Question

我一直在尝试显示网格线框，并将每个边缘作为顶点属性数组传递给自己的颜色。为此，我在顶点缓冲区中为网格的每个边使用了两个顶点。我可以正确显示边缘。问题出现在着色器中的属性位置2,3,4，似乎我没有收到我在VBO中加载的值。当我只重新排序顶点属性时，请说我放了＆＃39; eColor＆＃39;在位置0的属性，我开始在片段着色器中获得正确的值。我想知道原因，为什么会这样。我在不同的环境中使用glfw / Qt在不同的环境中执行了相同的代码，我遇到了同样的问题。任何人都可以指出我的错误。

以下是顶点属性绑定的代码：

    GL_CHECK( glBindVertexArray( mVAO ) );

    GL_CHECK( glUseProgram( mDebugProgram ) );

    GL_CHECK( glGenBuffers( 2 , mVBO ) );

    GL_CHECK( glBindBuffer( GL_ARRAY_BUFFER , mVBO[ 0 ] ) );
    GL_CHECK( glBufferData( GL_ARRAY_BUFFER , mDebugVertexData.size() * sizeof( DebugVertexData ) , mDebugVertexData.data() , GL_DYNAMIC_DRAW ) );

    GL_CHECK( glBindBuffer( GL_ELEMENT_ARRAY_BUFFER , mVBO[ 1 ] ) );

    GL_CHECK( glBufferData( GL_ELEMENT_ARRAY_BUFFER , mDebugWFIndices.size() * sizeof( GLuint ) , mDebugWFIndices.data() , GL_DYNAMIC_DRAW ) );




    int offset = 0;

    GL_CHECK( glVertexAttribPointer( 0 , 3, GL_FLOAT, GL_FALSE, sizeof( DebugVertexData )  , 0) );

    offset = 3 * sizeof( GLfloat );

    GL_CHECK( glVertexAttribPointer( 1 , 3 , GL_FLOAT, GL_FALSE, sizeof (  DebugVertexData  ) , ( float * )offset ) );

    offset = 3 * sizeof( GLfloat );

    GL_CHECK( glVertexAttribPointer( 2 , 3 , GL_FLOAT, GL_FALSE, sizeof (  DebugVertexData  ) , ( float * )offset ) );

    offset = 3 * sizeof( GLfloat );

    GL_CHECK( glVertexAttribPointer( 3 , 1 , GL_FLOAT, GL_FALSE, sizeof (  DebugVertexData  ) , ( float * )offset ) );

    offset = sizeof( GLfloat );

    GL_CHECK( glVertexAttribPointer( 4 , 1 , GL_FLOAT, GL_FALSE, sizeof (  DebugVertexData  ) , ( float * )offset ) );


GL_CHECK( glEnableVertexAttribArray(0) );
GL_CHECK( glEnableVertexAttribArray(1) );
GL_CHECK( glEnableVertexAttribArray(2) );
GL_CHECK( glEnableVertexAttribArray(3) );
GL_CHECK( glEnableVertexAttribArray(4) );



GL_CHECK( glBindBuffer( GL_ARRAY_BUFFER , 0 ) );
GL_CHECK( glBindBuffer( GL_ELEMENT_ARRAY_BUFFER , 0 ) );

GL_CHECK( glUseProgram( 0) );

GL_CHECK( glBindVertexArray(0) );

以下是我的顶点着色器：

#version 410

layout ( location=0 ) in vec3 position;
layout ( location=1 ) in vec3 normal;
layout ( location=2 ) in vec3 eColor;
layout ( location=3 ) in float underRegion;
layout ( location=4 ) in float isSplittable;

out vec4 vPosition;
out vec3 vNormal;
out vec3 vColor;
out float flag1;
out float flag2;


void main()
{
   vPosition = vec4( position , 1 ); 
   vNormal = normal;
   flag1 = underRegion;
   flag2 = isSplittable;

   vColor = eColor;
//   gl_Position = mvpMatrix * vec4( position , 1 ); 
}

这是几何着色器：

#version 410

layout( lines ) in;
layout( line_strip , max_vertices = 2 ) out;

uniform mat4 mvMatrix;
uniform mat4 mvpMatrix;

in vec4[ 2 ] vPosition;
in vec3[ 2 ] vNormal;
in vec3[ 2 ] vColor; 
in float[ 2 ] flag1;
in float[ 2 ] flag2;


// Output to the fragment shader
out float isEdgeSplittable;  
out vec3 edgeColor;


void main()
{

    float l = length( vPosition[ 0 ].xyz - vPosition[ 1 ].xyz );

    vec4 v1 = vPosition[ 0 ];
    vec4 v2 = vPosition[ 1 ];

    v1.xyz += vNormal[ 0 ] * l * 0.001;
    v2.xyz += vNormal[ 1 ] * l * 0.001;

    v1 = mvpMatrix * v1;
    v2 = mvpMatrix * v2;

    edgeColor = vColor[ 0 ];

    gl_Position = v1;

    if( flag1[ 0 ] > 0.5 )
    {
      isEdgeSplittable = 1.0;
    }
    else
    {
      isEdgeSplittable = 0.0;
    }



    EmitVertex();

    gl_Position = v2;

    if( flag1[ 0 ] > 0.5 )
    {
      isEdgeSplittable = 1.0;
    }
    else
    {
      isEdgeSplittable = 0.0;
    }

    edgeColor = vColor[ 1 ];

    EmitVertex();

    EndPrimitive();

}

以下是片段着色器：

#version 410

layout (location = 0) out vec4 color;

in float isEdgeSplittable;  
in vec3 edgeColor;

void main()
{


    color.xyz = edgeColor;//vec3(0 , 0 , 1) ;//eColor2;

    //color.w = 1.0;

    if( isEdgeSplittable > 0.5 )
    {
      color.xyz = vec3( 0 , 0 , 1 );
    }


}

此致

Avanindra

如果顶点属性索引大于2，则值不会正确传递给片段着色器

0 个答案: