God-Machine/Assets/Compute Shaders/automata.acompute

#kernel Seed
#kernel Automaton
#kernel Blit

#extension GL_ARB_gpu_shader_int64 : require


layout(rgba8, set = 0, binding = 0) uniform image2D _RenderTarget;
layout(r16f, set = 0, binding = 2) uniform image2D _AutomatonFrom;
layout(r16f, set = 0, binding = 3) uniform image2D _AutomatonTo;

layout(binding = 1) uniform UniformBufferObject {
	vec4 _Exposure;
};

layout(push_constant, std430) uniform Params {
	uint64_t _UpperLeftMask;
	uint64_t _UpperRightMask;
	uint64_t _LowerLeftMask;
	uint64_t _LowerRightMask;
};

float pseudo(vec2 v) {
	v = fract(v/128.)*128. + vec2(-64.340622, -72.465622);
	return fract(dot(v.xyx * v.xyy, vec3(20.390625, 60.703125, 2.4281209)));
}

[numthreads(8, 8, 1)]
void Seed() {
	ivec2 uv = ivec2(gl_GlobalInvocationID.xy);

	vec2 seeds = vec2(0.0, 0.0);

	float seed = pseudo(vec2(float(uv.x) * 0.1 + seeds.x, float(uv.y) * 0.1 + seeds.x * 3));

	if (seed < 0.75) seed = 0.0;
	else seed = 1.0;

	imageStore(_AutomatonFrom, uv, vec4(seed));
}


uint64_t encode_tile_to_uint(ivec2 uv) {
	uint64_t tile_bits = 0;

	for (int y = 0; y < 8; ++y) {
		for (int x = 0; x < 8; ++x) {
			uint bit_index = x + y * 8; // Convert to 1D index in 64 bit uint

			ivec2 world_coords = uv + ivec2(-x, -y);
			uint64_t cell_value = int(imageLoad(_AutomatonFrom, world_coords % 512).r);

			tile_bits |= (cell_value << bit_index);
		}
	}
	
	return tile_bits;
}

uint sum_uint_bits(uint64_t i) {
	uint sum = 0;

	while (i != 0) {
		sum += uint(i & 1);
		i >>= 1;
	}

	return sum;
}


[numthreads(8, 8, 1)]
void Automaton() {
	ivec2 uv = ivec2(gl_GlobalInvocationID.xy);

	int cell = int(imageLoad(_AutomatonFrom, uv).r);
	
	uint64_t top_row_mask = 18374686479671623680UL;
	uint64_t left_column_mask = 9259542123273814144UL;

	// GAME OF LIFE
	// uint64_t upper_left_mask = 770;
	// uint64_t upper_right_mask = 49216 & ~(left_column_mask);
	// uint64_t lower_left_mask = 144959613005987840UL & ~(top_row_mask);
	// uint64_t lower_right_mask = 4665729213955833856UL & ~(top_row_mask | left_column_mask);

	// BUGS
	// uint64_t upper_left_mask = 69540876599103UL;
	// uint64_t upper_right_mask = 278163506396412UL & ~(left_column_mask);
	// uint64_t lower_left_mask = 4557430888798814208UL & ~(top_row_mask);
	// uint64_t lower_right_mask = 18229723555195256832UL & ~(top_row_mask | left_column_mask);

	uint64_t upper_left_mask = _UpperLeftMask;
	uint64_t upper_right_mask = _UpperRightMask & ~(left_column_mask);
	uint64_t lower_left_mask = _LowerLeftMask & ~(top_row_mask);
	uint64_t lower_right_mask = _LowerRightMask & ~(top_row_mask | left_column_mask);


	uint64_t upper_left_quadrant_bits = encode_tile_to_uint(uv) & upper_left_mask;
	uint64_t upper_right_quadrant_bits = encode_tile_to_uint(uv + ivec2(7, 0)) & upper_right_mask;
	uint64_t lower_left_quadrant_bits = encode_tile_to_uint(uv + ivec2(0, 7)) & lower_left_mask;
	uint64_t lower_right_quadrant_bits = encode_tile_to_uint(uv + ivec2(7, 7)) & lower_right_mask;

	uint neighbor_count = 0;
	neighbor_count += sum_uint_bits(upper_left_quadrant_bits);
	neighbor_count += sum_uint_bits(upper_right_quadrant_bits);
	neighbor_count += sum_uint_bits(lower_left_quadrant_bits);
	neighbor_count += sum_uint_bits(lower_right_quadrant_bits);


	// for (int x = -1; x <= 1; ++x) {
	// 	for (int y = -1; y <= 1; ++y) {
	// 		if (x == 0 && y == 0) continue;

	// 		ivec2 texcoords = uv + ivec2(x, y);
	// 		texcoords = texcoords % 512;

	// 		neighbor_count += int(imageLoad(_AutomatonFrom, texcoords).r);
	// 	}
	// }

	if (neighbor_count <= 1) cell = 0;
	if (neighbor_count == 3) cell = 1;
	if (neighbor_count >= 4) cell = 0;
	
	// if (neighbor_count <= 33) cell = 0;
	// if (34 <= neighbor_count && neighbor_count <= 45) cell = 1;
	// if (58 <= neighbor_count && neighbor_count <= 121) cell = 0;

	imageStore(_AutomatonTo, uv, vec4(cell));
}

[numthreads(8, 8, 1)]
void Blit() {
	ivec2 uv = ivec2(gl_GlobalInvocationID.xy);

	float automata = imageLoad(_AutomatonTo, uv / 2).r;
	
	imageStore(_RenderTarget, uv, vec4(automata, 0, 0, 1.0));
}