Add tread marks

makefile

@@ -28,7 +28,7 @@ endif
 # ----------------------------
 
 SHELL = bash
-IMAGE_NAMES = {{{pl,en}_{base,turret},shell}_{0..8},mine_{0..2}}
+IMAGE_NAMES = {{{pl,en}_{base,turret},shell,tread}_{0..8},mine_{0..2}}
 CONVIMG_INPUT = $(shell echo src/data/gfx/trimmed/$(IMAGE_NAMES).png) src/data/gfx/tileset.png src/data/gfx/bg_tank.png src/data/gfx/fg_tank.png
 CONVIMG_OUTPUT = $(shell echo src/data/gfx/$(IMAGE_NAMES).{c,h}) src/data/gfx/tileset.c src/data/gfx/tileset.h src/data/gfx/bg_tank.c src/data/gfx/bg_tank.h src/data/gfx/fg_tank.c src/data/gfx/fg_tank.h src/data/gfx/palette.c src/data/gfx/palette.h src/data/gfx/gfx.h src/data/gfx/enemy_palette.bin
 BLENDER_OUTPUT = $(shell echo src/data/gfx/rendered/$(IMAGE_NAMES).png)

src/data/gfx/convimg.yaml

@@ -55,6 +55,7 @@ converts:
       - trimmed/pl_*.png
       - trimmed/shell_*.png
       - trimmed/mine_*.png
+      - trimmed/tread_*.png
       - bg_tank.png
       - fg_tank.png
       - explosion.png

src/graphics/dynamic_sprites.cpp

@@ -22,6 +22,14 @@ gfx_UninitedSprite(pl_turret_13, pl_turret_3_width, pl_turret_3_height);
 gfx_UninitedSprite(pl_turret_14, pl_turret_2_width, pl_turret_2_height);
 gfx_UninitedSprite(pl_turret_15, pl_turret_1_width, pl_turret_1_height);
 
+gfx_UninitedSprite(tread_9, tread_7_width, tread_7_height);
+gfx_UninitedSprite(tread_10, tread_6_width, tread_6_height);
+gfx_UninitedSprite(tread_11, tread_5_width, tread_5_height);
+gfx_UninitedSprite(tread_12, tread_4_width, tread_4_height);
+gfx_UninitedSprite(tread_13, tread_3_width, tread_3_height);
+gfx_UninitedSprite(tread_14, tread_2_width, tread_2_height);
+gfx_UninitedSprite(tread_15, tread_1_width, tread_1_height);
+
 gfx_UninitedSprite(shell_9, shell_7_width, shell_7_height);
 gfx_UninitedSprite(shell_10, shell_6_width, shell_6_height);
 gfx_UninitedSprite(shell_11, shell_5_width, shell_5_height);
@@ -72,6 +80,25 @@ extern gfx_sprite_t * const tank_turrets[NUM_TANK_TYPES][16] = {
         }
 };
 
+extern gfx_sprite_t * const tread_sprites[16] = {
+        tread_0,
+        tread_1,
+        tread_2,
+        tread_3,
+        tread_4,
+        tread_5,
+        tread_6,
+        tread_7,
+        tread_8,
+        (gfx_sprite_t*)tread_9_data,
+        (gfx_sprite_t*)tread_10_data,
+        (gfx_sprite_t*)tread_11_data,
+        (gfx_sprite_t*)tread_12_data,
+        (gfx_sprite_t*)tread_13_data,
+        (gfx_sprite_t*)tread_14_data,
+        (gfx_sprite_t*)tread_15_data,
+};
+
 extern gfx_sprite_t * const shell_sprites[16] = {
         shell_0,
         shell_1,
@@ -250,6 +277,44 @@ extern const uint8_t en_turret_y_offsets[16] = {
         en_turret_1_offset_y,
 };
 
