如何让texelFetch函数读取并返回整数类型数据？

函数texelFetch处理浮点型数据正常，但无法正确处理整数型数据。

浮点型可用示例 #

宿主代码 #

float Test[5][2] = { 2.0f, 2.0f };

GLuint tex;
GLuint tbo;
glGenBuffers(1, &tbo);
glBindBuffer(GL_TEXTURE_BUFFER, tbo);
glBufferData(GL_TEXTURE_BUFFER, sizeof(Test), Test, GL_STATIC_DRAW);
glGenTextures(1, &tex);
glBindTexture(GL_TEXTURE_BUFFER, tex);
glTexBuffer(GL_TEXTURE_BUFFER, GL_RG32F, tbo);

片段着色器代码 #

uniform samplerBuffer textureData;

void main()
{    
   vec2 TexBegin = texelFetch(textureData, 0).xy;

   if (TexBegin.x == 2)
   {
      color = vec4(1.0, 0.0, 0.0, 1.0); 
   }
   else
   {
       color = vec4(0.0, 0.0, 0.0, 1.0); 
   }
}

整数型异常示例（仅返回0） #

宿主代码 #

int Test[5][2] = { 2, 2 };

GLuint tex;
GLuint tbo;
glGenBuffers(1, &tbo);
glBindBuffer(GL_TEXTURE_BUFFER, tbo);
glBufferData(GL_TEXTURE_BUFFER, sizeof(Test), Test, GL_STATIC_DRAW);
glGenTextures(1, &tex);
glBindTexture(GL_TEXTURE_BUFFER, tex);
glTexBuffer(GL_TEXTURE_BUFFER, GL_RG32I, tbo);

片段着色器代码 #

uniform samplerBuffer textureData;

void main()
{    
   vec2 TexBegin = texelFetch(textureData, 0).xy;

   if (TexBegin.x == 2)
   {
      color = vec4(1.0, 0.0, 0.0, 1.0); 
   }
   else
   {
       color = vec4(0.0, 0.0, 0.0, 1.0); 
   }
}

将vec2改为ivec2时会报错：“cannot convert float to int”。

内容的提问来源于stack exchange，提问作者Couchy123