func NewParticleSystem(position, direction glm.Vec3, size int) *ParticleSystem {
ps := ParticleSystem{}
ps.root = position
ps.direction = direction
ps.transformfeedbacks = gl2.GenTransformFeedbacks(2)
MustNotGLError()
ps.buffers = gl2.GenBuffers(2)
MustNotGLError()
ps.particles = make([]Particle, size)
ps.isFirst = true
ps.program = gl2.CreateProgram()
vss, err := CompileShader(vs, gl2.VERTEX_SHADER)
if err != nil {
D(err)
}
ps.program.AttachShader(vss.Loc)
gss, err := CompileShader(gs, gl2.GEOMETRY_SHADER)
if err != nil {
D(err)
}
ps.program.AttachShader(gss.Loc)
fss, err := CompileShader(fs, gl2.FRAGMENT_SHADER)
if err != nil {
D(err)
}
ps.program.AttachShader(fss.Loc)
ps.program.Link()
if !ps.program.GetLinkStatus() {
var logLength int32
gl.GetProgramiv(uint32(ps.program), gl.INFO_LOG_LENGTH, &logLength)
log := strings.Repeat("\x00", int(logLength+1))
gl.GetProgramInfoLog(uint32(ps.program), logLength, nil, gl.Str(log))
}
ps.gDeltaTimeMillis = ps.program.GetUniformLocation("gDeltaTimeMillis")
ps.gTime = ps.program.GetUniformLocation("gTime")
ps.gRandomTexture = ps.program.GetUniformLocation("gRandomTexture")
ps.gLauncherLifetime = ps.program.GetUniformLocation("gLauncherLifetime")
ps.gShellLifetime = ps.program.GetUniformLocation("gShellLifetime")
ps.gSecondaryShellLifetime = ps.program.GetUniformLocation("gSecondaryShellLifetime")
ps.particles[0].Lifetime = 0
ps.particles[0].Position = position
ps.particles[0].Velocity = glm.Vec3{0, 0, 0}
ps.particles[0].Type = Launcher
for i := 0; i < len(ps.buffers); i++ {
ps.transformfeedbacks[i].Bind()
MustNotGLError()
ps.buffers[i].Bind(gl2.ARRAY_BUFFER)
MustNotGLError()
ps.buffers[i].Data(gl2.ARRAY_BUFFER, int(unsafe.Sizeof(Particle{}))*len(ps.particles), unsafe.Pointer(&ps.particles[0]), gl2.DYNAMIC_DRAW)
MustNotGLError()
ps.transformfeedbacks[i].BindBufferBase(gl2.TRANSFORM_FEEDBACK_BUFFER, 0, ps.buffers[i])
MustNotGLError()
}
return &ps
}
//NewProgram will create an OpenGL program from the given shaders, any combinations can be used
func NewProgram(shaders ...Shader) (gl.Program, error) {
program := gl.CreateProgram()
for _, shader := range shaders {
program.AttachShader(shader.Loc)
}
program.Link()
if !program.GetLinkStatus() {
return 0, fmt.Errorf("failed to link program: %v", program.GetInfoLog())
}
return program, nil
}