Make local work group size tweakable. (Not yet exposed to user)

4 files changed, 23 insertions, 10 deletions

diff --git a/BuddhaTest/Shaders/BuddhaCompute.glsl b/BuddhaTest/Shaders/BuddhaCompute.glsl
index 7a363ec..263e4c0 100644
--- a/BuddhaTest/Shaders/BuddhaCompute.glsl
+++ b/BuddhaTest/Shaders/BuddhaCompute.glsl
@@ -1,4 +1,6 @@
-#version 430

+//commented out, added by c-code that loads this shader.

+//#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

 {

@@ -187,7 +189,6 @@ void drawOrbit(vec2 offset)
     }

 }

 

-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.

 void main() {

     //we need to know how many total work groups are running this iteration

 

diff --git a/BuddhaTest/include/Helpers.h b/BuddhaTest/include/Helpers.h
index ad14305..8c897d5 100644
--- a/BuddhaTest/include/Helpers.h
+++ b/BuddhaTest/include/Helpers.h
@@ -7,7 +7,7 @@
 namespace Helpers

 {

 	GLuint LoadShaders(const char * vertex_file_path, const char * fragment_file_path);

-	GLuint LoadComputeShader(const char * compute_file_path);

+    GLuint LoadComputeShader(const char * compute_file_path, unsigned int localSizeX, unsigned int localSizeY, unsigned int localSizeZ);

 

     void WriteOutputPNG(const std::vector<uint32_t>& data, unsigned int width, unsigned int height);

 

diff --git a/BuddhaTest/src/BuddhaTest.cpp b/BuddhaTest/src/BuddhaTest.cpp
index d1b6a66..f8b9074 100644
--- a/BuddhaTest/src/BuddhaTest.cpp
+++ b/BuddhaTest/src/BuddhaTest.cpp
@@ -14,6 +14,9 @@ int main()
     unsigned int bufferWidth = 1600;

     unsigned int bufferHeight = 900;

 

+    unsigned int windowWidth = 1600;

+    unsigned int windowHeight = 900;

+

     unsigned int orbitLengthRed = 10;

     unsigned int orbitLengthGreen = 100;

     unsigned int orbitLengthBlue = 1000;

@@ -31,7 +34,7 @@ int main()
 	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

 

 	/* Create a windowed mode window and its OpenGL context */

-    window = glfwCreateWindow(1600, 900, "Buddhabrot", NULL, NULL);

+    window = glfwCreateWindow(windowWidth, windowHeight, "Buddhabrot", NULL, NULL);

 	if (!window)

 	{

 		std::cerr << "Failed to create OpenGL 4.3 core context. We do not support compatibility contexts." << std::endl;

@@ -77,7 +80,7 @@ int main()
 	// Create and compile our GLSL program from the shaders

 	GLuint VertexAndFragmentShaders = Helpers::LoadShaders("Shaders/BuddhaVertex.glsl", "Shaders/BuddhaFragment.glsl");

 	//Do the same for the compute shader:

-	GLuint ComputeShader = Helpers::LoadComputeShader("Shaders/BuddhaCompute.glsl");

+    GLuint ComputeShader = Helpers::LoadComputeShader("Shaders/BuddhaCompute.glsl", 1024, 1, 1);

 

     uint32_t iterationCount{0};

     glUseProgram(ComputeShader);

@@ -103,7 +106,7 @@ int main()
 		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

 		glUseProgram(VertexAndFragmentShaders);

 		

-		glEnableVertexAttribArray(0);

+        glEnableVertexAttribArray(0);

 		glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer);

 		glVertexAttribPointer(

 			0,                  // attribute 0. No particular reason for 0, but must match the layout in the shader.

@@ -113,12 +116,12 @@ int main()
 			0,                  // stride

 			(void*)0            // array buffer offset

 		);

-		// Draw the triangle !

+        // Draw the triangle strip!

 		glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); // Triangle strip with 4 vertices -> quad.

 		glDisableVertexAttribArray(0);

 

 		/* Swap front and back buffers */

-		glfwSwapBuffers(window);

+        glfwSwapBuffers(window);

 

 		/* Poll for and process events */

 		glfwPollEvents();

@@ -133,6 +136,10 @@ int main()
         Helpers::WriteOutputPNG(readBackBuffer,bufferWidth,bufferHeight);

     }

 

+    //a bit of cleanup

+    glDeleteBuffers(1,&vertexbuffer);

+    glDeleteBuffers(1,&drawBuffer);

+

 	glfwTerminate();

 	return 0;

 }

diff --git a/BuddhaTest/src/Helpers.cpp b/BuddhaTest/src/Helpers.cpp
index 3512d0f..b092dc2 100644
--- a/BuddhaTest/src/Helpers.cpp
+++ b/BuddhaTest/src/Helpers.cpp
@@ -98,7 +98,7 @@ namespace Helpers
 		return ProgramID;

 	}

 

-	GLuint LoadComputeShader(const char* compute_file_path)

+    GLuint LoadComputeShader(const char* compute_file_path, unsigned int localSizeX, unsigned int localSizeY, unsigned int localSizeZ)

 	{

 		GLuint ComputeShaderID = glCreateShader(GL_COMPUTE_SHADER);

 		// Read the compute shader

@@ -107,6 +107,11 @@ namespace Helpers
 			std::ifstream ComputeShaderCodeStream(compute_file_path, std::ios::in);

 			if (ComputeShaderCodeStream.is_open()) {

 				std::stringstream sstr;

+                sstr << "#version 430" <<

+                        std::endl <<

+                        "layout (local_size_x = " << localSizeX <<

+                        ", local_size_y = " << localSizeY <<

+                        ", local_size_z = " << localSizeZ << ") in;" << std::endl;

 				sstr << ComputeShaderCodeStream.rdbuf();

 				ComputeShaderCode = sstr.str();

 				ComputeShaderCodeStream.close();

@@ -158,7 +163,7 @@ namespace Helpers
             rows[i] = pngData.data()+3*width*i;

         }

 

-        uint32_t maxValue{UINT32_C(0)};

+        uint32_t maxValue{UINT32_C(1)};

         for(unsigned int i = 0; i < data.size();++i)

         {

             maxValue = std::max(maxValue,data[i]);