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Color = SrcColor * SrcBlend + DestColor * DestBlend

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Color = (Rs * S1 + Rd * D1, Gs * S2 + Gd * D2, Bs * S3 + Bd * D3, As * S4 + Ad * D4)

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// IDirect3DDevice9* _d3d_device;

// set alpha blend for source color

 _d3d_device->SetRenderState(D3DRS_SRCBLEND, D3DBLEND_SRCALPHA);// set alpha blend for dest color  
  _d3d_device->SetRenderState(D3DRS_DESTBLEND, D3DBLEND_INVSRCALPHA);

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//Defines the supported blend mode.
typedef enum D3DBLEND
{
    D3DBLEND_ZERO = 1,
    D3DBLEND_ONE = 2,
    D3DBLEND_SRCCOLOR = 3,
    D3DBLEND_INVSRCCOLOR = 4,
    D3DBLEND_SRCALPHA = 5,
    D3DBLEND_INVSRCALPHA = 6,
    D3DBLEND_DESTALPHA = 7,
    D3DBLEND_INVDESTALPHA = 8,
    D3DBLEND_DESTCOLOR = 9,
    D3DBLEND_INVDESTCOLOR = 10,
    D3DBLEND_SRCALPHASAT = 11,
    D3DBLEND_BOTHSRCALPHA = 12,
    D3DBLEND_BOTHINVSRCALPHA = 13,
    D3DBLEND_BLENDFACTOR = 14,
    D3DBLEND_INVBLENDFACTOR = 15,
    D3DBLEND_FORCE_DWORD = 0x7fffffff,
} D3DBLEND, *LPD3DBLEND;

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/*************************************************************************************  
 [Include File]

 PURPOSE:   
    Define for alpha blend.  
*************************************************************************************/

#ifndef ALPHA_BLEND_H  
#define ALPHA_BLEND_H

struct CUSTOM_VERTEX  
{  
    float x, y, z;  
    float nx, ny, nz;  
};

#define CUSTOM_VERTEX_FVF   (D3DFVF_XYZ | D3DFVF_NORMAL)

class ALPHA_BLEND  
{  
private:  
    IDirect3D9* _d3d;  
    IDirect3DDevice9* _d3d_device;  
    IDirect3DVertexBuffer9* _vertex_buffer1;  
    IDirect3DVertexBuffer9* _vertex_buffer2;

public:  
    ALPHA_BLEND();  
    ~ALPHA_BLEND();

    bool Create_D3D_Device(HWND hwnd, bool full_screen = true);  
    bool Init_Vertex_Buffer1();  
    bool Init_Vertex_Buffer2();  
    void Compute_Triangle_Normal(D3DXVECTOR3& v1, D3DXVECTOR3& v2, D3DXVECTOR3& v3, D3DVECTOR& normal);  
    void Set_Camera();  
    void Set_Point_Light();  
    void Set_Object_Material(D3DCOLORVALUE& dif, D3DCOLORVALUE& amb, D3DCOLORVALUE& spe,   
                             D3DCOLORVALUE& emi, float power);  
    void Render();  
    void Release_COM_Object();  
};

#endif

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/*************************************************************************************  
 [Implement File]

 PURPOSE:   
    Define for alpha blend.  
*************************************************************************************/

#include "GE_COMMON.h"  
#include "AlphaBlend.h"

//------------------------------------------------------------------------------------  
// Constructor, initialize all pointer with NULL.  
//------------------------------------------------------------------------------------  
ALPHA_BLEND::ALPHA_BLEND()  
{  
    _d3d            = NULL;  
    _d3d_device     = NULL;  
    _vertex_buffer1 = NULL;  
    _vertex_buffer2 = NULL;  
}

//------------------------------------------------------------------------------------  
// Destructor, release all COM object.  
//------------------------------------------------------------------------------------  
ALPHA_BLEND::~ALPHA_BLEND()  
{  
    Release_COM_Object();  
}

//------------------------------------------------------------------------------------  
// Create direct3D interface and direct3D device.  
//------------------------------------------------------------------------------------  
bool ALPHA_BLEND::Create_D3D_Device(HWND hwnd, bool full_screen)  
{  
    // Create a IDirect3D9 object and returns an interace to it.  
    _d3d = Direct3DCreate9(D3D_SDK_VERSION);  
    if(_d3d == NULL)  
        return false;

