// Algorithm from section 2.14.1 of OpenGL 2.1 specification.
attribute highp vec4 vertex;
attribute highp vec3 normal;
attribute highp vec4 texcoord;
uniform mediump mat4 matrix;
uniform mediump mat4 modelView;
uniform mediump mat3 normalMatrix;
varying highp vec4 qTexCoord;
uniform mediump vec4 scli; // Specular intensity of the light
uniform mediump vec3 pli; // Position of the light
uniform mediump float pliw; // 0 for directional, 1 for positional.
uniform mediump vec4 acm; // Ambient color of the material
uniform mediump vec4 dcm; // Diffuse color of the material
uniform mediump vec4 scm; // Specular color of the material
uniform mediump float srm; // Specular exponent of the material
uniform mediump vec4 acs; // Light model's ambient color of the scene
uniform bool viewerAtInfinity; // Light model indicates viewer at infinity
varying mediump vec4 qColor;
varying mediump vec4 qSecondaryColor;
void qLightVertex(vec4 vertex, vec3 normal)
{
int i, material;
vec3 toEye, toLight, h;
float angle, spot, attenuation;
vec4 color, scolor;
vec4 adcomponent, scomponent;
// Start with the material's emissive color and the ambient scene color.
// ecm is assumed to be black.
color = acm * acs;
scolor = vec4(0, 0, 0, 0);
// Vector from the vertex to the eye position (i.e. the origin).
if (viewerAtInfinity)
toEye = vec3(0, 0, 1);
else
toEye = normalize(-vertex.xyz);
// Determine the cosine of the angle between the normal and the
// vector from the vertex to the light.
if (pliw == 0.0)
toLight = normalize(pli);
else
toLight = normalize(pli - vertex.xyz);
angle = max(dot(normal, toLight), 0.0);
// Calculate the ambient and diffuse light components.
// Assumptions: acli = (0, 0, 0, 1), dcli = (1, 1, 1, 1).
adcomponent = acm * vec4(0, 0, 0, 1) + angle * dcm;
// Calculate the specular light components.
if (angle != 0.0) {
h = normalize(toLight + toEye);
angle = max(dot(normal, h), 0.0);
scomponent = pow(angle, srm) * scm; // scli = (1, 1, 1, 1).
} else {
scomponent = vec4(0, 0, 0, 0);
}
// Add up the color components we computed.
color += adcomponent;
scolor += scomponent;
// Generate the final output colors.
float alpha = dcm.a;
qColor = vec4(clamp(color.rgb, 0.0, 1.0), alpha);
qSecondaryColor = clamp(scolor, 0.0, 1.0);
}
void main(void)
{
gl_Position = matrix * vertex;
highp vec4 vertex = modelView * vertex;
highp vec3 norm = normalize(normalMatrix * normal);
qLightVertex(vertex, norm);
qTexCoord = texcoord;
}