01: Add simple animation and movement

.gitignore

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+.ccls-cache/
+build/

01-introduction/Makefile

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+CC=gcc 
+CFLAGS=`pkg-config --cflags sdl2 SDL2_image`
+LDFLAGS=`pkg-config --libs sdl2 SDL2_image`
+TARGET=introduction
+SDIR=src
+ADIR=assets
+ODIR=build
+
+SRC=$(shell find $(SDIR) -type f -name *.c) 
+OBJ=$(SRC:.c=.o)
+
+all: $(TARGET)
+
+.PHONY: default
+$(TARGET): $(OBJ) 
+	mkdir -p build 
+	cp -rf $(ADIR) $(ODIR)/$(ADIR)
+	$(CC) -o $(ODIR)/$@ $^ $(LDFLAGS)
+
+%.o: %.c 
+	$(CC) $(CFLAGS) -o $@ -c $< 
+
+run: 
+	$(ODIR)/$(TARGET)
+
+.PHONY: clean 
+clean: 
+	rm -f $(ODIR)/$(TARGET) $(OBJ)

01-introduction/src/main.c

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+#include <stdio.h>
+#include <SDL2/SDL.h>
+#include <SDL2/SDL_image.h>
+#include "structs.h"
+
+const int SCREEN_WIDTH = 640; 
+const int SCREEN_HEIGHT = 480;
+const Uint32 WINDOW_FLAGS = SDL_WINDOW_SHOWN | SDL_WINDOW_OPENGL | SDL_WINDOW_BORDERLESS; 
+const Uint32 RENDERER_FLAGS = SDL_RENDERER_ACCELERATED;
+int GAME_RUNNING = 1;
+struct game game; 
+int movement_speed = 5;
+int animation_frames = 100;
+int frames = 0;
+
+void prepare_scene(void) {
+    SDL_SetRenderDrawColor(game.renderer, 96, 128, 255, 255);
+    SDL_RenderClear(game.renderer);
+}
+
+void key(SDL_KeyboardEvent *event) {
+    if (event->repeat != 0)
+        return;   
+
+    if (event->keysym.scancode == SDL_SCANCODE_W)
+        game.up = !game.up;
+    if (event->keysym.scancode == SDL_SCANCODE_S)
+        game.down = !game.down;
+    if (event->keysym.scancode == SDL_SCANCODE_A)
+        game.left = !game.left;
+    if (event->keysym.scancode == SDL_SCANCODE_D)
+        game.right = !game.right;
+}
+
+void handle_input(void) {
+    SDL_Event event; 
+
+    while (SDL_PollEvent(&event)) {
+        switch (event.type) {
+            case SDL_QUIT: 
+                GAME_RUNNING = 0; 
+                break;
+            case SDL_KEYDOWN: 
+            case SDL_KEYUP: 
+                key(&event.key); 
+                break;
+            default:
+                break;
+        }
+        if (event.type == SDL_QUIT) {
+            GAME_RUNNING = 0;
+        }
+    }
+}
+
+SDL_Texture *load_texture(const char *path) {
+    SDL_Texture *texture; 
+    
+    SDL_LogMessage(SDL_LOG_CATEGORY_APPLICATION, SDL_LOG_PRIORITY_INFO, "Loading %s", path);
+    
+    texture = IMG_LoadTexture(game.renderer, path);
+
+    return texture;
+}
+
+struct object *create_object(const char *texture_path, int x, int y, int scale, int resolution) {
+    struct object *object = (struct object *) calloc(1, sizeof(struct object));
+
+    if (object == NULL) {
+        fprintf(stderr, "Error: failed allocating memory for new object\n");
+        return NULL;
+    }
+
+    object->texture = load_texture(texture_path);
+
+    if (object->texture == NULL) {
+        fprintf(stderr, "Error: loading texture into new object\n");
+        return NULL;
+    }
+
+    object->x = x; 
+    object->y = y;
+    object->scale = scale;
+    object->resolution = resolution;
+
+    return object;
+}
+
+void draw_object(struct object *object) {
+    SDL_Rect src;
+    SDL_Rect dest;
+
+    src.x = object->state * object->resolution;
+    src.y = 0;
+
+    src.w = object->resolution;
+    src.h = object->resolution;
+
+    dest.x = object->x; 
+    dest.y = object->y; 
+    dest.w = object->resolution * object->scale;
+    dest.h = object->resolution * object->scale;
+
+    SDL_RenderCopy(game.renderer, object->texture, &src, &dest);
+}
+
+void present_scene(void) {
+    SDL_RenderPresent(game.renderer);
+}
+
+int main(int argc, char *argv[]) {
+    if (SDL_Init(SDL_INIT_VIDEO) != 0) {
+        fprintf(stderr, "Error: could not initialize SDL\n%s\n", SDL_GetError());
+        return -1;
+    }
+
+    game.window = SDL_CreateWindow("01-introduction", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, SCREEN_WIDTH, SCREEN_HEIGHT, WINDOW_FLAGS);
+
+    if (game.window == NULL) {
+        fprintf(stderr, "Error: could not create window\n%s\n", SDL_GetError());
+        return -1;
+    }
+
+    game.renderer = SDL_CreateRenderer(game.window, -1, RENDERER_FLAGS);    
+
+    if (game.renderer == NULL) {
+        fprintf(stderr, "Error: could not create renderer\n%s\n", SDL_GetError());
+        return -1;
+    }
+
+    struct object *player = create_object("assets/player.png", SCREEN_WIDTH/2, SCREEN_HEIGHT/2, 3, 48);
+
+    // game loop
+    while (GAME_RUNNING) {
+        frames++;
+        prepare_scene();
+        handle_input(); 
+
+        if (game.up)
+            player->y -= movement_speed; 
+        if (game.down)
+            player->y += movement_speed;
+        if (game.left) 
+            player->x -= movement_speed; 
+        if (game.right) 
+            player->x += movement_speed;
+
+        player->state = ((frames % animation_frames)/5) % 10;
+
+        draw_object(player);
+
+        present_scene();
+
+        SDL_Delay(16);
+    }
+
+    SDL_DestroyWindow(game.window);
+    SDL_Quit();
+
+    return 0; 
+}

01-introduction/src/structs.h

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+#ifndef STRUCTS_H
+#define STRUCTS_H
+
+#include <SDL2/SDL.h>
+
+struct game {
+    SDL_Window *window; 
+    SDL_Renderer *renderer;
+
+    int up; 
+    int down; 
+    int left; 
+    int right;
+};
+
+struct object {
+    SDL_Texture *texture; 
+    int resolution; // of the texture/each tiles
+
+    int x; 
+    int y;
+    int scale;
+
+    // animation 
+    int state;
+};
+
+#endif 

README

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+SDL Playground 
+==============
+
+My little playground for SDL.