slang-shaders/retro/shaders/smootheststep.slang

62 lines
1.4 KiB
Plaintext
Raw Normal View History

2017-01-24 09:23:57 +11:00
#version 450
/*
Fragment shader based on "Improved texture interpolation" by I<>igo Qu<51>lez
Original description: http://www.iquilezles.org/www/articles/texture/texture.htm
*/
layout(push_constant) uniform Push
{
vec4 SourceSize;
vec4 OriginalSize;
vec4 OutputSize;
uint FrameCount;
} params;
layout(std140, set = 0, binding = 0) uniform UBO
{
mat4 MVP;
} global;
#pragma stage vertex
layout(location = 0) in vec4 Position;
layout(location = 1) in vec2 TexCoord;
layout(location = 0) out vec2 vTexCoord;
void main()
{
gl_Position = global.MVP * Position;
vTexCoord = TexCoord;
}
#pragma stage fragment
layout(location = 0) in vec2 vTexCoord;
layout(location = 0) out vec4 FragColor;
layout(set = 0, binding = 2) uniform sampler2D Source;
void main()
{
vec2 p = vTexCoord.xy;
p = p * params.SourceSize.xy + vec2(0.5, 0.5);
vec2 i = floor(p);
vec2 f = p - i;
// Smoothstep - amazingly, smoothstep() is slower than calculating directly the expression!
// f = smoothstep(0.0, 1.0, f);
// f = f * f * ( -2.0 * f + 3.0);
// Quilez - This is sharper than smoothstep.
//f = f * f * f * (f * (f * 6.0 - vec2(15.0, 15.0)) + vec2(10.0, 10.0));
// smootheststep - This is even sharper than Quilez!
f = f * f * f * f * (f * (f * (-20.0 * f + vec2(70.0, 70.0)) - vec2(84.0, 84.0)) + vec2(35.0, 35.0));
p = i + f;
p = (p - vec2(0.5, 0.5)) * params.SourceSize.zw;
// final sum and weight normalization
FragColor = vec4(texture(Source, p).rgb, 1.0);
}