2021-07-24 02:31:35 +02:00
|
|
|
#version 430
|
|
|
|
|
|
|
|
layout (location = 1) uniform vec4 t;
|
|
|
|
|
|
|
|
layout(local_size_x = 1, local_size_y = 1) in; // size of local work group - 1 pixel
|
|
|
|
layout(rgba32f, binding = 0) uniform image2D img_output; // rgba32f defines internal format, image2d for random write to output texture
|
|
|
|
|
|
|
|
const float INF = 1000000.0f;
|
|
|
|
|
2021-07-30 00:39:04 +02:00
|
|
|
#include sphere.glsl
|
2021-07-24 02:31:35 +02:00
|
|
|
|
|
|
|
struct Ray
|
|
|
|
{
|
|
|
|
vec3 origin;
|
|
|
|
vec3 direction;
|
|
|
|
};
|
|
|
|
|
|
|
|
struct RayHit
|
|
|
|
{
|
|
|
|
vec3 position;
|
|
|
|
float distance;
|
|
|
|
vec3 normal;
|
|
|
|
};
|
|
|
|
|
|
|
|
void intersectSphere(Ray ray, inout RayHit bestHit, Sphere sphere)
|
|
|
|
{
|
|
|
|
vec3 d = ray.origin-sphere.center;
|
|
|
|
float p1 = -dot(ray.direction,d);
|
|
|
|
float p2sqr = p1*p1-dot(d,d)+sphere.radius*sphere.radius;
|
|
|
|
|
|
|
|
if (p2sqr < 0) return;
|
|
|
|
|
|
|
|
float p2 = sqrt(p2sqr);
|
|
|
|
float t = p1-p2 > 0 ? p1-p2 : p1+p2;
|
|
|
|
if (t > 0 && t < bestHit.distance)
|
|
|
|
{
|
|
|
|
bestHit.distance = t;
|
|
|
|
bestHit.position = ray.origin + t*ray.direction;
|
|
|
|
bestHit.normal = normalize(bestHit.position-sphere.center);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
Ray createCameraRay(vec2 uv)
|
|
|
|
{
|
|
|
|
// transform -1..1 -> 0..1
|
2021-07-30 00:39:04 +02:00
|
|
|
//uv = uv*0.5+0.5;
|
2021-07-24 02:31:35 +02:00
|
|
|
//uv.x=1-uv.x;
|
|
|
|
|
|
|
|
// transform camera origin to world space
|
|
|
|
// TODO: c2w matrix!! for now we just assume the camera is at the origin
|
|
|
|
// float3 origin = mul(_CameraToWorld, float4(0.0,0.0,0.0,1.0)).xyz;
|
|
|
|
|
|
|
|
// TODO: offset from centre of the lens for depth of field
|
|
|
|
// float2 rd = _CameraLensRadius * randomInUnitDisk();
|
|
|
|
// float3 offset = _CameraU * rd.x + _CameraV * rd.y;
|
|
|
|
|
|
|
|
// ...
|
|
|
|
|
|
|
|
float max_x = 5.0;
|
|
|
|
float max_y = 5.0;
|
|
|
|
|
|
|
|
Ray ray;
|
|
|
|
ray.origin = vec3(uv.x * max_x, uv.y * max_y, 0.0);
|
|
|
|
ray.direction = vec3(0.0,0.0,1.0); // ortho forwards
|
|
|
|
|
|
|
|
return ray;
|
|
|
|
}
|
|
|
|
|
|
|
|
void main()
|
|
|
|
{
|
|
|
|
// base pixel colour for the image
|
|
|
|
vec4 pixel = vec4(0.0, 0.0, 0.0, 1.0);
|
|
|
|
// get index in global work group ie xy position
|
|
|
|
ivec2 pixel_coords = ivec2(gl_GlobalInvocationID.xy);
|
|
|
|
|
|
|
|
// set up ray based on pixel position, project it forward with an orthographic projection
|
|
|
|
ivec2 dims = imageSize(img_output); // fetch image dimensions
|
|
|
|
vec2 uv;
|
|
|
|
uv.x = (float(pixel_coords.x * 2 - dims.x) / dims.x) * dims.x/dims.y; // account for aspect ratio
|
|
|
|
uv.y = (float(pixel_coords.y * 2 - dims.y) / dims.y);
|
|
|
|
|
|
|
|
Ray ray = createCameraRay(uv);
|
|
|
|
|
|
|
|
RayHit hit;
|
|
|
|
hit.position = vec3(0.0,0.0,0.0);
|
|
|
|
hit.distance = INF;
|
|
|
|
hit.normal = vec3(0.0,0.0,0.0);
|
|
|
|
|
|
|
|
Sphere sphere;
|
|
|
|
sphere.center = vec3(0.0,0.0,10.0);
|
|
|
|
sphere.radius = 3.0+t.y;
|
|
|
|
|
|
|
|
// ray-sphere intersection
|
|
|
|
intersectSphere(ray, hit, sphere);
|
|
|
|
|
|
|
|
if (hit.distance < INF)
|
|
|
|
{
|
|
|
|
pixel = vec4(t.y,1.0-t.y,1.0,1.0);
|
|
|
|
}
|
|
|
|
|
|
|
|
// output to a specific pixel in the image
|
|
|
|
imageStore(img_output, pixel_coords, pixel);
|
|
|
|
}
|