CG_Lession 1

最新推荐文章于 2021-09-12 20:45:45 发布

sun_kang

最新推荐文章于 2021-09-12 20:45:45 发布

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分类专栏： CG 文章标签： float matrix null buffer shader parameters

本文链接：https://blog.youkuaiyun.com/sun_kang/article/details/1095727

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struct CGStruct
{
CGparameter modelViewProj ;
CGparameter modelViewInverse ;
CGparameter globalAmbient ;
CGparameter lightColor ;
CGparameter lightPosition ;
CGparameter eyePosition ;
CGparameter Ke ;
CGparameter Ka ;
CGparameter Kd ;
CGparameter Ks ;
CGparameter shininess ;
}CGP;

Vertex g_pVertexArray[24] =
{
//    tu   tv     r    g    b    a      nx    ny    nz       x     y     z
    // Front face
    { 0.0f,0.0f, 1.0f,1.0f,1.0f,1.0f, 0.0f, 0.0f, 1.0f, -1.0f,-1.0f, 1.0f },
    { 1.0f,0.0f, 1.0f,1.0f,1.0f,1.0f, 0.0f, 0.0f, 1.0f,   1.0f,-1.0f, 1.0f },
    { 1.0f,1.0f, 1.0f,1.0f,1.0f,1.0f, 0.0f, 0.0f, 1.0f,   1.0f, 1.0f, 1.0f },
    { 0.0f,1.0f, 1.0f,1.0f,1.0f,1.0f, 0.0f, 0.0f, 1.0f, -1.0f, 1.0f, 1.0f },
    // Back face
    { 1.0f,0.0f, 1.0f,1.0f,1.0f,1.0f, 0.0f, 0.0f,-1.0f, -1.0f,-1.0f,-1.0f },
    { 1.0f,1.0f, 1.0f,1.0f,1.0f,1.0f, 0.0f, 0.0f,-1.0f, -1.0f, 1.0f,-1.0f },
    { 0.0f,1.0f, 1.0f,1.0f,1.0f,1.0f, 0.0f, 0.0f,-1.0f,   1.0f, 1.0f,-1.0f },
    { 0.0f,0.0f, 1.0f,1.0f,1.0f,1.0f, 0.0f, 0.0f,-1.0f,   1.0f,-1.0f,-1.0f },
    // Top face
    { 0.0f,1.0f, 1.0f,1.0f,1.0f,1.0f, 0.0f, 1.0f, 0.0f, -1.0f, 1.0f,-1.0f },
    { 0.0f,0.0f, 1.0f,1.0f,1.0f,1.0f, 0.0f, 1.0f, 0.0f, -1.0f, 1.0f, 1.0f },
    { 1.0f,0.0f, 1.0f,1.0f,1.0f,1.0f, 0.0f, 1.0f, 0.0f,   1.0f, 1.0f, 1.0f },
    { 1.0f,1.0f, 1.0f,1.0f,1.0f,1.0f, 0.0f, 1.0f, 0.0f,   1.0f, 1.0f,-1.0f },
    // Bottom face
    { 1.0f,1.0f, 1.0f,1.0f,1.0f,1.0f, 0.0f,-1.0f, 0.0f, -1.0f,-1.0f,-1.0f },
    { 0.0f,1.0f, 1.0f,1.0f,1.0f,1.0f, 0.0f,-1.0f, 0.0f,   1.0f,-1.0f,-1.0f },
    { 0.0f,0.0f, 1.0f,1.0f,1.0f,1.0f, 0.0f,-1.0f, 0.0f,   1.0f,-1.0f, 1.0f },
    { 1.0f,0.0f, 1.0f,1.0f,1.0f,1.0f, 0.0f,-1.0f, 0.0f, -1.0f,-1.0f, 1.0f },
    // Right face
    { 1.0f,0.0f, 1.0f,1.0f,1.0f,1.0f, 1.0f, 0.0f, 0.0f,   1.0f,-1.0f,-1.0f },
    { 1.0f,1.0f, 1.0f,1.0f,1.0f,1.0f, 1.0f, 0.0f, 0.0f,   1.0f, 1.0f,-1.0f },
    { 0.0f,1.0f, 1.0f,1.0f,1.0f,1.0f, 1.0f, 0.0f, 0.0f,   1.0f, 1.0f, 1.0f },
    { 0.0f,0.0f, 1.0f,1.0f,1.0f,1.0f, 1.0f, 0.0f, 0.0f,   1.0f,-1.0f, 1.0f },
    // Left face
    { 0.0f,0.0f, 1.0f,1.0f,1.0f,1.0f, -1.0f, 0.0f, 0.0f, -1.0f,-1.0f,-1.0f },
    { 1.0f,0.0f, 1.0f,1.0f,1.0f,1.0f, -1.0f, 0.0f, 0.0f, -1.0f,-1.0f, 1.0f },
    { 1.0f,1.0f, 1.0f,1.0f,1.0f,1.0f, -1.0f, 0.0f, 0.0f, -1.0f, 1.0f, 1.0f },
    { 0.0f,1.0f, 1.0f,1.0f,1.0f,1.0f, -1.0f, 0.0f, 0.0f, -1.0f, 1.0f,-1.0f }
};

