saturn-examples/vdp2/nbg0_16color.cpp

136 lines
4.0 KiB
C++

#include <stdint.h>
#include "vdp2.h"
#include "../common/vdp2_func.hpp"
extern void * _kirby_data_pal_start __asm("_binary_res_kirby_data_pal_start");
extern void * _kirby_data_pal_size __asm("_binary_res_kirby_data_pal_size");
extern void * _kirby_data_start __asm("_binary_res_kirby_data_start");
extern void * _kirby_data_size __asm("_binary_res_kirby_data_size");
inline constexpr uint16_t rgb15(const uint8_t * buf)
{
return ((buf[2] >> 3) << 10) // blue
| ((buf[1] >> 3) << 5) // green
| ((buf[0] >> 3) << 0); // red
}
void palette_data()
{
const uint32_t buf_size = reinterpret_cast<uint32_t>(&_kirby_data_pal_size);
const uint8_t * buf = reinterpret_cast<uint8_t*>(&_kirby_data_pal_start);
uint32_t buf_ix = 0;
for (uint32_t i = 0; i < (buf_size / 3); i++) {
vdp2.cram.u16[i] = rgb15(&buf[buf_ix]);
buf_ix += 3;
}
}
uint32_t cell_data(const uint32_t top)
{
const uint32_t buf_size = reinterpret_cast<uint32_t>(&_kirby_data_size);
const uint8_t * buf = reinterpret_cast<uint8_t*>(&_kirby_data_start);
// round to nearest multiple of 32
const uint32_t table_size = ((buf_size / 2) + 0x20 - 1) & (-0x20);
const uint32_t base_address = top - table_size; // in bytes
// px is a conversion from 8 bits per index to 4 bits per index
// the value is shifted to its position in a 32-bit big-endian value
#define px(x) (buf[i * 8 + ((x) & 0xf)] << ((7 - ((x) & 0xf)) * 4))
for (uint32_t i = 0; i < (buf_size / 8); i++) {
// write an entire row all at once
vdp2.vram.u32[(base_address / 4) + i] =
//vdp2.vram.u32[i] =
px(0) | px(1) | px(2) | px(3) | px(4) | px(5) | px(6) | px(7);
}
#undef px
return base_address;
}
template <typename T>
void fill(T * buf, T v, int32_t n) noexcept
{
while (n > 0) {
*buf++ = v;
n -= (sizeof (T));
}
}
void main()
{
v_blank_in();
// DISP: Please make sure to change this bit from 0 to 1 during V blank.
vdp2.reg.TVMD = ( TVMD__DISP | TVMD__LSMD__NON_INTERLACE
| TVMD__VRESO__240 | TVMD__HRESO__NORMAL_320);
/* set the color mode to 5bits per channel, 1024 colors */
vdp2.reg.RAMCTL = RAMCTL__CRMD__RGB_5BIT_1024;
vdp2.reg.VRSIZE = 0;
/* enable display of NBG0 */
vdp2.reg.BGON = BGON__N0ON | BGON__N0TPON;
/* set character format for NBG0 to palettized 16 color
set enable "cell format" for NBG0
set character size for NBG0 to 1x1 cell */
vdp2.reg.CHCTLA = CHCTLA__N0CHCN__16_COLOR
| CHCTLA__N0BMEN__CELL_FORMAT
| CHCTLA__N0CHSZ__1x1_CELL;
/* "Note: In color RAM modes 0 and 2, 2048-color becomes 1024-color" */
/* plane size */
vdp2.reg.PLSZ = PLSZ__N0PLSZ__1x1;
/* map plane offset
1-word: value of bit 6-0 * 0x2000
2-word: value of bit 5-0 * 0x4000
*/
constexpr int plane_a = 0;
constexpr int plane_a_offset = plane_a * 0x4000;
constexpr int page_size = 64 * 64 * 2; // N0PNB__1WORD (16-bit)
constexpr int plane_size = page_size * 1;
vdp2.reg.CYCA0 = 0x0F44F99F;
vdp2.reg.CYCB0 = 0x0F44F99F;
vdp2.reg.MPOFN = MPOFN__N0MP(0); // bits 8~6
vdp2.reg.MPABN0 = MPABN0__N0MPB(0) | MPABN0__N0MPA(plane_a); // bits 5~0
vdp2.reg.MPCDN0 = MPABN0__N0MPD(0) | MPABN0__N0MPC(0); // bits 5~0
// zeroize character/cell data from 0 up to plane_a_offset
fill<uint32_t>(&vdp2.vram.u32[(0 / 4)], 0, plane_a_offset);
uint32_t top = (sizeof (union vdp2_vram));
palette_data();
uint32_t kirby_address = top = cell_data(top);
uint32_t pattern_name = kirby_address / 32;
/* use 1-word (16-bit) pattern names */
//vdp2.reg.PNCN0 = PNCN0__N0PNB__1WORD | PNCN0__N0CNSM | PNCN0__N0SCN((pattern_name >> 10) & 0x1f);
//fill<uint16_t>(&vdp2.vram.u16[(plane_a_offset / 4)], pattern_name & 0xfff, plane_size);
/* use 2-word (32-bit) pattern names */
vdp2.reg.PNCN0 = PNCN0__N0PNB__2WORD;
fill<uint32_t>(&vdp2.vram.u32[(plane_a_offset / 2)], pattern_name, plane_size);
// both 1-word and 2-word have identical behavior; 2-word is enabled to reduce/focus suspicion.
}
extern "C"
void start(void)
{
main();
while (1) {}
}