remove x2, y2

field.c

@@ -19,7 +19,7 @@ void Field_init(Field *f, SDL_Renderer *rend, int w, int h) {
 void Field_scroll(Field *f, SDL_Renderer *rend) {
     int w = f->pics[0]->w;
     int h = f->pics[0]->h;
-    if (f->offset.y < f->tl->y1) {
+    if (f->offset.y < f->tl->y) {
         SWAP(f->tl, f->bl);
         SWAP(f->tr, f->br);
         Picture_move(f->tl, 0, -2*h);
@@ -27,7 +27,7 @@ void Field_scroll(Field *f, SDL_Renderer *rend) {
         Picture_render(f->tl, rend);
         Picture_render(f->tr, rend);
     }
-    if (f->offset.x < f->tl->x1) {
+    if (f->offset.x < f->tl->x) {
         SWAP(f->tl, f->tr);
         SWAP(f->bl, f->br);
         Picture_move(f->tl, -2*w, 0);
@@ -35,7 +35,7 @@ void Field_scroll(Field *f, SDL_Renderer *rend) {
         Picture_render(f->tl, rend);
         Picture_render(f->bl, rend);
     }
-    if (f->offset.y >= f->br->y1) {
+    if (f->offset.y >= f->br->y) {
         SWAP(f->tl, f->bl);
         SWAP(f->tr, f->br);
         Picture_move(f->bl, 0, 2*h);
@@ -43,7 +43,7 @@ void Field_scroll(Field *f, SDL_Renderer *rend) {
         Picture_render(f->bl, rend);
         Picture_render(f->br, rend);
     }
-    if (f->offset.x >= f->br->x1) {
+    if (f->offset.x >= f->br->x) {
         SWAP(f->tl, f->tr);
         SWAP(f->bl, f->br);
         Picture_move(f->tr, 2*w, 0);
@@ -57,7 +57,7 @@ void Field_draw(Field *f, SDL_Renderer *rend) {
     for (int i = 0; i < 4; i++) {
         Picture *p = f->pics[i];
         SDL_FRect dst = {
-            p->x1 - f->offset.x, p->y1 - f->offset.y, p->w, p->h,
+            p->x - f->offset.x, p->y - f->offset.y, p->w, p->h,
         };
         SDL_RenderTexture(rend, p->texture, NULL, &dst);
     }

picture.c

@@ -8,10 +8,8 @@ Picture *Picture_new(SDL_Renderer *rend,
     
     Picture *p = calloc(1, sizeof(Picture));
 
-    p->x1 = x;
-    p->x2 = x + w;
-    p->y1 = y;
-    p->y2 = y + h;
+    p->x = x;
+    p->y = y;
     p->w = w;
     p->h = h;
     p->color = color;
@@ -37,9 +35,9 @@ void Picture_render(Picture *p, SDL_Renderer *rend) {
     };
     const uint32_8 y0 = { 0, 0, 0, 0, 0, 0, 0, 0 };
     const uint32_8 x0 = { 0, 1, 2, 3, 4, 5, 6, 7 };
-    uint32_8 y = y0 + p->y1;
+    uint32_8 y = y0 + p->y;
     for (int j = 0, r = 0; j < h; j++, y += 1) {
-        uint32_8 x = x0 + p->x1;
+        uint32_8 x = x0 + p->x;
         for (int i = 0; i < w; i += 8, r += 8, x += 8) {
             uint32_8 z = (x ^ y) % 9;
             uint32_8 f = (z==0) & c;
@@ -56,9 +54,7 @@ void Picture_render(Picture *p, SDL_Renderer *rend) {
 }
 
 void Picture_move(Picture *p, int x, int y) {
-    p->x1 += x;
-    p->x2 += x;
-    p->y1 += y;
-    p->y2 += y;
+    p->x += x;
+    p->y += y;
 }
 

picture.h

@@ -4,10 +4,8 @@
 #include <SDL3/SDL.h>
 
 typedef struct {
-    int x1;
-    int y1;
-    int x2;
-    int y2;
+    int x;
+    int y;
     int w;
     int h;
     int s;

xormod.c

@@ -72,7 +72,7 @@ int main() {
         Field_draw(&f, rend);
 
         if (debug) {
-            char buf[72];
+            char buf[52];
             SDL_SetRenderDrawColor(rend, 0, 0, 0, 255);
             SDL_RenderFillRect(rend, &(SDL_FRect) {
                 0, 0, sizeof(buf)*font_w, 8*font_h
@@ -87,8 +87,7 @@ int main() {
             char *q[] = {"TL", "TR", "BL", "BR"};
             for (int i = 0; i < 4; i++) {
                 Picture *p = f.pics[i];
-                len = snprintf(buf, sizeof(buf), "%s \xB3 x1: %05d, x2: %05d, y1: %05d, y2: %05d, p: %p",
-                    q[i], p->x1, p->x2, p->y1, p->y2, p);
+                len = snprintf(buf, sizeof(buf), "%s \xB3 x: %05d, y: %05d, p: %p", q[i], p->x, p->y, p);
                 draw_text(rend, buf, len, RC(3+i, 1), 255, 255, 255);
             }
         }