Extract terrain concept

1 files changed, 62 insertions, 40 deletions

diff --git a/main.c b/main.c
index 9bcd467..539180a 100644
--- a/main.c
+++ b/main.c
@@ -26,6 +26,28 @@ typedef struct {
 	int alive;
 } Projectile;
 
+typedef struct {
+	float *mask;
+	int width;
+	int height;
+	int updated;
+} Terrain;
+
+void PaintTerrain(Terrain *t, float x, float y, float color, float size) {
+	for (int j = y - size; j < y + size; j++) {
+		for (int i = x - size; i < x + size; i++) {
+			float dj = y - j;
+			float di = x - i;
+			if (i > 0 && i < t->width && j > 0 && j < t->height
+					&& dj * dj + di * di <= size * size / 2) {
+				size_t index = i + j * t->width;
+				t->mask[index] = color;
+			}
+		}
+	}
+	t->updated = 1;
+}
+
 static inline double GetCurrentTimestamp() {
 	return (double) SDL_GetTicks64() / 1000.0;
 }
@@ -53,41 +75,31 @@ SDL_Texture *CreateTiledTexture(SDL_Renderer *context, const char *filename, int
 	return texture;
 }
 
-void PaintMask(float *mask, int width, int height, float x, float y, float color, float size) {
-	for (int j = y - size; j < y + size; j++) {
-		for (int i = x - size; i < x + size; i++) {
-			float dj = y - j;
-			float di = x - i;
-			if (i > 0 && i < width && j > 0 && j < height
-					&& dj * dj + di * di <= size * size / 2) {
-				size_t index = i + j * width;
-				mask[index] = color;
-			}
-		}
-	}
-}
-
 void GameMain(SDL_Renderer *context) {
 	SDL_Texture *background = CreateTiledTexture(context, "background.bmp", WINDOW_W, WINDOW_H);
 
 	SDL_Texture *foreground = CreateTiledTexture(context, "foreground.bmp", WINDOW_W, WINDOW_H);
 	SDL_SetTextureBlendMode(foreground, SDL_BLENDMODE_MOD);
 
-	SDL_Texture *terrain = SDL_CreateTexture(context,
+	SDL_Texture *terrain_texture = SDL_CreateTexture(context,
 			SDL_PIXELFORMAT_RGBA8888,
 			SDL_TEXTUREACCESS_TARGET,
 			WINDOW_W, WINDOW_H);
-	SDL_SetTextureBlendMode(terrain, SDL_BLENDMODE_BLEND);
+	SDL_SetTextureBlendMode(terrain_texture, SDL_BLENDMODE_BLEND);
 
 	SDL_Texture *mask_texture = SDL_CreateTexture(context,
 			SDL_PIXELFORMAT_RGBA8888,
 			SDL_TEXTUREACCESS_STREAMING,
 			WINDOW_W, WINDOW_H);
 
-	float *mask = calloc(WINDOW_W * WINDOW_H, sizeof(float));
+	Terrain terrain = {0};
+	terrain.width = WINDOW_W;
+	terrain.height = WINDOW_H;
+	terrain.mask = calloc(WINDOW_W * WINDOW_H, sizeof(float));
 	for (int i = 0; i < 100 * WINDOW_W; i++) {
-		mask[i] = 1.0;
+		terrain.mask[i] = 1.0;
 	}
+	terrain.updated = 1;
 
 	Cannon player = {0};
 	player.x = 100;
@@ -100,15 +112,12 @@ void GameMain(SDL_Renderer *context) {
 
 	int exit = 0;
 	while (!exit) {
-		double new_t = GetCurrentTimestamp();
-		double dt = (new_t - old_t) * 10;
-		old_t = new_t;
-
 		SDL_Event event;
 		while (SDL_PollEvent(&event)) {
 			if (event.type == SDL_QUIT) {
 				exit = 1;
-			} else if (event.type == SDL_KEYDOWN && event.key.state == SDL_PRESSED && event.key.keysym.sym == SDLK_SPACE && !projectile.alive) {
+			} else if (event.type == SDL_KEYDOWN && event.key.state == SDL_PRESSED &&
+					event.key.keysym.sym == SDLK_SPACE && !projectile.alive) {
 				projectile.alive = 1;
 				projectile.x = player.x;
 				projectile.y = player.y;
@@ -116,13 +125,20 @@ void GameMain(SDL_Renderer *context) {
 				projectile.vx = cos(player.angle) * player.power;
 			}
 		}
+		int simulation_frames = 10;
+		while (simulation_frames > 0) {
+			simulation_frames--;
+		double new_t = GetCurrentTimestamp();
+		double dt = (new_t - old_t);
+		old_t = new_t;
+
 		int mouse_x, mouse_y;
 		Uint32 mouse_state = SDL_GetMouseState(&mouse_x, &mouse_y);
 		float size = 20;
 		if (mouse_state & SDL_BUTTON_LMASK) {
-			PaintMask(mask, WINDOW_W, WINDOW_H, mouse_x, WINDOW_H - mouse_y, 1.0, size);
+			PaintTerrain(&terrain, mouse_x, WINDOW_H - mouse_y, 1.0, size);
 		} else if (mouse_state & SDL_BUTTON_RMASK) {
-			PaintMask(mask, WINDOW_W, WINDOW_H, mouse_x, WINDOW_H - mouse_y, 0.0, size);
+			PaintTerrain(&terrain, mouse_x, WINDOW_H - mouse_y, 0.0, size);
 		}
 
