First commit with compute pausability

2 files changed, 35 insertions, 12 deletions

diff --git a/BuddhaTest/src/BuddhaTest.cpp b/BuddhaTest/src/BuddhaTest.cpp
index 5d03ad4..fcc76a3 100644
--- a/BuddhaTest/src/BuddhaTest.cpp
+++ b/BuddhaTest/src/BuddhaTest.cpp
@@ -122,15 +122,27 @@ int main(int argc, char * argv[])
     }

     glBindBuffer(GL_SHADER_STORAGE_BUFFER, 0);

 

+    const uint32_t workersPerFrame = settings.globalWorkGroupSizeX*settings.globalWorkGroupSizeY*settings.globalWorkGroupSizeZ*settings.localWorkgroupSizeX*settings.localWorkgroupSizeY*settings.localWorkgroupSizeZ;

+    GLuint stateBuffer;

+    glGenBuffers(1,&stateBuffer);

+    glBindBuffer(GL_SHADER_STORAGE_BUFFER,stateBuffer);

+    glBufferData(GL_SHADER_STORAGE_BUFFER, 4*(4*workersPerFrame+1),nullptr,GL_DYNAMIC_COPY);

+    glClearBufferData(GL_SHADER_STORAGE_BUFFER,GL_R8,GL_RED,GL_UNSIGNED_INT,nullptr);

+    glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 5, stateBuffer);

+

     uint32_t iterationCount{0};

     glUseProgram(ComputeShader);

     GLint iterationCountUniformHandle = glGetUniformLocation(ComputeShader, "iterationCount");

     GLint orbitLengthUniformHandle = glGetUniformLocation(ComputeShader, "orbitLength");

     GLint widthUniformComputeHandle = glGetUniformLocation(ComputeShader, "width");

     GLint heightUniformComputeHandle = glGetUniformLocation(ComputeShader, "height");

+    GLint iterationChangedHandle = glGetUniformLocation(ComputeShader, "iterationChanged");

+    GLint iterationsPerDispatchHandle = glGetUniformLocation(ComputeShader, "iterationsPerDispatch");

     glUniform3ui(orbitLengthUniformHandle,settings.orbitLengthRed,settings.orbitLengthGreen,settings.orbitLengthBlue);

     glUniform1ui(widthUniformComputeHandle, settings.imageWidth);

     glUniform1ui(heightUniformComputeHandle, bufferHeight);

+    glUniform1ui(iterationChangedHandle,1);

+    glUniform1ui(iterationsPerDispatchHandle, settings.iterationsPerFrame);

 

     glUseProgram(VertexAndFragmentShaders);

     GLint widthUniformFragmentHandle = glGetUniformLocation(VertexAndFragmentShaders, "width");

@@ -140,29 +152,37 @@ int main(int argc, char * argv[])
 

     glClearColor(0.0f, 0.0f, 0.4f, 0.0f);

 

-    //uint32_t iterationsPerFrame = settings.globalWorkGroupSizeX*settings.globalWorkGroupSizeY*settings.globalWorkGroupSizeZ*settings.localWorkgroupSizeX*settings.localWorkgroupSizeY*settings.localWorkgroupSizeZ;

-    //bool bWarningShown{false};

-

 	/* Loop until the user closes the window */

 	while (!glfwWindowShouldClose(window))

 	{

-        //commented out, as with the new y-decoupling we will get more points in 2D even after we had all integer values for x.

-        //check if we are "done"

-        //if(iterationsPerFrame * iterationCount <= iterationsPerFrame && iterationCount > 1 && !bWarningShown)

-        //{

-        //    std::cout << "The program covered all possible integer values for starting point computation. Leaving it running will not improve the image any more." << std::endl;

-        //    bWarningShown = true;

-        //}

+        //clear first integer in state buffer. That's the "boolean" we use to determine if we should increment iterationCount.

+        glBindBuffer(GL_SHADER_STORAGE_BUFFER,stateBuffer);

+        glClearBufferSubData(GL_SHADER_STORAGE_BUFFER,GL_R8,0,4,GL_RED,GL_UNSIGNED_INT,nullptr);

 

 		//let the compute shader do something

 		glUseProgram(ComputeShader);

-        //increase iterationCount, which is used for pseudo random generation

-        glUniform1ui(iterationCountUniformHandle,++iterationCount);

+        //set iterationCount, which is used for pseudo random generation

+        glUniform1ui(iterationCountUniformHandle,iterationCount);

         glDispatchCompute(settings.globalWorkGroupSizeX, settings.globalWorkGroupSizeY, settings.globalWorkGroupSizeZ);

 

         //before reading the values in the ssbo, we need a memory barrier:

         glMemoryBarrier(GL_SHADER_STORAGE_BARRIER_BIT); //I hope this is the correct (and only required) bit

 

+        //read back first bit of state buffer. If it's zero, increment iterationcount and set glUniform1ui(iterationChangedHandle,1);

+        //if it's nonzero set glUniform1ui(iterationChangedHandle,0);

+        glBindBuffer(GL_SHADER_STORAGE_BUFFER,stateBuffer);

+        uint accumulatedState;

+        glGetBufferSubData(GL_SHADER_STORAGE_BUFFER,0,4,&accumulatedState);

+        if(accumulatedState)

+        {

+            glUniform1ui(iterationChangedHandle,0);

+        }

+        else

+        {

+            glUniform1ui(iterationChangedHandle,1);

+            ++iterationCount;

+        }

+

 		/* Render here */

 		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

 		glUseProgram(VertexAndFragmentShaders);

@@ -210,6 +230,7 @@ int main(int argc, char * argv[])
     //a bit of cleanup

     glDeleteBuffers(1,&vertexbuffer);

     glDeleteBuffers(3,drawBuffer);

+    glDeleteBuffers(1,&stateBuffer);

 

 	glfwTerminate();

 	return 0;

diff --git a/BuddhaTest/src/Helpers.cpp b/BuddhaTest/src/Helpers.cpp
index 3cb786c..5197421 100644
--- a/BuddhaTest/src/Helpers.cpp
+++ b/BuddhaTest/src/Helpers.cpp
@@ -332,6 +332,7 @@ namespace Helpers
             {"--globalWorkgroupSizeX", &globalWorkGroupSizeX},

             {"--globalWorkgroupSizeY", &globalWorkGroupSizeY},

             {"--globalWorkgroupSizeZ", &globalWorkGroupSizeZ},

+            {"--iterationsPerFrame", &iterationsPerFrame},

             {"--imageGamma",&pngGamma},

             {"--imageColorScale",&pngColorScale},

             {"--output", &pngFilename},

@@ -362,6 +363,7 @@ namespace Helpers
                              "--globalWorkgroupSizeX [integer] : How often the local work group should be invoked per frame. Values up to 65535 are guaranteed to work. Default is 1024." << std::endl <<

                              "--globalWorkgroupSizeY [integer] : How often the local work group should be invoked per frame. Values up to 65535 are guaranteed to work. Default is 1." << std::endl <<

                              "--globalWorkgroupSizeZ [integer] : How often the local work group should be invoked per frame. Values up to 65535 are guaranteed to work. Default is 1." << std::endl <<

+                             "--iterationsPerFrame [integer] : Limit how many iteration steps the shader may make per frame. Use this to keep the desktop responsive while rendering high iteration count images. Default: 1000." << std::endl <<

                              "--ignoreMaxBufferSize [0,1] : If set to 1, a failed maximum buffer size check is not treated as error. Some graphics drivers report lower values than their absolute limit. Do this on your own risk, though." << std::endl;

                 return false;

             }