Animate4x1.fp

uniform float timer;

vec4 ProcessTexel()
{
	vec4 finalTex = vec4(0.0,0.0,0.0,0.0);
	vec2 XY = vTexCoord.st;
	vec2 offset = vec2(0.0,0.0);
	vec4 tex0 = getTexel(XY);

	//green channel off the initial texture color offsets timer
	float timer2 = timer * 0.1 + tex0.y;

	//or as another example, the X position is used
	//float timer2 = timer * 0.1 + XY.x;

	//needed as timer2 will be modified later
	float timer3 = timer2;

	XY.x *= 0.25;

	//ensures that only	1 image in the strip is visible at a time
	XY.x = mod(XY.x, 0.25);

	//mirrors image because why not
	XY.x = 0.125 - abs(0.125 - XY.x);

	vec2 XYtwo;
	XYtwo.x = XY.x;
	XYtwo.y = XY.y;

	//animates image
	timer2 = floor(mod(timer2 * 4, 4)) * 0.25;

	//first image
	XY.x += timer2;

	//second image
	XYtwo.x = XY.x + 0.25;
	vec4 tex1 = getTexel(XY);
	vec4 tex2 = getTexel(XYtwo);

	//blend factor. increases until 2nd image is completely visible.
	//when it goes back to 0, the 2nd image becomes the 1st image
	float mixrate = mod(timer3, 0.25) * 4;

	finalTex = ((tex1 * (1 - mixrate)) + (tex2 * mixrate));
	return finalTex;
}