gba.c

#include "gba.h"
#include "myLib.h"

volatile unsigned short *videoBuffer = (volatile unsigned short *) 0x6000000;
u32 vBlankCounter = 0;

void waitForVBlank(void) {
    // TA-TODO: IMPLEMENT

    // Write a while loop that loops until we're NOT in vBlank anymore:
    // (This prevents counting one VBlank more than once if your app is too fast)

    // Write a while loop that keeps going until we're in vBlank:

    // Finally, increment the vBlank counter:
    while (SCANLINECOUNTER > 160);  // wait till VDraw
    while (SCANLINECOUNTER < 160); // wait till VBlank
    if (SCANLINECOUNTER == 160) {
        vBlankCounter++;
        on_vblank();
    }
}

static int __qran_seed = 42;

static int qran(void) {
    __qran_seed = 1664525 * __qran_seed + 1013904223;
    return (__qran_seed >> 16) & 0x7FFF;
}

int randint(int min, int max) {
    return (qran() * (max - min) >> 15) + min;
}

void setPixel(int x, int y, u16 color) {
    videoBuffer[OFFSET(y, x, 240)] = color;
}

void drawRectDMA(int x, int y, int width, int height, volatile u16 color) {
    for (int i = 0; i < height; i++) {
        DMA[3].src = &color;
        DMA[3].dst = &videoBuffer[OFFSET(y + i, x, 240)];
        DMA[3].cnt = width | DMA_ON | DMA_SOURCE_FIXED;
    }
}


void drawFullScreenImageDMA(const unsigned short *image) {
    DMA[3].src = &image;
    DMA[3].dst = &videoBuffer[0];
    DMA[3].cnt = 240 * 160 | DMA_ON | DMA_SOURCE_INCREMENT | DMA_DESTINATION_INCREMENT;
    // TA-TODO: IMPLEMENT
}



void drawImageDMA(int x, int y, int width, int height, const u16 *image) {
    for (int i = 0; i < height; i++) {
        DMA[3].src = image + OFFSET(i, 0, width);
        DMA[3].dst = videoBuffer + OFFSET(y + i, x, 240);
        DMA[3].cnt = width | DMA_ON | DMA_SOURCE_INCREMENT | DMA_DESTINATION_INCREMENT;
    }
}

void fillScreenDMA(volatile u16 color) {
    DMA[3].src = &color;
    DMA[3].dst = &videoBuffer[0];
    DMA[3].cnt = 240 * 160 | DMA_ON | DMA_SOURCE_FIXED;
}

void drawChar(int col, int row, char ch, u16 color) {
    for (int r = 0; r < 8; r++) {
        for (int c = 0; c < 6; c++) {
            if (fontdata_6x8[OFFSET(r, c, 6) + ch * 48]) {
                setPixel(col + c, row + r, color);
            }
        }
    }
}

void drawString(int col, int row, char *str, u16 color) {
    while (*str) {
        drawChar(col, row, *str++, color);
        col += 6;
    }
}

void drawCenteredString(int x, int y, int width, int height, char *str, u16 color) {
    u32 len = 0;
    char *strCpy = str;
    while (*strCpy) {
        len++;
        strCpy++;
    }

    u32 strWidth = 6 * len;
    u32 strHeight = 8;

    int col = x + ((width - strWidth) >> 1);
    int row = y + ((height - strHeight) >> 1);
    drawString(col, row, str, color);
}