optimisation: make drawing level faster

No more framedrops. Nice.

include/conf.h

@@ -2,22 +2,23 @@
 /* Copyright (C) 2021 KikooDX */
 #pragma once
 
-#define TILE_WIDTH  16
-#define TILE_HEIGHT 16
-#define TARGET_FPS  30
-#define TARGET_UPS  60
-#define ACC_GND     0.1
-#define ACC_AIR     0.025
-#define MAX_HSPD    3.0
-#define FRC_GND     (ACC_GND / MAX_HSPD)
-#define FRC_AIR     (ACC_AIR / MAX_HSPD)
-#define AIR_RES     0.02
-#define GRAVITY     0.2
-#define JUMP_SPD    -4.0
-#define AIR_JMP_SPD -3.0
-#define JUMP_BUFFER 10
-#define JUMP_GRACE  10
-#define AIR_JUMPS   3
-#define BURST_BOOST 0.5
-#define V_TRANS_SPD (1.0 / 15.0)
-#define H_TRANS_SPD (1.0 / 20.0)
+#define TILE_WIDTH    16
+#define TILE_HEIGHT   16
+#define TILESET_WIDTH 16
+#define TARGET_FPS    30
+#define TARGET_UPS    60
+#define ACC_GND       0.1
+#define ACC_AIR       0.025
+#define MAX_HSPD      3.0
+#define FRC_GND       (ACC_GND / MAX_HSPD)
+#define FRC_AIR       (ACC_AIR / MAX_HSPD)
+#define AIR_RES       0.02
+#define GRAVITY       0.2
+#define JUMP_SPD      -4.0
+#define AIR_JMP_SPD   -3.0
+#define JUMP_BUFFER   10
+#define JUMP_GRACE    10
+#define AIR_JUMPS     3
+#define BURST_BOOST   0.5
+#define V_TRANS_SPD   (1.0 / 15.0)
+#define H_TRANS_SPD   (1.0 / 20.0)

include/level.h

@@ -9,9 +9,17 @@
 
 typedef unsigned int Tile;
 
+struct VisualTile {
+	int visible;
+	int x;
+	int y;
+	int texture_x;
+	int texture_y;
+};
+
 struct Level {
 	Tile data[LEVEL_WIDTH * LEVEL_HEIGHT];
-	int autotiling[LEVEL_WIDTH * LEVEL_HEIGHT];
+	struct VisualTile visual_data[LEVEL_WIDTH * LEVEL_HEIGHT];
 	int width;
 	int height;
 	int gold;

src/level/draw.c

@@ -11,39 +11,17 @@ extern const bopti_image_t bimg_tileset;
 
 void level_draw(void)
 {
-	int x;
-	int y;
-	const int tileset_width = bimg_tileset.width / TILE_WIDTH;
+	int i;
 
-	y = level.height;
-	while (y-- > 0) {
-		const int draw_y = y * TILE_HEIGHT;
-		x = level.width;
-		while (x-- > 0) {
-			const int draw_x = x * TILE_WIDTH;
-			const int tile_index = x + y * level.width;
-			const Tile tile = level.data[tile_index];
-			switch (tile) {
-			case TILE_VOID:
-				break;
-			case TILE_SOLID: {
-				const int autotile =
-				    level.autotiling[tile_index];
-				dsubimage(draw_x, draw_y, &bimg_tileset,
-				          autotile, TILE_HEIGHT,
-				          TILE_WIDTH, TILE_HEIGHT,
-				          DIMAGE_NOCLIP);
-			} break;
-			default:
-				dsubimage(draw_x, draw_y, &bimg_tileset,
-				          (int)(tile % tileset_width) *
-				              TILE_WIDTH,
-				          (int)(tile / tileset_width) *
-				              TILE_HEIGHT,
-				          TILE_WIDTH, TILE_HEIGHT,
-				          DIMAGE_NOCLIP);
-				break;
-			}
+	i = level.height * level.width;
+	while (i-- > 0) {
+		const struct VisualTile *visual_tile =
+		    &level.visual_data[i];
+		if (visual_tile->visible) {
+			dsubimage(visual_tile->x, visual_tile->y,
+			          &bimg_tileset, visual_tile->texture_x,
+			          visual_tile->texture_y, TILE_WIDTH,
+			          TILE_HEIGHT, DIMAGE_NOCLIP);
 		}
 	}
 }

src/level/load.c

@@ -93,13 +93,36 @@ void level_load(void)
 	/* set level id for display */
 	level.id = level_id;
 
-	/* compute autotiling */
+	/* compute visuals */
 	y = level.height;
+	i = 0;
 	while (y-- > 0) {
 		x = level.width;
 		while (x-- > 0) {
-			level.autotiling[x + y * level.width] =
-			    autotile_value(x, y) * TILE_WIDTH;
+			tile = level.data[x + y * level.width];
+			struct VisualTile visual_data;
+			visual_data.x = x * TILE_WIDTH;
+			visual_data.y = y * TILE_HEIGHT;
+			visual_data.visible = tile != TILE_START;
+			if (tile == TILE_SOLID) {
+				const int autotile =
+				    autotile_value(x, y);
+				visual_data.texture_x =
+				    autotile * TILE_WIDTH;
+				visual_data.texture_y = TILE_HEIGHT;
+				visual_data.visible = autotile != 15;
+			} else if (tile != TILE_VOID) {
+				visual_data.texture_x =
+				    (int)(tile % TILESET_WIDTH) *
+				    TILE_WIDTH;
+				visual_data.texture_y =
+				    (int)(tile / TILESET_WIDTH) *
+				    TILE_HEIGHT;
+			} else {
+				visual_data.visible = 0;
+			}
+			level.visual_data[x + y * level.width] =
+			    visual_data;
 		}
 	}
 

src/player/collide.c

@@ -84,6 +84,8 @@ static int collide_sub_single(int x, int y, Tile sub, Tile rep)
 
 		/* replace tile */
 		level.data[tile_index] = rep;
+		if (rep == TILE_VOID)
+			level.visual_data[tile_index].visible = 0;
 
 		/* spawn animations */
 		switch (sub) {

src/player/init.c

@@ -31,9 +31,6 @@ struct Player player_init(void)
 		while (y-- > 0) {
 			if (level.data[x + y * level.width] ==
 			    TILE_START) {
-				/* erase start tile */
-				level.data[x + y * level.width] =
-				    TILE_VOID;
 				/* set player position */
 				player.x =
 				    x * TILE_WIDTH +