cool-bun-demo/main.c

#include <stdio.h>

#include <clib/exec_protos.h>
#include <clib/graphics_protos.h>
#include <exec/exec.h>

#include <hardware/custom.h>
#include <hardware/dmabits.h>

#include <graphics/gfx.h>

#include "system/blitter.h"
#include "system/copper.h"
#include "system/system.h"

#include "screen.h"
#include "types.h"

extern struct Custom far custom;
extern unsigned char far coolbun[];

#define COOL_BUN_WIDTH (32)
#define COOL_BUN_WIDTH_BYTES (COOL_BUN_WIDTH / 8)
#define COOL_BUN_HEIGHT (32)
#define COOL_BUN_PLANES (2)

#define COOL_BUN_PLANE_SIZE (COOL_BUN_WIDTH_BYTES * COOL_BUN_HEIGHT)
#define COOL_BUN_MEMORY_SIZE (COOL_BUN_PLANE_SIZE * COOL_BUN_PLANES)

// this should be large enough to hold one bitplane of the largest object
// you are blitting, plus one additional word on each side
#define SCRATCH_AREA_WIDTH_BYTES (8)
#define SCRATCH_AREA_HEIGHT_ROWS (34)
#define SCRATCH_AREA_MEMORY_SIZE (SCRATCH_AREA_WIDTH_BYTES * SCRATCH_AREA_HEIGHT_ROWS)

volatile short *dbg = (volatile short *)0x100;

unsigned char *coolbunArea;
unsigned char *scratchArea;
struct ScreenSetup screenSetup;

void bun_offRightSide(int plusXValue, int y) {
  uint8_t i, plane = 0;
  uint8_t shift = plusXValue & 15;
  uint8_t wordShift = (plusXValue >> 4);
  uint16_t bltalwm;

  for (plane = 0; plane < 2; ++plane) {
    custom.bltcon0 = 0xc0 + (1 << 8) + (1 << 10) + (shift << 12);
    custom.bltcon1 = (shift << 12);

    custom.bltadat = 0xffff;
    custom.bltbpt = coolbunArea + plane * COOL_BUN_PLANE_SIZE;
    custom.bltdpt = screenSetup.memoryStart + plane * screenSetup.nextBitplaneAdvance + (y * screenSetup.width + screenSetup.width - COOL_BUN_WIDTH) / 8 + wordShift * 2;

    custom.bltafwm = 0xffff;
    bltalwm = 0x0000;
    for (i = 0; i < 15 - shift; ++i) {
      bltalwm += (1 << (15 - i));
    }
    custom.bltalwm = bltalwm;

    custom.bltbmod = wordShift * 2;
    custom.bltdmod = (screenSetup.width - COOL_BUN_WIDTH) / 8 + wordShift * 2;

    custom.bltsize = 2 - wordShift + (COOL_BUN_HEIGHT << 6);

    WaitBlit();
  }
}

void bun_offLeftSide(int minusXValue, int y) {
  unsigned char plane;
  uint8_t shift = minusXValue & 15;
  uint8_t wordShift = (minusXValue >> 4);
  uint8_t i;
  uint16_t bltalwm;

  // y can't be 0 otherwise we will corrupt memory for now
  if (y == 0) return;

  for (plane = 0; plane < 2; ++plane) {
    // shift left, so desccending
    custom.bltcon0 = 0xc0 + (1 << 8) + (1 << 10) + (shift << 12);
    custom.bltcon1 = (1 << 1) + (shift << 12);

    // a has a mask we're shifting
    custom.bltadat = 0xffff;
    // b has bun data
    custom.bltbpt = coolbunArea + 2 + ((COOL_BUN_HEIGHT - 1) * 4) + plane * COOL_BUN_PLANE_SIZE;

    // d is the part on screen
    custom.bltdpt = screenSetup.memoryStart + screenSetup.nextBitplaneAdvance * plane + (screenSetup.width * (y + COOL_BUN_HEIGHT - 1) / 8) + 2 - wordShift * 2;

    custom.bltafwm = 0xffff;
    bltalwm = 0x0000;
    for (i = 0; i < 15 - shift; ++i) {
      bltalwm += (1 << i);
    }
    custom.bltalwm = bltalwm;

    custom.bltbmod = wordShift * 2;
    custom.bltdmod = screenSetup.width / 8 - 4 + wordShift * 2;

    custom.bltsize = 2 - wordShift + (COOL_BUN_HEIGHT << 6);

