我目前正在使用以下片段着色器来实现基本的黑白效果:
uniform sampler2D texture;
uniform float time_passed_fraction;
//gl_Color: in the fragment shader, the interpolated color passed from the vertex shader
void main()
{
// lookup the pixel in the texture
vec4 pixel = texture2D(texture, gl_TexCoord[0].xy);
vec3 texel = pixel .rgb;
gl_FragColor = pixel;
float bw_val = max(texel.r,max(texel.g,texel.b));
gl_FragColor.r = pixel.r * (1-time_passed_fraction) + bw_val * time_passed_fraction;
gl_FragColor.g = pixel.g * (1-time_passed_fraction) + bw_val * time_passed_fraction;
gl_FragColor.b = pixel.b * (1-time_passed_fraction) + bw_val * time_passed_fraction;
gl_FragColor.a = pixel.a;
// multiply it by the color
//gl_FragColor = gl_Color * pixel;
}
这个片段着色器在我的电脑上完美运行。但是我从人们那里得到了一些反馈,他们收到了以下错误:
ERROR: 0:17: '-' : wrong operand types no operation '-' exists that takes a left-hand operand of type 'const int' and a right operand of type 'uniform float' (or there is no acceptable conversion)
ERROR: 0:17: '*' : wrong operand types no operation '*' exists that takes a left-hand operand of type 'float' and a right operand of type 'const int' (or there is no acceptable conversion)
ERROR: 0:18: '-' : wrong operand types no operation '-' exists that takes a left-hand operand of type 'const int' and a right operand of type 'uniform float' (or there is no acceptable conversion)
ERROR: 0:18: '*' : wrong operand types no operation '*' exists that takes a left-hand operand of type 'float' and a right operand of type 'const int' (or there is no acceptable conversion)
ERROR: 0:19: '-' : wrong operand types no operation '-' exists that takes a left-hand operand of type 'const int' and a right operand of type 'uniform float' (or there is no acceptable conversion)
这似乎暗示了某些类型错误,但我不明白不一致的来源。有人可以解释一下吗?
注意:第17行是这一行)
gl_FragColor.r = pixel.r * (1-time_passed_fraction) + bw_val * time_passed_fraction;
最佳答案
着色器开头缺少的 #version
指令意味着 #version 110
,正如三十二上校指出的那样,它不支持隐式 int
-> float
转换。
请注意 typeof(1)
== int
!= float
== typeof(1.0)
。
所以你的台词是这样的:
gl_FragColor.r = pixel.r * (1-time_passed_fraction) + bw_val * time_passed_fraction;
^ nope
需要:
gl_FragColor.r = pixel.r * (1.0-time_passed_fraction) + bw_val * time_passed_fraction;
^^^ fix'd
关于c++ - GLSL 类型不一致,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/33579110/