+extern const uint8_t tread_x_offsets[16] = {
+        tread_0_offset_x,
+        tread_1_offset_x,
+        tread_2_offset_x,
+        tread_3_offset_x,
+        tread_4_offset_x,
+        tread_5_offset_x,
+        tread_6_offset_x,
+        tread_7_offset_x,
+        tread_8_offset_x,
+        tank_sprite_total_width - tread_7_offset_x - tread_7_width,
+        tank_sprite_total_width - tread_6_offset_x - tread_6_width,
+        tank_sprite_total_width - tread_5_offset_x - tread_5_width,
+        tank_sprite_total_width - tread_4_offset_x - tread_4_width,
+        tank_sprite_total_width - tread_3_offset_x - tread_3_width,
+        tank_sprite_total_width - tread_2_offset_x - tread_2_width,
+        tank_sprite_total_width - tread_1_offset_x - tread_1_width,
+};
+
+extern const uint8_t tread_y_offsets[16] = {
+        tread_0_offset_y,
+        tread_1_offset_y,
+        tread_2_offset_y,
+        tread_3_offset_y,
+        tread_4_offset_y,
+        tread_5_offset_y,
+        tread_6_offset_y,
+        tread_7_offset_y,
+        tread_8_offset_y,
+        tread_7_offset_y,
+        tread_6_offset_y,
+        tread_5_offset_y,
+        tread_4_offset_y,
+        tread_3_offset_y,
+        tread_2_offset_y,
+        tread_1_offset_y,
+};
+
 extern const uint8_t shell_x_offsets[16] = {
         shell_0_offset_x,
         shell_1_offset_x,

src/graphics/dynamic_sprites.h

@@ -9,6 +9,8 @@ extern gfx_sprite_t *tank_turrets[NUM_TANK_TYPES][16];
 extern gfx_sprite_t *const enemy_bases_unconv[9];
 extern gfx_sprite_t *const enemy_turrets_unconv[9];
 
+extern gfx_sprite_t *tread_sprites[9];
+
 extern gfx_sprite_t *shell_sprites[16];
 
 extern gfx_sprite_t *mine_sprites[4];
@@ -23,6 +25,9 @@ extern const uint8_t en_base_y_offsets[16];
 extern const uint8_t en_turret_x_offsets[16];
 extern const uint8_t en_turret_y_offsets[16];
 
+extern const uint8_t tread_x_offsets[16];
+extern const uint8_t tread_y_offsets[16];
+
 extern const uint8_t shell_x_offsets[16];
 extern const uint8_t shell_y_offsets[16];
 

src/graphics/graphics.cpp

@@ -9,7 +9,6 @@
 #include "gui.h"
 #include "../data/gfx/enemy_pal.h"
 #include "tiles.h"
-#include "repalettize.h"
 
 bool needs_redraw;
 
@@ -23,6 +22,7 @@ void init_graphics() {
     for(uint8_t i = 1; i < 8; i++) {
         gfx_FlipSpriteY(tank_bases[PLAYER][i], tank_bases[PLAYER][16 - i]);
         gfx_FlipSpriteY(tank_turrets[PLAYER][i], tank_turrets[PLAYER][16 - i]);
+        gfx_FlipSpriteY(tread_sprites[i], tread_sprites[16 - i]);
         gfx_FlipSpriteY(shell_sprites[i], shell_sprites[16 - i]);
     }
 }
@@ -71,11 +71,10 @@ void render() {
     // restrict drawing to only the play area, to prevent the banners from being overwritten
     gfx_SetClipRegion(SCREEN_X_CONST(0), SCREEN_Y_CONST(-TILE_SIZE), SCREEN_X_CONST(LEVEL_SIZE_X * TILE_SIZE),
                       SCREEN_Y_CONST((LEVEL_SIZE_Y - 2) * TILE_SIZE));
-    for(auto *it: PhysicsBody::objects) {
-        it->render(0);
-    }
-    for(auto *it: PhysicsBody::objects) {
-        it->render(1);
+    for(uint8_t layer = 0; layer < 3; layer++) {
+        for(auto *it: PhysicsBody::objects) {
+            it->render(layer);
+        }
     }
     gfx_SetClipRegion(0, 0, LCD_WIDTH, LCD_HEIGHT);
     profiler_end(render_pbs);

