Render is now its own package.

[raymarcher.git] / Render.lua

diff --git a/Render.lua b/Render.lua
new file mode 100644 (file)
index 0000000..17f244d
--- /dev/null
+++ b/Render.lua
@@ -0,0 +1,89 @@
+-- Main rendering functions
+
+require "Vector"
+local V = Vector
+
+require "Primitives"
+local P = Primitives
+
+require "Operations"
+local O = Operations
+
+require "Textures"
+local T = Textures
+
+local eps = 0.01
+local max_dist2 = 30^2
+local bg_col = {0.1,0.1,0.1}
+
+local function calculate_normal(sdf, l)
+   local delta = 1e-3;
+   return V.new{sdf(l+V.x*delta).dist-sdf(l-V.x*delta).dist,
+                sdf(l+V.y*delta).dist-sdf(l-V.y*delta).dist,
+                sdf(l+V.z*delta).dist-sdf(l-V.z*delta).dist}/(2*delta)
+end
+
+local function march(start, location, ray_dir, sdf, count)
+   if V.norm2(location-start) > max_dist2 then
+      return bg_col
+   end
+   
+   local p = sdf(location)
+   if p.dist < eps then
+      return p.texture(location, ray_dir,
+                       calculate_normal(sdf, location-(ray_dir*eps)),
+                       count, sdf)
+   else
+      return march(start, location + ray_dir*p.dist,
+                   ray_dir, sdf, count+1)
+   end
+end
+
+local function render(scene, width, height, filename) 
+   print("Rendering to file " .. filename .. "...")
+   
+   local f = io.open(filename, "w")
+   f:write("P3 ", width, " ", height, " 255\n")
+
+   local c = scene.camera
+   local cam_dir = V.normalize(c.point_at - c.location)
+   local right = V.normalize(c.right)
+   local up = V.cross(right,cam_dir)
+   local aspect = height/width;
+
+   local normalize = V.normalize -- optimization
+   
+   for y=1,height do
+
+      if y % math.floor(height/10) == 0 then
+         print(y/math.floor(height/10) * 10 .. "%")
+      end
+
+      local rayy = cam_dir + up*((0.5 - y/height)*c.fov*aspect)
+
+      for x=1,width do
+         local ray_dir = normalize(rayy + right*((x/width - 0.5)*c.fov))
+         local col = march(c.location, c.location, ray_dir, scene.sdf, 0)
+         col = {math.min(col[1]*255, 255),
+                math.min(col[2]*255, 255),
+                math.min(col[3]*255, 255)}
+
+         f:write(math.floor(col[1]), " ", math.floor(col[2]), " ", math.floor(col[3]), " ")
+      end
+      f:write("\n")
+   end
+   f:write("\n")
+
+   f:close()
+
+   print("done")
+end
+
+Render = {
+   eps = eps,
+   max_dist2 = max_dist2,
+   bg_col = bg_col,
+   render = render
+}
+
+return Render