SameBoy/Shaders/CRT.fsh

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2018-11-19 16:52:11 +00:00
#define COLOR_LOW 0.7
#define COLOR_HIGH 1.0
#define VERTICAL_BORDER_DEPTH 0.6
#define SCANLINE_DEPTH 0.3
#define CURVENESS 0.3
STATIC vec4 scale(sampler2D image, vec2 position, vec2 input_resolution, vec2 output_resolution)
{
/* Curve and pixel ratio */
float y_curve = cos(position.x - 0.5) * CURVENESS + (1 - CURVENESS);
float y_multiplier = 8.0 / 7.0 / y_curve;
position.y *= y_multiplier;
position.y -= (y_multiplier - 1) / 2;
if (position.y < 0.0) return vec4(0,0,0,0);
if (position.y > 1.0) return vec4(0,0,0,0);
float x_curve = cos(position.y - 0.5) * CURVENESS + (1 - CURVENESS);
float x_multiplier = 1/x_curve;
position.x *= x_multiplier;
position.x -= (x_multiplier - 1) / 2;
if (position.x < 0.0) return vec4(0,0,0,0);
if (position.x > 1.0) return vec4(0,0,0,0);
/* Setting up common vars */
vec2 pos = fract(position * input_resolution);
vec2 sub_pos = fract(position * input_resolution * 6);
vec4 center = texture(image, position);
vec4 left = texture(image, position - vec2(1.0 / input_resolution.x, 0));
vec4 right = texture(image, position + vec2(1.0 / input_resolution.x, 0));
/* Vertical blurring */
if (pos.y < 1.0 / 6.0) {
center = mix(center, texture(image, position + vec2(0, -1.0 / input_resolution.y)), 0.5 - sub_pos.y / 2.0);
left = mix(left, texture(image, position + vec2(-1.0 / input_resolution.x, -1.0 / input_resolution.y)), 0.5 - sub_pos.y / 2.0);
right = mix(right, texture(image, position + vec2( 1.0 / input_resolution.x, -1.0 / input_resolution.y)), 0.5 - sub_pos.y / 2.0);
}
else if (pos.y > 5.0 / 6.0) {
center = mix(center, texture(image, position + vec2(0, 1.0 / input_resolution.y)), sub_pos.y / 2.0);
left = mix(left, texture(image, position + vec2(-1.0 / input_resolution.x, 1.0 / input_resolution.y)), sub_pos.y / 2.0);
right = mix(right, texture(image, position + vec2( 1.0 / input_resolution.x, 1.0 / input_resolution.y)), sub_pos.y / 2.0);
}
/* Scanlines */
float scanline_multiplier;
if (pos.y < 0.5) {
scanline_multiplier = (pos.y * 2) * SCANLINE_DEPTH + (1 - SCANLINE_DEPTH);
}
else {
scanline_multiplier = ((1 - pos.y) * 2) * SCANLINE_DEPTH + (1 - SCANLINE_DEPTH);
}
center *= scanline_multiplier;
left *= scanline_multiplier;
right *= scanline_multiplier;
/* Vertical seperator for shadow masks */
bool odd = bool(int((position * input_resolution).x) & 1);
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if (odd) {
pos.y += 0.5;
pos.y = fract(pos.y);
}
if (pos.y < 1.0 / 3.0) {
float gradient_position = pos.y * 3.0;
center *= gradient_position * VERTICAL_BORDER_DEPTH + (1 - VERTICAL_BORDER_DEPTH);
left *= gradient_position * VERTICAL_BORDER_DEPTH + (1 - VERTICAL_BORDER_DEPTH);
right *= gradient_position * VERTICAL_BORDER_DEPTH + (1 - VERTICAL_BORDER_DEPTH);
}
else if (pos.y > 2.0 / 3.0) {
float gradient_position = (1 - pos.y) * 3.0;
center *= gradient_position * VERTICAL_BORDER_DEPTH + (1 - VERTICAL_BORDER_DEPTH);
