I am making a 2D game in C++ with OpenGL where a maze is generated and you have to move the character through the maze and get it to the end. I have achieved all this, but now I want to make it more challenging by having everything pitch-black but a small light around the character. How can I achieve this? I don't want the light to be complicated and I don't want it to only go through the tunnels. I just want a simple light around the character to illuminate that area of the maze.
So, I'm working with OpenGL (I'm not exactly sure of the version), and I want to do an old-style lighting setup by essentially drawing a black rectangle over the screen, and drawing white circles over the areas that should be lit. I already have the rectangle and the circles, but I can't figure out how to make it so that the white circles are transparent when applied to the black areas. Any ideas? I tried to use blending modes, but it still evades me...  EDIT: Here's the code that I'm using (Python).  view_buf = Buffer(GL_INT, 4) glGetIntegerv(GL_VIEWPORT, view_buf) view = view_buf.to_list() if hasattr(view_buf, "to_list") else view_buf.list  glDisable(GL_DEPTH_TEST)  glDisable(GL_LIGHTING)  glEnable(GL_BLEND)  if logic.lights['smooth']:     glEnable(GL_LINE_SMOOTH)  # # Make sure we're using smooth shading instead of flat # glShadeModel(GL_SMOOTH)  # Setup the matrices  glMatrixMode(GL_PROJECTION) glPushMatrix() glLoadIdentity() gluOrtho2D(0, view[2], 0, view[3]) glMatrixMode(GL_MODELVIEW) glPushMatrix() glLoadIdentity()  #glAlphaFunc(GL_GREATER, 0.5)  glColor4f(0.0, 0, 0, 0.75)  glBegin(GL_QUADS);                              # Draw Black screen glVertex2d(0.0, 0.0); glVertex2d(view[2], 0.0); glVertex2d(view[2], view[3]); glVertex2d(0.0, view[3]); glEnd()  glColor4f(1, 1, 1, 1)  degtorad = 3.14159/180.0   glBlendFunc(GL_ZERO, GL_SRC_ALPHA)  def DrawCircle(x, y, radius, fill = 1, step = 11):      glVertex2f(x, y)      if fill:         glBegin(GL_TRIANGLE_FAN)     else:         glBegin(GL_LINE_LOOP)      for a in range(0, 360, step):         angle = degtorad * a         glVertex2f(x + (sin(angle) * radius), y + (cos(angle) * radius))      glEnd()   #for layer in range(len(logic.lights['layers'])): #   size =  for light in logic.lights['points']:     DrawCircle(light[0][0] * view[2], (1 - light[0][1]) * view[3], light[1], step = light[2])     if logic.lights['smooth']:         DrawCircle(light[0][0] * view[2], (1 - light[0][1]) * view[3], light[1], 0, light[2])  # Reset the state glPopMatrix() glMatrixMode(GL_PROJECTION) glPopMatrix()
What is the difference between an SLR and a DSLR? What are the differences between SLRs and DSLRs? (I know that DSLRs are Digital SLRs but are there any actual differences?)  Also, what are the advantages/disadvantages of both? Anonymous questions and Avatars Some Stack Exchange sites allow to ask an anonymous question by specifying a one-time user name and an email which is "required, but never shown". However the Gravatar attached to the email is shown anyway. Anonymous users do not want their picture to appear - someone can find their identity via google image search or someone that knows them.  Example: open incognito window and : Rules of thumb for divisibility Given a number presented in decimal form $n=\sum_{k=0} d_k10^k$ there are some nice thumb rules to decide whether it is divisible with a prime number  $p\in\{7,11,13,17,19,23,29\}$.   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We're not bothered about what's in there and what will be lost, we just want the continuous password prompts to go away. In how many ways can a number be expressed as a sum of consecutive numbers? Can a probability distribution value exceeding 1 be OK? On the , there is this line:      $p(\mathrm{height}|\mathrm{male}) = 1.5789$ (A probability distribution over 1 is OK. It is the area under the bell curve that is equal to 1.)    How can a value $&gt;1$ be OK? I thought all probability values were expressed in the range $0 \leq p \leq 1$. Furthermore, given that it is possible to have such a value, how is that value obtained in the example shown on the page? Regular Expression to match valid dates If $f:\mathbb R \to \mathbb R$ satisfies $f'(x) <L$ for some $L<1$, then $f$ has a unique fixed point Word for a person who continually tries to teach you when it's not necessary I've experienced this way too many times, and the best example I can give is a person who treats you like you have no idea how to do X and who keeps teaching you how to do it. I feel handicapped. Take for example how to play a card game. You know how to play the game because you've played it 5 times. However, there is a person always insists on explaining the game to you - like you are always new to the game - when you don't actually need any help and you just want to think for yourself. Another example situation is doing a repetitive task which you already have experience with, and yet the person continually tries to 'teach' you when you don't need help/already know how to do it. It almost makes you mad because you really don't need help. 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US doctor working in Tripoli wants me to open online account Can the Universe be deterministic and still allow free will? Possible Duplicate:             As asked in the title, can a Universe which is deterministic at its fundamental level still allow free will? If there is a unique left identity, then it is also a right identity Let $(R,+,\cdot)$ be a ring, and $e \in R$ be an element such that $ea=a$ for all $a\in R$. I'm trying to prove that if $e$ is unique with this property, then $ae=a$ for all $a\in R $.  So far I have $e^2 = e$ (using uniqueness), but I am stuck. I saw a proof of this fact for groups which used the existence of inverses, which we don't have here. I wonder if the result is really true here. Can someone help? Thanks. A word to describe "work that is ready to be done" How to align multiple subfigures in a grid? I have three images and I want to align them in the way that one image is above the other two. Here's an example:    How can I achieve this? For my other figures I use the subcaption package, but I am not able to align the pictures that way with it.    Thanks for all your replys! The answer that is working for me is the one supposed by karlkoeller:  \documentclass{article} \usepackage{graphicx} \usepackage{subcaption}  \begin{document}  \begin{figure} \centering \begin{subfigure}[b]{.45\linewidth} \includegraphics[width=\linewidth]{example-image-a} \caption{A mouse}\label{fig:mouse} \end{subfigure}  \begin{subfigure}[b]{.45\linewidth} \includegraphics[width=\linewidth]{example-image-b} \caption{A gull}\label{fig:gull} \end{subfigure} \begin{subfigure}[b]{.45\linewidth} \includegraphics[width=\linewidth]{example-image-c} \caption{A tiger}\label{fig:tiger} \end{subfigure} \caption{Picture of animals} \label{fig:animals} \end{figure}  \end{document} get all page IDs from wp_list_pages In how many different ways can you split $10$ people into two groups of $5$ people?