Mercurial > repos > blastem
view vgm.c @ 2490:a0837ea61fda
Get static images working in GL mode
author | Michael Pavone <pavone@retrodev.com> |
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date | Wed, 17 Apr 2024 21:54:44 -0700 |
parents | 327332138c5c |
children |
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#include <stdlib.h> #include <string.h> #include <stddef.h> #include "vgm.h" vgm_writer *vgm_write_open(char *filename, uint32_t rate, uint32_t clock, uint32_t cycle) { FILE *f = fopen(filename, "wb"); if (!f) { return NULL; } vgm_writer *writer = calloc(sizeof(vgm_writer), 1); memcpy(writer->header.ident, "Vgm ", 4); writer->header.version = 0x150; writer->header.data_offset = sizeof(writer->header) - offsetof(vgm_header, data_offset); writer->header.rate = rate; writer->f = f; if (1 != fwrite(&writer->header, sizeof(writer->header), 1, f)) { free(writer); fclose(f); return NULL; } writer->master_clock = clock; writer->last_cycle = cycle; return writer; } void vgm_sn76489_init(vgm_writer *writer, uint32_t clock, uint16_t feedback, uint8_t shift_reg_size, uint8_t flags) { if (flags && writer->header.version < 0x151) { writer->header.version = 0x151; } writer->header.sn76489_clk = clock, writer->header.sn76489_fb = feedback; writer->header.sn76489_shift = shift_reg_size; writer->header.sn76489_flags = flags; } static void wait_commands(vgm_writer *writer, uint32_t delta) { if (!delta) { return; } if (delta <= 0x10) { fputc(CMD_WAIT_SHORT + (delta - 1), writer->f); } else if (delta >= 735 && delta <= (735 + 0x10)) { fputc(CMD_WAIT_60, writer->f); wait_commands(writer, delta - 735); } else if (delta >= 882 && delta <= (882 + 0x10)) { fputc(CMD_WAIT_50, writer->f); wait_commands(writer, delta - 882); } else if (delta > 0xFFFF) { uint8_t cmd[3] = {CMD_WAIT, 0xFF, 0xFF}; fwrite(cmd, 1, sizeof(cmd), writer->f); wait_commands(writer, delta - 0xFFFF); } else { uint8_t cmd[3] = {CMD_WAIT, delta, delta >> 8}; fwrite(cmd, 1, sizeof(cmd), writer->f); } } #include "util.h" static void add_wait(vgm_writer *writer, uint32_t cycle) { if (cycle < writer->last_cycle) { //This can happen when a YM-2612 write happens immediately after a PSG write //due to the relatively low granularity of the PSG's internal clock //given that VGM only has a granularity of 44.1 kHz ignoring this is harmless return; } uint64_t last_sample = (uint64_t)writer->last_cycle * (uint64_t)44100; last_sample /= (uint64_t)writer->master_clock; uint64_t sample = ((uint64_t)cycle + (uint64_t)writer->extra_delta) * (uint64_t)44100; sample /= (uint64_t)writer->master_clock; uint32_t delta = sample - last_sample; writer->last_cycle = cycle; writer->extra_delta = 0; writer->header.num_samples += delta; wait_commands(writer, delta); } static uint8_t last_cmd; void vgm_sn76489_write(vgm_writer *writer, uint32_t cycle, uint8_t value) { add_wait(writer, cycle); uint8_t cmd[2] = {CMD_PSG, value}; last_cmd = CMD_PSG; fwrite(cmd, 1, sizeof(cmd), writer->f); } void vgm_ym2612_init(vgm_writer *writer, uint32_t clock) { writer->header.ym2612_clk = clock; } void vgm_ym2612_part1_write(vgm_writer *writer, uint32_t cycle, uint8_t reg, uint8_t value) { add_wait(writer, cycle); uint8_t cmd[3] = {CMD_YM2612_0, reg, value}; last_cmd = CMD_YM2612_0; fwrite(cmd, 1, sizeof(cmd), writer->f); } void vgm_ym2612_part2_write(vgm_writer *writer, uint32_t cycle, uint8_t reg, uint8_t value) { add_wait(writer, cycle); uint8_t cmd[3] = {CMD_YM2612_1, reg, value}; last_cmd = CMD_YM2612_1; fwrite(cmd, 1, sizeof(cmd), writer->f); } void vgm_adjust_cycles(vgm_writer *writer, uint32_t deduction) { if (deduction > writer->last_cycle) { writer->extra_delta += deduction - writer->last_cycle; writer->last_cycle = 0; } else { writer->last_cycle -= deduction; } } void vgm_close(vgm_writer *writer) { uint8_t cmd = 0x66; fwrite(&cmd, 1, sizeof(cmd), writer->f); writer->header.eof_offset = ftell(writer->f) - offsetof(vgm_header, eof_offset); fseek(writer->f, SEEK_SET, 0); fwrite(&writer->header, sizeof(writer->header), 1, writer->f); fclose(writer->f); free(writer); }