initial

.gitignore

@@ -0,0 +1,2 @@
+*.o
+main

Makefile

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+CC=gcc
+
+COMMON=-Wall -std=gnu99 
+CFLAGS=$(COMMON)
+
+LDFLAGS=
+
+main:        test01.o
+	$(CC) -o $@ $(LDFLAGS) $^
+
+.c.o:
+	$(CC) $(CFLAGS) -c $<
+
+.S.o:
+	$(CC) $(ASFLAGS) -c $<
+
+
+.PHONY: all
+all:    main
+
+.PHONY: clean
+clean:
+	-rm -f *.o *.elf *.map *.txt main
+
+

test01.c

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+#include <stdio.h>
+#include <stdint.h>
+#include <string.h>
+
+
+#define CANVAS_HEIGHT  20
+#define CANVAS_WIDTH  10
+
+uint8_t canvas[CANVAS_WIDTH][CANVAS_HEIGHT];
+
+#define O_HEIGHT 2
+#define O_WIDTH 2
+#define O_COLOR 1
+
+typedef enum {e_O} t_shape;
+
+typedef struct {
+  t_shape shape;
+
+  uint8_t x;
+  uint8_t y;
+
+  uint8_t rotation; // 0 = 12 o'clock, 1 = 3 o'clock, 2 = 6 o'clock, 3 = 9 o'clock
+
+  union {
+    uint8_t O[O_WIDTH][O_HEIGHT];
+  };
+} t_object;
+
+t_object object;
+
+typedef enum {e_Down, e_Left, e_Right} t_direction;
+
+
+void showCanvas() {
+  for (uint8_t y = 0; y < CANVAS_HEIGHT; y++) {
+    for (uint8_t x = 0; x < CANVAS_WIDTH; x++) {
+      printf("%02x ", canvas[x][y]);
+    }
+    printf("\n");
+  }
+  printf("\n");
+}
+
+void initObject(t_shape shape, uint8_t x, uint8_t y) {
+  object.shape = shape;
+  object.x = x;
+  object.y = y;
+  object.rotation = 0;
+
+  switch (shape) {
+    case e_O:
+      memset(object.O, O_COLOR, O_HEIGHT * O_WIDTH);
+      break;
+  }
+}
+
+void drawObject() { 
+  switch (object.shape) {
+    case e_O:
+      switch (object.rotation) {
+        case 0:
+          canvas[object.x][object.y] = object.O[0][0];
+          canvas[object.x][object.y+1] = object.O[0][1];
+          canvas[object.x+1][object.y] = object.O[1][0];
+          canvas[object.x+1][object.y+1] = object.O[1][1];
+          break;
+      }
+  }
+}
+
+void wipeObject() { 
+  switch (object.shape) {
+    case e_O:
+      switch (object.rotation) {
+        case 0:
+          canvas[object.x][object.y] = 0;
+          canvas[object.x][object.y+1] = 0;
+          canvas[object.x+1][object.y] = 0;
+          canvas[object.x+1][object.y+1] = 0;
+          break;
+      }
+  }
+}
+
+int moveObject(t_direction direction) {
+  int res = 0;
+  uint8_t new_value;
+  switch (direction) {
+    case e_Down:
+      new_value = object.y + 1;
+      if (new_value >= 0 && new_value <= CANVAS_HEIGHT-O_HEIGHT) {
+        object.y = new_value;
+      } else {
+        res = -1;
+      }
+      break;
+    case e_Left:
+      new_value = object.x - 1;
+      if (new_value >= 0 && new_value < CANVAS_WIDTH-O_WIDTH) {
+        object.x = new_value;
+      } else {
+        res = -1;
+      }
+      break;
+    case e_Right:
+      new_value = object.x + 1;
+      if (new_value >= 0 && new_value <= CANVAS_WIDTH-O_WIDTH) {
+        object.x = new_value;
+      } else {
+        res = -1;
+      }
+      break;
+  }
+  return res;
+}
+
+int main(int argc, char *argv[]) {
+  memset(canvas, 0, CANVAS_HEIGHT * CANVAS_WIDTH);
+
+  showCanvas();
+
+  initObject(e_O, 2, 0);
+
+  drawObject();
+  showCanvas();
+
+  while (1) {
+    wipeObject();
+    int err = moveObject(e_Down);
+    if (err != 0) {
+      printf("object would stick out canvas\n");
+      break;
+    } else {
+      drawObject();
+      showCanvas();
+    }
+  }
+  
+  while (1) {
+    wipeObject();
+    int err = moveObject(e_Right);
+    if (err != 0) {
+      printf("object would stick out canvas\n");
+      break;
+    } else {
+      drawObject();
+      showCanvas();
+    }
+  }
+  
+  while (1) {
+    wipeObject();
+    int err = moveObject(e_Left);
+    if (err != 0) {
+      printf("object would stick out canvas\n");
+      break;
+    } else {
+      drawObject();
+      showCanvas();
+    }
+  }
+  
+}
+