fx: add fxaa post-process shader

vtm/resources/assets/shaders/post_fxaa.h

@@ -0,0 +1,116 @@
+precision mediump float;
+uniform vec2 u_pixel;
+attribute vec4 a_pos;
+varying vec2 tex_pos;
+
+void
+main()
+{
+  gl_Position = a_pos;
+  tex_pos = (a_pos.xy + 1.0) * 0.5;
+  //tex_pos.zw = tex_pos.xz - u_pixel * vec2 (0.5);
+}
+§
+precision mediump float;
+//uniform sampler2D m_Texture;
+//uniform vec2 g_Resolution;
+//uniform vec2 g_Resolution;
+uniform sampler2D u_texColor;
+uniform vec2 u_pixel;
+varying vec2 tex_pos;
+
+//uniform float m_VxOffset;
+//uniform float m_SpanMax;
+//uniform float m_ReduceMul;
+
+const vec2 m_SpanMax = vec2(2.5, 2.5);
+const float m_ReduceMul = 0.15;
+
+//varying vec2 texCoord;
+//varying vec4 pos;
+
+//#define FxaaTex(t, p) texture2D(t, p)
+//#define OffsetVec(a, b) vec2(a, b)
+//#define FxaaTexOff(t, p, o, r) texture2D(t, p + o * r)
+// Output of FxaaVertexShader interpolated across screen.
+// Input texture.
+// Constant {1.0/frameWidth, 1.0/frameHeight}.
+
+#define FXAA_REDUCE_MIN   (1.0/128.0)
+
+//float FxaaLuma(float3 rgb) {
+//  return rgb.g * (0.587/0.299) + rgb.b;
+//}
+
+vec4
+FxaaPixelShader(vec2 pos, sampler2D tex, vec2 pixel){
+
+  //#define FXAA_REDUCE_MUL   (1.0/8.0)
+  //#define FXAA_SPAN_MAX     8.0
+
+  vec3 rgbNW = texture2D(tex, pos + vec2(-1.0, -1.0) * pixel).xyz;
+//	vec3 rgbNE = FxaaTexOff(tex, pos.zw, OffsetVec(1,0), pixel.xy).xyz;
+//	vec3 rgbSW = FxaaTexOff(tex, pos.zw, OffsetVec(0,1), pixel.xy).xyz;
+//	vec3 rgbSE = FxaaTexOff(tex, pos.zw, OffsetVec(1,1), pixel.xy).xyz;
+
+  vec3 rgbNE = texture2D(tex, pos + vec2(1.0, -1.0) * pixel).xyz;
+  vec3 rgbSW = texture2D(tex, pos + vec2(-1.0, 1.0) * pixel).xyz;
+  vec3 rgbSE = texture2D(tex, pos + vec2(1.0, 1.0) * pixel).xyz;
+
+  vec3 rgbM = texture2D(tex, pos).xyz;
+
+  //return vec4(rgbM - (rgbNW + rgbNE)*0.25,1.0);
+
+  vec3 luma = vec3(0.299, 0.587, 0.114);
+  float lumaNW = dot(rgbNW, luma);
+  float lumaNE = dot(rgbNE, luma);
+  float lumaSW = dot(rgbSW, luma);
+  float lumaSE = dot(rgbSE, luma);
+  float lumaM = dot(rgbM, luma);
+
+  float lumaMin = min(lumaM, min(min(lumaNW, lumaNE), min(lumaSW, lumaSE)));
+  float lumaMax = max(lumaM, max(max(lumaNW, lumaNE), max(lumaSW, lumaSE)));
+
+  //vec4 rgb = texture2D (tex, pos);
+  //return vec4(0.5 + lumaM - lumaMin, lumaM, 0.5 + lumaM - lumaMax, 1.0) * rgb.a;
+
+  vec2 dir;
+  dir.x = -((lumaNW + lumaNE) - (lumaSW + lumaSE));
+  dir.y = ((lumaNW + lumaSW) - (lumaNE + lumaSE));
+
+  //return vec4(dir*0.5, 0.5, 1.0);
+
+  float dirReduce = max((lumaNW + lumaNE + lumaSW + lumaSE) * (0.25 * m_ReduceMul), FXAA_REDUCE_MIN);
+
+  float rcpDirMin = 1.0 / (dirReduce + min(abs(dir.x), abs(dir.y)));
+
+  dir = min(m_SpanMax, max(-m_SpanMax, dir * rcpDirMin)) * pixel;
+
+  vec4 rgbA = 0.5 * (texture2D(tex, pos + dir * vec2(1.0 / 3.0 - 0.5))
+                   + texture2D(tex, pos + dir * vec2(2.0 / 3.0 - 0.5)));
+
+  vec4 rgbB = rgbA * 0.5 + 0.25 * (texture2D(tex, pos + dir * vec2(0.0 / 3.0 - 0.5))
+                                 + texture2D(tex, pos + dir * vec2(3.0 / 3.0 - 0.5)));
+
+  float lumaB = dot(rgbB.xyz, luma.xyz);
+
+  float d = step(lumaB, lumaMin) + step(lumaMax, lumaB);
+
+  return (1.0 - d) * rgbB + d * rgbA;
+
+  //  if ((lumaB < lumaMin) || (lumaB > lumaMax))
+  //    { return rgbA; } else { return rgbB; }
+}
+
+void
+main(){
+  //vec2 rcpFrame = vec2(1.0) / g_Resolution;
+  //gl_FragColor = vec4(FxaaPixelShader(pos, m_Texture, rcpFrame), 1.0);
+  gl_FragColor = FxaaPixelShader(tex_pos, u_texColor, u_pixel * 3.15);
+  //gl_FragColor = FxaaPixelShader (tex_pos, u_texColor, u_pixel * 2.35);
+
+  //vec4 c = texture2D (u_texColor, tex_pos);
+  //gl_FragColor = vec4 (c.rgb * 0.5, 1.0) + vec4(FxaaPixelShader (tex_pos, u_texColor, u_pixel * 3.15).rgb - c.rgb, 1.0) * 2.0;
+
+  //gl_FragColor = 0.2*c + (FxaaPixelShader (tex_pos, u_texColor, u_pixel * 1.2)) * 0.8;
+}