/* clang-format off */
[vertex]

layout(location = 0) in highp vec4 vertex_attrib;
/* clang-format on */
#if defined(USE_CUBEMAP) || defined(USE_PANORAMA)
layout(location = 4) in vec3 cube_in;
#else
layout(location = 4) in vec2 uv_in;
#endif
layout(location = 5) in vec2 uv2_in;

#if defined(USE_CUBEMAP) || defined(USE_PANORAMA)
out vec3 cube_interp;
#else
out vec2 uv_interp;
#endif

out vec2 uv2_interp;

// These definitions are here because the shader-wrapper builder does
// not understand `#elif defined()`
#ifdef USE_DISPLAY_TRANSFORM
#endif

#ifdef USE_COPY_SECTION

uniform vec4 copy_section;

#elif defined(USE_DISPLAY_TRANSFORM)

uniform highp mat4 display_transform;

#endif

void main() {

#if defined(USE_CUBEMAP) || defined(USE_PANORAMA)
	cube_interp = cube_in;
#elif defined(USE_ASYM_PANO)
	uv_interp = vertex_attrib.xy;
#else
	uv_interp = uv_in;
#ifdef V_FLIP
	uv_interp.y = 1.0 - uv_interp.y;
#endif

#endif
	uv2_interp = uv2_in;
	gl_Position = vertex_attrib;

#ifdef USE_COPY_SECTION

	uv_interp = copy_section.xy + uv_interp * copy_section.zw;
	gl_Position.xy = (copy_section.xy + (gl_Position.xy * 0.5 + 0.5) * copy_section.zw) * 2.0 - 1.0;
#elif defined(USE_DISPLAY_TRANSFORM)

	uv_interp = (display_transform * vec4(uv_in, 1.0, 1.0)).xy;
#endif
}

/* clang-format off */
[fragment]

#ifdef USE_EXTERNAL_SAMPLER
// Leave the ifdef so we have this define, for now the extension is loaded through custom defines
// #extension GL_OES_EGL_image_external_essl3 : require
#endif

#define M_PI 3.14159265359

#if !defined(USE_GLES_OVER_GL)
precision mediump float;
#endif

#if defined(USE_CUBEMAP) || defined(USE_PANORAMA)
in vec3 cube_interp;
#else
in vec2 uv_interp;
#endif

#ifdef USE_ASYM_PANO
uniform highp mat4 pano_transform;
uniform highp vec4 asym_proj;
#endif

// These definitions are here because the shader-wrapper builder does
// not understand `#elif defined()`
#ifdef USE_TEXTURE3D
#endif
#ifdef USE_TEXTURE2DARRAY
#endif
#ifdef YCBCR_TO_SRGB
#endif

#ifdef USE_CUBEMAP
uniform samplerCube source_cube; //texunit:0
#elif defined(USE_TEXTURE3D)
uniform sampler3D source_3d; //texunit:0
#elif defined(USE_TEXTURE2DARRAY)
uniform sampler2DArray source_2d_array; //texunit:0
#elif defined(USE_EXTERNAL_SAMPLER)
uniform samplerExternalOES source;
#else
uniform sampler2D source; //texunit:0
#endif

#ifdef SEP_CBCR_TEXTURE
uniform sampler2D CbCr; //texunit:1
#endif

/* clang-format on */

#ifdef USE_LOD
uniform float mip_level;
#endif

#if defined(USE_TEXTURE3D) || defined(USE_TEXTURE2DARRAY)
uniform float layer;
#endif

#ifdef USE_MULTIPLIER
uniform float multiplier;
#endif

#if defined(USE_PANORAMA) || defined(USE_ASYM_PANO)
uniform highp mat4 sky_transform;

vec4 texturePanorama(vec3 normal, sampler2D pano) {

	vec2 st = vec2(
			atan(normal.x, normal.z),
			acos(normal.y));

	if (st.x < 0.0)
		st.x += M_PI * 2.0;

	st /= vec2(M_PI * 2.0, M_PI);

	return textureLod(pano, st, 0.0);
}

#endif

uniform vec2 pixel_size;

in vec2 uv2_interp;

#ifdef USE_BCS

uniform vec3 bcs;

#endif

#ifdef USE_COLOR_CORRECTION

uniform sampler2D color_correction; //texunit:1

#endif

layout(location = 0) out vec4 frag_color;

void main() {

	//vec4 color = color_interp;

#ifdef USE_PANORAMA

	vec3 cube_normal = normalize(cube_interp);
	cube_normal.z = -cube_normal.z;
	cube_normal = mat3(sky_transform) * cube_normal;
	cube_normal.z = -cube_normal.z;

	vec4 color = texturePanorama(cube_normal, source);

#elif defined(USE_ASYM_PANO)

