Added tiled 9-grid texture rendering function

* New function SDL_RenderTexture9GridTiled, borders and center is tiled instead of stretched
libsdl-org · Jan 24, 2025 · 23da655 · 23da655
1 parent cb3d6dc
commit 23da655
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diff --git a/include/SDL3/SDL_render.h b/include/SDL3/SDL_render.h
@@ -2182,6 +2182,40 @@ extern SDL_DECLSPEC bool SDLCALL SDL_RenderTextureTiled(SDL_Renderer *renderer,
  */
 extern SDL_DECLSPEC bool SDLCALL SDL_RenderTexture9Grid(SDL_Renderer *renderer, SDL_Texture *texture, const SDL_FRect *srcrect, float left_width, float right_width, float top_height, float bottom_height, float scale, const SDL_FRect *dstrect);
 
+/**
+ * Perform a scaled copy using the 9-grid algorithm to the current rendering
+ * target at subpixel precision.
+ *
+ * The pixels in the texture are split into a 3x3 grid, using the different
+ * corner sizes for each corner, and the sides and center making up the
+ * remaining pixels. The corners are then scaled using `scale` and fit into
+ * the corners of the destination rectangle. The sides and center are then
+ * tiled into place to cover the remaining destination rectangle.
+ *
+ * \param renderer the renderer which should copy parts of a texture.
+ * \param texture the source texture.
+ * \param srcrect the SDL_Rect structure representing the rectangle to be used
+ *                for the 9-grid, or NULL to use the entire texture.
+ * \param left_width the width, in pixels, of the left corners in `srcrect`.
+ * \param right_width the width, in pixels, of the right corners in `srcrect`.
+ * \param top_height the height, in pixels, of the top corners in `srcrect`.
+ * \param bottom_height the height, in pixels, of the bottom corners in
+ *                      `srcrect`.
+ * \param scale the scale used to transform `srcrect` into the `dstrect`,
+ *                      or 0.0f for an unscaled copy.
+ * \param dstrect a pointer to the destination rectangle, or NULL for the
+ *                entire rendering target.
+ * \returns true on success or false on failure; call SDL_GetError() for more
+ *          information.
+ *
+ * \threadsafety This function should only be called on the main thread.
+ *
+ * \since This function is available since SDL 3.2.0.
+ *
+ * \sa SDL_RenderTexture
+ */
+extern SDL_DECLSPEC bool SDLCALL SDL_RenderTexture9GridTiled(SDL_Renderer *renderer, SDL_Texture *texture, const SDL_FRect *srcrect, float left_width, float right_width, float top_height, float bottom_height, float scale, const SDL_FRect *dstrect);
+
 /**
  * Render a list of triangles, optionally using a texture and indices into the
  * vertex array Color and alpha modulation is done per vertex

diff --git a/src/dynapi/SDL_dynapi_overrides.h b/src/dynapi/SDL_dynapi_overrides.h
@@ -772,6 +772,7 @@
 #define SDL_RenderRects SDL_RenderRects_REAL
 #define SDL_RenderTexture SDL_RenderTexture_REAL
 #define SDL_RenderTexture9Grid SDL_RenderTexture9Grid_REAL
+#define SDL_RenderTexture9GridTiled SDL_RenderTexture9GridTiled_REAL
 #define SDL_RenderTextureRotated SDL_RenderTextureRotated_REAL
 #define SDL_RenderTextureTiled SDL_RenderTextureTiled_REAL
 #define SDL_RenderViewportSet SDL_RenderViewportSet_REAL

