GLSL方向光。
vertex shader的程式碼：
void main()
{
vec3 normal, lightDir, viewVector, halfVector;
vec4 diffuse, ambient, globalAmbient, specular = vec4(0.0);
float NdotL,NdotHV;
/* first transform the normal into eye space and normalize the result */
normal = normalize(gl_NormalMatrix * gl_Normal);
/* now normalize the light's direction. Note that according to the
OpenGL specification, the light is stored in eye space. Also since
we're talking about a directional light, the position field is actually
direction */
lightDir = normalize(vec3(gl_LightSource[0].position));
/* compute the cos of the angle between the normal and lights direction.
The light is directional so the direction is constant for every vertex.
Since these two are normalized the cosine is the dot product. We also
need to clamp the result to the [0,1] range. */
NdotL = max(dot(normal, lightDir), 0.0);
/* Compute the diffuse, ambient and globalAmbient terms */
diffuse = gl_FrontMaterial.diffuse * gl_LightSource[0].diffuse;
ambient = gl_FrontMaterial.ambient * gl_LightSource[0].ambient;
globalAmbient = gl_LightModel.ambient * gl_FrontMaterial.ambient;
/* compute the specular term if NdotL is larger than zero */
if (NdotL > 0.0) {
NdotHV = max(dot(normal, normalize(gl_LightSource[0].halfVector.xyz)),0.0);
specular = gl_FrontMaterial.specular * gl_LightSource[0].specular * pow(NdotHV,gl_FrontMaterial.shininess);
}
gl_FrontColor = globalAmbient + NdotL * diffuse + ambient + specular;
gl_Position = ftransform();
}
fragment shader的程式碼：
void main()
{
gl_FragColor = gl_Color;
}
執行結果：
參考：
逍遙文工作室 
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