OpenGL(使用GLSL)使用glTexBuffer和texelFetch

Question

尝试在OpenGL桌面中渲染一个矩形,但是使用的内部格式glTexBuffer(...)和相应的代码texelFetch(...)对我来说不起作用.我有正确的原始渲染,只需要纠正纹理缓冲部分.以下是相关的代码段

---

unsigned char texData [16] = 
    { 
        255, 0, 0, 0, //Red 
        0,255,0,255, //Green 
        0,0,255,255, //Blue 
        255,0,255,255, //PINK
    }; 
    glGenBuffers( 2,texBuffObj);
    glBindBuffer( GL_TEXTURE_BUFFER,texBuffObj[0]);
    glBufferData( GL_TEXTURE_BUFFER,sizeof(texData),texData,GL_DYNAMIC_DRAW);

    glGenTextures(1, &textureID);
    glBindTexture(GL_TEXTURE_BUFFER, textureID);
    glTexBuffer(GL_TEXTURE_BUFFER,GL_RGBA8UI,texBuffObj[0]);
Fragement Shader Snippet:    


#version 330 core
uniform usamplerBuffer samplerTexBuffer;
out vec4 color;
in vec2 vs_texCoord;
in vec3 vert_Color;
void main()        
{
    int offset = 8; // 0:RED 4:GREEN 8:BLUE 12:PINK
    vec4 colBuff;
    colBuff = texelFetch(samplerTexBuffer,offset) ;
    color = colBuff;
}

---

所需的渲染是这样的:

偏移值0的原始颜色:255,0,0,0,//红色
偏移值4原始颜色:0,255,0,255,//绿色
偏移值8原始颜色:0,0,255,255,//蓝色
偏移值12原始颜色:255,0,255,255,// PINK

---

需要哪些必要的更正？

Answer 1

texelFetch获取纹素坐标,而不是缓冲区中的字节偏移量.由于您的纹素是4个字节宽,您想要使用索引0,1,2,3而不是0,4,8,12来检索它们.