src/objects/mine.cpp

@@ -50,7 +50,7 @@ void Mine::process() {
 }
 
 void Mine::render(uint8_t layer) {
-    if(layer != 0) return;
+    if(layer != 1) return;
     profiler_add(render_mines);
 
     if(countdown > EXPLOSION_ANIM) {

src/objects/physicsbody.h

@@ -10,8 +10,6 @@
 #include "../fwd.h"
 #include "../physics/physics.h"
 
-#define MAX_OBJECTS 255
-
 class PhysicsBody {
 public:
     PhysicsBody();

src/objects/shell.cpp

@@ -50,7 +50,7 @@ void Shell::process() {
 }
 
 void Shell::render(uint8_t layer) {
-    if(layer != 1) return;
+    if(layer != 2) return;
     profiler_add(render_shells);
 
     uint8_t sprite = direction;

src/objects/tank.cpp

@@ -46,6 +46,8 @@ Tank::Tank(const serialized_tank_t *ser_tank, uint8_t id) {
     tread_rot = 0;
     shot_cooldown = 0;
     mine_cooldown = 0;
+    tread_distance = TREAD_DISTANCE;
+    draw_treads = false;
 
     if(id == 0) {
         game.player = this;
@@ -90,7 +92,24 @@ void Tank::process() {
 }
 
 void Tank::render(uint8_t layer) {
-    if(layer != 1) return;
+    if(layer == 0) {
+        tread_distance += abs(velocity_x) + abs(velocity_y);
+        if(draw_treads) {
+            gfx_TransparentSprite(tread_sprite, tread_pos.xmin, tread_pos.ymin);
+            redraw_tiles(&tread_pos, 0);
+            draw_treads = false;
+        }
+        if(tread_distance > TREAD_DISTANCE) {
+            uint8_t base_index = (((uint8_t) -((tread_rot >> (INT_BITS - 8)) - 64)) >> 3) & 0xF;
+            get_sprite_footprint(&tread_pos, this, tread_sprites, tread_x_offsets, tread_y_offsets, base_index);
+            tread_distance -= TREAD_DISTANCE;
+            tread_sprite = tread_sprites[base_index];
+            gfx_TransparentSprite(tread_sprite, tread_pos.xmin, tread_pos.ymin);
+            redraw_tiles(&tread_pos, 0);
+            draw_treads = true;
+        }
+    }
+    if(layer != 2) return;
     profiler_add(render_tanks);
 
     uint8_t base_index = (((uint8_t) -((tread_rot >> (INT_BITS - 8)) - 64)) >> 3) & 0xF;

src/objects/tank.h

@@ -4,6 +4,7 @@
 #include "../fwd.h"
 
 #include <cstdint>
+#include <graphx.h>
 
 #include "../ai/ai_state.h"
 #include "../physics/collision.h"
@@ -27,6 +28,8 @@ typedef uint8_t tank_type_t;
 #define SHOT_COOLDOWN 5
 #define MINE_COOLDOWN 10
 
+#define TREAD_DISTANCE (TILE_SIZE / 3)
+
 #define MAX_NUM_TANKS 16
 
 enum {
@@ -65,9 +68,15 @@ class Tank: public PhysicsBody {
     uint8_t num_mines = 0;
     uint8_t shot_cooldown;
     uint8_t mine_cooldown;
+    uint tread_distance;
     ai_move_state_t ai_move;
     ai_fire_state_t ai_fire;
 
+    // Used to (somewhat lazily) draw stuff on the background across two frame buffers
+    bool draw_treads;
+    gfx_sprite_t *tread_sprite;
+    gfx_region_t tread_pos;
+
     // Kill this physics body, then destroy it
     void kill();
     void process();