如何改善2D灯光的外观？

Question

我想照个好灯。我不确定应该怎么称呼它，但是当我实际显示一些示例时，您会看到。

我的好意思是这样的场景：

看起来光有一定区域，在某处结束。

我试图做的是计算从当前像素到光源位置的距离，并将该距离用作光源，看起来一点也不好

我的最后一枪是尝试3D闪电技术。我为场景定义了法线vec3(0.0f, 0.0f, 1.0f)并计算了点光源

struct PointLight
{
    vec3 position;

    float constant;
    float linear;
    float quadratic;  

    vec3 ambient;
    vec3 diffuse;
};

vec3 CalcPointLight(PointLight light, vec3 fragPos)
{
    vec3 normal = normalize(vec3(0.0f, 0.0f, 1.0f));

    vec3 lightDir = normalize(light.position - fragPos);
    float diff = max(dot(normal, lightDir), 0.0);

    float distance = length(light.position - fragPos);
    float attenuation = 1.0 / (light.constant + light.linear * distance + 
                 light.quadratic * (distance * distance));    

    vec3 ambient = light.ambient;
    vec3 diffuse = light.diffuse * diff;

    ambient *= attenuation;
    diffuse *= attenuation;

    return ambient + diffuse;
} 

像这样照亮：

    PointLight light;
    light.position = vec3(0.0f, 0.0f, 0.005f);
    light.constant = 0.5f;
    light.linear = 0.09f;
    light.quadratic = 0.032f;
    light.ambient = vec3(0.1f);
    light.diffuse = vec3(0.8f);

    vec3 result = CalcPointLight(light, vec3(v_position, 0.0f));

    f_color = vec4(result, 1.0) * texture(u_texture, v_uv);

我讨厌的光线中间有一个点！ （当光的z位置为0时，点消失了[也不总是，有时光不起作用]，它看起来很奇怪，但是），当第一个屏幕截图显示为“最大”暗度值，总的来说，我的光线看起来根本不如上面的屏幕那么酷。

整个着色器

#version 460 core

out vec2 v_uv;
out vec2 v_position;

vec4 position[4] = {
    vec4(-1.0f, 1.0f, 0.0f, 1.0f),
    vec4(-1.0f, -1.0f, 0.0f, 0.0f),
    vec4(1.0f, -1.0f, 1.0f, 0.0f),
    vec4(1.0f, 1.0f, 1.0f, 1.0f)
};

void main()
{
    v_uv = position[gl_VertexID].zw;
    v_position = position[gl_VertexID].xy;
    gl_Position = vec4(position[gl_VertexID].xy, 0.0f, 1.0f);
}

#version 460 core

layout (location = 0) out vec4 f_color;

in vec2 v_uv;
in vec2 v_position;

uniform sampler2D u_texture;

struct PointLight
{
    vec3 position;

    float constant;
    float linear;
    float quadratic;  

    vec3 ambient;
    vec3 diffuse;
};

PointLight pointLights[4];

vec3 CalcPointLight(PointLight light, vec3 fragPos)
{
    vec3 normal = normalize(vec3(0.0f, 0.0f, 1.0f));

    vec3 lightDir = normalize(light.position - fragPos);
    float diff = max(dot(normal, lightDir), 0.0);

    float distance = length(light.position - fragPos);
    float attenuation = 1.0 / (light.constant + light.linear * distance + 
                 light.quadratic * (distance * distance));    

    vec3 ambient = light.ambient;
    vec3 diffuse = light.diffuse * diff;

    ambient *= attenuation;
    diffuse *= attenuation;

    return ambient + diffuse;
} 

void main()
{        
    PointLight light;
    light.position = vec3(0.0f, 0.0f, 0.005f);
    light.constant = 1.0f;
    light.linear = 0.09f;
    light.quadratic = 0.032f;
    light.ambient = vec3(0.1f);
    light.diffuse = vec3(0.8f);

    vec3 result = CalcPointLight(light, vec3(v_position, 0.0f));

    light.position = vec3(-0.5f, 0.7f, 0.005f);
    light.constant = 0.5f;
    light.linear = 0.09f;
    light.quadratic = 0.032f;
    light.ambient = vec3(0.1f);
    light.diffuse = vec3(0.8f);

   // result += CalcPointLight(light, vec3(v_position, 0.0f));

    light.position = vec3(0.5f, 0.5f, 0.00f);
    light.constant = 1.0f;
    light.linear = 0.09f;
    light.quadratic = 0.032f;
    light.ambient = vec3(0.1f);
    light.diffuse = vec3(0.8f);

   // result += CalcPointLight(light, vec3(v_position, 0.0f));

    f_color = vec4(result, 1.0) * texture(u_texture, v_uv);
}

如何获得第一张照片所示的效果？

Answer 1

您可以执行smoothstep，类似：

gl_FragColor = smoothstep( yourFinalColour, vec3( 0 ), length( yourLight, uv );