ogc: do not clear the EFB when saving it

We don't need to clear the EFB, since we are going to immediately load a
texture onto it.
But at the same time we must make sure that there is no blending when we
loat the new texture onto the EFB, because we want to completely replace
its contents.

Author: mardy

src/render/ogc/SDL_render_ogc.c

@@ -107,6 +107,7 @@ static void load_efb_from_texture(SDL_Renderer *renderer, SDL_Texture *texture)
 
     OGC_load_texture(ogc_tex->texels, texture->w, texture->h,
                      ogc_tex->format, SDL_ScaleModeNearest);
+    OGC_SetBlendMode(renderer, SDL_BLENDMODE_NONE);
 
     /* The viewport is reset when OGC_SetRenderTarget() returns. */
     OGC_set_viewport(0, 0, texture->w, texture->h);
@@ -137,7 +138,7 @@ static void load_efb_from_texture(SDL_Renderer *renderer, SDL_Texture *texture)
     GX_End();
 }
 
-static void save_efb_to_texture(SDL_Texture *texture)
+static void save_efb_to_texture(SDL_Texture *texture, bool must_clear)
 {
     OGC_TextureData *ogc_tex = texture->driverdata;
     u32 texture_size;
@@ -148,7 +149,7 @@ static void save_efb_to_texture(SDL_Texture *texture)
 
     GX_SetTexCopySrc(0, 0, texture->w, texture->h);
     GX_SetTexCopyDst(texture->w, texture->h, ogc_tex->format, GX_FALSE);
-    GX_CopyTex(ogc_tex->texels, GX_TRUE);
+    GX_CopyTex(ogc_tex->texels, must_clear ? GX_TRUE : GX_FALSE);
     GX_PixModeSync();
 }
 
@@ -275,14 +276,14 @@ static int OGC_SetRenderTarget(SDL_Renderer *renderer, SDL_Texture *texture)
     u8 desired_efb_pixel_format = GX_PF_RGB8_Z24;
 
     if (data->render_target) {
-        save_efb_to_texture(data->render_target);
+        save_efb_to_texture(data->render_target, false);
     } else if (data->ops_after_present > 0) {
         /* Save the current EFB contents if we already drew something onto
          * it. We'll restore it later, when the rendering target is reset
          * to NULL (the screen). */
         if (!data->saved_efb_texture)
             data->saved_efb_texture = create_efb_texture(data, renderer->window);
-        save_efb_to_texture(data->saved_efb_texture);
+        save_efb_to_texture(data->saved_efb_texture, false);
     }
 
     if (texture) {
@@ -462,7 +463,7 @@ static int OGC_RenderClear(SDL_Renderer *renderer, SDL_RenderCommand *cmd)
     data->clear_color = c;
     GX_SetCopyClear(c, GX_MAX_Z24);
     if (renderer->target) {
-        save_efb_to_texture(renderer->target);
+        save_efb_to_texture(renderer->target, true);
     } else {
         GX_CopyDisp(OGC_video_get_xfb(SDL_GetVideoDevice()), GX_TRUE);
     }