Question

我正在研究个人图形引擎，我开始开发聚光灯。问题是渲染不合逻辑。为简单起见，我在下面的着色器示例中清除了有关光和纹理管理的所有信息。

这是顶点着色器代码：

#version 400

layout (location = 0) in vec3 VertexPosition;

uniform mat4 ModelViewMatrix;
uniform mat4 MVP;

out vec3 VPosition;

void main(void)
{
    VPosition = vec3(ModelViewMatrix * vec4(VertexPosition, 1.0f));     //Eye coordinates vertex position
    gl_Position = MVP * vec4(VertexPosition, 1.0f);
}

片段着色器代码：

#version 400

in vec3 Position;   //IN EYE COORDINATES

layout (location = 0) out vec4 FragColor;

uniform int lightCount;

struct SpotLight
{
    vec4 Position;      //ALREADY IN EYE COORDINATES
    vec3 La, Ld, Ls;
    vec3 direction;
    float exponent;
    float cutoff;
};

uniform SpotLight LightInfos[1];

vec3 getLightIntensity(void)
{
    vec3 LightIntensity = vec3(0.0f);

    for (int idx = 0; idx < lightCount; idx++)
    {
        vec3 lightDirNorm = normalize(vec3(LightInfos[idx].Position) - Position);
        vec3 spotDirNorm = normalize(LightInfos[idx].direction);
        float angle = acos(dot(-lightDirNorm, spotDirNorm));
        float cutoff = radians(clamp(LightInfos[idx].cutoff, 0.0f, 90.0f));

        vec3 ambient = vec3(0.1f, 0.1f, 0.8f);      //Color out of the spotlight's cone.
        vec3 spotColor = vec3(0.1f, 0.8f, 0.1f);    //Color within the spotlight's cone.

        if (angle < cutoff)
        {
            LightIntensity = spotColor;
        }
        else
        {
            LightIntensity = ambient;
        }
    }
    return (LightIntensity);
}

void main(void)
{
    FragColor = vec4(getLightIntensity(), 1.0f);
}

这是我发送灯光位置属性的C ++代码：

glm::vec4 lightPositionVec = viewMatrix * glm::vec4(lightPosition[0], lightPosition[1], lightPosition[2], lightPosition[3]);

program->setUniform(std::string("LightInfos[").append(Utils::toString<int>(idx)).append("].Position").c_str(), lightPositionVec);

以下是聚光灯属性：

<position x="0.0" y="2.0" z="0.0" w="1" />
<direction x="0.0" y="-1.0" z="0.0" />
<exponent>3.0</exponent>
<cutoff>50.0</cutoff>

视图属性：

<camera name="cam1">
  <perspective fovy="70.0" ratio="1.0" nearClipPlane="0.1" farClipPlane="1000.0"/>
  <lookat>
     <eye x="0.0" y="50.0" z="50.0" />
     <target x="0.0" y="0.0" z="0.0" />
     <up x="0.0" y="1.0" z="0.0"/>
  </lookat>
</camera>

我在将这些信息发送到我的C ++代码中的程序着色器之前检查了这些信息，它们是正确的。

这是结果：

enter image description here

如果我将相机放置在具有以下相机属性的平面附近：

 <camera name="cam1">
      <perspective fovy="70.0" ratio="1.0" nearClipPlane="0.1" farClipPlane="1000.0"/>
      <lookat>
         <eye x="0.0" y="10.0" z="20.0" />
         <target x="0.0" y="0.0" z="0.0" />
         <up x="0.0" y="1.0" z="0.0"/>
      </lookat>
    </camera>

结果如下（更接近现实，但仍然不正确）：

enter image description here