Flutter Shaders 错误：'exp'：找不到匹配的重载函数

Question

我尝试按照 The Book of Shaders 中的示例来学习 Flutter 中的着色器，但出现以下错误：

'exp'：找不到匹配的重载函数

这是我的着色器：

#include <flutter/runtime_effect.glsl>

// Uniform variables passed from the application
uniform vec2 uResolution; // The resolution of the screen (width, height)
uniform float uTime;      // The elapsed time in seconds
uniform vec2 uMouse;      // The mouse position (x, y)

// Output color of the fragment
out vec4 fragColor;

// Function to plot a line on the Y-axis using a value between 0.0 and 1.0
float plot(vec2 normalizedCoords, float lineYPosition) {    
    // Create a smooth transition around the lineYPosition
    return smoothstep(lineYPosition - 0.02, lineYPosition, normalizedCoords.y) 
         - smoothstep(lineYPosition, lineYPosition + 0.02, normalizedCoords.y);
}

void main() {
    // Normalize the fragment coordinates to the range [0.0, 1.0]
    vec2 normalizedCoords = FlutterFragCoord().xy / uResolution;

    // Calculate the y position using a power function to create a curve
    float y = exp(normalizedCoords.x, 5);

    // Initialize the color vector with the calculated y value
    vec3 color = vec3(y);

    // Plot a line at the calculated y position
    float lineYPosition = plot(normalizedCoords, y);
    
    // Blend the line color (green) with the base color
    color = (1.0 - lineYPosition) * color + lineYPosition * vec3(0.0, 1.0, 0.0);

    // Output the final color with premultiplied alpha
    fragColor = vec4(color, 1.0);
}

Answer 1

问题是 exp() 采用单个参数，因此您不能像文本所示那样在着色器中替换它。更新后的着色器可以正常工作：

#include <flutter/runtime_effect.glsl>

// Uniform variables passed from the application
uniform vec2 uResolution; // The resolution of the screen (width, height)
uniform float uTime;      // The elapsed time in seconds
uniform vec2 uMouse;      // The mouse position (x, y)

// Output color of the fragment
out vec4 fragColor;

// Function to plot a line on the Y-axis using a value between 0.0 and 1.0
float plot(vec2 normalizedCoords, float lineYPosition) {    
    // Create a smooth transition around the lineYPosition
    return smoothstep(lineYPosition - 0.02, lineYPosition, normalizedCoords.y) 
         - smoothstep(lineYPosition, lineYPosition + 0.02, normalizedCoords.y);
}

void main() {
    // Normalize the fragment coordinates to the range [0.0, 1.0]
    vec2 normalizedCoords = FlutterFragCoord().xy / uResolution;

    // Calculate the y position using a power function to create a curve
    float y = exp(normalizedCoords.x * .5) * 0.5;

    // Initialize the color vector with the calculated y value
    vec3 color = vec3(y);

    // Plot a line at the calculated y position
    float lineYPosition = plot(normalizedCoords, y);
    
    // Blend the line color (green) with the base color
    color = (1.0 - lineYPosition) * color + lineYPosition * vec3(0.0, 1.0, 0.0);

    // Output the final color with premultiplied alpha
    fragColor = vec4(color, 1.0);
}