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StudioLight: Use texel size as input size 

Bettter light distribution for diffuse shading
This commit is contained in:
Jeroen Bakker 2018-06-12 16:18:07 +02:00
parent b236400ff5
commit 866127d9f2
1 changed files with 34 additions and 13 deletions
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47
source/blender/blenkernel/intern/studiolight.c
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@ -347,8 +347,30 @@ static void studiolight_calculate_diffuse_light(StudioLight *sl)
sl->flag |= STUDIOLIGHT_DIFFUSE_LIGHT_CALCULATED;
}
static float area_element(float x, float y )
{
return atan2f(x * y, sqrt(x * x + y * y + 1));
}
static float texel_coord_solid_angle(float a_U, float a_V, int a_Size)
{
//scale up to [-1, 1] range (inclusive), offset by 0.5 to point to texel center.
float u = (2.0f * ((float)a_U + 0.5f) / (float)a_Size ) - 1.0f;
float v = (2.0f * ((float)a_V + 0.5f) / (float)a_Size ) - 1.0f;
float resolution_inv = 1.0f / a_Size;
// U and V are the -1..1 texture coordinate on the current face.
// Get projected area for this texel
float x0 = u - resolution_inv;
float y0 = v - resolution_inv;
float x1 = u + resolution_inv;
float y1 = v + resolution_inv;
return area_element(x0, y0) - area_element(x0, y1) - area_element(x1, y0) + area_element(x1, y1);
}
BLI_INLINE void studiolight_evaluate_specular_radiance_buffer(
ImBuf *radiance_buffer, const float specular, const float normal[3], float color[3], int *hits,
ImBuf *radiance_buffer, const float normal[3], float color[3],
int xoffset, int yoffset, int zoffset, float zvalue)
{
if (radiance_buffer == NULL) {
@ -360,13 +382,14 @@ BLI_INLINE void studiolight_evaluate_specular_radiance_buffer(
for (int y = 0; y < STUDIOLIGHT_RADIANCE_CUBEMAP_SIZE; y ++) {
for (int x = 0; x < STUDIOLIGHT_RADIANCE_CUBEMAP_SIZE; x ++) {
// calculate light direction;
float u = (x / (float)STUDIOLIGHT_RADIANCE_CUBEMAP_SIZE) - 0.5f;
float v = (y / (float)STUDIOLIGHT_RADIANCE_CUBEMAP_SIZE) - 0.5f;
direction[zoffset] = zvalue;
direction[xoffset] = (x / (float)STUDIOLIGHT_RADIANCE_CUBEMAP_SIZE) - 0.5f;
direction[yoffset] = (y / (float)STUDIOLIGHT_RADIANCE_CUBEMAP_SIZE) - 0.5f;
direction[xoffset] = u;
direction[yoffset] = v;
normalize_v3(direction);
angle = pow(fmax(0.0f, dot_v3v3(direction, normal)), specular);
angle = fmax(0.0f, dot_v3v3(direction, normal)) * texel_coord_solid_angle(x, y, STUDIOLIGHT_RADIANCE_CUBEMAP_SIZE);
madd_v3_v3fl(color, radiance_color, angle);
(*hits) ++;
radiance_color += 4;
}
}
@ -375,30 +398,28 @@ BLI_INLINE void studiolight_evaluate_specular_radiance_buffer(
static void studiolight_calculate_specular_irradiance(StudioLight *sl, float color[3], const float normal[3])
{
const float specular = 1.0f;
int hits = 0;
copy_v3_fl(color, 0.0f);
/* back */
studiolight_evaluate_specular_radiance_buffer(
sl->radiance_cubemap_buffers[STUDIOLIGHT_Y_POS], specular, normal, color, &hits, 0, 2, 1, 0.5);
sl->radiance_cubemap_buffers[STUDIOLIGHT_Y_POS], normal, color, 0, 2, 1, 0.5);
/* front */
studiolight_evaluate_specular_radiance_buffer(
sl->radiance_cubemap_buffers[STUDIOLIGHT_Y_NEG], specular, normal, color, &hits, 0, 2, 1, -0.5);
sl->radiance_cubemap_buffers[STUDIOLIGHT_Y_NEG], normal, color, 0, 2, 1, -0.5);
/* left */
studiolight_evaluate_specular_radiance_buffer(
sl->radiance_cubemap_buffers[STUDIOLIGHT_X_POS], specular, normal, color, &hits, 1, 2, 0, 0.5);
sl->radiance_cubemap_buffers[STUDIOLIGHT_X_POS], normal, color, 1, 2, 0, 0.5);
/* right */
studiolight_evaluate_specular_radiance_buffer(
sl->radiance_cubemap_buffers[STUDIOLIGHT_X_NEG], specular, normal, color, &hits, 1, 2, 0, -0.5);
sl->radiance_cubemap_buffers[STUDIOLIGHT_X_NEG], normal, color, 1, 2, 0, -0.5);
/* top */
studiolight_evaluate_specular_radiance_buffer(
sl->radiance_cubemap_buffers[STUDIOLIGHT_Z_POS], specular, normal, color, &hits, 0, 1, 2, 0.5);
sl->radiance_cubemap_buffers[STUDIOLIGHT_Z_POS], normal, color, 0, 1, 2, 0.5);
/* bottom */
studiolight_evaluate_specular_radiance_buffer(
sl->radiance_cubemap_buffers[STUDIOLIGHT_Z_NEG], specular, normal, color, &hits, 0, 1, 2, -0.5);
sl->radiance_cubemap_buffers[STUDIOLIGHT_Z_NEG], normal, color, 0, 1, 2, -0.5);
mul_v3_fl(color, 1.0/ M_PI);
}