From 44f5ac32a68a617f93704d44c4339f7db13b323e Mon Sep 17 00:00:00 2001
From: Adrian Kummerlaender
Date: Sat, 15 Dec 2018 23:09:32 +0100
Subject: Hacky D2Q9 BGK LBM on GPU using GLSL compute shaders

Improvised on top of computicles's scaffolding.

Works in a world where _works_ is defined as "displays stuff on screen that invokes thoughts of fluid movement".
---
 src/buffer/vertex/fluid_cell_buffer.cc   | 33 ++++++++++++++++++++++++++
 src/buffer/vertex/fluid_cell_buffer.h    | 21 +++++++++++++++++
 src/buffer/vertex/lattice_cell_buffer.cc | 40 ++++++++++++++++++++++++++++++++
 src/buffer/vertex/lattice_cell_buffer.h  | 19 +++++++++++++++
 4 files changed, 113 insertions(+)
 create mode 100644 src/buffer/vertex/fluid_cell_buffer.cc
 create mode 100644 src/buffer/vertex/fluid_cell_buffer.h
 create mode 100644 src/buffer/vertex/lattice_cell_buffer.cc
 create mode 100644 src/buffer/vertex/lattice_cell_buffer.h

(limited to 'src/buffer/vertex')

diff --git a/src/buffer/vertex/fluid_cell_buffer.cc b/src/buffer/vertex/fluid_cell_buffer.cc
new file mode 100644
index 0000000..5056569
--- /dev/null
+++ b/src/buffer/vertex/fluid_cell_buffer.cc
@@ -0,0 +1,33 @@
+#include "fluid_cell_buffer.h"
+
+FluidCellBuffer::FluidCellBuffer():
+	_data(3*128*128, GLfloat{}) {
+	glGenVertexArrays(1, &_array);
+	glGenBuffers(1, &_buffer);
+
+	glBindVertexArray(_array);
+	glBindBuffer(GL_ARRAY_BUFFER, _buffer);
+	glBufferData(
+		GL_ARRAY_BUFFER,
+		_data.size() * sizeof(GLfloat),
+		_data.data(),
+		GL_DYNAMIC_DRAW
+	);
+
+	glEnableVertexAttribArray(0);
+	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, nullptr);
+}
+
+FluidCellBuffer::~FluidCellBuffer() {
+	glDeleteBuffers(1, &_buffer);
+	glDeleteVertexArrays(1, &_array);
+}
+
+GLuint FluidCellBuffer::getBuffer() const {
+	return _buffer;
+}
+
+void FluidCellBuffer::draw() const {
+	glBindVertexArray(_array);
+	glDrawArrays(GL_POINTS, 0, _data.size());
+}
diff --git a/src/buffer/vertex/fluid_cell_buffer.h b/src/buffer/vertex/fluid_cell_buffer.h
new file mode 100644
index 0000000..b2b880a
--- /dev/null
+++ b/src/buffer/vertex/fluid_cell_buffer.h
@@ -0,0 +1,21 @@
+#pragma once
+
+#include <vector>
+
+#include <GL/glew.h>
+
+class FluidCellBuffer {
+private:
+	std::vector<GLfloat> _data;
+
+	GLuint _array;
+	GLuint _buffer;
+
+public:
+	FluidCellBuffer();
+	~FluidCellBuffer();
+
+	GLuint getBuffer() const;
+
+	void draw() const;
+};
diff --git a/src/buffer/vertex/lattice_cell_buffer.cc b/src/buffer/vertex/lattice_cell_buffer.cc
new file mode 100644
index 0000000..7fb51d8
--- /dev/null
+++ b/src/buffer/vertex/lattice_cell_buffer.cc
@@ -0,0 +1,40 @@
+#include "lattice_cell_buffer.h"
+
+#include <fstream>
+
+LatticeCellBuffer::LatticeCellBuffer():
+	_data(9*128*128, GLfloat{1./9.}) {
+	glGenVertexArrays(1, &_array);
+	glGenBuffers(1, &_buffer);
+
+	for (int x = 50; x < 128-50; x++) {
+		for (int y = 50; y < 128-50; y++) {
+			for ( int i = -1; i <= 1; ++i ) {
+				for ( int j = -1; j <= 1; ++j ) {
+					_data[9*128*y + 9*x + (i+1)*3 + j+1] = 1./128.;
+				}
+			}
+		}
+	}
+
+	glBindVertexArray(_array);
+	glBindBuffer(GL_ARRAY_BUFFER, _buffer);
+	glBufferData(
+		GL_ARRAY_BUFFER,
+		_data.size() * sizeof(GLfloat),
+		_data.data(),
+		GL_DYNAMIC_DRAW
+	);
+
+	glEnableVertexAttribArray(0);
+	glVertexAttribPointer(0, 1, GL_FLOAT, GL_FALSE, 0, nullptr);
+}
+
+LatticeCellBuffer::~LatticeCellBuffer() {
+	glDeleteBuffers(1, &_buffer);
+	glDeleteVertexArrays(1, &_array);
+}
+
+GLuint LatticeCellBuffer::getBuffer() const {
+	return _buffer;
+}
diff --git a/src/buffer/vertex/lattice_cell_buffer.h b/src/buffer/vertex/lattice_cell_buffer.h
new file mode 100644
index 0000000..c28319e
--- /dev/null
+++ b/src/buffer/vertex/lattice_cell_buffer.h
@@ -0,0 +1,19 @@
+#pragma once
+
+#include <vector>
+
+#include <GL/glew.h>
+
+class LatticeCellBuffer {
+private:
+	std::vector<GLfloat> _data;
+
+	GLuint _array;
+	GLuint _buffer;
+
+public:
+	LatticeCellBuffer();
+	~LatticeCellBuffer();
+
+	GLuint getBuffer() const;
+};
-- 
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