 		const Uint8 *keys = SDL_GetKeyboardState(0);
@@ -136,6 +152,7 @@ void GameMain(SDL_Renderer *context) {
 			player.angle += PI / 180 * dt;
 		}
 		if (keys[SDL_SCANCODE_S] && player.angle > 0) {
+
 			player.angle -= PI / 180 * dt;
 		}
 
@@ -143,11 +160,11 @@ void GameMain(SDL_Renderer *context) {
 			player.y  = WINDOW_H - 1;
 			player.vy = 0;
 		}
-		if (mask[(int)player.x + (int)player.y * WINDOW_W] == 0.0 &&
+		if (terrain.mask[(int)player.x + (int)player.y * WINDOW_W] == 0.0 &&
 				player.y >= 0) {
 			player.y += player.vy * dt;
 			player.vy += GRAVITY * dt;
-			while (mask[(int)player.x + (int)player.y * WINDOW_W] != 0.0) {
+			while (terrain.mask[(int)player.x + (int)player.y * WINDOW_W] != 0.0) {
 				player.y += 1;
 				player.vy = 0;
 			}
@@ -156,45 +173,50 @@ void GameMain(SDL_Renderer *context) {
 		if (projectile.alive) {
 			if (projectile.y >= 0 && projectile.y < WINDOW_H &&
 					projectile.x >= 0 && projectile.x < WINDOW_W &&
-					mask[(int)projectile.x + (int)projectile.y * WINDOW_W] == 0.0) {
+					terrain.mask[(int)projectile.x + (int)projectile.y * WINDOW_W] == 0.0) {
 				projectile.x += projectile.vx * dt;
 				projectile.y += projectile.vy * dt;
 				projectile.vy += GRAVITY * dt;
 			} else {
 				projectile.alive = 0;
-				PaintMask(mask, WINDOW_W, WINDOW_H, projectile.x, projectile.y, 0.0, 40);
+				PaintTerrain(&terrain, projectile.x, projectile.y, 0.0, 40);
 			}
 		}
 
-		void *pixels;
-		int pitch;
-		SDL_LockTexture(mask_texture, 0, &pixels, &pitch);
-		Uint32 *p = (Uint32 *) pixels;
-		for (int j = 0; j < WINDOW_H; j++) {
-			for (int i = 0; i < WINDOW_W; i++) {
-				p[i + j * WINDOW_W] = mask[i + (WINDOW_H - j) * WINDOW_W] ? 0xffffffff : 0x00000000;
+		if (terrain.updated) {
+			void *pixels;
+			int pitch;
+			SDL_LockTexture(mask_texture, 0, &pixels, &pitch);
+			Uint32 *p = (Uint32 *) pixels;
+			for (int j = 0; j < WINDOW_H; j++) {
+				for (int i = 0; i < WINDOW_W; i++) {
+					p[i + j * WINDOW_W] = terrain.mask[i + (WINDOW_H - j) * WINDOW_W] ? 0xffffffff : 0x00000000;
+				}
 			}
+			SDL_UnlockTexture(mask_texture);
+			terrain.updated = 0;
+		}
 		}
-		SDL_UnlockTexture(mask_texture);
 
 		SDL_SetRenderDrawColor(context, 40, 40, 40, 255);
 		SDL_RenderClear(context);
 
 		SDL_RenderCopy(context, background, 0, 0);
 
-		SDL_SetRenderTarget(context, terrain);
+		SDL_SetRenderTarget(context, terrain_texture);
 		SDL_SetRenderDrawColor(context, 0, 0, 0, 0);
 		SDL_RenderClear(context);
 		SDL_RenderCopy(context, mask_texture, 0, 0);
 		SDL_RenderCopy(context, foreground, 0, 0);
 		SDL_SetRenderTarget(context, 0);
-		SDL_RenderCopy(context, terrain, 0, 0);
+		SDL_RenderCopy(context, terrain_texture, 0, 0);
 
 		SDL_SetRenderDrawColor(context, 255, 0, 0, 255);
 		SDL_Rect player_rect = {player.x - 5, WINDOW_H - player.y - 10, 10, 10 };
 		SDL_RenderFillRect(context, &player_rect);
 
-		SDL_RenderDrawLine(context, player.x, WINDOW_H - player.y, player.x + cos(player.angle) * 100, WINDOW_H - player.y - sin(player.angle) * 100);
+		SDL_RenderDrawLine(context, player.x, WINDOW_H - player.y, 
+				player.x + cos(player.angle) * 100, WINDOW_H - player.y - sin(player.angle) * 100);
 
 		if (projectile.alive) {
 			SDL_SetRenderDrawColor(context, 0, 255, 0, 255);