    WaitBlit();
  }
}

void bun_anywhere(int x, int y) {
  uint8_t plane;
  uint8_t shift = x & 15;
  uint8_t needsExtraWord = shift != 0;

  for (plane = 0; plane < 2; ++plane) {
    // if we extend the bun area by a word, we only need one write

    // buns will never interfere with a background so they don't need a mask
    // they do need the scratch area though
    custom.bltcon0 = 0xc0 + (1 << 8) + (1 << 10) + (shift << 12);
    custom.bltcon1 = (shift << 12);

    custom.bltadat = 0xffff;
    custom.bltbpt = coolbunArea + plane * COOL_BUN_PLANE_SIZE;
    custom.bltdpt = screenSetup.memoryStart + WORD_ALIGNED_BYTE_POSITION(screenSetup.width, x, y) + screenSetup.nextBitplaneAdvance * plane;

   // custom.bltdpt = screenSetup.memoryStart;
    custom.bltafwm = 0xffff;
    if (needsExtraWord) {
      custom.bltalwm = 0x0000;
    } else {
      custom.bltalwm = 0xffff;
    }
    custom.bltbmod = -(needsExtraWord * 2);
    custom.bltdmod = (screenSetup.width / 8) - COOL_BUN_WIDTH_BYTES - (needsExtraWord * 2);
    custom.bltsize = (2 + needsExtraWord) + (COOL_BUN_HEIGHT << 6);

    WaitBlit();
  }
}

void renderBun(int x, int y) {
  if (x < -31) return;
  if (x > screenSetup.width + 31) return;
  if (y < 1) return;
  if (y > screenSetup.height - COOL_BUN_HEIGHT - 1) return;

  if (x < 0) {
    bun_offLeftSide(-x, y);
  } else if (x > screenSetup.width - COOL_BUN_WIDTH) {
    bun_offRightSide(x - (screenSetup.width - COOL_BUN_WIDTH), y);
  } else {
    bun_anywhere(x, y);
  }
}

int main(void) {
  uint16_t *copperlist, *currentCopperlist;
  int i, x, y, plane, result;
  int blitShiftRight, memoryXOffset, blitWidth;

  int bunPosition = -31;

  color_t colors[16];

  unsigned char *currentCoolBunArea, *currentCoolBun;

  coolbunArea = AllocMem(COOL_BUN_MEMORY_SIZE, MEMF_CHIP | MEMF_CLEAR);
  currentCoolBun = coolbun;

  scratchArea = AllocMem(SCRATCH_AREA_MEMORY_SIZE, MEMF_CHIP | MEMF_CLEAR);

  colors[0] = 0x09b8;
  colors[1] = 0x0000;
  colors[2] = 0x0fff;
  colors[3] = 0x000f;

  prepareScreen(&screenSetup, SCREEN_WIDTH, SCREEN_HEIGHT, 4);
  allocateScreenMemory(&screenSetup);

  currentCoolBunArea = coolbunArea;

  for (plane = 0; plane < COOL_BUN_PLANES; ++plane) {
    for (y = 0; y < COOL_BUN_HEIGHT; ++y) {
      for (x = 0; x < COOL_BUN_WIDTH_BYTES; ++x) {
        *(currentCoolBunArea++) = *(currentCoolBun++);
      }
    }
  }


  // blitter copy the first bitplane row down to the second

  copperlist = prepareNewCopperlist();

  takeOverSystem();

  setCopperlist(copperlist);
  setUpDisplay(&screenSetup);

  currentCopperlist = addDisplayToCopperlist(copperlist, &screenSetup);
  currentCopperlist = addColorsToCopperlist(currentCopperlist, colors, 16);
  endCopperlist(currentCopperlist);

  for (i = -31; i < screenSetup.width - 1; ++i) {
    y = WaitBOF(250);
    for (plane = 0; plane < 2; ++plane) {
      custom.bltcon0 = 0xc0 + (1 << 8);
      custom.bltcon1 = 0;
      custom.bltadat = 0x0000;
      custom.bltafwm = 0xffff;
      custom.bltalwm = 0xffff;
      custom.bltdpt = screenSetup.memoryStart + (45 * screenSetup.width) / 8 + plane * screenSetup.nextBitplaneAdvance;
      custom.bltdmod = 0;
      custom.bltsize = 20 + (COOL_BUN_MEMORY_SIZE << 6);
      WaitBlit();
    }

    renderBun(i, 45);
  }

  giveBackSystem();

  freeScreenMemory(&screenSetup);

  freeCopperlist(copperlist);

  FreeMem(coolbunArea, COOL_BUN_MEMORY_SIZE);
  FreeMem(scratchArea, SCRATCH_AREA_MEMORY_SIZE);

  return 0;
}