    // retrieve adapter capability  
    D3DCAPS9 d3d_caps;      
    _d3d->GetDeviceCaps(D3DADAPTER_DEFAULT, D3DDEVTYPE_HAL, &d3d_caps);

         bool hardware_process_enable = (d3d_caps.DevCaps & D3DDEVCAPS_HWTRANSFORMANDLIGHT ? true : false);

    // Retrieves the current display mode of the adapter.  
    D3DDISPLAYMODE display_mode;  
    if(FAILED(_d3d->GetAdapterDisplayMode(D3DADAPTER_DEFAULT, &display_mode)))  
        return false;

    // set present parameter for direct3D device  
    D3DPRESENT_PARAMETERS present_param;

    ZeroMemory(&present_param, sizeof(present_param));

    present_param.BackBufferWidth      = WINDOW_WIDTH;  
    present_param.BackBufferHeight     = WINDOW_HEIGHT;  
    present_param.BackBufferFormat     = display_mode.Format;  
    present_param.BackBufferCount      = 1;  
    present_param.hDeviceWindow        = hwnd;  
    present_param.Windowed             = !full_screen;  
    present_param.SwapEffect           = D3DSWAPEFFECT_FLIP;  
    present_param.PresentationInterval = D3DPRESENT_INTERVAL_DEFAULT;

    // Creates a device to represent the display adapter.  
    DWORD behavior_flags;

    behavior_flags = hardware_process_enable ?  
 D3DCREATE_HARDWARE_VERTEXPROCESSING : D3DCREATE_SOFTWARE_VERTEXPROCESSING;

    if(FAILED(_d3d->CreateDevice(D3DADAPTER_DEFAULT, D3DDEVTYPE_HAL, hwnd, behavior_flags,   
                                 &present_param, &_d3d_device)))  
    {  
        return false;  
    }

         // create successfully  
    return true;  
}

//------------------------------------------------------------------------------------  
// Initialize vertex buffer for cone.  
//------------------------------------------------------------------------------------  
bool ALPHA_BLEND::Init_Vertex_Buffer1()  
{  
    CUSTOM_VERTEX custom_vertex[12];

         D3DXVECTOR3 v[] =   
    {  
        D3DXVECTOR3(5.0f, 6.0f, 5.0f),    // left triangle  
        D3DXVECTOR3(6.0f, 0.0f, 3.0f),  
        D3DXVECTOR3(1.0f, 0.0f, 7.0f),    
        D3DXVECTOR3(5.0f, 6.0f, 5.0f),    // right triangle  
        D3DXVECTOR3(10.0f, 0.0f, 8.0f),  
        D3DXVECTOR3(6.0f, 0.0f, 3.0f),   
        D3DXVECTOR3(5.0f, 6.0f, 5.0f),    // back triangle  
        D3DXVECTOR3(1.0f, 0.0f, 7.0f),  
        D3DXVECTOR3(10.0f, 0.0f, 8.0f),  
        D3DXVECTOR3(1.0f, 0.0f, 7.0f),    // bottom triangle  
        D3DXVECTOR3(6.0f, 0.0f, 3.0f),  
        D3DXVECTOR3(10.0f, 0.0f, 8.0f)        
    };

    D3DVECTOR normal;

    // compute all triangle normal  
    for(int i = 0; i < 12; i += 3)  
    {  
        // compute current triangle's normal  
        Compute_Triangle_Normal(v[i], v[i+1], v[i+2], normal);

        // assign current vertex coordinate and current triangle normal to custom vertex array  
        for(int j = 0; j < 3; j++)  
        {  
            int k = i + j;

            custom_vertex[k].x  = v[k].x;  
            custom_vertex[k].y  = v[k].y;  
            custom_vertex[k].z  = v[k].z;  
            custom_vertex[k].nx = normal.x;  
            custom_vertex[k].ny = normal.y;  
            custom_vertex[k].nz = normal.z;  
        }  
    }

    BYTE* vertex_data;

