Add basic gamma corrected linear and cubic filters.

cubic/cubic-gamma-correct.slang

@@ -0,0 +1,84 @@
+#version 450
+
+layout(std140, set = 0, binding = 0) uniform UBO
+{
+   mat4 MVP;
+   vec4 OutputSize;
+   vec4 OriginalSize;
+   vec4 SourceSize;
+} 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 weights(out vec4 x, out vec4 y, vec2 t)
+{
+   vec2 t2 = t * t;
+   vec2 t3 = t2 * t;
+
+   vec4 xs = vec4(1.0, t.x, t2.x, t3.x);
+   vec4 ys = vec4(1.0, t.y, t2.y, t3.y);
+
+   const vec4 p0 = vec4(+0.0, -0.5, +1.0, -0.5);
+   const vec4 p1 = vec4(+1.0,  0.0, -2.5, +1.5);
+   const vec4 p2 = vec4(+0.0, +0.5, +2.0, -1.5);
+   const vec4 p3 = vec4(+0.0,  0.0, -0.5, +0.5);
+
+   x = vec4(dot(xs, p0), dot(xs, p1), dot(xs, p2), dot(xs, p3));
+   y = vec4(dot(ys, p0), dot(ys, p1), dot(ys, p2), dot(ys, p3));
+}
+
+void main()
+{
+   vec2 uv = vTexCoord * global.SourceSize.xy - 0.5;
+   vec2 texel = floor(uv);
+   vec2 tex = (texel + 0.5) * global.SourceSize.zw;
+   vec2 phase = uv - texel;
+
+#define TEX(x, y) textureLodOffset(Source, tex, 0.0, ivec2(x, y)).rgb
+
+   vec4 x;
+   vec4 y;
+   weights(x, y, phase);
+
+   vec3 color;
+   vec4 row = x * y.x;
+   color  = TEX(-1, -1) * row.x;
+   color += TEX(+0, -1) * row.y;
+   color += TEX(+1, -1) * row.z;
+   color += TEX(+2, -1) * row.w;
+
+   row = x * y.y;
+   color += TEX(-1, +0) * row.x;
+   color += TEX(+0, +0) * row.y;
+   color += TEX(+1, +0) * row.z;
+   color += TEX(+2, +0) * row.w;
+
+   row = x * y.z;
+   color += TEX(-1, +1) * row.x;
+   color += TEX(+0, +1) * row.y;
+   color += TEX(+1, +1) * row.z;
+   color += TEX(+2, +1) * row.w;
+
+   row = x * y.w;
+   color += TEX(-1, +2) * row.x;
+   color += TEX(+0, +2) * row.y;
+   color += TEX(+1, +2) * row.z;
+   color += TEX(+2, +2) * row.w;
+
+   color = sqrt(clamp(color, vec3(0.0), vec3(1.0)));
+   FragColor = vec4(color, 1.0);
+}

cubic/cubic-gamma-correct.slangp

@@ -0,0 +1,10 @@
+shaders = 2
+shader0 = linearize.slang
+shader1 = cubic-gamma-correct.slang
+
+filter_linear0 = false 
+scale_type0 = source
+scale0 = 1.0
+srgb_framebuffer0 = true
+
+filter_linear1 = false 

cubic/cubic.slang

@@ -0,0 +1,83 @@
+#version 450
+
+layout(std140, set = 0, binding = 0) uniform UBO
+{
+   mat4 MVP;
+   vec4 OutputSize;
+   vec4 OriginalSize;
+   vec4 SourceSize;
+} 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 weights(out vec4 x, out vec4 y, vec2 t)
+{
+   vec2 t2 = t * t;
+   vec2 t3 = t2 * t;
+
+   vec4 xs = vec4(1.0, t.x, t2.x, t3.x);
+   vec4 ys = vec4(1.0, t.y, t2.y, t3.y);
+
+   const vec4 p0 = vec4(+0.0, -0.5, +1.0, -0.5);
+   const vec4 p1 = vec4(+1.0,  0.0, -2.5, +1.5);
+   const vec4 p2 = vec4(+0.0, +0.5, +2.0, -1.5);
+   const vec4 p3 = vec4(+0.0,  0.0, -0.5, +0.5);
+
+   x = vec4(dot(xs, p0), dot(xs, p1), dot(xs, p2), dot(xs, p3));
+   y = vec4(dot(ys, p0), dot(ys, p1), dot(ys, p2), dot(ys, p3));
+}
+
+void main()
+{
+   vec2 uv = vTexCoord * global.SourceSize.xy - 0.5;
+   vec2 texel = floor(uv);
+   vec2 tex = (texel + 0.5) * global.SourceSize.zw;
+   vec2 phase = uv - texel;
+
+#define TEX(x, y) textureLodOffset(Source, tex, 0.0, ivec2(x, y)).rgb
+
+   vec4 x;
+   vec4 y;
+   weights(x, y, phase);
+
+   vec3 color;
+   vec4 row = x * y.x;
+   color  = TEX(-1, -1) * row.x;
+   color += TEX(+0, -1) * row.y;
+   color += TEX(+1, -1) * row.z;
+   color += TEX(+2, -1) * row.w;
+
+   row = x * y.y;
+   color += TEX(-1, +0) * row.x;
+   color += TEX(+0, +0) * row.y;
+   color += TEX(+1, +0) * row.z;
+   color += TEX(+2, +0) * row.w;
+
+   row = x * y.z;
+   color += TEX(-1, +1) * row.x;
+   color += TEX(+0, +1) * row.y;
+   color += TEX(+1, +1) * row.z;
+   color += TEX(+2, +1) * row.w;
+
+   row = x * y.w;
+   color += TEX(-1, +2) * row.x;
+   color += TEX(+0, +2) * row.y;
+   color += TEX(+1, +2) * row.z;
+   color += TEX(+2, +2) * row.w;
+
+   FragColor = vec4(color, 1.0);
+}

cubic/cubic.slangp

@@ -0,0 +1,3 @@
+shaders = 1
+shader0 = cubic.slang
+filter_linear0 = false 

cubic/linearize.slang

@@ -0,0 +1,32 @@
+#version 450
+
+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;
+
+vec3 gamma(vec3 v)
+{
+   return v * v;
+}
+
+void main()
+{
+   FragColor = vec4(gamma(texture(Source, vTexCoord).rgb), 1.0);
+}

linear/linear-gamma-correct.slang

@@ -0,0 +1,31 @@
+#version 450
+
+layout(std140, set = 0, binding = 0) uniform UBO
+{
+   mat4 MVP;
+   vec4 OutputSize;
+   vec4 OriginalSize;
+   vec4 SourceSize;
+} 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()
+{
+   vec3 color = texture(Source, vTexCoord).rgb;
+   FragColor = vec4(sqrt(color), 1.0);
+}

linear/linear-gamma-correct.slangp

@@ -0,0 +1,10 @@
+shaders = 2
+shader0 = linearize.slang
+shader1 = linear-gamma-correct.slang
+
+filter_linear0 = false 
+scale_type0 = source
+scale0 = 1.0
+srgb_framebuffer0 = true
+
+filter_linear1 = true

linear/linearize.slang

@@ -0,0 +1,32 @@
+#version 450
+
+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;
+
+vec3 gamma(vec3 v)
+{
+   return v * v;
+}
+
+void main()
+{
+   FragColor = vec4(gamma(texture(Source, vTexCoord).rgb), 1.0);
+}