From eb19009d216f4fb0f7911b939b2f1bc698e40c79 Mon Sep 17 00:00:00 2001
From: Daniel Jones <admin@danieljon.es>
Date: Sun, 16 Aug 2020 22:01:10 +0930
Subject: SDL init stuff, test code

---
 main.c | 105 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 105 insertions(+)
 create mode 100644 main.c

(limited to 'main.c')

diff --git a/main.c b/main.c
new file mode 100644
index 0000000..056e5b1
--- /dev/null
+++ b/main.c
@@ -0,0 +1,105 @@
+#include <stdio.h>
+#include <SDL2/SDL.h>
+
+#define WIDTH 64
+#define HEIGHT 32
+
+/* references
+ * https://austinmorlan.com/posts/chip8_emulator/
+ * http://www.multigesture.net/articles/how-to-write-an-emulator-chip-8-interpreter/
+ * http://mattmik.com/files/chip8/mastering/chip8.html (lots of info)
+ * http://devernay.free.fr/hacks/chip8/C8TECH10.HTM#0.1
+ */
+
+#define VIDEO_SCALE 10
+
+SDL_Window *window;
+SDL_Renderer *renderer;
+SDL_Texture *texture;
+
+void init_video();
+void update_video();
+void toggle_pixel(int x, int y);
+void quit();
+
+void
+quit()
+{
+	SDL_DestroyTexture(texture);
+	SDL_DestroyRenderer(renderer);
+	SDL_DestroyWindow(window);
+	SDL_Quit();
+
+}
+
+void
+init_video()
+{
+	SDL_Init(SDL_INIT_VIDEO);
+	window = SDL_CreateWindow("chip8 interpreter", 0, 0, WIDTH*VIDEO_SCALE, HEIGHT*VIDEO_SCALE, SDL_WINDOW_SHOWN);
+	renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED);
+	texture = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_RGBA32, SDL_TEXTUREACCESS_STREAMING, WIDTH, HEIGHT);
+}
+
+uint32_t video[WIDTH*HEIGHT];
+
+void
+update_video()
+{
+	static int count = 0;
+	printf("frame %d\n", count++);
+	/*
+	for (uint32_t i = 0 ;i < WIDTH*HEIGHT; i++)
+	{
+
+		video[i] = (255<<16)|(255<<8)|255;
+	}
+	video[0] = (255);
+	video[1] = (255<<8);
+	video[2] = (255<<16);
+	*/
+
+	toggle_pixel(0, 0);
+	SDL_UpdateTexture(texture, NULL, video, sizeof(video[0])*WIDTH);
+	SDL_RenderClear(renderer);
+	SDL_RenderCopy(renderer, texture, NULL, NULL);
+	SDL_RenderPresent(renderer);
+}
+
+void
+toggle_pixel(int x, int y)
+{
+	// TODO: clean
+	uint32_t dos = video[WIDTH*y+x];
+	if (dos <= 0)
+		video[WIDTH*y+x] = (255<<16)|(255<<8)|255;
+	else
+		video[WIDTH*y+x] = 0;
+}
+
+int main(int argc, char *argv[])
+{
+	init_video();
+
+	const int fps = 60;
+	const int frame_delay = 1000/fps;
+	uint32_t  frame_start;
+	uint32_t frame_time;
+	int do_quit = 0;
+	while(!do_quit)
+	{
+		frame_start = SDL_GetTicks();
+
+		// logic
+		update_video();
+
+		frame_time = SDL_GetTicks() - frame_start;
+		if (frame_delay > frame_time)
+		{
+			SDL_Delay(frame_delay - frame_time);
+		}
+	}
+
+	quit();
+	return 0;
+}
-- 
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