Split buffer in three, one per color (as OpenGL guarantees that one can at least have 8 SSBOs), to allow three times larger images. Also make it possible to ignore maximum buffer size reported by the driver.

The maximum buffer size limitation is rather strict on radeonsi, so I decided to split the buffer in three, effectively increasing the maximum image size by a factor of three.
While doing so I realized that at least on radeonsi the reported maximum buffer size seems to be off. For this reason I added a new command line switch, that allows to ignore the maximum buffer size check.
For those curious: radeonsi reports a maximum buffer size of 128 MB, but I had no problems when using three buffers of 1098 MB each.

1 files changed, 14 insertions, 6 deletions

diff --git a/BuddhaTest/Shaders/BuddhaCompute.glsl b/BuddhaTest/Shaders/BuddhaCompute.glsl
index 9d8301a..ddcbace 100644
--- a/BuddhaTest/Shaders/BuddhaCompute.glsl
+++ b/BuddhaTest/Shaders/BuddhaCompute.glsl
@@ -2,9 +2,17 @@
 //#version 430

 //layout (local_size_x = 1024) in; //to be safe, we limit our local work group size to 1024. That's the minimum a GL 4.3 capable driver must support.

 

-layout(std430, binding=2) buffer renderedData

+layout(std430, binding=2) buffer renderedDataRed

 {

-        uint counts_SSBO[];

+        uint counts_SSBORed[];

+};

+layout(std430, binding=3) buffer renderedDataGreen

+{

+        uint counts_SSBOGreen[];

+};

+layout(std430, binding=4) buffer renderedDataBlue

+{

+        uint counts_SSBOBlue[];

 };

 

 uniform uint width;

@@ -15,10 +23,10 @@ uniform uvec3 orbitLength;
 

 void addToColorOfCell(uvec2 cell, uvec3 toAdd)

 {

-    uint firstIndex = 3*(cell.x + cell.y * width);

-    atomicAdd(counts_SSBO[firstIndex],toAdd.x);

-    atomicAdd(counts_SSBO[firstIndex+1],toAdd.y);

-    atomicAdd(counts_SSBO[firstIndex+2],toAdd.z);

+    uint firstIndex = (cell.x + cell.y * width);

+    atomicAdd(counts_SSBORed[firstIndex],toAdd.x);

+    atomicAdd(counts_SSBOGreen[firstIndex],toAdd.y);

+    atomicAdd(counts_SSBOBlue[firstIndex],toAdd.z);

 }

 

 uvec2 getCell(vec2 complex)