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Entries for tag "rendering", ordered from most recent. Entry count: 187.
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# DXGI Format Cheatsheet
Thu
29
Apr 2010
Today I've prepared another small, single page cheat sheet related to DirectX 11:
DXGI_Format_Cheatsheet.pdf
DXGI_Format_Cheatsheet.odt
I've also solved my problem with Visual C++ 2010 Express that crashed every compilation on my computer. I've submitted this bug to Microsoft Connect, expecting that it may be because I have a 64-bit Windows 7 or because I also have Visual Studio 2008 Professional installed. But with the help from Microsoft I've figured out that it was just because of the AMD CodeAnalyst profiler. Uninstalling this program helped me so my VC2010 doesn't crash any more :D
Comments | #visual studio #directx #rendering Share
# My First Triangle in DirectX 11
Tue
27
Apr 2010
Now as I have my new graphics card I've started learning Direct3D 11. I've been doing much coding in DirectX 9 before. I also looked at the DirectX 10 API but gained not much practical experience in it. I'm very excited about how the new API looks like and the possibilities it creates. The library interface looks better organized, more object-oriented and clear. It makes extensive use of descriptors - same concept I liked so much in PhysX.
But at the same time I must admit it's more difficult to get started than it was in DirectX 9. You have to create more objects to setup basic framework that could render anything. The so called Fixed Function Pipeline doesn't exist anymore, so you HAVE to write shaders to render anything. Better organization of all data forces you to pass shader constants in buffers instead one-by-one, fill descriptors, create and use state objects (like ID3D11DepthStencilState) instead of changing render states one-by-one, create views for resources (like ID3D11ShaderResourceView for ID3D11Texture2D) instead of using them directly, compile shaders from HLSL source to bytecode and then create the shader object with separate call etc.
There are also big changes in math support. They didn't provide new D3DX Math with DX11. You can still use the old one, but now it's recommended to make use of new, portable (to Xbox 360) and highly optimized XNA Math library. It's pretty but can be difficult for beginners. For example, now there is one universal type - XMVECTOR - that can represent a vector, color, plane, quaternion and more. It must be always aligned to 16 bytes (because it uses SSE). I suppose it's not easy to understand concepts like vector loading, storing or swizzling, which can be new for many DirectX programmers.
Where do learn DirectX 11 from? It looks like there are not many valuable sources online yet. The directx11tutorials.com website looks interesting, but it's just a blog with few pieces of code and the author tries to wrap everything into his own classes from the start, which makes no sense for me. The most valuable source of knowledge is the original documentation installed with DX SDK. It's far from being extensive because the chapter about DirectX 11 describes only new features, not everything about using DirectX like the documentation for version 9, but for somebody who already knows some graphics programming it should be OK.
What I want to show today is my first "Hello World" triangle made in Direct3D 11 and code that renders it. You can download whole source with project for Visual C++ 2008 from here: Dx11Test.zip. See also the code online: Dx11Test.cpp.
To code in DX11, you just need DirectX SDK - same as for DirectX 9 and 10, because it contains SDK for all of them. Programs that use DirectX 11 can run on Windows 7 as well as Vista, but not on XP. It's surprising that newest-generation graphics card is not needed - you can use DX11 API to code in different "feature levels" from D3D_FEATURE_LEVEL_9_1 to D3D_FEATURE_LEVEL_11_0, so you can write your code so it will run even on GPUs that support only Shader Model 2!
Comments | #directx #rendering Share
# ActionScript 3 Standard Library Primer
Thu
08
Apr 2010
I've recently blogged about the syntax of ActionScript 3 language. Today I'd like to present what I've learned about the Flash standard library, especially in terms of displaying graphics. The official documentation to this is avaiable as ActionScript 3.0 Language and Components Reference (offline version for download - multipage HTML packed in ZIP).
Main package for graphics-related classes is flash.graphics. When programming in Flash, you do not redraw whole screen every frame like you do in DirectX or OpenGL. Instead you create a persistent hierarchy of objects, change their parameters and they are automatically drawn and updated. Base class of all objects that can be placed in this hierarchy is flash.graphics.DisplayObject and the class that can have children (the composite design pattern appears here) is DisplayObjectContainer. DisplayObjectContainer has methods such as addChild or removeChild to manage subobject.
