I'm currently trying to learn ray-tracing in C++. I am getting help from two books: one is Ray Tracing from the Ground Up by Kevin Suffern, and the other one is Physically Based Rendering by Matt Pharr. These two books are great for learning basics and, later, advanced stuff.
I could create some basic shapes using user interface of Suffern's book. However when I tried to write all code on my own, things have gone wild. I realized that I don't even know how to open a window and fill pixels on that. Do you have any good resource to recommend that could teach me the basics of drawing in C++.
You could generate image files instead of drawing to windows. The PPM format is the simplest one to generate. Browsers usually can display PPM. Safari does.
If you want to generate PNG files use libpng.
SDL might work for you: http://www.libsdl.org/
You can allocate your own image buffer, write your pixels to it, and then save to file/draw to window as needed. I expect the Pharr book has its own version of this tucked away somewhere, courtesy of Literate Programming.
More concretely: GUI API's and image file format libraries will typically be able to read simple image buffer data, stored in row-major array order. I would recommend an RGBA pixel format, something like the following:
template<class T> class image_rgba {
unsigned m_rows, m_cols;
T *m_data;
public:
image_rgba(unsigned rows, unsigned columns)
: m_rows(rows)
, m_cols(columns)
, m_data(new T[rows*columns*4])
{}
~image_rgba() { delete[] m_data; }
typedef T pixel[4];
pixel index_pixel_ref(unsigned row, unsigned col) {
assert(row<m_rows && col<m_cols);
return m_data + (m_cols*row+col)*4;
}
}
(note that I have not tested the above -- best to treat it as pseudocode...)
Related
Recently,I am learning the SAT(summed area table) Varinance Shadow Mapping.It is suggested in the paper that I can use uint format SAT to prevent precision loss.So I change my SAT format from DXGI_FORMAT_R32G32_FLOAT to DXGI_FORMAT_R32G32_UINT.However, with the same code and shader except the texture format is different, the float format texture works fine, but the uint format texture always returns ZERO(I find this problem by using RenderDoc pixel debugger).This problem persists when I use Sample() method , Load() method and even compute shader!
I have tried many ways but nothing works.Please help me!!!!!!!!!
And I do not show any code here,because I have no idea about which part of code to show.
I am a Rookie just like my name.
So if you need some code,please tell me.Thanks a lot!!
If possible,please tell me some possible solutions of this problem. Thank you very much for your answers!
I'm currently creating a CCSprite like this:
CCSprite *s = [CCSprite spriteWithFile:#"image.png"];
This sprite is the background image of a CCLayer that's used relatively often. Is the following use of CCTextureCache more efficient?
CCTexture2D *t = [[CCTextureCache sharedTextureCache] addImage:#"image.png"];
CCSprite *s = [CCSprite spriteWithTexture:t];
No. Internally, all methods that use an image as a texture (not just CCSprite) will add the texture to the CCTextureCache.
The only reason why you would want to use addImage directly is when you want to pre-load certain textures so that the first appearance of a node using that texture won't cause a lag during gameplay.
First of all, if you look to the code of spriteWithFile: method, you will see that it adds image to the texture cache anyway if cannot find it there.
The second thing you must know, that if you store your art in atlases for reducing memory usage(for example, atlas 2048x2048 pixels with 20 different pictures), spriteWithTexture: will create sprite with whole huge atlas(2048x2048 pixels) texture.
I am in the process of learning LWJGL and also OpenGL. I have done the tutorials on quads, and also succesfully drawn polygons on a display. I am trying to draw lines using the same methods, but the lines are not created, or they are made invisible, possibly with a pixel width of 0? I have googled for an answer or a tutorial, but so far all of them seems to claim that I am doing the right thing. my method is as follows:
private void drawLine(Point point, Joint Point2) {
GL11.glColor3f(0.0f, 1.0f, 0.2f);
GL11.glBegin(GL11.GL_LINE);
GL11.glVertex2d(point.getX(), point.getY());
GL11.glVertex2d(point2.getX(), point2.getY());
GL11.glEnd();
}
I also tried to put this one in the middle, but no effect.
GL11.glLineWidth(3.8f);
As stated in the comments, The answer was that GL11.GL_LINE is not accepted as a constant in this case. GL11.LINE_STRIP however works like a charm.
I've already know how to dark-down a CCSprite object by:
sprite.color = ccc3(x, x, x); // x is a value less then 255
(As far as i know, it should be a direct mapping of openGL functions, so its easy to achieve.)
But when it comes to light-up, my current solution is adding another mask sprite (same shape but all in white), changing its blendFunc to { GL_SRC_ALPHA, GL_ONE } and overlaying it onto the target. Besides all the codes added, there should be a mask image for each need-to-light-up one.
Is there a way to do light-up as easily as dark-down?
However, not as easy as setColor, in Cocos2d 2.x, with OpenGL ES 2.0 support, you can achieve this by using custom shaders. You can get started here:
http://www.raywenderlich.com/10862/how-to-create-cool-effects-with-custom-shaders-in-opengl-es-2-0-and-cocos2d-2-x
You may also try inverting the sprite's darker color to get a lighter one.
I want to use DirectWrite for mixed-colour text formatting (syntax highlighting, to be precise), but can't seem to find a way to do it, either in the Layout or Typography options. The only option is passing a Brush when rendering the text, which doesn't work for me because I basically have just one Layout. Help!
Use IDWriteTextLayout::SetDrawingEffect to apply drawing effects on subranges. If you're using DWrite with D2D DrawTextLayout, which it sounds like you are, then that drawing effect would just be a brush (such as ID2D1Brush via CreateSolidColorBrush or one of the gradient brushes). If you have implemented your own IDWriteTextRenderer for IDWriteTextLayout::Draw, then the drawing effect can be whatever you interpret it to be. In the IDWriteTextRenderer::DrawGlyphRun callback, you then call QueryInterface on the drawingEffect parameter, or if you are certain it is your own type, just static_cast it directly.
// ... create the colored brushes and determine where to draw ...
wchar_t const* text = L"Red Green";
dwriteFactory->CreateTextLayout(....., OUT &textLayout);
DWRITE_TEXT_RANGE textRange1 = {0,3}, textRange2 = {4,5};
textLayout->SetDrawingEffect(redBrush, textRange1);
textLayout->SetDrawingEffect(greenBrush, textRange2);
renderer->DrawTextLayout(point, textLayout, defaultBrush);