Update/merge examples back into main repo (#192)

Examples/resources/shaders/glsl120/cross_stitching.fs

@@ -0,0 +1,55 @@
+# version 120
+
+// Input vertex attributes (from vertex shader)
+varying vec2 fragTexCoord;
+varying vec4 fragColor;
+
+// Input uniform values
+uniform sampler2D texture0;
+uniform vec4 colDiffuse;
+
+// NOTE: Add here your custom variables
+
+// NOTE: Render size values must be passed from code
+const float renderWidth = 800.0;
+const float renderHeight = 450.0;
+
+float stitchingSize = 6.0;
+int invert = 0;
+
+vec4 PostFX(sampler2D tex, vec2 uv)
+{
+    vec4 c = vec4(0.0);
+    float size = stitchingSize;
+    vec2 cPos = uv * vec2(renderWidth, renderHeight);
+    vec2 tlPos = floor(cPos / vec2(size, size));
+    tlPos *= size;
+
+    int remX = int(mod(cPos.x, size));
+    int remY = int(mod(cPos.y, size));
+
+    if (remX == 0 && remY == 0) tlPos = cPos;
+
+    vec2 blPos = tlPos;
+    blPos.y += (size - 1.0);
+
+    if ((remX == remY) || (((int(cPos.x) - int(blPos.x)) == (int(blPos.y) - int(cPos.y)))))
+    {
+        if (invert == 1) c = vec4(0.2, 0.15, 0.05, 1.0);
+        else c = texture2D(tex, tlPos * vec2(1.0/renderWidth, 1.0/renderHeight)) * 1.4;
+    }
+    else
+    {
+        if (invert == 1) c = texture2D(tex, tlPos * vec2(1.0/renderWidth, 1.0/renderHeight)) * 1.4;
+        else c = vec4(0.0, 0.0, 0.0, 1.0);
+    }
+
+    return c;
+}
+
+void main()
+{
+    vec3 tc = PostFX(texture0, fragTexCoord).rgb;
+
+    gl_FragColor = vec4(tc, 1.0);
+}