FluidSim2DProject.FluidSim.ApplyBuoyancy(UnityEngine.RenderTexture, UnityEngine.RenderTexture, UnityEngine.RenderTexture, UnityEngine.RenderTexture, float)

void FixedUpdate()
        {
            //Obstacles only need to be added once unless changed.
            AddObstacles();

            //Set the density field and obstacle color.
            m_guiMat.SetColor("_FluidColor", m_fluidColor);
            m_guiMat.SetColor("_ObstacleColor", m_obstacleColor);

            int READ = 0;
            int WRITE = 1;
            float dt = 0.125f;

            //Advect velocity against its self
            Advect(m_velocityTex[READ], m_velocityTex[READ], m_velocityTex[WRITE], m_velocityDissipation, dt);
            //Advect temperature against velocity
            Advect(m_velocityTex[READ], m_temperatureTex[READ], m_temperatureTex[WRITE], m_temperatureDissipation, dt);
            //Advect density against velocity
            Advect(m_velocityTex[READ], m_densityTex[READ], m_densityTex[WRITE], m_densityDissipation, dt);

            Swap(m_velocityTex);
            Swap(m_temperatureTex);
            Swap(m_densityTex);

            //Determine how the flow of the fluid changes the velocity
            ApplyBuoyancy(m_velocityTex[READ], m_temperatureTex[READ], m_densityTex[READ], m_velocityTex[WRITE], dt);

            Swap(m_velocityTex);

            //Refresh the impluse of density and temperature
            ApplyImpulse(m_temperatureTex[READ], m_temperatureTex[WRITE], m_implusePos, m_impluseRadius, m_impulseTemperature);
            ApplyImpulse(m_densityTex[READ], m_densityTex[WRITE], m_implusePos, m_impluseRadius, m_impulseDensity);

            Swap(m_temperatureTex);
            Swap(m_densityTex);

            //If left click down add impluse, if right click down remove impulse from mouse pos.
            if(Input.GetMouseButton(0) || Input.GetMouseButton(1))
            {
                Vector2 pos = Input.mousePosition;

                pos.x -= m_rect.xMin;
                pos.y -= m_rect.yMin;

                pos.x /= m_rect.width;
                pos.y /= m_rect.height;

                float sign = (Input.GetMouseButton(0)) ? 1.0f : -1.0f;

                ApplyImpulse(m_temperatureTex[READ], m_temperatureTex[WRITE], pos, m_mouseImpluseRadius, m_impulseTemperature);
                ApplyImpulse(m_densityTex[READ], m_densityTex[WRITE], pos, m_mouseImpluseRadius, m_impulseDensity * sign);

                Swap(m_temperatureTex);
                Swap(m_densityTex);
            }

            //Calculates how divergent the velocity is
            ComputeDivergence(m_velocityTex[READ], m_divergenceTex);

            ClearSurface(m_pressureTex[READ]);

            int i = 0;
            for (i = 0; i < m_numJacobiIterations; ++i)
            {
                Jacobi(m_pressureTex[READ], m_divergenceTex, m_pressureTex[WRITE]);
                Swap(m_pressureTex);
            }

            //Use the pressure tex that was last rendered into. This computes divergence free velocity
            SubtractGradient(m_velocityTex[READ], m_pressureTex[READ], m_velocityTex[WRITE]);

            Swap(m_velocityTex);

            //Render the tex you want to see into gui tex. Will only use the red channel
            m_guiMat.SetTexture("_Obstacles", m_obstaclesTex);
            Graphics.Blit(m_densityTex[READ], m_guiTex, m_guiMat);
        }