Vc framebuffer

Framebuffer to the graphics device access method of a computer system, in which each pixel on the screen is represented as locations of a specific portion of the random access memory map (main memory system)

Debian Based Instalation

sudo apt update

sudo apt install gcc-aarch64-linux-gnu

sudo apt install qemu-system-arm

sudo apt install gdb-multiarch

wget -P ~ git.io/.gdbinit

Commands

Check QEMU version:

apt show qemu-system-x86

Check Python version:

python3 --version or python --version

Makefile

• make clean: removes compiled images [ALLWAYS]
• make run: run QEMU in new window [WITHOUT DEBUG]
• make runQEMU: after make clean before make runGDB [DEBUG]
• make runGDB: after make runQEMU need to use in other console (remember path) [DEBUG]
• make remake: run make clean then make run

How to debug

stepi

Do breakpoint

b

continue

info b

delete b

Pixels

Resolution size: 640x480 pixels

Format: ARGB, 32 bits

The screen pixels are stored in a vertical framebuffer ordered row by row, with the 1st pixel being the top most left one.

The frame buffer stores each pixel as a 4 byte (32 bits) cell that encodes the color of that pixel.

Colours

Important: colours have 24bits.

R = 162 = 10100010

G = 85 = 01010101

B = 255 = 11111111

setColour:
	// Return
	// x18 Color a pintar
	// Args
	// x13 r
	// x14 g
	// x15 b
	// 24 bits
	lsl x13, x13, 16			// Movemos 16 bits
	lsl x14, x14, 8				// Movemos 8 bits
	add x18, x13, x14			// R+G
	add x18, x18, x15			// RG+B
	ret

   101000100000000000000000 (r) -> 24 bits
+         01010101000000000 (g) -> 24 bits
+                  11111111 (b) -> 24 bits

Final animation

doAnimacionInicial

Partial animation

circleAnimation1

rgbAnimation

Files

start.s → initialization of hardware

app.s → "main"

baseCore.s → low level abstractions for framebuffer manipulation

draw.s → basic lines and figures

font.s → upper case and lower case

animations.s → delay

aScreenAnimations.s → screen animations (animations across the screen)

todo.md

zowl.s → Pixel Art

zraven.s → Pixel Art

Links

Raspberry Pi

https://www.raspberrypi.org/

Pillow

https://pypi.org/project/Pillow/

Krita

https://krita.org/en/

Visual Studio Extensions

https://marketplace.visualstudio.com/items?itemName=ExodiusStudios.comment-anchors

https://marketplace.visualstudio.com/items?itemName=aaron-bond.better-comments

https://marketplace.visualstudio.com/items?itemName=dan-c-underwood.arm

Authors

• Gimenez, Diego (@diegogimenez04)

• Vispo, Valentina (@shirosweets)