diff --git a/src/dynapi/SDL_dynapi_procs.h b/src/dynapi/SDL_dynapi_procs.h
@@ -783,6 +783,7 @@ SDL_DYNAPI_PROC(bool,SDL_RenderRect,(SDL_Renderer *a, const SDL_FRect *b),(a,b),
 SDL_DYNAPI_PROC(bool,SDL_RenderRects,(SDL_Renderer *a, const SDL_FRect *b, int c),(a,b,c),return)
 SDL_DYNAPI_PROC(bool,SDL_RenderTexture,(SDL_Renderer *a, SDL_Texture *b, const SDL_FRect *c, const SDL_FRect *d),(a,b,c,d),return)
 SDL_DYNAPI_PROC(bool,SDL_RenderTexture9Grid,(SDL_Renderer *a, SDL_Texture *b, const SDL_FRect *c, float d, float e, float f, float g, float h, const SDL_FRect *i),(a,b,c,d,e,f,g,h,i),return)
+SDL_DYNAPI_PROC(bool,SDL_RenderTexture9GridTiled,(SDL_Renderer *a, SDL_Texture *b, const SDL_FRect *c, float d, float e, float f, float g, float h, const SDL_FRect *i),(a,b,c,d,e,f,g,h,i),return)
 SDL_DYNAPI_PROC(bool,SDL_RenderTextureRotated,(SDL_Renderer *a, SDL_Texture *b, const SDL_FRect *c, const SDL_FRect *d, double e, const SDL_FPoint *f, SDL_FlipMode g),(a,b,c,d,e,f,g),return)
 SDL_DYNAPI_PROC(bool,SDL_RenderTextureTiled,(SDL_Renderer *a, SDL_Texture *b, const SDL_FRect *c, float d, const SDL_FRect *e),(a,b,c,d,e),return)
 SDL_DYNAPI_PROC(bool,SDL_RenderViewportSet,(SDL_Renderer *a),(a),return)

diff --git a/src/render/SDL_render.c b/src/render/SDL_render.c
@@ -4483,6 +4483,141 @@ bool SDL_RenderTexture9Grid(SDL_Renderer *renderer, SDL_Texture *texture, const
     return true;
 }
 
