Setup the OAM for sprite drawing
+    // Setup the OAM for sprite drawing
     oam_init();
 
-    //Set some default DMG palette data
+    // Set some default DMG palette data
     rBGP = 0b11100100;
     rOBP0 = 0b11100100;
     rOBP1 = 0b11100100;
 
-    //Put some sprites on the screen
+    // Put some sprites on the screen
     shadow_oam[0].y = 0x20;
     shadow_oam[0].x = 0x20;
     shadow_oam[0].tile = 0x04;
@@ -33,31 +35,32 @@ void main() {
     shadow_oam[1].tile = 0x02;
     shadow_oam[1].attr = 0x00;
 
-    //Make sure sprites and the background are drawn
+    // Make sure sprites and the background are drawn
     rLCDC = LCDC_ON | LCDC_OBJON | LCDC_BGON;
 
-    //Setup the VBLANK interrupt, but we don't actually enable interrupt handling.
+    // Setup the VBLANK interrupt, but we don't actually enable interrupt
+    // handling.
     // We only do this, so HALT waits for VBLANK.
     rIF = 0;
     rIE = IE_VBLANK;
 
     vram_memset(0x9800, 0x05, 32 * 18);
-    for(uint8_t x=0; x<20; x++) {
+    for (uint8_t x = 0; x < 20; x++) {
         vram_set(0x9800 + x, 0x07);
         vram_set(0x9A20 + x, 0x07);
     }
-    for(uint8_t y=1; y<18; y++) {
+    for (uint8_t y = 1; y < 18; y++) {
         vram_set(0x9800 + y * 0x20, 0x07);
         vram_set(0x9800 + 19 + y * 0x20, 0x07);
     }
     vram_set(0x9800 + 3 + 3 * 0x20, 0x01);
 
-    while(1) {
+    while (1) {
         joypad_update();
-        if (joypad_state & PAD_LEFT) cursor_x --;
-        if (joypad_state & PAD_RIGHT) cursor_x ++;
-        if (joypad_state & PAD_UP) cursor_y --;
-        if (joypad_state & PAD_DOWN) cursor_y ++;
+        if (joypad_state & PAD_LEFT) cursor_x--;
+        if (joypad_state & PAD_RIGHT) cursor_x++;
+        if (joypad_state & PAD_UP) cursor_y--;
+        if (joypad_state & PAD_DOWN) cursor_y++;
         if (joypad_state & (PAD_A | PAD_B)) {
             vram_set(0x9800 + cursor_x / 8 + cursor_y / 8 * 0x20, 0x03);
         }
@@ -66,11 +69,12 @@ void main() {
         shadow_oam[0].y = cursor_y + 16;
         shadow_oam[0].x = cursor_x + 8;
 
-        //Wait for VBLANK
+        // Wait for VBLANK
         HALT();
-        rIF = 0;    //As global interrupts are not enabled, we need to clear the interrupt flag.
+        rIF = 0;  // As global interrupts are not enabled, we need to clear the
+                  // interrupt flag.
 
-        //Copy the sprites into OAM memory
+        // Copy the sprites into OAM memory
         oam_dma_copy();
     }
 }

src/util.h

@@ -0,0 +1,6 @@
+#ifndef IS_UTIL_H_
+#define IS_UTIL_H_
+
+#define ARRSIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
+
+#endif