[英]SpotLight is not seen - OpenGL
我正在OpenGL中进行聚光灯下的项目。 我想我写的代码正确,但是我看不到输出中的圆点。 您的帮助将不胜感激。 在这里,我正在编写片段着色器文件和灯光定义。
fragmentShader.fs
#version 330
in vec3 N; // interpolated normal for the pixel
in vec3 v; // interpolated position for the pixel
// Uniform block for the light source properties
layout (std140) uniform LightSourceProp {
// Light source position in eye space (i.e. eye is at (0, 0, 0))
uniform vec4 lightSourcePosition;
uniform vec4 diffuseLightIntensity;
uniform vec4 specularLightIntensity;
uniform vec4 ambientLightIntensity;
// for calculating the light attenuation
uniform float constantAttenuation;
uniform float linearAttenuation;
uniform float quadraticAttenuation;
// Spotlight direction
uniform vec3 spotDirection;
uniform float cutOffExponent;
// Spotlight cutoff angle
uniform float spotCutoff;
};
// Uniform block for surface material properties
layout (std140) uniform materialProp {
uniform vec4 Kambient;
uniform vec4 Kdiffuse;
uniform vec4 Kspecular;
uniform float shininess;
};
out vec4 color;
// This fragment shader is an example of per-pixel lighting.
void main() {
// Now calculate the parameters for the lighting equation:
// color = Ka * Lag + (Ka * La) + attenuation * ((Kd * (N dot L) * Ld) + (Ks * ((N dot HV) ^ shininess) * Ls))
// Ka, Kd, Ks: surface material properties
// Lag: global ambient light (not used in this example)
// La, Ld, Ls: ambient, diffuse, and specular components of the light source
// N: normal
// L: light vector
// HV: half vector
// shininess
// attenuation: light intensity attenuation over distance and spotlight angle
vec3 lightVector;
float attenuation = 1.0;
float se;
// point light source
lightVector = normalize(lightSourcePosition.xyz - v);
//Calculate Spoteffect
// calculate attenuation
float angle = dot( normalize(spotDirection),
normalize(lightVector));
angle = max(angle,0);
// Test whether vertex is located in the cone
if(acos (angle) > radians(5))
{
float distance = length(lightSourcePosition.xyz - v);
angle = pow(angle,2.0);
attenuation = angle / (constantAttenuation + (linearAttenuation * distance)
+(quadraticAttenuation * distance * distance));
//calculate Diffuse Color
float NdotL = max(dot(N,lightVector), 0.0);
vec4 diffuseColor = Kdiffuse * diffuseLightIntensity * NdotL;
// calculate Specular color. Here we use the original Phong illumination model.
vec3 E = normalize(-v); // Eye vector. We are in Eye Coordinates, so EyePos is (0,0,0)
vec3 R = normalize(-reflect(lightVector,N)); // light reflection vector
float RdotE = max(dot(R,E),0.0);
vec4 specularColor = Kspecular * specularLightIntensity * pow(RdotE,shininess);
// ambient color
vec4 ambientColor = Kambient * ambientLightIntensity;
color = ambientColor + attenuation * (diffuseColor + specularColor);
}
else
color = vec4(1,1,0,1); // lit (yellow)
}
main.cpp中的灯光定义
struct SurfaceMaterialProp {
float Kambient[4]; //ambient component
float Kdiffuse[4]; //diffuse component
float Kspecular[4]; // Surface material property: specular component
float shininess;
};
SurfaceMaterialProp surfaceMaterial1 = {
{1.0f, 1.0f, 1.0f, 1.0f}, // Kambient: ambient coefficient
{1.0f, 0.8f, 0.72f, 1.0f}, // Kdiffuse: diffuse coefficient
{1.0f, 1.0f, 1.0f, 1.0f}, // Kspecular: specular coefficient
5.0f // Shininess
};
struct LightSourceProp {
float lightSourcePosition[4];
float diffuseLightIntensity[4];
float specularLightIntensity[4];
float ambientLightIntensity[4];
float constantAttenuation;
float linearAttenuation;
float quadraticAttenuation;
float spotlightDirection[4];
float spotlightCutoffAngle;
float cutOffExponent;
};
LightSourceProp lightSource1 = {
{ 0.0,400.0,0.0, 1.0 }, // light source position
{1.0f, 0.0f, 0.0f, 1.0f}, // diffuse light intensity
{1.0f, 0.0f, 0.0f, 1.0f}, // specular light intensity
{1.0f, 0.2f, 0.0f, 1.0f}, // ambient light intensity
1.0f, 0.5, 0.1f, // constant, linear, and quadratic attenuation factors
{0.0,50.0,0.0}, // spotlight direction
{5.0f}, // spotlight cutoff angle (in radian)
{2.0f} // spotexponent
};
C ++代码中LightSourceProp
结构的几个成员的顺序与统一块中的顺序不同。
统一块的最后两个成员:
uniform float cutOffExponent;
uniform float spotCutoff;
};
C ++结构的最后两个成员:
float spotlightCutoffAngle;
float cutOffExponent;
};
这两个值被交换。
另外,截止角看起来也很大:
{5.0f}, // spotlight cutoff angle (in radian)
那是一个286度的角度,并不是什么亮点。 对于实际的聚光灯,您可能想要更小的东西,例如0.1f
或0.2f
。
可能给您带来意想不到的结果的另一个方面是您的环境强度很大:
{1.0f, 1.0f, 1.0f, 1.0f}, // Kambient: ambient coefficient
...
{1.0f, 0.2f, 0.0f, 1.0f}, // ambient light intensity
根据您在着色器代码中使用这些值的方式,很可能仅靠环境强度使颜色饱和,并且不会从光源和材质的其他术语中获得任何可见的贡献。 因为环境强度是恒定的,所以这将导致整个几何图形完全平坦。
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