+bool SDL_RenderTexture9GridTiled(SDL_Renderer *renderer, SDL_Texture *texture, const SDL_FRect *srcrect, float left_width, float right_width, float top_height, float bottom_height, float scale, const SDL_FRect *dstrect)
+{
+    SDL_FRect full_src, full_dst;
+    SDL_FRect curr_src, curr_dst;
+    float dst_left_width;
+    float dst_right_width;
+    float dst_top_height;
+    float dst_bottom_height;
+
+    CHECK_RENDERER_MAGIC(renderer, false);
+    CHECK_TEXTURE_MAGIC(texture, false);
+
+    if (renderer != texture->renderer) {
+        return SDL_SetError("Texture was not created with this renderer");
+    }
+
+    if (!srcrect) {
+        full_src.x = 0;
+        full_src.y = 0;
+        full_src.w = (float)texture->w;
+        full_src.h = (float)texture->h;
+        srcrect = &full_src;
+    }
+
+    if (!dstrect) {
+        GetRenderViewportSize(renderer, &full_dst);
+        dstrect = &full_dst;
+    }
+
+    if (scale <= 0.0f || scale == 1.0f) {
+        dst_left_width = SDL_ceilf(left_width);
+        dst_right_width = SDL_ceilf(right_width);
+        dst_top_height = SDL_ceilf(top_height);
+        dst_bottom_height = SDL_ceilf(bottom_height);
+    } else {
+        dst_left_width = SDL_ceilf(left_width * scale);
+        dst_right_width = SDL_ceilf(right_width * scale);
+        dst_top_height = SDL_ceilf(top_height * scale);
+        dst_bottom_height = SDL_ceilf(bottom_height * scale);
+    }
+
+    // Center
+    curr_src.x = srcrect->x + left_width;
+    curr_src.y = srcrect->y + top_height;
+    curr_src.w = srcrect->w - left_width - right_width;
+    curr_src.h = srcrect->h - top_height - bottom_height;
+    curr_dst.x = dstrect->x + dst_left_width;
+    curr_dst.y = dstrect->y + dst_top_height;
+    curr_dst.w = dstrect->w - dst_left_width - dst_right_width;
+    curr_dst.h = dstrect->h - dst_top_height - dst_bottom_height;
+    if (!SDL_RenderTextureTiled(renderer, texture, &curr_src, scale, &curr_dst)) {
+        return false;
+    }
+
+    // Upper-left corner
+    curr_src.x = srcrect->x;
+    curr_src.y = srcrect->y;
+    curr_src.w = left_width;
+    curr_src.h = top_height;
+    curr_dst.x = dstrect->x;
+    curr_dst.y = dstrect->y;
+    curr_dst.w = dst_left_width;
+    curr_dst.h = dst_top_height;
+    if (!SDL_RenderTexture(renderer, texture, &curr_src, &curr_dst)) {
+        return false;
+    }
+
+    // Upper-right corner
+    curr_src.x = srcrect->x + srcrect->w - right_width;
+    curr_src.w = right_width;
+    curr_dst.x = dstrect->x + dstrect->w - dst_right_width;
+    curr_dst.w = dst_right_width;
+    if (!SDL_RenderTexture(renderer, texture, &curr_src, &curr_dst)) {
+        return false;
+    }
+
+    // Lower-right corner
+    curr_src.y = srcrect->y + srcrect->h - bottom_height;
+    curr_dst.y = dstrect->y + dstrect->h - dst_bottom_height;
+    curr_dst.h = dst_bottom_height;
+    if (!SDL_RenderTexture(renderer, texture, &curr_src, &curr_dst)) {
+        return false;
+    }
+
+    // Lower-left corner
+    curr_src.x = srcrect->x;
+    curr_src.w = left_width;
+    curr_dst.x = dstrect->x;
+    curr_dst.w = dst_left_width;
+    if (!SDL_RenderTexture(renderer, texture, &curr_src, &curr_dst)) {
+        return false;
+    }
+
+    // Left
+    curr_src.y = srcrect->y + top_height;
+    curr_src.h = srcrect->h - top_height - bottom_height;
+    curr_dst.y = dstrect->y + dst_top_height;
+    curr_dst.h = dstrect->h - dst_top_height - dst_bottom_height;
+    if (!SDL_RenderTextureTiled(renderer, texture, &curr_src, scale, &curr_dst)) {
+        return false;
+    }
+
+    // Right
+    curr_src.x = srcrect->x + srcrect->w - right_width;
+    curr_src.w = right_width;
+    curr_dst.x = dstrect->x + dstrect->w - dst_right_width;
+    curr_dst.w = dst_right_width;
+    if (!SDL_RenderTextureTiled(renderer, texture, &curr_src, scale, &curr_dst)) {
+        return false;
+    }
+
+    // Top
+    curr_src.x = srcrect->x + left_width;
+    curr_src.y = srcrect->y;
+    curr_src.w = srcrect->w - left_width - right_width;
+    curr_src.h = top_height;
+    curr_dst.x = dstrect->x + dst_left_width;
+    curr_dst.y = dstrect->y;
+    curr_dst.w = dstrect->w - dst_left_width - dst_right_width;
+    curr_dst.h = dst_top_height;
+    if (!SDL_RenderTextureTiled(renderer, texture, &curr_src, scale, &curr_dst)) {
+        return false;
+    }
+
+    // Bottom
+    curr_src.y = srcrect->y + srcrect->h - bottom_height;
+    curr_dst.y = dstrect->y + dstrect->h - dst_bottom_height;
+    curr_dst.h = dst_bottom_height;
+    if (!SDL_RenderTextureTiled(renderer, texture, &curr_src, scale, &curr_dst)) {
+        return false;
+    }
+
+    return true;
+}
+
 bool SDL_RenderGeometry(SDL_Renderer *renderer,
                        SDL_Texture *texture,
                        const SDL_Vertex *vertices, int num_vertices,