textureSize 返回 vec2 但编译器告诉我它不是 vec2

Question

我从这篇文章中得到了这个 biqubic 着色器，但由于 vec2 错误识别问题，它无法在我的 glsl 代码中运行，我找不到答案

编译 FRAGMENT_SHADER 时出错：错误：0:44：“=”：无法从“int 的 highp 2 分量向量”转换为“float 的 highp 2 分量向量”

// from http://www.java-gaming.org/index.php?topic=35123.0
vec4 cubic(float v){
    vec4 n = vec4(1.0, 2.0, 3.0, 4.0) - v;
    vec4 s = n * n * n;
    float x = s.x;
    float y = s.y - 4.0 * s.x;
    float z = s.z - 4.0 * s.y + 6.0 * s.x;
    float w = 6.0 - x - y - z;
    return vec4(x, y, z, w) * (1.0/6.0);
}

vec4 textureBicubic(sampler2D sampler, vec2 texCoords){
   /// next line is there the issue is
   vec2 texSize = textureSize(sampler, vec2(0.0, 0.0)).rg;
   
   vec2 invTexSize = 1.0 / texSize;
      
   texCoords = texCoords * texSize - 0.5;
      
   vec2 fxy = fract(texCoords);
   texCoords -= fxy;

   vec4 xcubic = cubic(fxy.x);
   vec4 ycubic = cubic(fxy.y);

   vec4 c = texCoords.xxyy + vec2 (-0.5, +1.5).xyxy;
    
   vec4 s = vec4(xcubic.xz + xcubic.yw, ycubic.xz + ycubic.yw);
   vec4 offset = c + vec4 (xcubic.yw, ycubic.yw) / s;
    
   offset *= invTexSize.xxyy;
    
   vec4 sample0 = texture(sampler, offset.xz);
   vec4 sample1 = texture(sampler, offset.yz);
   vec4 sample2 = texture(sampler, offset.xw);
   vec4 sample3 = texture(sampler, offset.yw);

   float sx = s.x / (s.x + s.y);
   float sy = s.z / (s.z + s.w);

   return mix(
      mix(sample3, sample2, sx), mix(sample1, sample0, sx)
   , sy);
}

原帖：GLSL 中高效的双三次过滤代码？

从纹理中获取 xy 分量textureSize(sampler, vec2(0.0, 0.0)).rg;

Answer 1

当使用带有

textureSize()

的函数时，

ivec2

的返回值为

sampler2D

。而且参数化也不正确（

lod

是一个整数值）。应该是：

ivec2 texSize = textureSize(sampler, 0);

如果您需要浮点向量，请执行以下操作：

vec2 texSize = vec2(textureSize(sampler, 0));