Shaders/Compute.glsl

@@ -1,46 +1,30 @@
 #version 460 core
 
-layout(rgba32f, binding = 0) uniform writeonly image2D outputImage;
-
-layout(location = 0) uniform uint triangleCount;
-
-layout(std430, binding = 3) buffer layoutName
-{
+layout(std430, binding = 3) buffer layoutName {
   vec2 o_Points[];
 };
 
-// 1 -> 1
-// 2 -> 3
-// 3 -> 9
-// 4 -> 27
-// 5 -> 81
-// 6 -> 243
-// ...
-
-// 4  27
-// 1 + 3 + 9 = 13
-
-// Sn = ((3^n)-1)/2
-// S3 = 3^3 - 1 / 2
-// 3^4
-
-// gl_NumWorkGroups : This variable contains the number of work groups passed to the dispatch function.
-// gl_WorkGroupID : This is the current work group for this shader invocation. Each of the XYZ components will be on the half-open range [0, gl_NumWorkGroups.XYZ).
-// gl_LocalInvocationID : This is the current invocation of the shader within the work group. Each of the XYZ components will be on the half-open range [0, gl_WorkGroupSize.XYZ).
-
-// avant : 1 3 9
-// après : 3 9 27
-// count : 1 3 9
 layout(local_size_x = 64) in;
-void main()
-{
-    uint currentPoint = gl_GlobalInvocationID.x;
-    if (currentPoint >= triangleCount)
-      return;
 
-    uint offset = (triangleCount - 1) / 2;
-    uint firstPointIndex = offset * 3 + 1;
-    o_Points[firstPointIndex + currentPoint * 3] = o_Points[offset + currentPoint] / 2 + vec2(0, 0.36);
-    o_Points[firstPointIndex + currentPoint * 3 + 1] = o_Points[offset + currentPoint] / 2 + vec2(-0.5, -0.5);
-    o_Points[firstPointIndex + currentPoint * 3 + 2] = o_Points[offset + currentPoint] / 2 + vec2(0.5, -0.5);
+highp float rand(vec2 co)
+{
+    highp float a = 12.9898;
+    highp float b = 78.233;
+    highp float c = 43758.5453;
+    highp float dt= dot(co.xy ,vec2(a,b));
+    highp float sn= mod(dt,3.14);
+    return fract(sin(sn) * c);
+}
+
+void main() {
+	const uint total = gl_NumWorkGroups.x * gl_WorkGroupSize.x;
+    uint currentPoint = gl_GlobalInvocationID.x;
+	uint index = uint(rand(o_Points[currentPoint] + currentPoint) * 69);
+	if (index % 3 == 0) {
+		o_Points[currentPoint] = o_Points[currentPoint] / 2 + vec2(0, 0.36);
+	} else if (index % 3 == 1) {
+    	o_Points[currentPoint] = o_Points[currentPoint] / 2 + vec2(-0.5, -0.5);
+	} else {
+		o_Points[currentPoint] = o_Points[currentPoint] / 2 + vec2(0.5, -0.5);
+	}
 }

src/Main.cpp

@@ -139,7 +139,7 @@ int main()
 	GLuint vertexBuffer;
 	glCreateBuffers(1, &vertexBuffer);
 
-	constexpr int DEPTH = 14;
+	constexpr int DEPTH = 6;
 
 	auto vertices = GetPoints(DEPTH);
 
@@ -157,40 +157,19 @@ int main()
 
 	Timer timer;
 
+	constexpr int PARTICLE_COUNT = 64 * 5000;
+
 	GLuint ssbo;
 	glGenBuffers(1, &ssbo);
 	glBindBuffer(GL_SHADER_STORAGE_BUFFER, ssbo);
 	glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 3, ssbo);
-	glBufferData(GL_SHADER_STORAGE_BUFFER, sizeof(float) * vertices.size(), nullptr, GL_DYNAMIC_COPY); // sizeof(data) only works for statically sized C/C++ arrays.
+	glBufferData(GL_SHADER_STORAGE_BUFFER, sizeof(float) * PARTICLE_COUNT, nullptr, GL_DYNAMIC_COPY); // sizeof(data) only works for statically sized C/C++ arrays.
 
 	float lastTime = (float)glfwGetTime();
 
 	int fps = 0;
 	float secondsTimer = 0.0f;
 
-	// Compute
-	glUseProgram(s_ComputeShader);
-	glBindImageTexture(0, fb.ColorAttachment.Handle, 0, GL_FALSE, 0, GL_WRITE_ONLY, GL_RGBA32F);
-
-	std::size_t count = 1;
-	for (std::size_t i = 0; i < DEPTH; i++)
-	{
-		glUniform1ui(0, count);
-		std::cout << count << std::endl;
-
-		int dispatchCount = (count - 1) / 64 + 1;
-		std::cout << "DC : " <<dispatchCount<< std::endl;
-
-		glDispatchCompute(dispatchCount, 1, 1);
-
-		// Ensure all writes to the image are complete
-		glMemoryBarrier(GL_SHADER_IMAGE_ACCESS_BARRIER_BIT);
-
-		count *= 3;
-	}
-
-	std::cout << "Generated points in " << timer.ElapsedMillis() << " ms\n";
-
 	while (!glfwWindowShouldClose(window))
 	{
 		// ScopedTimer timer("Main Loop");
@@ -219,19 +198,19 @@ int main()
 			AttachTextureToFramebuffer(fb, computeShaderTexture);
 		}
 
+		// Compute
+
+		glUseProgram(s_ComputeShader);
+		glDispatchCompute(PARTICLE_COUNT / 64, 1, 1);
+
+		// Ensure all writes to the image are complete
+		glMemoryBarrier(GL_SHADER_IMAGE_ACCESS_BARRIER_BIT);
+
 		// Graphics
-		glBindFramebuffer(GL_FRAMEBUFFER, fb.Handle);
 		glUseProgram(s_GraphicsShader);
 
 		glBindVertexArray(vertexArray);
-		glDrawArraysInstanced(GL_POINTS, 0, 1, vertices.size());
-
-		glBindFramebuffer(GL_FRAMEBUFFER, 0);
-
-		// Blit
-		{
-			BlitFramebufferToSwapchain(fb);
-		}
+		glDrawArraysInstanced(GL_POINTS, 0, 1, PARTICLE_COUNT);
 
 		glfwSwapBuffers(window);
 		glfwPollEvents();