Skip to content

Commit

Permalink
Merge pull request #136 from brown-ccv/fix-blend-intensity
Browse files Browse the repository at this point in the history 
fix blend intensity
  • Loading branch information
@RobertGemmaJr
RobertGemmaJr committed Jul 25, 2022
2 parents 07425f1 + e7a7a12 commit 54f068b
Show file tree
Hide file tree
Showing 3 changed files with 129 additions and 88 deletions.
52 changes: 50 additions & 2 deletions package-lock.json
View file

Some generated files are not rendered by default. Learn more about how customized files appear on GitHub.

4 changes: 2 additions & 2 deletions package.json
View file
Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
{
"name": "react-volume-viewer",
"version": "1.1.2",
"version": "1.1.3",
"description": "Aframe container with custom controls for use in react applications",
"author": "brown-ccv",
"license": "MIT",
Expand Down Expand Up @@ -78,4 +78,4 @@
"/node_modules/(?!d3|d3-array|@reach/listbox|@reach/tabs/styles.css|rc-slider|internmap|delaunator|robust-predicates)"
]
}
}
}
161 changes: 77 additions & 84 deletions src/aframe/fragment-shader.frag
View file
Original file line number Diff line number Diff line change
@@ -1,18 +1,18 @@
# version 300 es
#version 300 es
precision mediump float;
precision highp sampler2D;

#define MAX_MODELS 4
struct ModelStruct {
struct ModelStruct{
bool use;
float intensity;
sampler2D model_texture;
sampler2D transfer_texture;
};

in vec3 vUV; // Coordinates of the texture
in vec3 camPos; // Coordinates of the camera
out vec4 fragColor; // Final output color
in vec3 vUV;// Coordinates of the texture
in vec3 camPos;// Coordinates of the camera
out vec4 fragColor;// Final output color

uniform bool apply_vr_clip;
uniform int blending;
Expand All @@ -25,11 +25,11 @@ uniform float step_size;
uniform mat4 vr_clip_matrix;

/**
Shader code for the VR Volume Viewer
t_: Translation vector
p_: Position vector
m_: Data for an individual model
v_: Data for the entire volume
Shader code for the VR Volume Viewer
t_: Translation vector
p_: Position vector
m_: Data for an individual model
v_: Data for the entire volume
*/

// Clip the volume between clip_min and clip_max
Expand All @@ -53,42 +53,42 @@ vec4 sample_model(ModelStruct model, vec2 start_position, vec2 end_position, flo
);
model_sample.a = max(model_sample.r, max(model_sample.g, model_sample.b));
if(model_sample.a < 0.25) model_sample.a *= 0.1;

// Sample transfer texture
return texture(
model.transfer_texture,
model.transfer_texture,
vec2(clamp(model_sample.a, 0.0, 1.0), 0.5)
);
}

void main() {
// Get the 3D texture coordinates for lookup into the volume dataset
vec3 data_position = vUV;

// Direction the ray is marching in
vec3 ray_direction = normalize(data_position - camPos);

// Get the t values for the intersection with the clipping values
vec2 t_hit = intersectBox(camPos, ray_direction, clip_min, clip_max);
float t_start = t_hit.x;
float t_end = t_hit.y;

/*
We dont want to sample voxels behind the eye if its inside the volume,
so keep the starting point at or in front of the eye
We dont want to sample voxels behind the eye if its inside the volume,
so keep the starting point at or in front of the eye
*/
t_start = max(t_start, 0.0);

/*
We don't know if the ray was cast from the back or the front face. To ensure we
update data_position and t_hit to reflect a ray from entry point to exit
We're shifting the clipping box to [0.0, end - start]
(Note: We only render the back face)
We don't know if the ray was cast from the back or the front face. To ensure we
update data_position and t_hit to reflect a ray from entry point to exit
We're shifting the clipping box to [0.0, end - start]
(Note: We only render the back face)
*/
data_position = camPos + t_start * ray_direction;
t_end = t_end - t_start;
t_start = 0.0;

// Get t for the clipping plane and overwrite the entry point
// This only occurs when grabbing volume in a VR headset
if(apply_vr_clip) {
Expand All @@ -99,81 +99,74 @@ void main() {
vec4 c_pos = vr_clip_matrix * vec4(data_position, 1);
vec4 c_dir = vr_clip_matrix * vec4(ray_direction, 0);
float t_clip = -c_pos.y / c_dir.y;

