功能： 修改指定像素颜色，实现如边框、头发的变色

用到的sprit2d图片为

演示：

js
shader_type canvas_item;

// uniform 变量，表示边框颜色
uniform vec4 border_color : source_color;
uniform float pxielsize = 2.0;
uniform vec2 textureSize = vec2(24.0, 24.0);

bool isThisPos(vec2 uv, vec2 targetPos)
{
	if((uv.y * textureSize.y>= targetPos.y) && (uv.y * textureSize.y < (targetPos.y+1.0)))
	{
		if((uv.x * textureSize.x >= targetPos.x) && (uv.x * textureSize.x < (targetPos.x+1.0)))
		{
			return true;
		}
	}
	return false;
}

void fragment() {
    // 获取当前像素的UV坐标
	
	float a = texture(TEXTURE, UV).a;
	if(a > 0.01)
	{
		for(int y = 0; y < int(textureSize.y); y++)
		{
			if(isThisPos(UV, vec2(0.0, float(y))))
			{
			    COLOR = border_color;
			}
			if(isThisPos(UV, vec2(1.0, float(y))))
			{
			    COLOR = border_color;
			}
			if(isThisPos(UV, vec2(22.0, float(y))))
			{
			    COLOR = border_color;
			}
			if(isThisPos(UV, vec2(23.0, float(y))))
			{
			    COLOR = border_color;
			}
		}
		for(int x = 0; x < int(textureSize.x); x++)
		{
			if(isThisPos(UV, vec2(float(x), 0.0)))
			{
			    COLOR = border_color;
			}
			if(isThisPos(UV, vec2(float(x), 1.0)))
			{
			    COLOR = border_color;
			}
			if(isThisPos(UV, vec2(float(x), 23.0)))
			{
			    COLOR = border_color;
			}
		}
		if(isThisPos(UV, vec2(2.0, 2.0)))
		{
		    COLOR = border_color;
		}
		if(isThisPos(UV, vec2(2.0, 22.0)))
		{
		    COLOR = border_color;
		}
		if(isThisPos(UV, vec2(21.0, 2.0)))
		{
		    COLOR = border_color;
		}
		if(isThisPos(UV, vec2(21.0, 22.0)))
		{
		    COLOR = border_color;
		}
	}
}

拓展

用此方法筛选点， 此时筛出来的点就是单独的图层，对此图层可做变换操作

js
shader_type canvas_item;

// uniform 变量，表示边框颜色
uniform vec4 border_color : source_color;
uniform float pxielsize = 2.0;
uniform vec2 textureSize = vec2(24.0, 24.0);


// 波浪的频率、振幅和速度
uniform float wave_frequency : hint_range(0.1, 10.0) = 1.0;
uniform float wave_amplitude : hint_range(0.1, 5.0) = 0.5;
uniform float wave_speed : hint_range(0.1, 5.0) = 1.0;


bool isThisPos(vec2 uv, vec2 targetPos)
{
	if((uv.y * textureSize.y>= targetPos.y) && (uv.y * textureSize.y < (targetPos.y+1.0)))
	{
		if((uv.x * textureSize.x >= targetPos.x) && (uv.x * textureSize.x < (targetPos.x+1.0)))
		{
			return true;
		}
	}
	return false;
}

void fragment() {
    // 获取当前像素的UV坐标
//	vec4 border_color = vec4(1.0*sin(PI*TIME),1.0*cos(PI*TIME),1.0*sin(PI*TIME)*cos(PI*TIME),1.0);
	bool isThisUV = false;
	float a = texture(TEXTURE, UV).a;
	if(a > 0.01)
	{
		for(int y = 0; y < int(textureSize.y); y++)
		{
			if(isThisPos(UV, vec2(0.0, float(y))))
			{
			    isThisUV = true;
			}
			if(isThisPos(UV, vec2(1.0, float(y))))
			{
			    isThisUV = true;
			}
			if(isThisPos(UV, vec2(22.0, float(y))))
			{
			    isThisUV = true;
			}
			if(isThisPos(UV, vec2(23.0, float(y))))
			{
			    isThisUV = true;
			}
		}
		for(int x = 0; x < int(textureSize.x); x++)
		{
			if(isThisPos(UV, vec2(float(x), 0.0)))
			{
			    isThisUV = true;
			}
			if(isThisPos(UV, vec2(float(x), 1.0)))
			{
			    isThisUV = true;
			}
			if(isThisPos(UV, vec2(float(x), 23.0)))
			{
			    isThisUV = true;
			}
		}
		if(isThisPos(UV, vec2(2.0, 2.0)))
		{
		    isThisUV = true;
		}
		if(isThisPos(UV, vec2(2.0, 22.0)))
		{
		    isThisUV = true;
		}
		if(isThisPos(UV, vec2(21.0, 2.0)))
		{
		    isThisUV = true;
		}
		if(isThisPos(UV, vec2(21.0, 22.0)))
		{
		    isThisUV = true;
		}
	}
	
	if(isThisUV)
	{
		vec2 uv = UV;

    	// 计算波浪效果
	    float wave = sin(uv.x * wave_frequency + TIME * wave_speed) * wave_amplitude;
	    float wave2 = sin(uv.y * wave_frequency + TIME * wave_speed) * wave_amplitude;

	    // 应用波浪效果到y坐标
	    uv.y += wave;
	    uv.x += wave2;

	    // 获取纹理颜色
	    vec4 current_color = texture(TEXTURE, uv);
		current_color.rgb = border_color.rgb;
	    // 设置最终颜色
	    COLOR = current_color;
	}
}