#pragma once

#include <string>

inline const std::string QUADVERTSRC = R"#(
uniform mat3 proj;
uniform vec4 color;
attribute vec2 pos;
attribute vec2 texcoord;
varying vec4 v_color;
varying vec2 v_texcoord;

void main() {
    gl_Position = vec4(proj * vec3(pos, 1.0), 1.0);
    v_color = color;
    v_texcoord = texcoord;
})#";

inline const std::string QUADFRAGSRC = R"#(
precision mediump float;
varying vec4 v_color;
varying vec2 v_texcoord;

void main() {
    gl_FragColor = v_color;
})#";

inline const std::string TEXVERTSRC = R"#(
uniform mat3 proj;
attribute vec2 pos;
attribute vec2 texcoord;
varying vec2 v_texcoord;

void main() {
	gl_Position = vec4(proj * vec3(pos, 1.0), 1.0);
	v_texcoord = texcoord;
})#";

inline const std::string TEXFRAGSRCRGBA = R"#(
precision mediump float;
varying vec2 v_texcoord; // is in 0-1
uniform sampler2D tex;
uniform float alpha;

uniform vec2 topLeft;
uniform vec2 bottomRight;
uniform vec2 fullSize;
uniform float radius;

void main() {

	vec2 pixCoord = fullSize * v_texcoord;

	if (pixCoord[0] < topLeft[0]) {
		// we're close left
		if (pixCoord[1] < topLeft[1]) {
			// top
			if (distance(topLeft, pixCoord) > radius) {
				discard;
				return;
			}
		} else if (pixCoord[1] > bottomRight[1]) {
			// bottom
			if (distance(vec2(topLeft[0], bottomRight[1]), pixCoord) > radius) {
				discard;
				return;
			}
		}
	}
	else if (pixCoord[0] > bottomRight[0]) {
		// we're close right
		if (pixCoord[1] < topLeft[1]) {
			// top
			if (distance(vec2(bottomRight[0], topLeft[1]), pixCoord) > radius) {
				discard;
				return;
			}
		} else if (pixCoord[1] > bottomRight[1]) {
			// bottom
			if (distance(bottomRight, pixCoord) > radius) {
				discard;
				return;
			}
		}
	}

	gl_FragColor = texture2D(tex, v_texcoord) * alpha;
})#";

inline const std::string TEXFRAGSRCRGBX = R"#(
precision mediump float;
varying vec2 v_texcoord;
uniform sampler2D tex;
uniform float alpha;

uniform vec2 topLeft;
uniform vec2 bottomRight;
uniform vec2 fullSize;
uniform float radius;

void main() {
	
	vec2 pixCoord = fullSize * v_texcoord;

	if (pixCoord[0] < topLeft[0]) {
		// we're close left
		if (pixCoord[1] < topLeft[1]) {
			// top
			if (distance(topLeft, pixCoord) > radius) {
				discard;
				return;
			}
		} else if (pixCoord[1] > bottomRight[1]) {
			// bottom
			if (distance(vec2(topLeft[0], bottomRight[1]), pixCoord) > radius) {
				discard;
				return;
			}
		}
	}
	else if (pixCoord[0] > bottomRight[0]) {
		// we're close right
		if (pixCoord[1] < topLeft[1]) {
			// top
			if (distance(vec2(bottomRight[0], topLeft[1]), pixCoord) > radius) {
				discard;
				return;
			}
		} else if (pixCoord[1] > bottomRight[1]) {
			// bottom
			if (distance(bottomRight, pixCoord) > radius) {
				discard;
				return;
			}
		}
	}

	gl_FragColor = vec4(texture2D(tex, v_texcoord).rgb, 1.0) * alpha;
})#";

// thanks to Loadus
// https://www.shadertoy.com/view/Mtl3Rj
// for this pseudo-gaussian blur!
inline const std::string FRAGBLUR1 = R"#(
precision mediump float;
varying vec2 v_texcoord; // is in 0-1
uniform sampler2D tex;

uniform float radius;
uniform vec2 resolution;
uniform float alpha;

float SCurve (float x) {
	x = x * 2.0 - 1.0;
	return -x * abs(x) * 0.5 + x + 0.5;
}

vec4 BlurH (vec2 size, vec2 uv) {
	if (radius >= 1.0) {
		vec4 A = vec4(0.0); 
		vec4 C = vec4(0.0); 

		float width = 1.0 / size.x;

		float divisor = 0.0; 
        float weight = 0.0;
        
        float radiusMultiplier = 1.0 / radius;
        
		for (float x = -radius; x <= radius; x++) {
			A = texture2D(tex, uv + vec2(x * width, 0.0));
            
            weight = SCurve(1.0 - (abs(x) * radiusMultiplier)); 
            
            C += A * weight; 
            
			divisor += weight; 
		}

		return vec4(C.r / divisor, C.g / divisor, C.b / divisor, 1.0);
	}

	return texture2D(tex, uv);
}


void main() {
	gl_FragColor = BlurH(resolution, v_texcoord) * alpha;
}

)#";

inline const std::string FRAGBLUR2 = R"#(
precision mediump float;
varying vec2 v_texcoord; // is in 0-1
uniform sampler2D tex;

uniform float radius;
uniform vec2 resolution;
uniform float alpha;

float SCurve (float x) {
	x = x * 2.0 - 1.0;
	return -x * abs(x) * 0.5 + x + 0.5;
}

vec4 BlurV (vec2 size, vec2 uv) {
	if (radius >= 1.0) {
		vec4 A = vec4(0.0); 
		vec4 C = vec4(0.0); 

		float height = 1.0 / size.y;

		float divisor = 0.0; 
        float weight = 0.0;
        
        float radiusMultiplier = 1.0 / radius;
        
		for (float y = -radius; y <= radius; y++) {
			A = texture2D(tex, uv + vec2(0.0, y * height));
            
            weight = SCurve(1.0 - (abs(y) * radiusMultiplier)); 
            
            C += A * weight; 
            
			divisor += weight; 
		}

		return vec4(C.r / divisor, C.g / divisor, C.b / divisor, 1.0);
	}

	return texture2D(tex, uv);
}


void main() {
	gl_FragColor = BlurV(resolution, v_texcoord) * alpha;
}

)#";

inline const std::string TEXFRAGSRCEXT = R"#(
#extension GL_OES_EGL_image_external : require

precision mediump float;
varying vec2 v_texcoord;
uniform samplerExternalOES texture0;
uniform float alpha;

uniform vec2 topLeft;
uniform vec2 bottomRight;
uniform vec2 fullSize;
uniform float radius;

void main() {

	vec2 pixCoord = fullSize * v_texcoord;

	if (pixCoord[0] < topLeft[0]) {
		// we're close left
		if (pixCoord[1] < topLeft[1]) {
			// top
			if (distance(topLeft, pixCoord) > radius) {
				discard;
				return;
			}
		} else if (pixCoord[1] > bottomRight[1]) {
			// bottom
			if (distance(vec2(topLeft[0], bottomRight[1]), pixCoord) > radius) {
				discard;
				return;
			}
		}
	}
	else if (pixCoord[0] > bottomRight[0]) {
		// we're close right
		if (pixCoord[1] < topLeft[1]) {
			// top
			if (distance(vec2(bottomRight[0], topLeft[1]), pixCoord) > radius) {
				discard;
				return;
			}
		} else if (pixCoord[1] > bottomRight[1]) {
			// bottom
			if (distance(bottomRight, pixCoord) > radius) {
				discard;
				return;
			}
		}
	}

	gl_FragColor = texture2D(texture0, v_texcoord) * alpha;
})#";