left *= gradient_position * VERTICAL_BORDER_DEPTH + (1 - VERTICAL_BORDER_DEPTH);
right *= gradient_position * VERTICAL_BORDER_DEPTH + (1 - VERTICAL_BORDER_DEPTH);
}
/* Blur the edges of the separators of adjacent columns */
if (pos.x < 1.0 / 6.0 || pos.x > 5.0 / 6.0) {
pos.y += 0.5;
pos.y = fract(pos.y);
if (pos.y < 1.0 / 3.0) {
float gradient_position = pos.y * 3.0;
if (pos.x < 0.5) {
gradient_position = 1 - (1 - gradient_position) * (1 - (pos.x) * 6.0);
}
else {
gradient_position = 1 - (1 - gradient_position) * (1 - (1 - pos.x) * 6.0);
}
center *= gradient_position * VERTICAL_BORDER_DEPTH + (1 - VERTICAL_BORDER_DEPTH);
left *= gradient_position * VERTICAL_BORDER_DEPTH + (1 - VERTICAL_BORDER_DEPTH);
right *= gradient_position * VERTICAL_BORDER_DEPTH + (1 - VERTICAL_BORDER_DEPTH);
}
else if (pos.y > 2.0 / 3.0) {
float gradient_position = (1 - pos.y) * 3.0;
if (pos.x < 0.5) {
gradient_position = 1 - (1 - gradient_position) * (1 - (pos.x) * 6.0);
}
else {
gradient_position = 1 - (1 - gradient_position) * (1 - (1 - pos.x) * 6.0);
}
center *= gradient_position * VERTICAL_BORDER_DEPTH + (1 - VERTICAL_BORDER_DEPTH);
left *= gradient_position * VERTICAL_BORDER_DEPTH + (1 - VERTICAL_BORDER_DEPTH);
right *= gradient_position * VERTICAL_BORDER_DEPTH + (1 - VERTICAL_BORDER_DEPTH);
}
}
/* Subpixel blurring, like LCD filter*/
vec4 midleft = mix(left, center, 0.5);
vec4 midright = mix(right, center, 0.5);
vec4 ret;
if (pos.x < 1.0 / 6.0) {
ret = mix(vec4(COLOR_HIGH * center.r, COLOR_LOW * center.g, COLOR_HIGH * left.b, 1),
vec4(COLOR_HIGH * center.r, COLOR_LOW * center.g, COLOR_LOW * left.b, 1),
sub_pos.x);
}
else if (pos.x < 2.0 / 6.0) {
ret = mix(vec4(COLOR_HIGH * center.r, COLOR_LOW * center.g, COLOR_LOW * left.b, 1),
vec4(COLOR_HIGH * center.r, COLOR_HIGH * center.g, COLOR_LOW * midleft.b, 1),
sub_pos.x);
}
else if (pos.x < 3.0 / 6.0) {
ret = mix(vec4(COLOR_HIGH * center.r , COLOR_HIGH * center.g, COLOR_LOW * midleft.b, 1),
vec4(COLOR_LOW * midright.r, COLOR_HIGH * center.g, COLOR_LOW * center.b, 1),
sub_pos.x);
}
else if (pos.x < 4.0 / 6.0) {
ret = mix(vec4(COLOR_LOW * midright.r, COLOR_HIGH * center.g , COLOR_LOW * center.b, 1),
vec4(COLOR_LOW * right.r , COLOR_HIGH * center.g, COLOR_HIGH * center.b, 1),
sub_pos.x);
}
else if (pos.x < 5.0 / 6.0) {
ret = mix(vec4(COLOR_LOW * right.r, COLOR_HIGH * center.g , COLOR_HIGH * center.b, 1),
vec4(COLOR_LOW * right.r, COLOR_LOW * midright.g, COLOR_HIGH * center.b, 1),
sub_pos.x);
}
else {
ret = mix(vec4(COLOR_LOW * right.r, COLOR_LOW * midright.g, COLOR_HIGH * center.b, 1),
vec4(COLOR_HIGH * right.r, COLOR_LOW * right.g , COLOR_HIGH * center.b, 1),
sub_pos.x);
}
/* Anti alias the curve */
vec2 pixel_position = position * output_resolution;
if (pixel_position.x < 1) {
ret *= pixel_position.x;
}
else if (pixel_position.x > output_resolution.x - 1) {
ret *= output_resolution.x - pixel_position.x;
}
if (pixel_position.y < 1) {
ret *= pixel_position.y;
}
else if (pixel_position.y > output_resolution.y - 1) {
ret *= output_resolution.y - pixel_position.y;
}
return ret;
}