// Update either entry or exit based on which is on the clipped side
if (p_in.y > 0.0) t_start = t_clip;
else t_end = t_clip;
if (p_in.y > 0.0) t_start = t_clip;
else t_end = t_clip;
} else {
/*
Both points lie on the same side of the plane, if one of them is
on the wrong side they can be clipped
Both points lie on the same side of the plane, if one of them is
on the wrong side they can be clipped
*/
if(p_in.y > 0.0) discard;
if(p_in.y>0.)discard;
}
}
data_position = data_position + t_start * ray_direction;

data_position=data_position+t_start*ray_direction;
// Starting from the entry point, march the ray through the volume and sample it
vec4 vFragColor = vec4(0);
vec4 v_sample;
float intensity = 0.0;
for(float t = t_start; t < t_end; t += step_size) {
vec4 vFragColor=vec4(0);
vec4 v_sample=vec4(0);
float intensity=0.;
float mix_factor=.5;
for(float t=t_start;t<t_end;t+=step_size){
// Get start position, end position, and mix factor to sample models as 3D objects
float z_start = floor(data_position.z / (1.0 / slices));
float z_end = min(z_start + 1.0, slices - 1.0);
vec2 p_start = vec2(mod(z_start, dim), dim - floor(z_start / dim) - 1.0);
vec2 p_end = vec2(mod(z_end, dim), dim - floor(z_end / dim) - 1.0);
vec2 start = vec2(
data_position.x / dim + p_start.x / dim,
data_position.y / dim + p_start.y / dim
float z_start=floor(data_position.z/(1./slices));
float z_end=min(z_start+1.,slices-1.);
vec2 p_start=vec2(mod(z_start,dim),dim-floor(z_start/dim)-1.);
vec2 p_end=vec2(mod(z_end,dim),dim-floor(z_end/dim)-1.);
vec2 start=vec2(
data_position.x/dim+p_start.x/dim,
data_position.y/dim+p_start.y/dim
);
vec2 end = vec2(
data_position.x / dim + p_end.x / dim,
data_position.y / dim + p_end.y / dim
vec2 end=vec2(
data_position.x/dim+p_end.x/dim,
data_position.y/dim+p_end.y/dim
);
float mix_position = data_position.z * slices - z_start;

float mix_position=data_position.z*slices-z_start;
// Sample and mix models into a single volume
if(model_structs[0].use) {
v_sample = sample_model(model_structs[0], start, end, mix_position);
intensity = model_structs[0].intensity;

#pragma unroll_loop_start
for(int i = 1; i < 4; i++) {
if(model_structs[i].use) {
// Sample model and mix in to volume
vec4 m_sample = sample_model(model_structs[i], start, end, mix_position);

// Final intensity is the maximum of the models
intensity = max(model_structs[i].intensity, intensity);

// Calculate the mix factor (0: Max, 1: Min, 2: Average)
float mix_factor = 0.5;
if(blending == 0) mix_factor = max(v_sample.a, m_sample.a);
else if(blending == 1) mix_factor = min(v_sample.a, m_sample.a);
else if (blending == 2) {
// mix uses a percentage - get ratio of the alphas
mix_factor = v_sample.a / (v_sample.a + m_sample.a);
}

v_sample = mix(v_sample, m_sample, mix_factor);

#pragma unroll_loop_start
for(int i=0;i<4;i++){
if(model_structs[i].use){
// Sample model and mix in to volume
vec4 m_sample=sample_model(model_structs[i],start,end,mix_position);

// Artifically increase pixel intensity
m_sample.rgb*=model_structs[i].intensity;

// Calculate the mix factor (0: Max, 1: Min, 2: Average)
if(blending==0)mix_factor=max(v_sample.a,m_sample.a);
else if(blending==1)mix_factor=min(v_sample.a,m_sample.a);
else if(blending==2){
// mix uses a percentage - get ratio of the alphas
mix_factor=v_sample.a/(v_sample.a+m_sample.a);
}

v_sample=mix(v_sample,m_sample,mix_factor);
}
#pragma unroll_loop_end
} else break; // array is "empty", leave vFragColor transparent

// Artifically increase pixel intensity
v_sample.rgb *= intensity;

}
#pragma unroll_loop_end

// Blend front to back
vFragColor.rgb += (1.0 - vFragColor.a) * v_sample.a * v_sample.rgb;
vFragColor.a += (1.0 - vFragColor.a) * v_sample.a;

vFragColor.rgb+=(1.-vFragColor.a)*v_sample.a*v_sample.rgb;
vFragColor.a+=(1.-vFragColor.a)*v_sample.a;
// Early exit if 95% opacity is reached
if (vFragColor.a >= 0.95) break;

if(vFragColor.a>=.95)break;
// Advance point
data_position += ray_direction * step_size;
data_position+=ray_direction*step_size;
}
fragColor = vFragColor;
}
fragColor=vFragColor;
}

0 comments on commit 54f068b

Please sign in to comment.