add cmyk-halftone-dot shader and preset

misc/cmyk-halftone-dot.glsl

@@ -0,0 +1,146 @@
+/*
+CMYK Halftone Dot Shader
+
+Adapted from Stefan Gustavson's GLSL shader demo for WebGL:
+http://webstaff.itn.liu.se/~stegu/OpenGLinsights/shadertutorial.html
+
+Ported to RetroArch by hunterk
+
+This shader is licensed in the public domain, as per S. Gustavson's original license.
+Note: the MIT-licensed noise functions have been purposely removed.
+*/
+
+#pragma parameter frequency "CMYK HalfTone Dot Density" 225.0 25.0 700.0 25.0
+#define mul(a,b) (b*a)
+
+#if defined(VERTEX)
+
+#if __VERSION__ >= 130
+#define COMPAT_VARYING out
+#define COMPAT_ATTRIBUTE in
+#define COMPAT_TEXTURE texture
+#else
+#define COMPAT_VARYING varying 
+#define COMPAT_ATTRIBUTE attribute 
+#define COMPAT_TEXTURE texture2D
+#endif
+
+#ifdef GL_ES
+#define COMPAT_PRECISION mediump
+#else
+#define COMPAT_PRECISION
+#endif
+
+COMPAT_ATTRIBUTE vec4 VertexCoord;
+COMPAT_ATTRIBUTE vec4 COLOR;
+COMPAT_ATTRIBUTE vec4 TexCoord;
+COMPAT_VARYING vec4 COL0;
+COMPAT_VARYING vec4 TEX0;
+
+vec4 _oPosition1; 
+uniform mat4 MVPMatrix;
+uniform COMPAT_PRECISION int FrameDirection;
+uniform COMPAT_PRECISION int FrameCount;
+uniform COMPAT_PRECISION vec2 OutputSize;
+uniform COMPAT_PRECISION vec2 TextureSize;
+uniform COMPAT_PRECISION vec2 InputSize;
+
+// compatibility #defines
+#define vTexCoord TEX0.xy
+#define SourceSize vec4(TextureSize, 1.0 / TextureSize) //either TextureSize or InputSize
+#define OutSize vec4(OutputSize, 1.0 / OutputSize)
+
+void main()
+{
+    gl_Position = MVPMatrix * VertexCoord;
+    TEX0.xy = TexCoord.xy;
+}
+
+#elif defined(FRAGMENT)
+
+#if __VERSION__ >= 130
+#define COMPAT_VARYING in
+#define COMPAT_TEXTURE texture
+out vec4 FragColor;
+#else
+#define COMPAT_VARYING varying
+#define FragColor gl_FragColor
+#define COMPAT_TEXTURE texture2D
+#endif
+
+#ifdef GL_ES
+#ifdef GL_FRAGMENT_PRECISION_HIGH
+precision highp float;
+#else
+precision mediump float;
+#endif
+#define COMPAT_PRECISION mediump
+#else
+#define COMPAT_PRECISION
+#endif
+
+uniform COMPAT_PRECISION int FrameDirection;
+uniform COMPAT_PRECISION int FrameCount;
+uniform COMPAT_PRECISION vec2 OutputSize;
+uniform COMPAT_PRECISION vec2 TextureSize;
+uniform COMPAT_PRECISION vec2 InputSize;
+uniform sampler2D Texture;
+COMPAT_VARYING vec4 TEX0;
+
+// compatibility #defines
+#define Source Texture
+#define vTexCoord TEX0.xy
+#define texture(c, d) COMPAT_TEXTURE(c, d)
+#define SourceSize vec4(TextureSize, 1.0 / TextureSize) //either TextureSize or InputSize
+#define OutSize vec4(OutputSize, 1.0 / OutputSize)
+
+#ifdef PARAMETER_UNIFORM
+uniform float frequency;
+#else
+#define frequency 550.0 // controls the density of the dot pattern
+#endif
+
+void main()
+{
+	// Distance to nearest point in a grid of
+	// (frequency x frequency) points over the unit square
+	mat2 rotation_matrix = mat2(0.707, 0.707, -0.707, 0.707);
+	vec2 st2 = mul(rotation_matrix , vTexCoord);
+	vec2 nearest = 2.0 * fract(frequency * st2) - 1.0;
+	float dist = length(nearest);
+	vec3 texcolor = texture(Source, vTexCoord).rgb; // Unrotated coords
+	vec3 black = texcolor; // kinda cheating, but it makes the colors look much better
+
+	// Perform a rough RGB-to-CMYK conversion
+	vec4 cmyk;
+	cmyk.xyz = 1.0 - texcolor;
+	cmyk.w = min(cmyk.x, min(cmyk.y, cmyk.z)); // Create K
+
+	mat2 k_matrix = mat2(0.707, 0.707, -0.707, 0.707);
+	vec2 Kst = frequency * (TextureSize / InputSize) * mul(k_matrix , vTexCoord);
+	vec2 Kuv = 2.0 * fract(Kst) - 1.0;
+	float k = step(0.0, sqrt(cmyk.w) - length(Kuv));
+	mat2 c_matrix = mat2(0.966, 0.259, -0.259, 0.966);
+	vec2 Cst = frequency * (TextureSize / InputSize) * mul(c_matrix , vTexCoord);
+	vec2 Cuv = 2.0 * fract(Cst) - 1.0;
+	float c = step(0.0, sqrt(cmyk.x) - length(Cuv));
+	mat2 m_matrix = mat2(0.966, -0.259, 0.259, 0.966);
+	vec2 Mst = frequency * (TextureSize / InputSize) * mul(m_matrix , vTexCoord);
+	vec2 Muv = 2.0 * fract(Mst) - 1.0;
+	float m = step(0.0, sqrt(cmyk.y) - length(Muv));
+	vec2 Yst = frequency * (TextureSize / InputSize) * vTexCoord; // 0 deg
+	vec2 Yuv = 2.0 * fract(Yst) - 1.0;
+	float y = step(0.0, sqrt(cmyk.z) - length(Yuv));
+
+	vec3 rgbscreen = 1.0 - vec3(c,m,y);
+	rgbscreen = mix(rgbscreen, black, k);
+
+	float afwidth = 2.0 * frequency * length(OutSize.zw);
+	float blend = smoothstep(0.0, 1.0, afwidth);
+	
+	vec4 color = vec4(mix(rgbscreen , texcolor, blend), 1.0);
+	color = (max(texcolor.r, max(texcolor.g, texcolor.b)) < 0.01) ? vec4(0.,0.,0.,0.) : color; // make blacks actually black
+
+	FragColor = color;
+} 
+#endif

reshade/halftone-print.glslp

@@ -0,0 +1,10 @@
+shaders = 2
+
+shader0 = shaders/LUT/LUT.glsl
+shader1 = ../misc/cmyk-halftone-dot.glsl
+filter_linear1 = true
+
+textures = SamplerLUT
+
+SamplerLUT = shaders/LUT/cmyk-16.png
+SamplerLUT_linear = true