Fisheye effect

shader_effects["fisheye"] = {shader=basic_fsh..[[
uniform float amount;

void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
	vec2 p = fragCoord.xy / iResolution.x;//normalized coords with some cheat
	                                                         //(assume 1:1 prop)
	float prop = iResolution.x / iResolution.y;//screen proroption
	vec2 m = vec2(0.5, 0.5 / prop);//center coords
	vec2 d = p - m;//vector from center to current fragment
	float r = sqrt(dot(d, d)); // distance of pixel from center

	float power = ( 2.0 * 3.141592 / (2.0 * sqrt(dot(m, m))) ) *
				(amount - 0.5);//amount of effect

	float bind;//radius of 1:1 effect
	if (power > 0.0) bind = sqrt(dot(m, m));//stick to corners
	else {if (prop < 1.0) bind = m.x; else bind = m.y;}//stick to borders

	//Weird formulas
	vec2 uv;
	if (power > 0.0)//fisheye
		uv = m + normalize(d) * tan(r * power) * bind / tan( bind * power);
	else if (power < 0.0)//antifisheye
		uv = m + normalize(d) * atan(r * -power * 10.0) * bind / atan(-power * bind * 10.0);
	else uv = p;//no effect for power = 1.0

	vec3 col = texture2D(iChannel0, vec2(uv.x, uv.y * prop)).xyz;//Second part of cheat
	                                                  //for round effect, not elliptical
	fragColor = vec4(col, 1.0);
}

void main()
{
	vec4 color;
        mainImage(color, texcoord.xy*iResolution.xy);
	gl_FragColor = color;
}
]]}

shaderAddEffect("fisheye")
shaderEffectParam("fisheye", "amount", 0.45)

fisheye_amount = 0.5
bind("fisheye", "amount", field("fisheye_amount"))
startTween("fisheye_amount", fisheye_amount, 0.44, 1000, easeQuadInOut, true, true)

game.ShaderExclude = eShaderExcludeInterfaces -- excludes text, cursors & interfaces, or...
game.ShaderExclude = eShaderExcludeTextsAndCursor -- excludes text & cursors, or...
game.ShaderExclude = eShaderExcludeCursor -- excludes cursors.

game.ShaderExclude = eShaderExcludeInterfaces