// MinecraftPT — MotionBlur_FS
// Per-pixel camera motion blur using motion vectors.

#include "/Lib/Settings.glsl"
#include "/Lib/Utilities.glsl"
#include "/Lib/BasicFunctions/TemporalNoise.glsl"

uniform sampler2D colortex12;
uniform sampler2D colortex10;

layout(location = 0) out vec4 colorOut;

void main(){
	vec2 texelCoord = gl_FragCoord.xy;

	vec3 color = texelFetch(colortex12, ivec2(texelCoord), 0).rgb;

	#ifdef MOTION_BLUR
		if (MOTION_BLUR > 0){
			vec2 motion = texelFetch(colortex10, ivec2(texelCoord * 0.5), 0).xy * 2.0;
			float speed = length(motion);

			if (speed > 0.5){
				// Shutter angle sampling
				float shutterAngle = mix(90.0, 360.0, MOTION_BLUR_SUTTER_SPEED);
				float samples = float(MOTION_BLUR_QUALITY);
				float dither = BlueNoiseTemporal();

				vec2 dir = normalize(motion);
				float length = min(speed, 32.0) * 0.5;

				vec3 acc = vec3(0.0);
				for (int i = 0; i < MOTION_BLUR_QUALITY; i++){
					float t = (float(i) + dither) / samples - 0.5;
					vec2 sampleCoord = texelCoord + dir * length * t;
					acc += textureLod(colortex12, sampleCoord / screenSize, 0.0).rgb;
				}

				color = acc / samples;
			}
		}
	#endif

	colorOut = vec4(color, 1.0);
}