Fixed some typos

src/docs/asciidoc/jme3/advanced/pbr_part3.adoc

@@ -40,7 +40,7 @@ Here the reflected Ray is our reflection vector.
 
 Unfortunately we can’t take each pixel of the env map and compute light as if it was a direct light source and hope for the best.
 
-There’s crazy math around that topic, and to be honest I ddidn’tget all of it myself. So instead of explaining difficult math equations that may be confusing, I’m gonna go straight to the point : How are we going to compute lighting from the environment map?
+There’s crazy math around that topic, and to be honest I didn’t get all of it myself. So instead of explaining difficult math equations that may be confusing, I’m gonna go straight to the point : How are we going to compute lighting from the environment map?
 
 === IBL Diffuse
 
@@ -79,7 +79,7 @@ What’s that again? I won’t go into explaining them in details (because I can
 
 To put it simple, SH can help us to compute the irradiance map way faster. This article explains that it all boils down to compute only 9 spherical harmonics coefficients to efficiently approximate an irradiance factor.
 
-At this point you can even skip the pre computation of the irradiance map, and use those coefficients directly in your shader for each shaded pixels. That’s fast enough to be real time, and use less memory that a cube map.
+At this point you can even skip the pre computation of the irradiance map, and use those coefficients directly in your shader for each shaded pixels. That’s fast enough to be real time, and use less memory than a cube map.
 
 But still…it’s slower than one texture fetch, so I chose to compute the Irradiance map and use it in the shader.