new file mode 100644

Binary files /dev/null and b/doc/02_near-far.tga differ

@@ -25,8 +25,9 @@ auto const infinity = std::numeric_limits<float>::infinity();

 //// Ray

 struct Ray

 {

-    vec3 origin;

-    vec3 direction;

+    vec3  origin;

+    vec3  direction;

+    float range;

 };

 //// Trace

@@ -74,7 +75,7 @@ struct Scene

         for (auto const & shape : shapes)

         {

             auto const trace = shape.trace(ray);

-            if (trace.distance < nearest.distance)

+            if (trace.distance < min(nearest.distance, ray.range))

                 nearest = trace;

         }

         return nearest;

@@ -84,6 +85,8 @@ struct Scene

 //// Camera

 struct Camera

 {

+    float near;

+    float far;

     uvec2 size;

     Ray ray(vec4 const & frag_coord) const

     {

@@ -91,9 +94,11 @@ struct Camera

             (2.0F * vec2(frag_coord.xy) - vec2(size)) / float(size.y),

             -1.0F

         );

-        auto const origin    = vec3(0.0F);

-        auto const direction = normalize(point);

-        return Ray{origin, direction};

+        auto const origin    = near * point;

+        auto const stop      = far  * point;

+        auto const range     = length(stop - origin);

+        auto const direction = (stop - origin) / range;

+        return Ray{origin, direction, range};

     }

 };

@@ -159,8 +164,12 @@ int main(int argc, char const * argv[])

     //// Configure

     auto size        = uvec2(640, 480);

     auto framebuffer = Framebuffer(size);

-    auto camera      = Camera{size};

-    auto scene       = Scene{

+    auto camera = Camera{

+        1.0F,   // near

+        100.0F, // far

+        size,   // size

+    };

+    auto scene = Scene{

         { // shapes

             Sphere{{   6.0F,  -4.0F,  -24.0F}, 12.0F},

             Sphere{{   2.0F,   6.0F,  -16.0F},  8.0F},