feat(metal): Add scissor rect support

This is required for correct rendering of the ozone menu

gfx/common/metal/Context.h

@@ -61,6 +61,9 @@ typedef struct
 /*! @brief resets the viewport for the main render encoder to the drawable size */
 - (void)resetRenderViewport;
 
+/*! @brief resets the scissor rect for the main render encoder to the drawable size */
+- (void)resetScissorRect;
+
 /*! @brief draws a quad at the specified position (normalized coordinates) using the main render encoder */
 - (void)drawQuadX:(float)x y:(float)y w:(float)w h:(float)h
                 r:(float)r g:(float)g b:(float)b a:(float)a;

gfx/common/metal/Context.m

@@ -565,6 +565,17 @@
    [self.rce setViewport:vp];
 }
 
+- (void)resetScissorRect
+{
+   MTLScissorRect sr = {
+      .x       = 0,
+      .y       = 0,
+      .width   = _viewport.full_width,
+      .height  = _viewport.full_height,
+   };
+   [self.rce setScissorRect:sr];
+}
+
 - (void)drawQuadX:(float)x y:(float)y w:(float)w h:(float)h
                 r:(float)r g:(float)g b:(float)b a:(float)a
 {

gfx/common/metal/MenuDisplay.h

@@ -14,6 +14,8 @@
 - (instancetype)initWithContext:(Context *)context;
 - (void)drawPipeline:(menu_display_ctx_draw_t *)draw video:(video_frame_info_t *)video;
 - (void)draw:(menu_display_ctx_draw_t *)draw video:(video_frame_info_t *)video;
+- (void)setScissorRect:(MTLScissorRect)rect;
+- (void)clearScissorRect;
 
 #pragma mark - static methods
 

gfx/common/metal/MenuDisplay.m

@@ -14,8 +14,10 @@
 {
    Context *_context;
    MTLClearColor _clearColor;
-   bool _clearNextRender;
+   MTLScissorRect _scissorRect;
+   BOOL _useScissorRect;
    Uniforms _uniforms;
+   bool _clearNextRender;
 }
 
 - (instancetype)initWithContext:(Context *)context
@@ -25,6 +27,7 @@
       _context = context;
       _clearColor = MTLClearColorMake(0.0, 0.0, 0.0, 1.0);
       _uniforms.projectionMatrix = matrix_proj_ortho(0, 1, 0, 1);
+      _useScissorRect = NO;
    }
    return self;
 }
@@ -73,6 +76,19 @@
    return _clearColor;
 }
 
+- (void)setScissorRect:(MTLScissorRect)rect
+{
+   _scissorRect = rect;
+   _useScissorRect = YES;
+}
+
+- (void)clearScissorRect
+{
+   _useScissorRect = NO;
+   [_context resetScissorRect];
+}
+
+
 - (MTLPrimitiveType)_toPrimitiveType:(enum menu_display_prim_type)prim
 {
    switch (prim)
@@ -181,6 +197,10 @@
    };
    [rce setViewport:vp];
    
+   if (_useScissorRect) {
+      [rce setScissorRect:_scissorRect];
+   }
+   
    switch (draw->pipeline.id)
    {
 #if HAVE_SHADERPIPELINE

menu/drivers_display/menu_display_metal.m

@@ -88,6 +88,25 @@ static void menu_display_metal_viewport(menu_display_ctx_draw_t *draw,
 {
 }
 
+static void menu_display_metal_scissor_begin(video_frame_info_t *video_info, int x, int y, unsigned width, unsigned height)
+{
+   MetalDriver *md = GET_DRIVER(video_info);
+   if (!md)
+      return;
+   
+   MTLScissorRect r = {.x = (NSUInteger)x, .y = (NSUInteger)y, .width = width, .height = height};
+   [md.display setScissorRect:r];
+}
+
+static void menu_display_metal_scissor_end(video_frame_info_t *video_info)
+{
+   MetalDriver *md = GET_DRIVER(video_info);
+   if (!md)
+      return;
+   
+   [md.display clearScissorRect];
+}
+
 static void menu_display_metal_restore_clear_color(void)
 {
    // nothing to do
@@ -135,7 +154,7 @@ menu_display_ctx_driver_t menu_display_ctx_metal = {
    .type                   = MENU_VIDEO_DRIVER_METAL,
    .ident                  = "menu_display_metal",
    .handles_transform      = NO,
-   .scissor_begin          = NULL,
-   .scissor_end            = NULL
+   .scissor_begin          = menu_display_metal_scissor_begin,
+   .scissor_end            = menu_display_metal_scissor_end
 };