    // create vertex buffer  
    if(FAILED(_d3d_device->CreateVertexBuffer(12 * sizeof(CUSTOM_VERTEX), 0, CUSTOM_VERTEX_FVF,  
                            D3DPOOL_DEFAULT, &_vertex_buffer1, NULL)))  
    {  
        return false;  
    }

    // get data pointer to vertex buffer  
    if(FAILED(_vertex_buffer1->Lock(0, 0, (void **) &vertex_data, 0)))  
        return false;

    // copy custom vertex data into vertex buffer  
    memcpy(vertex_data, custom_vertex, sizeof(custom_vertex));

    // unlock vertex buffer  
    _vertex_buffer1->Unlock();

    return true;  
}

//------------------------------------------------------------------------------------  
// Initialize vertex buffer for cone.  
//------------------------------------------------------------------------------------  
bool ALPHA_BLEND::Init_Vertex_Buffer2()  
{  
    CUSTOM_VERTEX custom_vertex[12];

    float add = 1.3f;

         D3DXVECTOR3 v[] =   
    {  
        D3DXVECTOR3(5.0f + add, 6.0f + add, 5.0f + add),    // left triangle  
        D3DXVECTOR3(6.0f + add, 0.0f + add, 3.0f + add),  
        D3DXVECTOR3(1.0f + add, 0.0f + add, 7.0f + add),    
        D3DXVECTOR3(5.0f + add, 6.0f + add, 5.0f + add),    // right triangle  
        D3DXVECTOR3(10.0f + add, 0.0f + add, 8.0f + add),  
        D3DXVECTOR3(6.0f + add, 0.0f + add, 3.0f + add),   
        D3DXVECTOR3(5.0f + add, 6.0f + add, 5.0f + add),    // back triangle  
        D3DXVECTOR3(1.0f + add, 0.0f + add, 7.0f + add),  
        D3DXVECTOR3(10.0f + add, 0.0f + add, 8.0f + add),  
        D3DXVECTOR3(1.0f + add, 0.0f + add, 7.0f + add),    // bottom triangle  
        D3DXVECTOR3(6.0f + add, 0.0f + add, 3.0f + add),  
        D3DXVECTOR3(10.0f + add, 0.0f + add, 8.0f + add)        
    };

    D3DVECTOR normal;

    // compute all triangle normal  
    for(int i = 0; i < 12; i += 3)  
    {  
        // compute current triangle's normal  
        Compute_Triangle_Normal(v[i], v[i+1], v[i+2], normal);

        // assign current vertex coordinate and current triangle normal to custom vertex array  
        for(int j = 0; j < 3; j++)  
        {  
            int k = i + j;

            custom_vertex[k].x  = v[k].x;  
            custom_vertex[k].y  = v[k].y;  
            custom_vertex[k].z  = v[k].z;  
            custom_vertex[k].nx = normal.x;  
            custom_vertex[k].ny = normal.y;  
            custom_vertex[k].nz = normal.z;  
        }  
    }

    BYTE* vertex_data;

    // create vertex buffer  
    if(FAILED(_d3d_device->CreateVertexBuffer(12 * sizeof(CUSTOM_VERTEX), 0, CUSTOM_VERTEX_FVF,  
                            D3DPOOL_DEFAULT, &_vertex_buffer2, NULL)))  
    {  
        return false;  
    }

    // get data pointer to vertex buffer  
    if(FAILED(_vertex_buffer2->Lock(0, 0, (void **) &vertex_data, 0)))  
        return false;

    // copy custom vertex data into vertex buffer  
    memcpy(vertex_data, custom_vertex, sizeof(custom_vertex));

    // unlock vertex buffer  
    _vertex_buffer2->Unlock();

    return true;  
}

//------------------------------------------------------------------------------------  
// Set camera position.  
//------------------------------------------------------------------------------------  
void ALPHA_BLEND::Set_Camera()  
{  
    D3DXVECTOR3 eye(-6.0, 1.5, 10.0);  
    D3DXVECTOR3 at(6.0, 2.0, 3.0);  
    D3DXVECTOR3 up(0.0, 1.0, 0.0);

    D3DXMATRIX view_matrix;

    // Builds a left-handed, look-at matrix.  
    D3DXMatrixLookAtLH(&view_matrix, &eye, &at, &up);

