Sprite in psram on esp32

[rozrabiak]

Hi, it is possible to create sprite in PSRAM on ESP32?
Create sprite in psram and then push sprite to tft.
I don't have esp32 with psram so, I can't test this.

Anyone can test this?

[AnRich26]

Yes, it is possible to create Sprite with Psram, without Psram the Sprite creation wil fail. For displays 240x240 - 320x240 between 2-4 Mb Psram, for displays 320x240 and up 4-8 Mb Psram. It depends on screen size and what will be displayed the more graphics to push at one time the biger the Psram.

[rozrabiak]

I have Lolin32 without psram.
I can create sprite but with little dimensions.
TFT which I use is ILI9486 480x320px.
So, I need change Lolin to another board with psram.

Thank's a lot!

[AnRich26]

Strait from tft_espi.readme:

Sprites

A Sprite is notionally an invisible graphics screen that is kept in the processors RAM. Graphics can be drawn into the Sprite just as they can be drawn directly to the screen. Once the Sprite is completed it can be plotted onto the screen in any position. If there is sufficient RAM then the Sprite can be the same size as the screen and used as a frame buffer. Sprites by default use 16-bit colours, the bit depth can be set to 8 bits (256 colours) , or 1 bit (any 2 colours) to reduce the RAM needed. On an ESP8266 the largest 16-bit colour Sprite that can be created is about 160x128 pixels, this consumes 40Kbytes of RAM. On an ESP32 the workspace RAM is more limited than the datasheet implies so a 16-bit colour Sprite is limited to about 200x200 pixels (~80Kbytes), an 8-bit sprite to 320x240 pixels (~76kbytes). A 1 bit per pixel Sprite requires only 9600 bytes for a full 320 x 240 screen buffer, this is ideal for supporting use with 2 colour bitmap fonts.

One or more sprites can be created, a sprite can be any pixel width and height, limited only by available RAM. The RAM needed for a 16-bit colour depth Sprite is (2 x width x height) bytes, for a Sprite with 8-bit colour depth the RAM needed is (width x height) bytes. Sprites can be created and deleted dynamically as needed in the sketch, this means RAM can be freed up after the Sprite has been plotted on the screen, more RAM intensive WiFi based code can then be run and normal graphics operations still work.

Drawing graphics into a sprite is very fast, for those familiar with the Adafruit "graphicstest" example, this whole test completes in 18ms in a 160x128 sprite. Examples of sprite use can be found in the "examples/Sprite" folder.

Sprites can be plotted to the TFT with one colour being specified as "transparent", see Transparent_Sprite_Demo example.

If an ESP32 board has SPIRAM (i.e. PSRAM) fitted then Sprites will use the PSRAM memory and large full screen buffer Sprites can be created. Full screen Sprites take longer to render (~45ms for a 320 x 240 16-bit Sprite), so bear that in mind.