For example, knowing that Sprite class that is the base class of our Main class inherits from DisplayObjectContainer and the TextField class we use here inherits from DisplayObject, the simplest Flash application that shows anything may look like below. The display object hierarchy here is: main object of the Main class with the tf object of TextField class inside, added as a child.
Comments | #flash #rendering Share
# Coloring of Fractal Flame
Wed
23
Dec 2009
My next step in Fractal Flames rendering was to enhance the way I give colors to pixels on the final texture. As positions of the points iterated through the function system are discretized to a 3D matrix, but before it's processed into the final texture, I've introduced a choice of matrix format (inspired by texture formats in DirectX).
The simplest one is MATRIX_FORMAT_DENSITY, as it has only one component per cell - a density, equal to number of points that hit this particular cell. No coloring is done here, so each pixel is just white and there is only density influencing its brightness through tone mapping.
Second format is MATRIX_FORMAT_COLOR_DENSITY. It works similar to what is described in The Fractal Flame Algorithm paper. Each processed point carries a "color" with it, but this "color" is just a scalar value in range 0..1. Every possible transform (transforms are chosen in random manner according to their probabilities) pushes the color towards its "desired" value, defined for each transform. Current point color is added to the matrix cell so that final color is an average of colors of all points that hit this cell.
To visualize this scalar "color", it's nice to process it through some lookup table, gradient, palette or however you call it. I seems easy to generate or hardcode one, but I prefer to rely on existing gradients prepared by more talented people, so I've implemented reading of two gradient formats so far: gradient from a single-row texture or from a "cmap.UGR" file shipped with Apophysis (nice, free Windows application that render fractal flames according to the paper mentioned above). I'm also planning to support "ggr" files with gradients from GIMP, but it's far more sophisticated and powerful format.
And finally there is the third way of coloring fractal flames that seems most intuitive to me - MATRIX_FORMAT_RGB_DENSITY. Here, full three color components are carried with points and saved to the matrix. Each transform pushes the point color towards its own "desired" RGB value. Thanks to this, each transform influences not only shape, but also color of the fractal in direct and observable way (like the scaling transform here, that shrinks points to the center, which is red).
Comments | #math #fractals #rendering Share
# I Render Fractal Flames
Sun
20
Dec 2009
Continuing my learning/research of fractals, today I've finally managed to render something that looks like Fractal Flame. AFAIK the most important paper on this subject is The Fractal Flame Algorithm by Scott Draves and Erik Reckase. According to this document, I've first added to my program the ability to use colors, so each point, as it has the position iteratively processed by some functions, also carries current color. Now I am able to render colourful IFS fractals:
Implementing logarithmic tone mapping and gamma correction significantly improved quality. Colors can help visualising internal structure of a fractal:
Next I've coded (almost) all functions mentioned in this paper, so now not only affine transforms are possible in my program. This allows me to mix traditional fractals with new functionality:
And finally to render something that looks like famous Fractal Flames. But it's not easy to achieve this. Modifying numeric parameters in a text file is not convenient, and even if I had an editor with real-time preview, it's not obvious what parameters give what results and whether they will degenerate to something like a single point. There are simply too many degrees of freedom :) If we had a continuous function Beauty(Params), we could use some optimization algorithms to find and render its local extrema :) Anyway, here are my first renders (more in Fractal Flames Gallery).
