GB101:Hello Background

GB101 Class Notes
	Sections Home Installing Gameboy Development Tools Introduction to the Gameboy Advance Hello Background Working with Palettes Tiles and Background Maps Sprites Scrolling Backgrounds Collision Detection Fixed point math Affine Sprites Sound Where do I go from here?

Introduction

In this example we'll try to get acquainted with the GBA by using simple mode 3 to fill the screen with red pixels. In mode 3 each 16-bit short represents a RGB value. We use the RGB5 macro to convert r,g and b into a 16-bit short. We create a pointer to the video buffer which starts at 0x6000000 and then use a couple of simple loops to set the pixels. Obviously there are more efficient ways...

Implementation

#include <gba_video.h>
#include <gba_systemcalls.h>

int main(void) {
    // Memory location of video buffer
    unsigned short* VideoBuffer = (unsigned short*)0x6000000; 
    unsigned char x,y;  

    // Turn on mode 3 with background 2
    SetMode(MODE_3 | BG2_ENABLE);   

    // Fill the video buffer with red pixels
    for(x = 0; x < SCREEN_WIDTH; x++)   
        for(y = 0; y < SCREEN_HEIGHT; y++)  
            VideoBuffer [x + y * SCREEN_WIDTH] = RGB5(31,0,0);  

    // Loop indefinitely
    while(1){}  
}