R2LightProjective.h File Reference

Functions and types related to projective lighting. More...

#include "R2LightPositional.h"

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Data Structures
struct	R2_light_projective_vectors_t
	Vectors used when calculating projective lighting. More...

Functions
R2_light_projective_vectors_t	R2_lightProjectiveVectors (const R2_light_positional_t light, const vec3 p, const vec3 n, const mat4x4 m_eye_to_light_eye, const mat4x4 m_light_projection)

Detailed Description

Functions and types related to projective lighting.

Definition in file R2LightProjective.h.

Function Documentation

R2_lightProjectiveVectors()

R2_light_projective_vectors_t R2_lightProjectiveVectors	(	const R2_light_positional_t	light,
		const vec3	p,
		const vec3	n,
		const mat4x4	m_eye_to_light_eye,
		const mat4x4	m_light_projection
	)

Calculate the vectors required to calculate projective lighting.

Parameters

light	The light parameters
p	The surface position (eye-space)
n	The surface normal (eye-space)
m_eye_to_light_eye	A matrix to transform eye-space positions to light-eye-space
m_light_projection	The light's projection matrix

Returns

A set of lighting vectors

Definition at line 42 of file R2LightProjective.h.

{
  R2_light_positional_vectors_t positional =
    R2_lightPositionalVectors (light, p, n);

  vec4 surface_hom =
    vec4 (p, 1.0);
  vec4 surface_light_eye =
    m_eye_to_light_eye * surface_hom;
  vec4 surface_light_clip =
    m_light_projection * surface_light_eye;
  vec3 surface_light_ndc =
    surface_light_clip.xyz / surface_light_clip.w;
  vec2 surface_light_uv =
    (surface_light_ndc.xy + 1.0) * 0.5;

  // Back-projection test.
  float back_projected =
    (surface_light_clip.w < 0.0) ? 0.0 : 1.0;

  return R2_light_projective_vectors_t (
    positional,
    surface_light_eye,
    surface_light_clip,
    surface_light_ndc,
    surface_light_uv,
    back_projected
  );
}