From 7d60741c1393ebc0c572891cfeb19a25c4579ed6 Mon Sep 17 00:00:00 2001 From: Daniel Jones Date: Mon, 17 Aug 2020 15:16:02 +0930 Subject: sprite drawing basic implementation begin implementing sprite drawing, currently draws the chip8 fontset well, no idead about other sprites yet --- chip8.c | 38 +++++++++++++++++++++++++++++++++++++- 1 file changed, 37 insertions(+), 1 deletion(-) (limited to 'chip8.c') diff --git a/chip8.c b/chip8.c index 2ce911f..db2efd2 100644 --- a/chip8.c +++ b/chip8.c @@ -71,7 +71,7 @@ chip8_init() draw_flag = 1; // draw by default i guess delay_timer = 0; sound_timer = 0; - srand(time(NULL)); // seed rng + srand(time(NULL)); /* load font into memory at 0x00: we have 0x00 to 0x1FF free for anything we want */ //TODO: add whole alphabet, then can write a rom to write strings or something @@ -80,3 +80,39 @@ chip8_init() memory[0x0 + i] = chip8_fontset[i]; } } + +void +chip8_draw_sprite(int startx, int starty, uint8_t mem, uint8_t size) +{ + /* + * draw sprite located at loc of height size at startx,starty + */ + + uint8_t byte = 0; + uint8_t mask = 0x1; + uint8_t destbit = 0x0; + for (uint8_t byteoffset = 0; byteoffset < size; byteoffset++) + { + /* loop through each byte from mem to mem+size */ + byte = memory[mem+byteoffset]; + int bit = 0; + for (mask = 0x80; mask != 0; mask >>= 1) + { + if (byte&mask) + { + destbit = 1; + video[WIDTH*starty+(startx+bit)] = 0xFFFFFF; + } + else + { + destbit = 0; + video[WIDTH*starty+(startx+bit)] = 0x0; + } + printf("%d", destbit); + bit++; + } + starty++; + puts(""); + } + puts("---"); +} -- cgit v1.2.3