drivers: display: display_sdl: implement display_show

Adds frame synchronization to every frame.
This prevents frame tearing.

Signed-off-by: Martin Stumpf <[email protected]>

Author: Finomnis

doc/releases/release-notes-4.1.rst

@@ -95,6 +95,8 @@ Drivers and Sensors
   * Added flag ``frame_incomplete`` to ``display_write`` that indicates whether a write is the last
     write of the frame, allowing display drivers to implement double buffering / tearing enable
     signal handling (:github:`81250`)
+  * Added ``frame_incomplete`` handling to SDL display driver (:dtcompatible:`zephyr,sdl-dc`)
+    (:github:`81250`)
 
 * Ethernet
 

drivers/display/display_sdl.c

@@ -260,9 +260,9 @@ static int sdl_display_write(const struct device *dev, const uint16_t x,
 		sdl_display_write_bgr565(disp_data->buf, desc, buf);
 	}
 
-	sdl_display_write_bottom(desc->height, desc->width, x, y,
-				 disp_data->renderer, disp_data->mutex, disp_data->texture,
-				 disp_data->buf, disp_data->display_on);
+	sdl_display_write_bottom(desc->height, desc->width, x, y, disp_data->renderer,
+				 disp_data->mutex, disp_data->texture, disp_data->buf,
+				 disp_data->display_on, desc->frame_incomplete);
 
 	return 0;
 }

drivers/display/display_sdl_bottom.c

@@ -5,6 +5,8 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
+#include "display_sdl_bottom.h"
+
 #include <stdint.h>
 #include <stddef.h>
 #include <stdbool.h>
@@ -64,10 +66,9 @@ int sdl_display_init_bottom(uint16_t height, uint16_t width, uint16_t zoom_pct,
 	return 0;
 }
 
-void sdl_display_write_bottom(const uint16_t height, const uint16_t width,
-			      const uint16_t x, const uint16_t y,
-			      void *renderer, void *mutex, void *texture,
-			      uint8_t *buf, bool display_on)
+void sdl_display_write_bottom(const uint16_t height, const uint16_t width, const uint16_t x,
+			      const uint16_t y, void *renderer, void *mutex, void *texture,
+			      uint8_t *buf, bool display_on, bool frame_incomplete)
 {
 	SDL_Rect rect;
 	int err;
@@ -85,7 +86,7 @@ void sdl_display_write_bottom(const uint16_t height, const uint16_t width,
 
 	SDL_UpdateTexture(texture, &rect, buf, 4 * rect.w);
 
-	if (display_on) {
+	if (display_on && !frame_incomplete) {
 		SDL_RenderClear(renderer);
 		SDL_RenderCopy(renderer, texture, NULL, NULL);
 		SDL_RenderPresent(renderer);

drivers/display/display_sdl_bottom.h

@@ -23,14 +23,12 @@ extern "C" {
 int sdl_display_init_bottom(uint16_t height, uint16_t width, uint16_t zoom_pct,
 			    bool use_accelerator, void **window, void **renderer, void **mutex,
 			    void **texture, void **read_texture);
-void sdl_display_write_bottom(const uint16_t height, const uint16_t width,
-			      const uint16_t x, const uint16_t y,
-			      void *renderer, void *mutex, void *texture,
-			      uint8_t *buf, bool display_on);
-int sdl_display_read_bottom(const uint16_t height, const uint16_t width,
-			    const uint16_t x, const uint16_t y,
-			    void *renderer, void *buf, uint16_t pitch,
-			    void *mutex, void *texture, void **read_texture);
+void sdl_display_write_bottom(const uint16_t height, const uint16_t width, const uint16_t x,
+			      const uint16_t y, void *renderer, void *mutex, void *texture,
+			      uint8_t *buf, bool display_on, bool frame_incomplete);
+int sdl_display_read_bottom(const uint16_t height, const uint16_t width, const uint16_t x,
+			    const uint16_t y, void *renderer, void *buf, uint16_t pitch,
+			    void *mutex, void *texture, void *read_texture);
 void sdl_display_blanking_off_bottom(void *renderer, void *texture);
 void sdl_display_blanking_on_bottom(void *renderer);
 void sdl_display_cleanup_bottom(void **window, void **renderer, void **mutex, void **texture,