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vdp2: incomplete rbg0 example

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This commit is contained in:
Zack Buhman 2025-08-08 15:21:24 -05:00
parent 447602ef41
commit 4301bbd4b7
2 changed files with 109 additions and 1 deletions
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4
Makefile
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@ -55,7 +55,9 @@ vdp2/nbg0.elf: vdp2/nbg0.o res/butterfly.data.o res/butterfly.data.pal.o
vdp2/nbg0_16color.elf: vdp2/nbg0_16color.o res/kirby.data.o res/kirby.data.pal.o
vdp2/nbg0_font.elf: vdp2/nbg0_font.o font/hp_100lx_4bit.data.o
vdp2/nbg0_font.elf: vdp2/nbg0_font.o saturn/start.o font/hp_100lx_4bit.data.o
vdp2/rbg0_font.elf: vdp2/rbg0_font.o saturn/start.o font/hp_100lx_4bit.data.o
vdp2/color_calculation_ratio.elf: vdp2/color_calculation_ratio.o res/mai00.data.o res/mai.data.pal.o res/haohmaru.data.o res/haohmaru.data.pal.o res/forest.data.pal.o res/forest.pattern.o res/forest.tile.o

106
vdp2/rbg0_font.cpp Normal file
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@ -0,0 +1,106 @@
#include <stdint.h>
#include "vdp2.h"
#include "../common/vdp2_func.hpp"
#include "font/hp_100lx_4bit.data.h"
void cell_data()
{
const uint32_t * start = reinterpret_cast<uint32_t *>(&_binary_font_hp_100lx_4bit_data_start);
const int size = reinterpret_cast<uint32_t>(&_binary_font_hp_100lx_4bit_data_size);
// the start of VRAM-A0
for (int i = 0; i < (size / 4); i++) {
vdp2.vram.u32[i] = start[i];
}
}
void palette_data()
{
vdp2.cram.u16[0] = 0x0000;
vdp2.cram.u16[1] = 0xffff;
}
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
| RAMCTL__VRAMD
| RAMCTL__VRBMD
| RAMCTL__RDBSA0__CHARACTER_PATTERN_TABLE // VRAM-A0 0x000000
| RAMCTL__RDBSA1__PATTERN_NAME_TABLE; // VRAM-A1 0x020000
vdp2.reg.VRSIZE = 0;
/* enable display of NBG0 */
vdp2.reg.BGON = BGON__R0ON | BGON__R0TPON;
/* 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.CHCTLB = CHCTLB__R0CHCN__16_COLOR
| CHCTLB__R0BMEN__CELL_FORMAT
| CHCTLB__R0CHSZ__1x1_CELL;
/* plane size */
vdp2.reg.PLSZ = PLSZ__RAPLSZ__1x1
| PLSZ__RBPLSZ__1x1;
/* map plane offset
1-word: value of bit 6-0 * 0x2000
2-word: value of bit 5-0 * 0x4000
*/
// plane_a_offset is at the start of VRAM-A1
constexpr int plane_a = 8;
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;
/* cycle pattern table not used for RBG0 ? */
vdp2.reg.CYCA0 = 0x0F44F99F;
vdp2.reg.CYCA1 = 0x0F44F99F;
vdp2.reg.CYCB0 = 0x0F44F99F;
vdp2.reg.CYCB1 = 0x0F44F99F;
vdp2.reg.MPOFR = MPOFR__RAMP(0); // bits 8~6
vdp2.reg.MPABRA = MPABRA__RAMPB(plane_a) | MPABRA__RAMPA(plane_a); // bits 5~0
vdp2.reg.MPCDRA = MPCDRA__RAMPD(plane_a) | MPCDRA__RAMPC(plane_a); // bits 5~0
vdp2.reg.PNCR = PNCR__R0PNB__2WORD;
vdp2.reg.RPMD = RPMD__ROTATION_PARAMETER_A;
vdp2.reg.RPRCTL = 0;
vdp2.reg.KTCTL = 0;
vdp2.reg.KTAOF = 0;
vdp2.reg.RPTA = 0;
/* */
palette_data();
cell_data();
for (int i = 0; i < 64 * 64; i++) {
vdp2.vram.u32[(plane_a_offset / 4) + i] = ' ' - 0x20;
}
const char * test = "If sound level changes progressively, volume on 3 bit makes audi";
int ix = 0;
while (*test) {
uint8_t c = *test++;
vdp2.vram.u32[(plane_a_offset / 4) + ix++] = c - 0x20;
}
while (1);
}