    // Sets d3d device view transformation state.  
    _d3d_device->SetTransform(D3DTS_VIEW, &view_matrix);

    D3DXMATRIX proj_matrix;

    // Builds a left-handed perspective projection matrix based on a field of view.  
    D3DXMatrixPerspectiveFovLH(&proj_matrix, D3DX_PI/2, WINDOW_WIDTH / WINDOW_HEIGHT, 1.0, 1000.0);

         // Sets d3d device projection transformation state.  
    _d3d_device->SetTransform(D3DTS_PROJECTION, &proj_matrix);  
    // enable automatic normalization of vertex normals  
    _d3d_device->SetRenderState(D3DRS_NORMALIZENORMALS, true);  
}

//------------------------------------------------------------------------------------  
// Set point light.  
//------------------------------------------------------------------------------------  
void ALPHA_BLEND::Set_Point_Light()  
{  
    D3DLIGHT9 light;

    // clear memory with 0  
    ZeroMemory(&light, sizeof(D3DLIGHT9));

    light.Type          = D3DLIGHT_POINT;

    light.Diffuse.r     = 1.0;  
    light.Diffuse.g     = 0.0;  
    light.Diffuse.b     = 0.0;

    light.Ambient.r     = 0.0;  
    light.Ambient.g     = 1.0;  
    light.Ambient.b     = 0.0;

    light.Specular.r    = 0.0;  
    light.Specular.g    = 0.0;  
    light.Specular.b    = 0.0;

         light.Position.x    = 5.0;  
    light.Position.y    = 6.0;  
    light.Position.z    = -20.0;

    light.Attenuation0  = 1.0;  
    light.Attenuation1  = 0.0;  
    light.Attenuation2  = 0.0;

    light.Range         = 1000.0;

    // Assigns point lighting properties for this device  
    _d3d_device->SetLight(0, &light);  
    // enable point light  
    _d3d_device->LightEnable(0, TRUE);  
    // enable light     _d3d_device->SetRenderState(D3DRS_LIGHTING, TRUE);  
    // add ambient light  
    _d3d_device->SetRenderState(D3DRS_AMBIENT, D3DCOLOR_XRGB(50, 50, 50));  
}

//------------------------------------------------------------------------------------  
// Sets the material properties for the device.  
//------------------------------------------------------------------------------------  
void ALPHA_BLEND::Set_Object_Material(D3DCOLORVALUE& dif, D3DCOLORVALUE& amb, D3DCOLORVALUE& spe,   
                                       D3DCOLORVALUE& emi, float power)  
{  
    D3DMATERIAL9 material;

    material.Diffuse  = dif;  
    material.Ambient  = amb;  
    material.Specular = spe;  
    material.Emissive = emi;  
    material.Power    = power;

    // Sets the material properties for the device.  
    _d3d_device->SetMaterial(&material);  
}

//------------------------------------------------------------------------------------  
// Compute triangle normal.  
//------------------------------------------------------------------------------------  
void ALPHA_BLEND::Compute_Triangle_Normal(D3DXVECTOR3& v1, D3DXVECTOR3& v2, D3DXVECTOR3& v3, D3DVECTOR& normal)  
{  
    D3DXVECTOR3 vec1 = v1 - v2;  
    D3DXVECTOR3 vec2 = v1 - v3;  
    D3DXVECTOR3 normal_vec;

    D3DXVec3Cross(&normal_vec, &vec1, &vec2);  
    D3DXVec3Normalize(&normal_vec, &normal_vec);

    normal = (D3DVECTOR) normal_vec;  
}

//------------------------------------------------------------------------------------  
// Draw cones.  
//------------------------------------------------------------------------------------  
void ALPHA_BLEND::Render()  
{  
    if(_d3d_device == NULL)  
        return;

    // clear surface with black  
    _d3d_device->Clear(0, NULL, D3DCLEAR_TARGET, D3DCOLOR_XRGB(0, 0, 0), 1.0, 0);

    // begin scene  
    _d3d_device->BeginScene();

    // 1) draw cone 1

    // Binds a vertex buffer to a device data stream.