void initShader(void)
{
//
// Search for a valid vertex shader profile in this order:
//
// CG_PROFILE_ARBVP1 - GL_ARB_vertex_program
// CG_PROFILE_VP30 - GL_NV_vertex_program2
// CG_PROFILE_VP20 - GL_NV_vertex_program
//

   if( cgGLIsProfileSupported(CG_PROFILE_ARBVP1) )
        g_CGprofile = CG_PROFILE_ARBVP1;
    else
  if( cgGLIsProfileSupported(CG_PROFILE_VP30) )
        g_CGprofile = CG_PROFILE_VP30;
else if( cgGLIsProfileSupported(CG_PROFILE_VP20) )
        g_CGprofile = CG_PROFILE_VP20;
    else
    {
        MessageBox( NULL,"Failed to initialize vertex shader! Hardware doesn't "
           "support any of the vertex shading extensions!",
           "ERROR",MB_OK|MB_ICONEXCLAMATION );
  return;
    }

// Create the context...
g_CGcontext = cgCreateContext();

//
// Create the vertex shader...
//

g_CGprogram = cgCreateProgramFromFile( g_CGcontext,
             CG_SOURCE,
             "MyCG.cg",
             g_CGprofile,
             NULL,
             NULL );

//
// Load the program using Cg's expanded interface...
//

cgGLLoadProgram( g_CGprogram );

//
// Bind some parameters by name so we can set them later...
//
CGP.modelViewProj = cgGetNamedParameter( g_CGprogram, "modelViewProj" );
CGP.modelViewInverse = cgGetNamedParameter( g_CGprogram, "modelViewInverse" );
CGP.eyePosition = cgGetNamedParameter( g_CGprogram, "eyePosition" );
CGP.Ka = cgGetNamedParameter( g_CGprogram, "Ka" );
CGP.Kd = cgGetNamedParameter( g_CGprogram, "Kd" );
CGP.Ke = cgGetNamedParameter( g_CGprogram, "Ke" );
CGP.Ks = cgGetNamedParameter( g_CGprogram, "Ks" );
CGP.lightColor = cgGetNamedParameter( g_CGprogram, "lightColor" );
CGP.lightPosition = cgGetNamedParameter( g_CGprogram, "lightPosition" );
CGP.shininess= cgGetNamedParameter( g_CGprogram, "shininess" );

}

void setShaderConstants( void )
{
// This matrix will be used to transform the vertices from model-space to clip-space
cgGLSetStateMatrixParameter( CGP.modelViewProj,
CG_GL_MODELVIEW_PROJECTION_MATRIX,
CG_GL_MATRIX_IDENTITY );

