Add transitions (#33)

data/examples/fade-transition.shader

@@ -0,0 +1,20 @@
+uniform texture2d image_a;
+uniform texture2d image_b;
+uniform float transition_time<
+    string label = "Transittion Time";
+    string widget_type = "slider";
+    float minimum = 0.0;
+    float maximum = 1.0;
+    float step = 0.001;
+> = 0.5;
+uniform bool convert_linear = true;
+
+float4 mainImage(VertData v_in) : TARGET
+{
+    float4 a_val = image_a.Sample(textureSampler, v_in.uv);
+	float4 b_val = image_b.Sample(textureSampler, v_in.uv);
+	float4 rgba = lerp(a_val, b_val, transition_time);
+    if(convert_linear)
+        rgba.rgb = srgb_nonlinear_to_linear(rgba.rgb);
+	return rgba;
+}

data/examples/pixelation-transition.shader

@@ -0,0 +1,52 @@
+uniform float transition_time<
+    string label = "Transittion Time";
+    string widget_type = "slider";
+    float minimum = 0.0;
+    float maximum = 1.0;
+    float step = 0.001;
+> = 0.5;
+uniform bool convert_linear = true;
+uniform float power<
+    string label = "Power";
+    string widget_type = "slider";
+    float minimum = 0.5;
+    float maximum = 8.0;
+    float step = 0.01;
+> = 3.0;
+uniform float center_x<
+    string label = "X";
+    string widget_type = "slider";
+	string group = "Center";
+    float minimum = 0.0;
+    float maximum = 1.0;
+    float step = 0.001;
+> = 0.5;
+uniform float center_y<
+    string label = "Y";
+    string widget_type = "slider";
+	string group = "Center";
+    float minimum = 0.0;
+    float maximum = 1.0;
+    float step = 0.001;
+> = 0.5;
+
+float4 mainImage(VertData v_in) : TARGET
+{
+	//1..0..1
+	float scale = abs(transition_time - 0.5) * 2.0;
+	scale = pow(scale, power);
+
+	float2 uv = v_in.uv;
+	uv -= float2(center_x, center_y);
+	uv *= uv_size;
+	uv *= scale;
+	uv = floor(uv);
+	uv /= scale;
+	uv /= uv_size;
+	uv += float2(center_x, center_y);
+	uv = clamp(uv, 1.0/uv_size, 1.0);
+	float4 rgba = image.Sample(textureSampler, uv);
+	if(convert_linear)
+        rgba.rgb = srgb_nonlinear_to_linear(rgba.rgb);
+	return rgba;
+}