Comments | #rendering #math #fractals Share
# Further Experiments with Fractals
Sun
13
Dec 2009
Today I woke up with an idea of inventing my own simple IFS fractal with four pieces sheared or rotated to form a hole in the center. I must admin that effects are not impressive :) What I've learned is that it's difficult to imagine how overall fractal will generally look like when you design affine transforms for a single step that will be processed recursively. But anyway I'll show my results, with single step on the left and final render on the right:
Shear transform which unexpectedly formed round shapes:
Rotation transform with boundaries exceeding -1..1 range:
Rotation transform bound in range (-1..1, -1..1):
Comments | #math #rendering #fractals Share
# Rendering Mandelbrot and Julia Fractal
Thu
10
Dec 2009
I've been playing recently with Mandelbrot and Julia sets. These are fractals rendered in the completely different way that my last experiments with IFS (Iterated Function Systems). In IFS I had a set of points with given (x,y) positions and I've been transforming their positions iteratively by some functions before I rendered them. I'll blog more about IFS another time. Rendering Mandelbrot and Julia fractals is more like writing a pixel shader - for every pixel on the screen with its (x,y) coordinates we do some computations to calculate final color. I didn't extend my framework to render such things yet, but instead I've been doing my experiments in EvalDraw (where I can freely pan and zoom the view) and AMD RenderMonkey (where I can write pixel shaders executed on GPU).
Complex Numbers for Game Developers :) Fractal is a mathematical concept and so there is lots of hardcore math involved in the foundation of these beautiful objects. But fortunately we don't have to understand all that stuff to be able to render them. Mandelbrot and Julia fractals are created using complex numbers, but for us they can be thought of just as float2/D3DXVECTOR2 2-component (x,y) vectors with some operations defined:
That's actually all we need to render Mandelbrot and Julia fractals. The general formula for both of them is: z = z^2 + c where z and c are complex numbers, c is a constant and z is recalculated many times through this function. It was a mystery for me for a long time how to apply this formula. Now it turned out that when we calculate it many times for each pixel with staring z_start = (0, 0) and c dependant on pixel position in range (-2..2, -2..2) and draw all the pixels for which z is bounded and do not go to infinity, we get the shape of the Mandelbrot fractal. Of course we are not going to iterate this function inifinite times in our computers like mathematicians do in their heads, so instead we do it several times and treat all pixels for which length(z_final) < 2 as being "inside" the shape. Here is a draft made in EvalDraw. Unfortunately we meet some limitations of floating point numbers here, like limited precision and infinites and that's why the space outside is white.
To render Julia set we do something similar, but this time we use pixel position as starting z and set c to some constant, like (-0.1, 0.7). Different constants make different images.
A question arises about how to render a fractal - how to map a complex number to pixel color? The algorithm I like the most is called Escape Time Algorith and it goes like this: recalculate z for several iterations, but only while the length of z=(x,y) vector is less than 2 (that is zx*zx + zy*zy < 2*2). If the loop reached the iteration count limit, this pixel is inside the fractal - draw in in black. If not, then color of this pixel depends on number of iterations done.
Here are my implementations of these fractals in EvalDraw and RenderMonkey. They are very simple so the whole source code is visible on the screenshots. You can also download the code here: Fractals_for_RenderMonkey.rfx, Mandelbrot_for_EvalDraw_1.kc, Julia_for_EvalDraw_1.kc, Multibrot_for_EvalDraw_1.kc. You can find more screenshots in my fractals gallery.
Some variations of these fractals have also been discovered. For example when we do absolute value of z components before every iteration in Mandelbrot fractal, we get an interesting shape called Burning Ship.
Alternatively, if we raise z to any real power instead of 2, we make Mandelbrot fractal "unfolding", having more and more "bulbs" as the exponent grows. It is called Multibrot set. Raising a complex number to power with any real exponent is a little bit more complicated, as it has to use polar form (HLSL-like pseudocode here):
float2 ComplexPow(float2 v, float n)
{
float len = sqrt(x*x + y*y); // Standard 2D vector length
float n_fi = n * atan2(y, x);
return pow(len, n) * float2( cos(n_fi), sin(n_fi) ); // scalar * vector
}
Comments | #rendering #math #fractals Share
# New Fractal Renders
Sun
06
Dec 2009
Continuing playing with fractals, I've improved my experiment framework so now I can render any IFS (Iterated Function System) fractals described by a set of affine transformations with subpixel quality. Here are my today renders (these with colors are processed with GIMP). You can find more in my Gallery / Fractals.
Where do I get information from? There is a great website with ready formulas for each of these fractals: Classic Iterated Function Systems by Larry Riddle from Agnes Scott College.