/**
* @fn Flo::Initialize()
* @brief Initializes the Flo simulator.
*
* Here we initialize the simulation.
*/
void Flo::Initialize(CGcontext context)
{
// create the offscreen buffer -- this has to be a float buffer because
// we need float precision for the simulation.
_pOffscreenBuffer = new RenderTexture(_iWidth, _iHeight, false);
// Offscreen buffer does not update a texture object, it calls
// wglShareLists, it has no depth/stencil, mipmaps, or aniso filtering.
// 32 bits per channel.
_pOffscreenBuffer->Initialize(true, false, false, false, false,
32, 32, 32, 32);
// Set the constant state for the pbuffer.
_pOffscreenBuffer->BeginCapture();
{
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glMatrixMode(GL_PROJECTION);
gluOrtho2D(0, 1, 0, 1);
glDisable(GL_DEPTH_TEST);
glClearColor(0, 0, 0, 0);
}
_pOffscreenBuffer->EndCapture();
// create texture objects -- there are four: velocity, pressure, divergence,
// and density. All are float textures.
int iTex = 0;
glGenTextures(TEXTURE_COUNT, _iTextures);
for (iTex = 0; iTex < TEXTURE_COUNT; ++iTex)
{
glBindTexture(GL_TEXTURE_RECTANGLE_NV, _iTextures[iTex]);
glTexImage2D(GL_TEXTURE_RECTANGLE_NV, 0, GL_FLOAT_RGBA_NV,
_iWidth, _iHeight, 0, GL_RGBA, GL_FLOAT, NULL);
glTexParameteri(GL_TEXTURE_RECTANGLE_NV,
GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_RECTANGLE_NV,
GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_RECTANGLE_NV,
GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_RECTANGLE_NV,
GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
}
glGenTextures(1, &_iBCTexture);
glBindTexture(GL_TEXTURE_RECTANGLE_NV, _iBCTexture);
glTexImage2D(GL_TEXTURE_RECTANGLE_NV, 0, GL_RGBA8,
_iWidth, _iHeight, 0, GL_RGBA, GL_FLOAT, NULL);
glTexParameteri(GL_TEXTURE_RECTANGLE_NV,
GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_RECTANGLE_NV,
GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_RECTANGLE_NV,
GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_RECTANGLE_NV,
GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
_ClearTexture(_iBCTexture);
glGenTextures(1, &_iBCDisplayTexture);
glBindTexture(GL_TEXTURE_2D, _iBCDisplayTexture);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, 64, 64, 0, GL_RGBA, GL_FLOAT, NULL);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
_ClearTexture(_iBCDisplayTexture, GL_TEXTURE_2D);
// create the display texture
glGenTextures(1, &_iDisplayTexture);
glBindTexture(GL_TEXTURE_2D, _iDisplayTexture);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, _iWidth, _iHeight,
0, GL_RGBA, GL_FLOAT, NULL);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
unsigned char *bcColor = NULL;
int bcWidth, bcHeight, bcChannels;
LoadTGA("bc.tga", bcColor, bcWidth, bcHeight, bcChannels);
glGenTextures(1, &_iBCDetailTexture);
glBindTexture(GL_TEXTURE_2D, _iBCDetailTexture);
glTexImage2D(GL_TEXTURE_2D, 0, bcChannels == 3 ? GL_RGB8 : GL_RGBA8,
bcWidth, bcHeight, 0, bcChannels == 3 ? GL_RGB : GL_RGBA,
GL_UNSIGNED_BYTE, bcColor);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
_CreateOffsetTextures();
// Initialize the slabops...