	// When an asymmetrical projection matrix is used (applicable for stereoscopic rendering i.e. VR) we need to do this calculation per fragment to get a perspective correct result.
	// Asymmetrical projection means the center of projection is no longer in the center of the screen but shifted.
	// The Matrix[2][0] (= asym_proj.x) and Matrix[2][1] (= asym_proj.z) values are what provide the right shift in the image.

	vec3 cube_normal;
	cube_normal.z = -1.0;
	cube_normal.x = (cube_normal.z * (-uv_interp.x - asym_proj.x)) / asym_proj.y;
	cube_normal.y = (cube_normal.z * (-uv_interp.y - asym_proj.z)) / asym_proj.a;
	cube_normal = mat3(sky_transform) * mat3(pano_transform) * cube_normal;
	cube_normal.z = -cube_normal.z;

	vec4 color = texturePanorama(normalize(cube_normal.xyz), source);

#elif defined(USE_CUBEMAP)
	vec4 color = texture(source_cube, normalize(cube_interp));

#elif defined(USE_TEXTURE3D)
	vec4 color = textureLod(source_3d, vec3(uv_interp, layer), 0.0);
#elif defined(USE_TEXTURE2DARRAY)
	vec4 color = textureLod(source_2d_array, vec3(uv_interp, layer), 0.0);
#elif defined(SEP_CBCR_TEXTURE)
	vec4 color;
	color.r = textureLod(source, uv_interp, 0.0).r;
	color.gb = textureLod(CbCr, uv_interp, 0.0).rg - vec2(0.5, 0.5);
	color.a = 1.0;
#else
#ifdef USE_LOD
	vec4 color = textureLod(source, uv_interp, mip_level);
#else
	vec4 color = textureLod(source, uv_interp, 0.0);
#endif
#endif

#ifdef LINEAR_TO_SRGB
	// regular Linear -> SRGB conversion
	vec3 a = vec3(0.055);
	color.rgb = mix((vec3(1.0) + a) * pow(color.rgb, vec3(1.0 / 2.4)) - a, 12.92 * color.rgb, lessThan(color.rgb, vec3(0.0031308)));

#elif defined(YCBCR_TO_SRGB)

	// YCbCr -> SRGB conversion
	// Using BT.709 which is the standard for HDTV
	color.rgb = mat3(
						vec3(1.00000, 1.00000, 1.00000),
						vec3(0.00000, -0.18732, 1.85560),
						vec3(1.57481, -0.46813, 0.00000)) *
				color.rgb;

#endif

#ifdef SRGB_TO_LINEAR

	color.rgb = mix(pow((color.rgb + vec3(0.055)) * (1.0 / (1.0 + 0.055)), vec3(2.4)), color.rgb * (1.0 / 12.92), lessThan(color.rgb, vec3(0.04045)));
#endif

#ifdef DEBUG_GRADIENT
	color.rg = uv_interp;
	color.b = 0.0;
#endif

#ifdef DISABLE_ALPHA
	color.a = 1.0;
#endif

#ifdef GAUSSIAN_HORIZONTAL
	color *= 0.38774;
	color += texture(source, uv_interp + vec2(1.0, 0.0) * pixel_size) * 0.24477;
	color += texture(source, uv_interp + vec2(2.0, 0.0) * pixel_size) * 0.06136;
	color += texture(source, uv_interp + vec2(-1.0, 0.0) * pixel_size) * 0.24477;
	color += texture(source, uv_interp + vec2(-2.0, 0.0) * pixel_size) * 0.06136;
#endif

#ifdef GAUSSIAN_VERTICAL
	color *= 0.38774;
	color += texture(source, uv_interp + vec2(0.0, 1.0) * pixel_size) * 0.24477;
	color += texture(source, uv_interp + vec2(0.0, 2.0) * pixel_size) * 0.06136;
	color += texture(source, uv_interp + vec2(0.0, -1.0) * pixel_size) * 0.24477;
	color += texture(source, uv_interp + vec2(0.0, -2.0) * pixel_size) * 0.06136;
#endif

#ifdef USE_BCS

	color.rgb = mix(vec3(0.0), color.rgb, bcs.x);
	color.rgb = mix(vec3(0.5), color.rgb, bcs.y);
	color.rgb = mix(vec3(dot(vec3(1.0), color.rgb) * 0.33333), color.rgb, bcs.z);

#endif

#ifdef USE_COLOR_CORRECTION

	color.r = texture(color_correction, vec2(color.r, 0.0)).r;
	color.g = texture(color_correction, vec2(color.g, 0.0)).g;
	color.b = texture(color_correction, vec2(color.b, 0.0)).b;
#endif

#ifdef USE_MULTIPLIER
	color.rgb *= multiplier;
#endif
	frag_color = color;
}