我想一次渲染大量的点，所以我通过顶点缓冲区对象(VBO)将所有点的数据传递给着色器程序。到目前为止，一切都很好。

缓冲区不仅包含位置信息，还包含一些整数，这些整数应该代表每个点的某些属性。

public struct DataVertex
 {
      public Vector3 position;
      public int tileType;
      public int terrainType;

      public DataVertex(Vector3 position, int tileType, int terrainType)
      {
           this.position = position;
           this.tileType = tileType;
           this.terrainType = terrainType;
      }
 }

为了测试这一点，我想根据整数改变每个点的颜色。为此，我将整数数据从顶点着色器传递到几何体着色器，最后传递到片段着色器，我要在其中设置颜色。但是如果我想请求碎片着色器中的值(通过if语句)，顶点着色器中的制服就消失了(优化了吗？)。问题出在哪里？

顶点明暗器：

# version 450 core

layout (location = 0) in vec3 aPos;
layout (location = 1) in int aTileType;
layout (location = 2) in int aTerrainType;

out DATA
{
    int tileType;
    int terrainType;
    mat4 projection;
} data_out;

uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;

void main()
{   
    gl_Position = vec4(aPos, 1.0) * model;

    data_out.tileType = aTileType;
    data_out.terrainType = aTerrainType;
    data_out.projection = view * projection;
}

几何体着色器：

# version 450 core

layout (points) in;
layout(points, max_vertices = 1) out;

in DATA
{
    int tileType;
    int terrainType;
    mat4 projection;
} data_in[];

out int oTileType;
out int oTerrainType;

void main()
{
    oTileType = data_in[0].tileType;
    oTerrainType = data_in[0].terrainType;
    gl_Position = gl_in[0].gl_Position * data_in[0].projection;
    EmitVertex();

    EndPrimitive();
}

片段着色器：

# version 450 core

out vec4 FragColor;

in int oTileType;
in int oTerrainType;

void main()
{
    if (oTileType == 0)
        FragColor = vec4(0.0f, 0.0f, 1.0f, 1.00f);
    else if (oTileType == 1)
        FragColor = vec4(0.0f, 1.0f, 0.0f, 1.00f);

    else if (oTerrainType == 2)
        FragColor = vec4(1.0f, 1.0f, 0.0f, 1.00f);
}

此版本的片段着色器可以工作：

# version 450 core

out vec4 FragColor;

in int oTileType;
in int oTerrainType;

void main()
{
    FragColor = vec4(1.0f, 1.0f, 0.0f, 1.00f);
}

无论谁对完整的源代码感兴趣，请查看https://github.com/BanditBloodwyn/SimulateTheWorld

相关的类别包括：

• SimulateTheWorld.Graphics.Rendering/Rendering/OpenGLRenderer.cs
• SimulateTheWorld.Graphics.Data/OpenGL/ShaderProgram.cs
• SimulateTheWorld.Graphics.Resources/Rendering/Shaders/中的“点”着色器
• SimulateTheWorld.Graphics.Data.Components.PointCloud.cs