_InitializeSlabOps(context);
// clear the textures
Reset();
}
void FluidBase::Initialize(CGcontext context)
{
_CreateOffsetTextures();
data_path media;
media.path.push_back(".");
media.path.push_back("Media");
std::string programsPath = media.get_path("programs/gpgpu_fluid/flo.cg");
if (programsPath.empty())
{
printf("Error: Unable to locate Cg programs...\n");
}
programsPath += "/";
std::string args = "-I" + programsPath;
std::vector<const char*> fpargs;
fpargs.clear();
fpargs.push_back(args.c_str());
fpargs.push_back(0);
// Compute the minimum and maximum vertex and texture coordinates for
// rendering the Stream interiors (sans boundaries).
float xMin = 1.0f / (float)_iWidth; // one pixel from left
float xMax = 1.0f - 1.0f / (float)_iWidth; // one pixel from right
float yMin = 1.0f / (float)_iHeight; // on pixel from bottom
float yMax = 1.0f - 1.0f / (float)_iHeight; // one pixel from top
float sMin = 1.0f; // the same, this time in
float sMax = (float)_iWidth - 1.0f; // texture coordinates
float tMin = 1.0f;
float tMax = (float)_iHeight - 1.0f;
//*?* I think this is where at least one change goes.
/*xMin = sMin;
xMax = sMax;
yMin = tMin;
yMax = tMax;*/
// Add Impulse. This renders a Gaussian "splat" into the specified texture,
// with the specified position, radius, and color.
_addImpulse.InitializeFP(context, programsPath + "splat.cg", "splat");
_addImpulse.SetFragmentParameter2f("windowDims",
(float)_iWidth, (float)_iHeight);
_addImpulse.SetTexCoordRect(0, sMin, tMin, sMax, tMax);
_addImpulse.SetStreamRect(xMin, yMin, xMax, yMax);
// Advection: This advects a field by the moving velocity field. This is
// used to advect both velocity and scalar values, such as mass. The result
// of applying this to the velocity field is a moving but divergent velocity
// field. The next few steps correct that divergence to give a divergence-
// free velocity field.
_advect.SetFPArgs(fpargs);
_advect.InitializeFP(context, programsPath + "flo.cg", "advect");
_advect.SetFragmentParameter1f("rdx", 1.0f / _dx);
_advect.SetFragmentParameter1f("dissipation", 1);
_advect.SetTexCoordRect(0, sMin, tMin, sMax, tMax);
_advect.SetStreamRect(xMin, yMin, xMax, yMax);
// Divergence of velocity: This computes how divergent the velocity field is
// (how much in/out flow there is at every point). Used as input to the
// Poisson solver, below.
_divergence.SetFPArgs(fpargs);
_divergence.InitializeFP(context, programsPath + "flo.cg", "divergence");
_divergence.SetFragmentParameter1f("halfrdx", 0.5f / _dx);
_divergence.SetTexCoordRect(0, sMin, tMin, sMax, tMax);
_divergence.SetStreamRect(xMin, yMin, xMax, yMax);
// Poisson-pressure solver: By running this Jacobi Relaxation solver for
// multiple iterations, this solves for the pressure disturbance in the
// fluid given the divergence of the velocity.
_poissonSolver.SetFPArgs(fpargs);
_poissonSolver.InitializeFP(context, programsPath + "flo.cg", "jacobi");
_poissonSolver.SetFragmentParameter1f("alpha", -_dx * _dx);
_poissonSolver.SetFragmentParameter1f("rBeta", 0.25f);
_poissonSolver.SetTexCoordRect(0, sMin, tMin, sMax, tMax);
_poissonSolver.SetStreamRect(xMin, yMin, xMax, yMax);
// Poisson solver for viscous diffusion: By running this Jacobi Relaxation
// solver for multiple iterations, this solves for the velocity diffusion in
// a viscous fluid.
_poissonSolverVec2.SetFPArgs(fpargs);
_poissonSolverVec2.InitializeFP(context, programsPath + "flo.cg", "jacobiVec2");
_poissonSolverVec2.SetTexCoordRect(0, sMin, tMin, sMax, tMax);
_poissonSolverVec2.SetStreamRect(xMin, yMin, xMax, yMax);
// Subtract Gradient. After solving for the pressure disturbance, this
// subtracts the pressure gradient from the divergent velocity field to
// give a divergence-free field.
