presentation

presentation.md

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+# BlackPink (ND Manifold Raymarching Renderer)
+
+#### _"A Blazing 100x100px at 10FPS"_
+
+
+---
+
+(we had to name it that because Joel likes naming things after pop artists.)
+
+---
+
+# Objective
+
+Can we use raymarching to render primitive objects inside an arbitrary manifold
+in real time?
+
+"Non-euclidean rendering" in the most generalised form possible.
+
+---
+
+# Raymarching
+
+- an approximate and fast form of 'raytracing'
+- good for primitives (spheres, boxes et cetera.)
+- still very expensive
+
+---
+
+# Manifolds
+
+Only one of us does galaxy brain maths.
+
+---
+
+# Tech Stack Requirements
+
+- Fast, compiled code
+- We are relatively familiar with it (that disqualifies any _modern_ or "good"
+    language, and C++)
+- Need n-dimensional vectors
+- Need to draw pixels on a window
+- not Java
+
+---
+
+# C and libSDL2
+
+Its fast (to run) and we "know" it. C is a nice language if only for the 
+simplicity of its mental model. 
+
+libSDL2 is what the big kids like Valve use.
+
+- nicely handles threading, drawing, timers, and gets out of the way. 
+
+---
+
+Richal spent 10 hours writing a vector library from scratch.
+
+N-dimentional determinants and cross products _sound_ simple. 
+
+---
+
+At one point we were leaking memory at approximately 150Mb per second.
+
+![lots of vagrind errors](img/b1.jpg)
+
+---
+
+The first success was 1pm on saturday, where we got a circle drawn to the
+screen. 
+
+![circle](img/b3.png)
+
+---
+
+Fail states were often interesting. 
+
+![cool errors](img/b2.png)
+
+---
+
+# Results
+
+video? image? demo?
+
+---
+
+
+# Takeaways 1
+
+- sticking raymarching vectors to manifolds in 4 dimensions is possible but has 
+    a lot of edge cases 
+
+---
+
+# Takeaways 2 
+
+- having RAII would be really nice when writing a vector library 
+
+```c
+    if (1 || keyboardstate[SDL_SCANCODE_UP]) {
+        struct ray cameraray = {.pos = copy_vec(camera->pos), .dir = camera->y};
+        manifoldturn(&cameraray, camera->x, 0);
+        free_vec(cameraray.pos);
+
+        cameraray.pos = copy_vec(camera->pos);
+        manifoldturn(&cameraray, camera->y, 0);
+        free_vec(cameraray.pos);
+
+        cameraray.pos = camera->pos;
+        manifoldstep(&cameraray, dist);
+        free_vec(cameraray.pos);
+    }
+```
+