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#version 100
precision mediump float;
varying vec3 fragPosition;
varying vec2 fragTexCoord;
varying vec4 fragColor;
varying vec3 fragNormal;
uniform sampler2D texture0;
uniform sampler2D texture1;
uniform sampler2D texture2;
uniform vec4 colAmbient;
uniform vec4 colDiffuse;
uniform vec4 colSpecular;
uniform float glossiness;
uniform int useNormal;
uniform int useSpecular;
uniform mat4 modelMatrix;
uniform vec3 viewDir;
struct Light {
int enabled;
int type;
vec3 position;
vec3 direction;
vec4 diffuse;
float intensity;
float radius;
float coneAngle;
};
const int maxLights = 8;
uniform Light lights[maxLights];
vec3 CalcPointLight(Light l, vec3 n, vec3 v, float s)
{
vec3 surfacePos = vec3(modelMatrix*vec4(fragPosition, 1));
vec3 surfaceToLight = l.position - surfacePos;
// Diffuse shading
float brightness = clamp(dot(n, surfaceToLight)/(length(surfaceToLight)*length(n)), 0, 1);
float diff = 1.0/dot(surfaceToLight/l.radius, surfaceToLight/l.radius)*brightness*l.intensity;
// Specular shading
float spec = 0.0;
if (diff > 0.0)
{
vec3 h = normalize(-l.direction + v);
spec = pow(dot(n, h), 3 + glossiness)*s;
}
return (diff*l.diffuse.rgb + spec*colSpecular.rgb);
}
vec3 CalcDirectionalLight(Light l, vec3 n, vec3 v, float s)
{
vec3 lightDir = normalize(-l.direction);
// Diffuse shading
float diff = clamp(dot(n, lightDir), 0.0, 1.0)*l.intensity;
// Specular shading
float spec = 0.0;
if (diff > 0.0)
{
vec3 h = normalize(lightDir + v);
spec = pow(dot(n, h), 3 + glossiness)*s;
}
// Combine results
return (diff*l.intensity*l.diffuse.rgb + spec*colSpecular.rgb);
}
vec3 CalcSpotLight(Light l, vec3 n, vec3 v, float s)
{
vec3 surfacePos = vec3(modelMatrix*vec4(fragPosition, 1));
vec3 lightToSurface = normalize(surfacePos - l.position);
vec3 lightDir = normalize(-l.direction);
// Diffuse shading
float diff = clamp(dot(n, lightDir), 0.0, 1.0)*l.intensity;
// Spot attenuation
float attenuation = clamp(dot(n, lightToSurface), 0.0, 1.0);
attenuation = dot(lightToSurface, -lightDir);
float lightToSurfaceAngle = degrees(acos(attenuation));
if (lightToSurfaceAngle > l.coneAngle) attenuation = 0.0;
float falloff = (l.coneAngle - lightToSurfaceAngle)/l.coneAngle;
// Combine diffuse and attenuation
float diffAttenuation = diff*attenuation;
// Specular shading
float spec = 0.0;
if (diffAttenuation > 0.0)
{
vec3 h = normalize(lightDir + v);
spec = pow(dot(n, h), 3 + glossiness)*s;
}
return (falloff*(diffAttenuation*l.diffuse.rgb + spec*colSpecular.rgb));
}
void main()
{
// Calculate fragment normal in screen space
// NOTE: important to multiply model matrix by fragment normal to apply model transformation (rotation and scale)
mat3 normalMatrix = transpose(inverse(mat3(modelMatrix)));
vec3 normal = normalize(normalMatrix*fragNormal);
// Normalize normal and view direction vectors
vec3 n = normalize(normal);
vec3 v = normalize(viewDir);
// Calculate diffuse texture color fetching
vec4 texelColor = texture2D(texture0, fragTexCoord);
vec3 lighting = colAmbient.rgb;
// Calculate normal texture color fetching or set to maximum normal value by default
if (useNormal == 1)
{
n *= texture2D(texture1, fragTexCoord).rgb;
n = normalize(n);
}
// Calculate specular texture color fetching or set to maximum specular value by default
float spec = 1.0;
if (useSpecular == 1) spec *= normalize(texture2D(texture2, fragTexCoord).r);
for (int i = 0; i < maxLights; i++)
{
// Check if light is enabled
if (lights[i].enabled == 1)
{
// Calculate lighting based on light type
if(lights[i].type == 0) lighting += CalcPointLight(lights[i], n, v, spec);
else if(lights[i].type == 1) lighting += CalcDirectionalLight(lights[i], n, v, spec);
else if(lights[i].type == 2) lighting += CalcSpotLight(lights[i], n, v, spec);
}
}
// Calculate final fragment color
gl_FragColor = vec4(texelColor.rgb*lighting*colDiffuse.rgb, texelColor.a*colDiffuse.a);
}
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