/* clang-format off */
[vertex]

layout(location = 0) in highp vec4 vertex_attrib;
/* clang-format on */
layout(location = 4) in vec2 uv_in;

out vec2 uv_interp;

#ifdef USE_BLUR_SECTION

uniform vec4 blur_section;

#endif

void main() {
	uv_interp = uv_in;
	gl_Position = vertex_attrib;
#ifdef USE_BLUR_SECTION

	uv_interp = blur_section.xy + uv_interp * blur_section.zw;
	gl_Position.xy = (blur_section.xy + (gl_Position.xy * 0.5 + 0.5) * blur_section.zw) * 2.0 - 1.0;
#endif
}

/* clang-format off */
[fragment]

#if !defined(GLES_OVER_GL)
precision mediump float;
#endif
/* clang-format on */

in vec2 uv_interp;
uniform sampler2D source_color; //texunit:0

#ifdef SSAO_MERGE
uniform sampler2D source_ssao; //texunit:1
#endif

uniform float lod;
uniform vec2 pixel_size;

layout(location = 0) out vec4 frag_color;

#ifdef SSAO_MERGE

uniform vec4 ssao_color;

#endif

#if defined(GLOW_GAUSSIAN_HORIZONTAL) || defined(GLOW_GAUSSIAN_VERTICAL)

uniform float glow_strength;

#endif

#if defined(DOF_FAR_BLUR) || defined(DOF_NEAR_BLUR)

#ifdef DOF_QUALITY_LOW
const int dof_kernel_size = 5;
const int dof_kernel_from = 2;
const float dof_kernel[5] = float[](0.153388, 0.221461, 0.250301, 0.221461, 0.153388);
#endif

#ifdef DOF_QUALITY_MEDIUM
const int dof_kernel_size = 11;
const int dof_kernel_from = 5;
const float dof_kernel[11] = float[](0.055037, 0.072806, 0.090506, 0.105726, 0.116061, 0.119726, 0.116061, 0.105726, 0.090506, 0.072806, 0.055037);

#endif

#ifdef DOF_QUALITY_HIGH
const int dof_kernel_size = 21;
const int dof_kernel_from = 10;
const float dof_kernel[21] = float[](0.028174, 0.032676, 0.037311, 0.041944, 0.046421, 0.050582, 0.054261, 0.057307, 0.059587, 0.060998, 0.061476, 0.060998, 0.059587, 0.057307, 0.054261, 0.050582, 0.046421, 0.041944, 0.037311, 0.032676, 0.028174);
#endif

uniform sampler2D dof_source_depth; //texunit:1
uniform float dof_far_begin;
uniform float dof_far_end;
uniform float dof_near_begin;
uniform float dof_near_end;
uniform vec2 dof_dir;
uniform float dof_radius;

#endif

#ifdef GLOW_FIRST_PASS

uniform float exposure;
uniform float white;
uniform highp float luminance_cap;

#ifdef GLOW_USE_AUTO_EXPOSURE

uniform highp sampler2D source_auto_exposure; //texunit:1
uniform highp float auto_exposure_grey;

#endif

uniform float glow_bloom;
uniform float glow_hdr_threshold;
uniform float glow_hdr_scale;

#endif

uniform float camera_z_far;
uniform float camera_z_near;

void main() {
#ifdef GAUSSIAN_HORIZONTAL
	vec2 pix_size = pixel_size;
	pix_size *= 0.5; //reading from larger buffer, so use more samples
	// sigma 2
	vec4 color = textureLod(source_color, uv_interp + vec2(0.0, 0.0) * pix_size, lod) * 0.214607;
	color += textureLod(source_color, uv_interp + vec2(1.0, 0.0) * pix_size, lod) * 0.189879;
	color += textureLod(source_color, uv_interp + vec2(2.0, 0.0) * pix_size, lod) * 0.131514;
	color += textureLod(source_color, uv_interp + vec2(3.0, 0.0) * pix_size, lod) * 0.071303;
	color += textureLod(source_color, uv_interp + vec2(-1.0, 0.0) * pix_size, lod) * 0.189879;
	color += textureLod(source_color, uv_interp + vec2(-2.0, 0.0) * pix_size, lod) * 0.131514;
	color += textureLod(source_color, uv_interp + vec2(-3.0, 0.0) * pix_size, lod) * 0.071303;
	frag_color = color;
#endif

#ifdef GAUSSIAN_VERTICAL
	vec4 color = textureLod(source_color, uv_interp + vec2(0.0, 0.0) * pixel_size, lod) * 0.38774;
	color += textureLod(source_color, uv_interp + vec2(0.0, 1.0) * pixel_size, lod) * 0.24477;
	color += textureLod(source_color, uv_interp + vec2(0.0, 2.0) * pixel_size, lod) * 0.06136;
	color += textureLod(source_color, uv_interp + vec2(0.0, -1.0) * pixel_size, lod) * 0.24477;
	color += textureLod(source_color, uv_interp + vec2(0.0, -2.0) * pixel_size, lod) * 0.06136;
	frag_color = color;
#endif