_subtractGradient.SetFPArgs(fpargs);
_subtractGradient.InitializeFP(context, programsPath + "flo.cg", "gradient");
_subtractGradient.SetFragmentParameter1f("halfrdx", 0.5f / _dx);
_subtractGradient.SetTexCoordRect(0, sMin, tMin, sMax, tMax);
_subtractGradient.SetStreamRect(xMin, yMin, xMax, yMax);
// vorticity computation.
_vorticity.SetFPArgs(fpargs);
_vorticity.InitializeFP(context, programsPath + "flo.cg", "vorticity");
_vorticity.SetFragmentParameter1f("halfrdx", 0.5f / _dx);
_vorticity.SetTexCoordRect(0, sMin, tMin, sMax, tMax);
_vorticity.SetStreamRect(xMin, yMin, xMax, yMax);
// vorticity confinement force computation.
_vorticityForce.SetFPArgs(fpargs);
_vorticityForce.InitializeFP(context, programsPath + "flo.cg", "vortForce");
_vorticityForce.SetFragmentParameter1f("halfrdx", 0.5f / _dx);
_vorticityForce.SetTexCoordRect(0, sMin, tMin, sMax, tMax);
_vorticityForce.SetStreamRect(xMin, yMin, xMax, yMax);
// This applies pure neumann boundary conditions (see floPoissonBC.cg) to
// the pressure field once per iteration of the poisson-pressure jacobi
// solver. Also no-slip BCs to velocity once per time step.
_boundaries.SetFPArgs(fpargs);
_boundaries.InitializeFP(context, programsPath + "flo.cg", "boundary");
_boundaries.SetTexCoordRect(0, 0, (float)_iWidth, (float)_iHeight);
_boundaries.SetTexResolution(_iWidth, _iHeight);
_boundaries.SetFragmentParameter1f("scale", 0);
_updateOffsets.SetFPArgs(fpargs);
_updateOffsets.InitializeFP(context, programsPath + "flo.cg", "updateOffsets");
_updateOffsets.SetTexCoordRect(0, 0, 0, (float)_iWidth, (float)_iHeight);
_updateOffsets.SetStreamRect(xMin, yMin, xMax, yMax);
// setup the arbitrary boundary operations.
_arbitraryVelocityBC.SetFPArgs(fpargs);
_arbitraryVelocityBC.InitializeFP(context, programsPath + "flo.cg",
"arbitraryVelocityBoundary");
_arbitraryVelocityBC.SetTexCoordRect(0, 0, 0, (float)_iWidth, (float)_iHeight);
_arbitraryVelocityBC.SetStreamRect(xMin, yMin, xMax, yMax);
_arbitraryPressureBC.SetFPArgs(fpargs);
_arbitraryPressureBC.InitializeFP(context, programsPath + "flo.cg",
"arbitraryPressureBoundary");
_arbitraryPressureBC.SetTexCoordRect(0, 0, 0, (float)_iWidth, (float)_iHeight);
_arbitraryPressureBC.SetStreamRect(xMin, yMin, xMax, yMax);
_zcullSetupBoundaries.SetFPArgs(fpargs);
_zcullSetupBoundaries.InitializeFP(context, programsPath + "flo.cg", "zCullSetupBoundaries");
_zcullSetupBoundaries.SetTexCoordRect(0, 0, (float)_iWidth, (float)_iHeight);
_zcullSetupBoundaries.SetStreamRect(xMin, yMin, xMax, yMax, 1);
_zcullSetupPressure.SetFPArgs(fpargs);
_zcullSetupPressure.InitializeFP(context, programsPath + "flo.cg", "zCullSetupPressure");
_zcullSetupPressure.SetTexCoordRect(0, 0, (float)_iWidth, (float)_iHeight);
_zcullSetupPressure.SetStreamRect(xMin, yMin, xMax, yMax, 1);
}