89 lines
2.2 KiB
C
89 lines
2.2 KiB
C
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#include "camera.h"
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static int8_t dither_random(uint8_t x, uint8_t y)
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{
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static bool once = false;
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static int8_t random[128*112];
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if (!once) {
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unsigned int r = 0x1337c0de;
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for (int i = 0; i < sizeof(random); i++) {
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random[i] = r % 85 - 42;
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r += 11;
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r *= 25214903917;
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}
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once = true;
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}
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return random[x + y * 128];
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}
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uint8_t GB_camera_read_image(GB_gameboy_t *gb, uint16_t addr)
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{
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uint8_t tile_x = addr / 0x10 % 0x10;
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uint8_t tile_y = addr / 0x10 / 0x10;
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uint8_t y = ((addr >> 1) & 0x7) + tile_y * 8;
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uint8_t bit = addr & 1;
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uint8_t ret = 0;
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for (uint8_t x = tile_x * 8; x < tile_x * 8 + 8; x++) {
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int color = gb->camera_get_pixel_callback? ~gb->camera_get_pixel_callback(gb, x,y) : (rand() & 0xFF);
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/* Dither using a deterministic random */
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color += dither_random(x, y);
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if (color > 255) {
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color = 255;
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}
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else if (color < 0) {
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color = 0;
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}
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ret <<= 1;
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ret |= (color >> (6 + bit)) & 1;
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}
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return ret;
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}
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void GB_set_camera_get_pixel_callback(GB_gameboy_t *gb, GB_camera_get_pixel_callback_t callback)
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{
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gb->camera_get_pixel_callback = callback;
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}
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void GB_set_camera_update_request_callback(GB_gameboy_t *gb, GB_camera_update_request_callback_t callback)
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{
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gb->camera_update_request_callback = callback;
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}
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void GB_camera_updated(GB_gameboy_t *gb)
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{
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gb->camera_registers[0] = 0;
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}
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void GB_camera_write_register(GB_gameboy_t *gb, uint16_t addr, uint8_t value)
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{
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addr &= 0x7F;
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if (addr == 0) {
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if ((value & 1) && gb->camera_update_request_callback) {
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/* If no callback is set, ignore the write as if the camera is instantly done */
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gb->camera_update_request_callback(gb);
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gb->camera_registers[0] = 1;
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}
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}
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else {
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if (addr >= 0x36) {
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GB_log(gb, "Wrote invalid camera register %02x: %2x\n", addr, value);
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}
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/* Todo: find out what these registers do */
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gb->camera_registers[addr] = value;
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}
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}
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uint8_t GB_camera_read_register(GB_gameboy_t *gb, uint16_t addr)
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{
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if ((addr & 0x7F) == 0) {
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return gb->camera_registers[0];
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}
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return 0;
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}
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