// This matrix will be used to transform the normals from model-space to view-space

cgGLSetStateMatrixParameter( CGP.modelViewInverse ,
CG_GL_MODELVIEW_MATRIX,
CG_GL_MATRIX_INVERSE_TRANSPOSE );

typedef float float3[3] ;
float3 globalAmbient={ 0.8, 0.8, 0.8 } ;
float3 lightColor = { 1.0,0.0,0.0 } ;
float3 Ke ={ 0.8,0.8,0.8} ;
float3 Ka ={ 1.0,1.0,1.0} ;
float3 Ks ={ 0.8,0.0,0.5} ;
float3 Kd ={ 1.0,1.0,1.0} ;
float shininess[]={5.0f };

cgGLSetParameter4fv( CGP.globalAmbient ,globalAmbient );
cgGLSetParameter4fv( CGP.lightColor , lightColor );
cgGLSetParameter4fv( CGP.Ka ,Ka );
cgGLSetParameter4fv( CGP.Ke ,Ke );
cgGLSetParameter4fv( CGP.Ks , Ks );
cgGLSetParameter4fv( CGP.Kd , Kd );
cgGLSetParameter4fv( CGP.shininess , shininess );
}

void render( void )
{
// Clear the screen and the depth buffer
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );

glMatrixMode( GL_MODELVIEW );
glLoadIdentity();
glTranslatef( 0.0f, 0.0f, -5.0f );
// glRotatef( -g_fSpinY, 1.0f, 0.0f, 0.0f );
// glRotatef( -g_fSpinX, 0.0f, 1.0f, 0.0f );

setShaderConstants();

cgGLBindProgram( g_CGprogram );
cgGLEnableProfile( g_CGprofile );

glInterleavedArrays( GL_T2F_C4F_N3F_V3F, 0, g_pVertexArray );
glDrawArrays( GL_QUADS, 0, 24 );

cgGLDisableProfile( g_CGprofile );

SwapBuffers( g_hDC );
}

void shutDown(void)
{

cgDestroyProgram(g_CGprogram);
cgDestroyContext(g_CGcontext);

if( g_hRC != NULL )
{
  wglMakeCurrent( NULL, NULL );
  wglDeleteContext( g_hRC );
  g_hRC = NULL;
}

if( g_hDC != NULL )
{
ReleaseDC( g_hWnd, g_hDC );
g_hDC = NULL;
}
}

MyCG.cg :

void main(float4 position : POSITION,
float3 normal : NORMAL ,

out float4 oPosition : POSITION,
out float4 color : COLOR,

       uniform float4x4   modelViewProj,
       uniform float4x4   modelViewInverse,
       uniform float3 globalAmbient,
       uniform float3 lightColor,
       uniform float3 lightPosition,
       uniform float3 eyePosition,
       uniform float3 Ke,
       uniform float3 Ka,
       uniform float3 Kd,
       uniform float3 Ks,
       uniform float   shininess)
{
// position.z=0.0 ;
oPosition = mul( modelViewProj , position ) ;

float3 P = position.xyz ;
float3 N = normal ;

float3 emissive = Ke ;

float3 ambient = Ka * globalAmbient ;

float3 L = normalize(lightPosition-P ) ;
float diffuseLight = max( dot(N,L),0 );
color=float4( 0.0,0.0,0.0,0.0 ) ;
if(diffuseLight>0.0)
{
  float3 diffuse = Kd * lightColor * diffuseLight ;

  float3 V = normalize( eyePosition - P ) ;
  float3 H = normalize( L+V ) ;
  float3 specular = Ks * lightColor * pow( max(dot(N,H) ,0),shininess ) ;

color.xyz=diffuse + specular ;
}

color.xyz =color.xyz + ambient+emissive ;
color.w = 1 ;
}