commit d52298d1d16f4214dbaafcddae6a9ab0389630d0
parent 7f8e5e1d44a19afb0a0e0d00b3f5932fa5062071
Author: Vincent Forest <vincent.forest@meso-star.com>
Date: Wed, 7 Oct 2015 18:10:20 +0200
Add comments to the estimator code
Diffstat:
2 files changed, 47 insertions(+), 42 deletions(-)
diff --git a/src/salgae_estimator.c b/src/salgae_estimator.c
@@ -39,7 +39,7 @@
#include <star/s3d.h>
#include <star/ssp.h>
-#define NDIRS 5
+#define NDIRS 1 /* # Sampled directions */
struct salgae_estimator {
size_t nsteps;
@@ -63,18 +63,18 @@ morton2D_decode(const uint32_t u32)
return (uint16_t)x;
}
+/* Compute an orthonormal basis where `dir' is the Z axis */
static void
build_basis(const float dir[3], float basis[9])
{
float dir_abs[3];
float axis_min[3];
int i;
- ASSERT(dir && basis);
+ ASSERT(dir && basis && f3_is_normalized(dir));
/* Define which axis direction is minimal and use its unit vector to compute
- * a vector ortogonal to `dir' named `axis0'. This ensures that the unit
- * vector and `dir' are not colinear and thus that their cross product is not
- * a zero vector */
+ * a vector ortogonal to `dir'. This ensures that the unit vector and `dir'
+ * are not colinear and thus that their cross product is not a zero vector */
FOR_EACH(i, 0, 3) dir_abs[i] = absf(dir[i]);
if(dir_abs[0] < dir_abs[1]) {
if(dir_abs[0] < dir_abs[2]) f3(axis_min, 1.f, 0.f, 0.f);
@@ -85,87 +85,91 @@ build_basis(const float dir[3], float basis[9])
}
f3_normalize(basis + 0, f3_cross(basis + 0, dir, axis_min));
- f3_normalize(basis + 3, f3_cross(basis + 3, dir, basis + 0));
+ f3_cross(basis + 3, dir, basis + 0);
f3_set(basis + 6, dir);
}
+/* Compute a 3x4 affine transformation from a orthonormal basis and the
+ * position of the origin */
static FINLINE void
-build_transform(const float pos[3], const float basis[9], float transform[12])
+build_transform
+ (const float pos[3], /* Position of the origin */
+ const float basis[9], /* Column major */
+ float transform[12]) /* Column major */
{
ASSERT(pos && basis && transform);
- /* `transform' is the matrix from world to footprint space while basis is a
- * 3x3 matrix from local to world space. The linear part of the transform
- * matrix is thus the inverse of the `basis' matrix. Since basis encodes an
- * orthonormal transformation, a simple transposition is sufficient to
- * inverse it */
+ /* The linear part of the transformamatrix is the inverse of the
+ * orthonormal basis (i.e. its transpose) */
f3(transform + 0, basis[0], basis[3], basis[6]);
f3(transform + 3, basis[1], basis[4], basis[7]);
f3(transform + 6, basis[2], basis[5], basis[8]);
+
/* Affine part of the transform matrix */
transform[9 ] = -f3_dot(basis+0, pos);
transform[10] = -f3_dot(basis+3, pos);
transform[11] = -f3_dot(basis+6, pos);
}
+/* Cast rays into the RT volume */
static void
-trace_rays
+draw_thumbnail
(struct s3d_scene* scn,
- const float basis[9],
- const float pos[3],
- const float lower[3], /* Transform space lower boundary of the RT volume */
- const float upper[3], /* Transform space upper boundary of the RT volume */
- const char* name)
+ const float basis[9], /* World space basis of the RT volume */
+ const float pos[3], /* World space centroid of the RT volume */
+ const float lower[3], /* Lower boundary of the RT volume */
+ const float upper[3], /* Upper boundary of the RT volume */
+ const char* name) /* Filename of the thumbnail */
{
#define DEFINITION 128
STATIC_ASSERT(IS_POW2(DEFINITION), Invalid_thumbnail_definition);
-
+ const float range[2] = { 0, FLT_MAX };
