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/shader/wrap/compute_shader.cc | 51 +++++++++++++++++++++++++++++++++++++++
 src/shader/wrap/compute_shader.h  | 32 ++++++++++++++++++++++++
 src/shader/wrap/graphic_shader.cc | 45 ++++++++++++++++++++++++++++++++++
 src/shader/wrap/graphic_shader.h  | 29 ++++++++++++++++++++++
 4 files changed, 157 insertions(+)
 create mode 100644 src/shader/wrap/compute_shader.cc
 create mode 100644 src/shader/wrap/compute_shader.h
 create mode 100644 src/shader/wrap/graphic_shader.cc
 create mode 100644 src/shader/wrap/graphic_shader.h

(limited to 'src/shader/wrap')

diff --git a/src/shader/wrap/compute_shader.cc b/src/shader/wrap/compute_shader.cc
new file mode 100644
index 0000000..c90c370
--- /dev/null
+++ b/src/shader/wrap/compute_shader.cc
@@ -0,0 +1,51 @@
+#include "compute_shader.h"
+
+#include "shader/util.h"
+
+ComputeShader::Guard::Guard(GLuint id):
+	_id(id) {
+	glUseProgram(_id);
+}
+
+ComputeShader::Guard::~Guard() {
+	glUseProgram(0);
+}
+
+ComputeShader::Guard ComputeShader::use() const {
+	return Guard(_id);
+}
+
+ComputeShader::ComputeShader(const std::string& src):
+	_id(glCreateProgram()) {
+	GLint shader = util::compileShader(src, GL_COMPUTE_SHADER);
+
+	if ( shader != -1 ) {
+		glAttachShader(_id, shader);
+		glLinkProgram(_id);
+		_good = true;
+	}
+}
+
+ComputeShader::~ComputeShader() {
+	glDeleteProgram(_id);
+}
+
+bool ComputeShader::isGood() const {
+	return _good;
+}
+
+GLuint ComputeShader::setUniform(const std::string& name, float x, float y) const {
+	GLuint id = util::getUniform(_id, name);
+	glUniform2f(id, x, y);
+	return id;
+}
+
+void ComputeShader::workOn(GLuint bufferA, GLuint bufferB, GLuint bufferC) const {
+	glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 1, bufferA);
+	glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 2, bufferB);
+	glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 3, bufferC);
+}
+
+void ComputeShader::dispatch() const {
+	glDispatchCompute(128, 128, 1);
+}
diff --git a/src/shader/wrap/compute_shader.h b/src/shader/wrap/compute_shader.h
new file mode 100644
index 0000000..74c8270
--- /dev/null
+++ b/src/shader/wrap/compute_shader.h
@@ -0,0 +1,32 @@
+#pragma once
+
+#include <string>
+
+#include <GL/glew.h>
+
+class ComputeShader {
+private:
+	const GLuint _id;
+
+	bool _good;
+
+public:
+	struct Guard {
+		const GLuint _id;
+
+		Guard(GLuint id);
+		~Guard();
+	};
+
+	Guard use() const;
+
+	ComputeShader(const std::string& src);
+	~ComputeShader();
+
+	bool isGood() const;
+
+	GLuint setUniform(const std::string& name, float x, float y) const;
+
+	void workOn(GLuint bufferA, GLuint bufferB, GLuint bufferC) const;
+	void dispatch() const;
+};
diff --git a/src/shader/wrap/graphic_shader.cc b/src/shader/wrap/graphic_shader.cc
new file mode 100644
index 0000000..0ed37ff
--- /dev/null
+++ b/src/shader/wrap/graphic_shader.cc
@@ -0,0 +1,45 @@
+#include "graphic_shader.h"
+
+#include "shader/util.h"
+
+GraphicShader::Guard::Guard(GLuint id):
+	_id(id) {
+	glUseProgram(_id);
+}
+
+GraphicShader::Guard::~Guard() {
+	glUseProgram(0);
+}
+
+GraphicShader::Guard GraphicShader::use() const {
+	return Guard(_id);
+}
+
+GraphicShader::GraphicShader(const std::string& vertex, const std::string fragment):
+	_id(glCreateProgram()) {
+	glAttachShader(_id, util::compileShader(vertex, GL_VERTEX_SHADER));
+	glAttachShader(_id, util::compileShader(fragment, GL_FRAGMENT_SHADER));
+	glLinkProgram(_id);
+}
+
+GraphicShader::~GraphicShader() {
+	glDeleteProgram(_id);
+}
+
+GLuint GraphicShader::setUniform(const std::string& name, int value) const {
+	GLuint id = util::getUniform(_id, name);
+	glUniform1i(id, value);
+	return id;
+}
+
+GLuint GraphicShader::setUniform(const std::string& name, const std::vector<GLuint>& v) const {
+	GLuint id = util::getUniform(_id, name);
+	glUniform1iv(id, v.size(), reinterpret_cast<const GLint*>(v.data()));
+	return id;
+}
+
+GLuint GraphicShader::setUniform(const std::string& name, glm::mat4& M) const {
+	GLuint id = util::getUniform(_id, name);
+	glUniformMatrix4fv(id, 1, GL_FALSE, &M[0][0]);
+	return id;
+}
diff --git a/src/shader/wrap/graphic_shader.h b/src/shader/wrap/graphic_shader.h
new file mode 100644
index 0000000..25a5efb
--- /dev/null
+++ b/src/shader/wrap/graphic_shader.h
@@ -0,0 +1,29 @@
+#pragma once
+
+#include <vector>
+#include <string>
+
+#include <GL/glew.h>
+#include <glm/glm.hpp>
+
+class GraphicShader {
+private:
+	const GLuint _id;
+
+public:
+	struct Guard {
+		const GLuint _id;
+
+		Guard(GLuint id);
+		~Guard();
+	};
+
+	Guard use() const;
+
+	GraphicShader(const std::string& vertex, const std::string fragment);
+	~GraphicShader();
+
+	GLuint setUniform(const std::string& name, int value) const;
+	GLuint setUniform(const std::string& name, const std::vector<GLuint>& v) const;
+	GLuint setUniform(const std::string& name, glm::mat4& M) const;
+};
-- 
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