    _d3d_device->SetStreamSource(0, _vertex_buffer1, 0, sizeof(CUSTOM_VERTEX));

    // Sets the current vertex stream declaration.  
    _d3d_device->SetFVF(CUSTOM_VERTEX_FVF);

    // Renders a sequence of nonindexed, geometric primitives of the specified type from the current   
    // set of data input streams.  
    _d3d_device->DrawPrimitive(D3DPT_TRIANGLELIST, 0, 4);

    // enable alpha-blended transparency  
    _d3d_device->SetRenderState(D3DRS_ALPHABLENDENABLE, true);

         // set alpha blend for source cone  
    _d3d_device->SetRenderState(D3DRS_SRCBLEND, D3DBLEND_SRCALPHA);  
    // set alpha blend for dest cone  
    _d3d_device->SetRenderState(D3DRS_DESTBLEND, D3DBLEND_INVSRCALPHA);

    // 2) draw cone 2

    // Binds a vertex buffer to a device data stream. 

    _d3d_device->SetStreamSource(0, _vertex_buffer2, 0, sizeof(CUSTOM_VERTEX));

    // Sets the current vertex stream declaration.  
    _d3d_device->SetFVF(CUSTOM_VERTEX_FVF);

    // draw square  
    _d3d_device->DrawPrimitive(D3DPT_TRIANGLELIST, 0, 4);

    // disable alpha blend for d3d device  
    _d3d_device->SetRenderState(D3DRS_ALPHABLENDENABLE, false);

    // end scene  
    _d3d_device->EndScene();

    // Presents the contents of the next buffer in the sequence of back buffers owned by the device.  
    _d3d_device->Present(NULL, NULL, NULL, NULL);  
}

//------------------------------------------------------------------------------------  
// Release all COM object.  
//------------------------------------------------------------------------------------  
void ALPHA_BLEND::Release_COM_Object()  
{  
    Safe_Release(_vertex_buffer1);  
    Safe_Release(_vertex_buffer2);  
    Safe_Release(_d3d_device);  
    Safe_Release(_d3d);  
}

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/*************************************************************************************  
 [Implement File]

 PURPOSE:   
    Test for alpha blending.  
*************************************************************************************/

#define DIRECTINPUT_VERSION 0x0800

#include "GE_COMMON.h"  
#include "GE_APP.h"  
#include "AlphaBlend.h"

#pragma warning(disable : 4305 4996)int WINAPI WinMain(HINSTANCE instance, HINSTANCE, LPSTR cmd_line, int cmd_show)  
{  
    GE_APP ge_app;  
    ALPHA_BLEND alpha_blend;

    MSG msg = {0};// create window  
    if(! ge_app.Create_Window("Alpha blending test", instance, cmd_show))        return false;

    HWND hwnd = ge_app.Get_Window_Handle();    

    SetWindowPos(hwnd, 0, 0,0,0,0, SWP_NOSIZE);  
    SetCursorPos(0, 0);

// Create direct3D interface and direct3D device.  
    if(! alpha_blend.Create_D3D_Device(hwnd, false))        return false;// Initialize cone 1 vertex buffer with curstom vertex structure.  
    if(! alpha_blend.Init_Vertex_Buffer1())        return false;// Initialize cone 2 vertex buffer with curstom vertex structure.  
    if(! alpha_blend.Init_Vertex_Buffer2())        return false;// Set camera position.  
    alpha_blend.Set_Camera();

    D3DCOLORVALUE dif = {1.0f, 1.0f, 1.0f, 0.6f};  
    D3DCOLORVALUE amb = {1.0f, 1.0f, 1.0f, 0.0f};  
    D3DCOLORVALUE spe = {0.0f, 0.0f, 0.0f, 0.0f};  
    D3DCOLORVALUE emi = {0.0f, 0.0f, 0.0f, 0.0f};// Sets the material properties for the device.  
    alpha_blend.Set_Object_Material(dif, amb, spe, emi, 0);// Set point light.  
    alpha_blend.Set_Point_Light();// Draw all cones  
    alpha_blend.Render();while(msg.message != WM_QUIT)  
    {        if(PeekMessage(&msg, NULL, 0,0 , PM_REMOVE))  
        {  
            TranslateMessage(&msg);  
            DispatchMessage(&msg);  
        }  
    }    

    UnregisterClass(WINDOW_CLASS_NAME, instance);

return true;  
}