+ const float pixel_size = 1.f/(float)DEFINITION;
float axis_x[3], axis_y[3], axis_z[3];
float plane_size[2];
- float pixel_size[2];
float ray_org[3];
float org[3];
- float depth;
- float range[2] = {0, FLT_MAX};
uint32_t npixels = (uint32_t)(DEFINITION * DEFINITION);
- uint32_t ipixel;
- uint16_t ipixel_x, ipixel_y;
+ uint32_t mcode;
unsigned char* img = NULL;
ASSERT(basis && pos && lower && upper);
+ /* Allocate the thumbnail buffer */
img = sa_add(img, DEFINITION*DEFINITION);
ASSERT(img != NULL);
+ /* Define the projection axis */
f2_sub(plane_size, upper, lower);
f3_mulf(axis_x, basis + 0, plane_size[0] * 0.5f);
f3_mulf(axis_y, basis + 3, plane_size[1] * 0.5f);
f3_set(axis_z, basis + 6);
- depth = lower[2] + 1.e-3f; /* Ensure to be outside the RT volume */
- f3_add(org, pos, f3_mulf(org, axis_z, depth));
+ /* Compute the origin of the projection plane */
+ f3_add(org, pos, f3_mulf(org, axis_z, lower[2]));
- pixel_size[0] = 1.f/(float)DEFINITION;
- pixel_size[1] = 1.f/(float)DEFINITION;
-
- FOR_EACH(ipixel, 0, npixels) {
+ FOR_EACH(mcode, 0, npixels) {
struct s3d_hit hit;
+ size_t ipixel;
float sample[2], x[3], y[3];
- size_t idst;
+ uint16_t ipixel_x, ipixel_y;
- ipixel_x = morton2D_decode(ipixel);
- ipixel_y = morton2D_decode(ipixel>>1);
- sample[0] = ((float)ipixel_x + 0.5f) * pixel_size[0];
- sample[1] = ((float)ipixel_y + 0.5f) * pixel_size[1];
+ /* Compute the sample position in [0, 1)^2 onto the projection plane */
+ ipixel_x = morton2D_decode(mcode);
+ ipixel_y = morton2D_decode(mcode>>1);
+ sample[0] = ((float)ipixel_x + 0.5f) * pixel_size;
+ sample[1] = ((float)ipixel_y + 0.5f) * pixel_size;
+ /* Compute the ray origin */
f3_mulf(x, axis_x, sample[0]*2.f - 1.f);
f3_mulf(y, axis_y, sample[1]*2.f - 1.f);
f3_add(ray_org, f3_add(ray_org, x, y), org);
S3D(scene_trace_ray(scn, ray_org, axis_z, range, &hit));
- idst = (size_t)(ipixel_y * DEFINITION + ipixel_x);
+ /* Simple shading */
+ ipixel = (size_t)(ipixel_y * DEFINITION + ipixel_x);
if(S3D_HIT_NONE(&hit)) {
- img[idst] = 0;
+ img[ipixel] = 0;
} else {
float N[3] = {0.f,0.f,0.f};
float cosine;
@@ -173,7 +177,7 @@ trace_rays
if(0 > (cosine = f3_dot(N, axis_z))) {
cosine = f3_dot(f3_minus(N, N), axis_z);
}
- img[idst] = (unsigned char)(cosine*255.f);
+ img[ipixel] = (unsigned char)(cosine*255.f + 0.5f/*Round*/);
}
}
image_ppm_write(name, DEFINITION, DEFINITION, 1, img);
@@ -260,14 +264,15 @@ radiative_path_length
}
/* Compute the AABB of the footprint */
- f3_splat(lower, FLT_MAX);
- f3_splat(upper,-FLT_MAX);
+ f3_splat(lower, FLT_MAX); f3_splat(upper,-FLT_MAX);
FOR_EACH(i, 0, 8) {
f3_min(lower, lower, pt[i]);
f3_max(upper, upper, pt[i]);
}
+
+ /* Compute an image of the shape transformed in the footprint space */
sprintf(thumb_name, "%d_%d.ppm", istep, idir);
- trace_rays(scene, basis, centroid, lower, upper, thumb_name);
+ draw_thumbnail(scene, basis, centroid, lower, upper, thumb_name);
}
S3D(scene_end_session(scene));
diff --git a/src/test_salgae_estimator.c b/src/test_salgae_estimator.c
@@ -184,7 +184,7 @@ main(int argc, char** argv)
CHECK(salgae_integrate(NULL, NULL, &desc, 0, 1, &estimator), RES_BAD_ARG);
CHECK(salgae_integrate(dev, NULL, &desc, 0, 1, &estimator), RES_BAD_ARG);
CHECK(salgae_integrate(NULL, rng, &desc, 0, 1, &estimator), RES_BAD_ARG);
- CHECK(salgae_integrate(dev, rng, &desc, 0, 10, &estimator), RES_OK);
+ CHECK(salgae_integrate(dev, rng, &desc, 0, 100, &estimator), RES_OK);
CHECK(salgae_estimator_ref_get(NULL), RES_BAD_ARG);
CHECK(salgae_estimator_ref_get(estimator), RES_OK);
