From 928b1b0503d2ecab09cc275e9775593a41e417cb Mon Sep 17 00:00:00 2001
From: ladevieq <ladevie.quentin@gmail.com>
Date: Thu, 7 Jul 2022 23:01:36 +0200
Subject: Interpolation function & no more triangle structure in shader

---
 shaders/compute.comp   | 17 +++++------------
 shaders/include/math.h |  8 ++++++++
 shaders/include/ray.h  | 11 +++--------
 3 files changed, 16 insertions(+), 20 deletions(-)

diff --git a/shaders/compute.comp b/shaders/compute.comp
index 6ca193e..0f85da6 100644
--- a/shaders/compute.comp
+++ b/shaders/compute.comp
@@ -36,16 +36,10 @@ struct sphere {
     float[3] padding;
 };
 
-struct vertex {
-    vec3 position;
-    vec3 normal;
-    vec2 uv;
-};
-
 struct triangle {
-    vertex  v1;
-    vertex  v2;
-    vertex  v3;
+    vec3 positions[3];
+    vec3 normals[3];
+    vec2 uvs[3];
     material mat;
 };
 
@@ -141,11 +135,10 @@ vec3 ray_color(ray r, uint seed) {
 
 
 
-        // TODO: Interpolation function & indices decoding function
         triangle tri = get_triangle(info.primitive_id);
 
-        vec3 shading_normal = normalize(tri.v1.normal * info.barycentrics.x + tri.v2.normal * info.barycentrics.y + tri.v3.normal * info.barycentrics.z);
-        vec2 uv = tri.v1.uv * info.barycentrics.x + tri.v2.uv * info.barycentrics.y + tri.v3.uv * info.barycentrics.z;
+        vec2 uv = interpolate_attribute(tri.uvs, info.barycentrics);
+        vec3 shading_normal = normalize(interpolate_attribute(tri.normals, info.barycentrics));
 
         vec3 diffuse_color = srgb_to_linear(texture(
             sampler2D(
diff --git a/shaders/include/math.h b/shaders/include/math.h
index cc4e2f4..c95b065 100644
--- a/shaders/include/math.h
+++ b/shaders/include/math.h
@@ -43,3 +43,11 @@ vec3 rotate_point(vec4 q, vec3 v) {
     const vec3 q_axis = q.xyz;
     return 2.0f * dot(q_axis, v) * q_axis + (q.w * q.w - dot(q_axis, q_axis)) * v + 2.0f * q.w * cross(q_axis, v);
 }
+
+vec3 interpolate_attribute(vec3 values[3], vec3 weights) {
+    return values[0] * weights.x + values[1] * weights.y + values[2] * weights.z;
+}
+
+vec2 interpolate_attribute(vec2 values[3], vec3 weights) {
+    return values[0] * weights.x + values[1] * weights.y + values[2] * weights.z;
+}
diff --git a/shaders/include/ray.h b/shaders/include/ray.h
index 3732c42..221202f 100644
--- a/shaders/include/ray.h
+++ b/shaders/include/ray.h
@@ -55,15 +55,10 @@ vec2[3] get_triangle_uvs(uvec3 indices) {
 
 triangle get_triangle(uint triangle_id) {
     uvec4 indices = decode_triangle_indices(triangle_id);
-    vec3 positions[3] = get_triangle_positions(indices.xyz);
-    vec3 normals[3] = get_triangle_normals(indices.xyz);
-    vec2 uvs[3] = get_triangle_uvs(indices.xyz);
-
-    vertex v1 = vertex(positions[0], normals[0], uvs[0]);
-    vertex v2 = vertex(positions[1], normals[1], uvs[1]);
-    vertex v3 = vertex(positions[2], normals[2], uvs[2]);
     return triangle(
-        v1, v2, v3,
+        get_triangle_positions(indices.xyz),
+        get_triangle_normals(indices.xyz),
+        get_triangle_uvs(indices.xyz),
         bufs.materials_arr.materials[indices.w]
     );
 }
-- 
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