shader-demo: change easing and adjust zoom location

src/shader/shader-demo.cpp

@@ -24,8 +24,8 @@ float alpha = 1.0f; //0.0-1.0
 //contrast boost
 int contrast_boost = 15; //0.0-255
 int max_iterations = 500;
-float center_x = -0.12;
-float center_y = 0.132;
+float center_x = -0.1196;
+float center_y = 0.1325;
 float zoom = 1.0;
 float zoom_add = 0.99;
 long iterations = 0;
@@ -247,6 +247,10 @@ void load_shader(){
     shader_program_hdl = init_shader(vert.c_str(),  frag.c_str(), "fragColor");
 }
 
+float easeInOutQuint(float x) {
+    return x < 0.5f ? 16.0f * x * x * x * x * x : 1.0f - std::pow(-2.0f * x + 2.0f, 5.0f) / 2.0f;
+}
+
 float easeInOutQubic(float x) {
     return x < 0.5f ? 4.0f * x * x * x : 1.0f - std::pow(-2.0f * x + 2.0f, 3.0f) / 2.0f;
 }
@@ -285,7 +289,7 @@ void render_scene(const cv::Size& sz) {
     glUniform1i(max_iterations_hdl, max_iterations);
     glUniform1f(center_y_hdl, center_y);
     glUniform1f(center_x_hdl, center_x);
-    glUniform1f(zoom_hdl, easeInOutSine(zoom+=zoom_add));
+    glUniform1f(zoom_hdl, easeInOutQuint(zoom+=zoom_add));
 
 #ifndef __EMSCRIPTEN__
     glBindVertexArray(VAO);