	//glow uses larger sigma for a more rounded blur effect

#ifdef GLOW_GAUSSIAN_HORIZONTAL
	vec2 pix_size = pixel_size;
	pix_size *= 0.5; //reading from larger buffer, so use more samples
	vec4 color = textureLod(source_color, uv_interp + vec2(0.0, 0.0) * pix_size, lod) * 0.174938;
	color += textureLod(source_color, uv_interp + vec2(1.0, 0.0) * pix_size, lod) * 0.165569;
	color += textureLod(source_color, uv_interp + vec2(2.0, 0.0) * pix_size, lod) * 0.140367;
	color += textureLod(source_color, uv_interp + vec2(3.0, 0.0) * pix_size, lod) * 0.106595;
	color += textureLod(source_color, uv_interp + vec2(-1.0, 0.0) * pix_size, lod) * 0.165569;
	color += textureLod(source_color, uv_interp + vec2(-2.0, 0.0) * pix_size, lod) * 0.140367;
	color += textureLod(source_color, uv_interp + vec2(-3.0, 0.0) * pix_size, lod) * 0.106595;
	color *= glow_strength;
	frag_color = color;
#endif

#ifdef GLOW_GAUSSIAN_VERTICAL
	vec4 color = textureLod(source_color, uv_interp + vec2(0.0, 0.0) * pixel_size, lod) * 0.288713;
	color += textureLod(source_color, uv_interp + vec2(0.0, 1.0) * pixel_size, lod) * 0.233062;
	color += textureLod(source_color, uv_interp + vec2(0.0, 2.0) * pixel_size, lod) * 0.122581;
	color += textureLod(source_color, uv_interp + vec2(0.0, -1.0) * pixel_size, lod) * 0.233062;
	color += textureLod(source_color, uv_interp + vec2(0.0, -2.0) * pixel_size, lod) * 0.122581;
	color *= glow_strength;
	frag_color = color;
#endif

#if defined(DOF_FAR_BLUR) || defined(DOF_NEAR_BLUR)

	vec4 color_accum = vec4(0.0);

	float depth = textureLod(dof_source_depth, uv_interp, 0.0).r;
	depth = depth * 2.0 - 1.0;
#ifdef USE_ORTHOGONAL_PROJECTION
	depth = ((depth + (camera_z_far + camera_z_near) / (camera_z_far - camera_z_near)) * (camera_z_far - camera_z_near)) / 2.0;
#else
	depth = 2.0 * camera_z_near * camera_z_far / (camera_z_far + camera_z_near - depth * (camera_z_far - camera_z_near));
#endif

	// Combine near and far, our depth is unlikely to be in both ranges
	float amount = 1.0;
#ifdef DOF_FAR_BLUR
	amount *= 1.0 - smoothstep(dof_far_begin, dof_far_end, depth);
#endif
#ifdef DOF_NEAR_BLUR
	amount *= smoothstep(dof_near_end, dof_near_begin, depth);
#endif
	amount = 1.0 - amount;

	if (amount > 0.0) {
		float k_accum = 0.0;

		for (int i = 0; i < dof_kernel_size; i++) {
			int int_ofs = i - dof_kernel_from;
			vec2 tap_uv = uv_interp + dof_dir * float(int_ofs) * amount * dof_radius;

			float tap_k = dof_kernel[i];

			float tap_depth = texture(dof_source_depth, tap_uv, 0.0).r;
			tap_depth = tap_depth * 2.0 - 1.0;
#ifdef USE_ORTHOGONAL_PROJECTION
			tap_depth = ((tap_depth + (camera_z_far + camera_z_near) / (camera_z_far - camera_z_near)) * (camera_z_far - camera_z_near)) / 2.0;
#else
			tap_depth = 2.0 * camera_z_near * camera_z_far / (camera_z_far + camera_z_near - tap_depth * (camera_z_far - camera_z_near));
#endif
			float tap_amount = 1.0;
#ifdef DOF_FAR_BLUR
			tap_amount *= mix(1.0 - smoothstep(dof_far_begin, dof_far_end, tap_depth), 0.0, int_ofs == 0);
#endif
#ifdef DOF_NEAR_BLUR
			tap_amount *= mix(smoothstep(dof_near_end, dof_near_begin, tap_depth), 0.0, int_ofs == 0);
#endif
			tap_amount = 1.0 - tap_amount;
			tap_amount *= tap_amount * tap_amount; //prevent undesired glow effect

			vec4 tap_color = textureLod(source_color, tap_uv, 0.0) * tap_k;

			k_accum += tap_k * tap_amount;
			color_accum += tap_color * tap_amount;
		}

		if (k_accum > 0.0) {
			color_accum /= k_accum;
		}

		frag_color = color_accum; ///k_accum;
	} else {
		// We're in focus, no need to waste time sampling the same UV a bunch of times...
		frag_color = textureLod(source_color, uv_interp, 0.0);
	}
#endif

#ifdef GLOW_FIRST_PASS

#ifdef GLOW_USE_AUTO_EXPOSURE

	frag_color /= texelFetch(source_auto_exposure, ivec2(0, 0), 0).r / auto_exposure_grey;
#endif
	frag_color *= exposure;

	float luminance = max(frag_color.r, max(frag_color.g, frag_color.b));
	float feedback = max(smoothstep(glow_hdr_threshold, glow_hdr_threshold + glow_hdr_scale, luminance), glow_bloom);

	frag_color = min(frag_color * feedback, vec4(luminance_cap));

#endif

#ifdef SIMPLE_COPY
	vec4 color = textureLod(source_color, uv_interp, 0.0);
	frag_color = color;
#endif

#ifdef SSAO_MERGE

	vec4 color = textureLod(source_color, uv_interp, 0.0);
	float ssao = textureLod(source_ssao, uv_interp, 0.0).r;

	frag_color = vec4(mix(color.rgb, color.rgb * mix(ssao_color.rgb, vec3(1.0), ssao), color.a), 1.0);

#endif
}