kicad-developers team mailing list archive

[Henner Zeller <h.zeller@xxxxxxx>]

On Wed, 1 May 2019 at 06:14, John Beard <john.j.beard@xxxxxxxxx> wrote:
>
> On 01/05/2019 13:57, Mário Luzeiro wrote:
> > Hi John,
> >
> > yeah the Morton code is to improve cache hits.
> >
> > Regarding the speed test, since OS are multi-tasking there could be some interference on the results so 1s difference is not a very measurable difference ( 4% ).
> > A possibility would be to run the same scene multiple times and make an average of the times.
>
> Sure, it was just a fun observation. It does change a bit from run to
> run, but I was at least expecting a small penalty. Next up, wipes[1] and
> then perhaps Snake :-D
>
> A more robust benchmarking harness would probably be the way to go if we
> really were serious about putting the pedal to the metal here.
>
> But I think the centre-first approach is certainly better usability, but
> I'm unsure about the checkerboard.

I agree, without checkerboard it makes it quicker to see what is going
on in the center. Attached the (even simpler) just spiraling out from
the center patch.

>
> Cheers,
>
> John
>
> [1]: https://www.youtube.com/watch?v=cGqAu9gj_F0

diff --git a/3d-viewer/3d_rendering/3d_render_raytracing/c3d_render_raytracing.cpp b/3d-viewer/3d_rendering/3d_render_raytracing/c3d_render_raytracing.cpp
index b059cfeaf..f7fc54b21 100644
--- a/3d-viewer/3d_rendering/3d_render_raytracing/c3d_render_raytracing.cpp
+++ b/3d-viewer/3d_rendering/3d_render_raytracing/c3d_render_raytracing.cpp
@@ -32,6 +32,7 @@
 #include <atomic>
 #include <thread>
 #include <chrono>
+#include <algorithm>
 
 #include "c3d_render_raytracing.h"
 #include "mortoncodes.h"
@@ -2074,6 +2075,13 @@ bool C3D_RENDER_RAYTRACING::initializeOpenGL()
 }
 
 
+static float distance(const SFVEC2UI &a, const SFVEC2UI &b)
+{
+    const float dx = (float)a.x - (float)b.x;
+    const float dy = (float)a.y - (float)b.y;
+    return hypotf(dx, dy);
+}
+
 void C3D_RENDER_RAYTRACING::initialize_block_positions()
 {
 
@@ -2123,26 +2131,26 @@ void C3D_RENDER_RAYTRACING::initialize_block_positions()
     m_postshader_ssao.UpdateSize( m_realBufferSize );
 
 
-    // Calc block positions
+    // Calc block positions for regular rendering. Choose an 'inside out'
+    // style of rendering
     // /////////////////////////////////////////////////////////////////////
     m_blockPositions.clear();
-    m_blockPositions.reserve( (m_realBufferSize.x / RAYPACKET_DIM) *
-                              (m_realBufferSize.y / RAYPACKET_DIM) );
-
-    i = 0;
-
-    while(1)
-    {
-        SFVEC2UI blockPos( DecodeMorton2X(i) * RAYPACKET_DIM,
-                           DecodeMorton2Y(i) * RAYPACKET_DIM );
-        i++;
-
-        if( (blockPos.x >= m_realBufferSize.x) && (blockPos.y >= m_realBufferSize.y) )
-            break;
-
-        if( (blockPos.x < m_realBufferSize.x) && (blockPos.y < m_realBufferSize.y) )
-            m_blockPositions.push_back( blockPos );
-    }
+    const int blocks_x = m_realBufferSize.x / RAYPACKET_DIM;
+    const int blocks_y = m_realBufferSize.y / RAYPACKET_DIM;
+    m_blockPositions.reserve( blocks_x * blocks_y );
+
+    for (int x = 0; x < blocks_x; ++x)
+        for (int y = 0; y < blocks_y; ++y)
+            m_blockPositions.push_back(SFVEC2UI(x * RAYPACKET_DIM,
+                                                y * RAYPACKET_DIM));
+
+    const SFVEC2UI center(m_realBufferSize.x/2, m_realBufferSize.y/2);
+    std::sort(m_blockPositions.begin(), m_blockPositions.end(),
+              [&](const SFVEC2UI &a, const SFVEC2UI &b)
+                  {
+                      // Sort order: inside out.
+                      return distance(a, center) < distance(b, center);
+                  });
 
     // Create m_shader buffer
     delete[] m_shaderBuffer;