1 files changed, 143 insertions, 0 deletions
diff --git a/externals/g3dlite/G3D.lib/source/GLight.cpp b/externals/g3dlite/G3D.lib/source/GLight.cpp
new file mode 100644
index 00000000000..8acb066ef54
--- /dev/null
+++ b/externals/g3dlite/G3D.lib/source/GLight.cpp
@@ -0,0 +1,143 @@
+/**
+  @file GLight.cpp
+
+  @maintainer Morgan McGuire, matrix@graphics3d.com
+
+  @created 2003-11-12
+  @edited  2007-10-22
+*/
+
+#include "G3D/GLight.h"
+#include "G3D/Sphere.h"
+
+namespace G3D {
+
+GLight::GLight() {
+    position        = Vector4(0, 0, 0, 0);
+    color           = Color3::white();
+    spotDirection   = Vector3(0, 0, -1);
+    spotCutoff      = 180;
+    enabled         = false;
+    attenuation[0]  = 1.0;
+    attenuation[1]  = 0.0;
+    attenuation[2]  = 0.0;
+    specular        = true;
+    diffuse         = true;
+}
+
+
+GLight GLight::directional(const Vector3& toLight, const Color3& color, bool s, bool d) {
+    GLight L;
+    L.position = Vector4(toLight.direction(), 0);
+    L.color    = color;
+    L.specular = s;
+    L.diffuse  = d;
+    return L;
+}
+
+
+GLight GLight::point(const Vector3& pos, const Color3& color, float constAtt, float linAtt, float quadAtt, bool s, bool d) {
+    GLight L;
+    L.position = Vector4(pos, 1);
+    L.color    = color;
+    L.attenuation[0] = constAtt;
+    L.attenuation[1] = linAtt;
+    L.attenuation[2] = quadAtt;
+    L.specular       = s;
+    L.diffuse        = d;
+    return L;
+}
+
+
+GLight GLight::spot(const Vector3& pos, const Vector3& pointDirection, float cutOffAngleDegrees, const Color3& color, float constAtt, float linAtt, float quadAtt, bool s, bool d) {
+    GLight L;
+    L.position       = Vector4(pos, 1.0f);
+    L.spotDirection  = pointDirection.direction();
+    debugAssert(cutOffAngleDegrees <= 90);
+    L.spotCutoff     = cutOffAngleDegrees;
+    L.color          = color;
+    L.attenuation[0] = constAtt;
+    L.attenuation[1] = linAtt;
+    L.attenuation[2] = quadAtt;
+    L.specular       = s;
+    L.diffuse        = d;
+    return L;
+}
+
+
+bool GLight::operator==(const GLight& other) const {
+    return (position == other.position) && 
+        (spotDirection == other.spotDirection) &&
+        (spotCutoff == other.spotCutoff) &&
+        (attenuation[0] == other.attenuation[0]) &&
+        (attenuation[1] == other.attenuation[1]) &&
+        (attenuation[2] == other.attenuation[2]) &&
+        (color == other.color) &&
+        (enabled == other.enabled) &&
+        (specular == other.specular) &&
+        (diffuse == other.diffuse);
+}
+
+bool GLight::operator!=(const GLight& other) const {
+    return !(*this == other);
+}
+
+
+Sphere GLight::effectSphere(float cutoff) const {
+    if (position.w == 0) {
+        // Directional light
+        return Sphere(Vector3::zero(), (float)inf());
+    } else {
+        // Avoid divide by zero
+        cutoff = max(cutoff, 0.0001f);
+        float maxIntensity = max(color.r, max(color.g, color.b));
+
+        float radius = (float)inf();
+            
+        if (attenuation[2] != 0) {
+
+            // Solve I / attenuation.dot(1, r, r^2) < cutoff for r
+            //
+            //  a[0] + a[1] r + a[2] r^2 > I/cutoff
+            //
+            
+            float a = attenuation[2];
+            float b = attenuation[1];
+            float c = attenuation[0] - maxIntensity / cutoff;
+            
+            float discrim = square(b) - 4 * a * c;
+            
+            if (discrim >= 0) {
+                discrim = sqrt(discrim);
+                
+                float r1 = (-b + discrim) / (2 * a);
+                float r2 = (-b - discrim) / (2 * a);
+
+                if (r1 < 0) {
+                    if (r2 > 0) {
+                        radius = r2;
+                    }
+                } else if (r2 > 0) {
+                    radius = min(r1, r2);
+                } else {
+                    radius = r1;
+                }
+            }
+                
+        } else if (attenuation[1] != 0) {
+            
+            // Solve I / attenuation.dot(1, r) < cutoff for r
+            //
+            // r * a[1] + a[0] = I / cutoff
+            // r = (I / cutoff - a[0]) / a[1]
+
+            float radius = (maxIntensity / cutoff - attenuation[0]) / attenuation[1];
+            radius = max(radius, 0.0f);
+        }
+
+        return Sphere(position.xyz(), radius);
+
+    }
+}
+
+}