Visual C++: Good way to draw and animated fill path to screen? - winapi

Question

I want to use Visual C++ to animate fill paths to screen. I have done it with C# before, but now switch to C++ for better perfomance and want do more complex works in the future.
Here is the concept in C#:
In a Canvas I have a number of Path. These paths are closed geometries combine of LineTo and QuadraticBezierTo functions.
Firstly, I fill Silver color for all path.
Then for each path, I fill Green color from one end to other end (up/down/left/right direction) (imagine a progress bar increase its value from min to max). I do it by set the Fill brush of the path to a LinearGradientBrush with two color Green and Silver with same offset, then increase the offset from 0 to 1 by Timer.
When a path is fully green, continue with next path.
When all path is fill with Green, come back first step.
I want to do same thing in Visual C++. I need to know an effective way to:
Create and store paths in a collection to reuse. Because the path is quite lot of point, recreate them repeatly take lots of CPU usage.
Draw all paths to a window.
Do animation fill like step 2, 3, 4 in above concept.
So, what I need is:
A suitable way to create and store closed paths. Note: paths are combine of points connect by functions same with C# LineTo and QuadraticBezierTo function.
Draw and animated fill the paths to screen.
Can you please suggest one way to do above step? (outline what I have to read, then I can study about it myself). I know basic of Visual C++, Win32 GUI and a little about draw context (HDC) and GDI, but only start to learn Graphic/Drawing.
Sorry about my English! If anythings I explain dont clear, please let me know.

Answer 1

how many is quite lot of point ? what is the target framerate? for low enough counts you can use GDI for this otherwise you need HW acceleration like OpenGL,DirectX.
I assume 2D so You need:
store your path as list of segments
for example like this:
struct path_segment
{
int p0[2],p1[2],p2[2]; // points
int type; // line/bezier
float length; // length in pixels or whatever
};
const int MAX=1024; // max number of segments
path_segment path[MAX]; // list of segments can use any template like List<path_segment> path; instead
int paths=0; // actual number of segments;
float length=0.0; // while path length in pixels or whatever
write functions to load and render path[]
The render is just for visual check if you load is OK ... for now atlest
rewrite the render so
it take float t=<0,1> as input parameter which will render path below t with one color and the rest with other. something like this:
int i;
float l=0.0,q,l0=t*length; // separation length;
for (i=0;i<paths;i++)
{
q=l+path[i].length;
if (q>=l0)
{
// split/render path[i] to < 0,l-l0> with color1
// split/render path[i] to <l-l0,q-l0> with color2
// if you need split parameter in <0,1> then =(l-l0)/path[i].length;
i++; break;
}
else
{
//render path[i] with color1
}
l=q;
}
for (;i<paths;i++)
{
//render path[i] with color2
}
use backbuffer for speedup
so render whole path with color1 to some bitmap. On each animation step just render the newly added color1 stuff. And on each redraw just copy the bitmap to screen instead of rendering the same geometry over and over. Of coarse if you have zoom/pan/resize capabilities you need to redraw the bitmap fully on each of those changes ...