[rtextures] ImageDraw(): Implement drawing to mipmaps

src/rtextures.c

@@ -3916,7 +3916,6 @@ void ImageDraw(Image *dst, Image src, Rectangle srcRec, Rectangle dstRec, Color
     if ((dst->data == NULL) || (dst->width == 0) || (dst->height == 0) ||
         (src.data == NULL) || (src.width == 0) || (src.height == 0)) return;
 
-    if (dst->mipmaps > 1) TRACELOG(LOG_WARNING, "Image drawing only applied to base mipmap level");
     if (dst->format >= PIXELFORMAT_COMPRESSED_DXT1_RGB) TRACELOG(LOG_WARNING, "Image drawing not supported for compressed formats");
     else
     {
@@ -4029,6 +4028,34 @@ void ImageDraw(Image *dst, Image src, Rectangle srcRec, Rectangle dstRec, Color
         }
 
         if (useSrcMod) UnloadImage(srcMod);     // Unload source modified image
+
+        if (dst->mipmaps > 1 && src.mipmaps > 1) {
+            Image mipmapDst = *dst;
+            mipmapDst.data = (char *) mipmapDst.data + GetPixelDataSize(mipmapDst.width, mipmapDst.height, mipmapDst.format);
+            mipmapDst.width /= 2;
+            mipmapDst.height /= 2;
+            mipmapDst.mipmaps--;
+
+            Image mipmapSrc = src;
+            mipmapSrc.data = (char *) mipmapSrc.data + GetPixelDataSize(mipmapSrc.width, mipmapSrc.height, mipmapSrc.format);
+            mipmapSrc.width /= 2;
+            mipmapSrc.height /= 2;
+            mipmapSrc.mipmaps--;
+
+            Rectangle mipmapSrcRec = srcRec;
+            mipmapSrcRec.width /= 2;
+            mipmapSrcRec.height /= 2;
+            mipmapSrcRec.x /= 2;
+            mipmapSrcRec.y /= 2;
+
+            Rectangle mipmapDstRec = dstRec;
+            mipmapDstRec.width /= 2;
+            mipmapDstRec.height /= 2;
+            mipmapDstRec.x /= 2;
+            mipmapDstRec.y /= 2;
+
+            ImageDraw(&mipmapDst, mipmapSrc, mipmapSrcRec, mipmapDstRec, tint);
+        }
     }
 }