From a47d2c2b57dace249a6f9a4425fb49ddfa9fd6bd Mon Sep 17 00:00:00 2001
From: maelstrom <maelstrom@maelstrom.dev>
Date: Sun, 6 Apr 2025 23:09:04 +0200
Subject: [PATCH] fix(renderer): studs were not properly tiled nor aligned

---
 assets/shaders/phong.fs         | 25 ++++++++++++++++++++++---
 assets/shaders/phong.vs         | 20 ++++----------------
 core/src/rendering/renderer.cpp |  5 +++++
 3 files changed, 31 insertions(+), 19 deletions(-)

diff --git a/assets/shaders/phong.fs b/assets/shaders/phong.fs
index c468124..965919b 100644
--- a/assets/shaders/phong.fs
+++ b/assets/shaders/phong.fs
@@ -39,8 +39,9 @@ const int FaceFront	= 5;
 // I/O
 
 in vec3 vPos;
+in vec3 lPos;
 in vec3 vNormal;
-in vec2 vTexCoords;
+in vec3 lNormal;
 flat in int vSurfaceZ;
 
 out vec4 FragColor;
@@ -54,12 +55,13 @@ uniform DirLight sunLight;
 uniform Material material;
 uniform sampler2DArray studs;
 uniform float transparency;
+uniform vec3 texScale;
 
 // Functions
 
 vec3 calculateDirectionalLight(DirLight light);
 vec3 calculatePointLight(PointLight light);
-
+mat3 lookAlong(vec3 pos, vec3 forward, vec3 up);
 
 // Main
 
@@ -71,11 +73,28 @@ void main() {
     for (int i = 0; i < numPointLights; i++) {
         result += calculatePointLight(pointLights[i]);
     }
+
+    vec3 otherVec = abs(dot(lNormal, vec3(0, 1, 0))) > 0.99 ? vec3(0, 0, 1)
+                    : abs(dot(lNormal, vec3(0, 0, 1))) > 0.99 ? vec3(1, 0, 0)
+                    : vec3(0, 1, 0);
+                    // We use abs(lNormal) so opposing sides "cut" from the same side
+    mat3 transform = transpose(inverse(lookAlong(vec3(0, 0, 0), abs(lNormal), otherVec)));
     
-    vec4 studPx = texture(studs, vec3(vTexCoords, vSurfaceZ));
+    vec2 texCoords = vec2((transform * lPos) * (transform * texScale) / 2) - vec2(mod((transform * texScale) / 4, 1));
+
+    vec4 studPx = texture(studs, vec3(texCoords, vSurfaceZ));
     FragColor = vec4(mix(result, vec3(studPx), studPx.w), 1) * (1-transparency);
 }
 
+mat3 lookAlong(vec3 pos, vec3 forward, vec3 up) {
+    vec3 f = normalize(forward); // Forward/Look
+	vec3 u = normalize(up); // Up
+	vec3 s = normalize(cross(f, u)); // Right
+	u = normalize(cross(s, f));
+
+	return mat3(s, u, f);
+}
+
 vec3 calculateDirectionalLight(DirLight light) {
     // Calculate diffuse
     vec3 norm = normalize(vNormal);
diff --git a/assets/shaders/phong.vs b/assets/shaders/phong.vs
index 1a9a9c3..989d10d 100644
--- a/assets/shaders/phong.vs
+++ b/assets/shaders/phong.vs
@@ -18,7 +18,9 @@ const int SurfaceInlets = 4;
 const int SurfaceUniversal = 5;
 
 out vec3 vPos;
+out vec3 lPos;
 out vec3 vNormal;
+out vec3 lNormal;
 out vec2 vTexCoords;
 flat out int vSurfaceZ;
 
@@ -33,7 +35,9 @@ void main()
 {
     gl_Position = projection * view * model * vec4(aPos, 1.0);
     vPos = vec3(model * vec4(aPos, 1.0));
+    lPos = aPos;
     vNormal = normalMatrix * aNormal;
+    lNormal = aNormal;
     int vFace = aNormal == vec3(0,1,0) ? FaceTop :
             aNormal == vec3(0, -1, 0) ? FaceBottom :
             aNormal == vec3(1, 0, 0) ? FaceRight :
@@ -43,20 +47,4 @@ void main()
 
     vSurfaceZ = surfaces[vFace];
     // if (surfaces[vFace] > SurfaceUniversal) vSurfaceZ = 0;
-
-    switch (vFace) {
-    case FaceTop:
-    case FaceBottom:
-        // vTexCoords = aTexCoords * vec2(texScale.x / 2, fract(surfaceOffset + texScale.z / 12));
-        vTexCoords = aTexCoords * vec2(texScale.x, texScale.z) / 2;
-        break;
-    case FaceLeft:
-    case FaceRight:
-        vTexCoords = aTexCoords * vec2(texScale.y, texScale.z) / 2;
-        break;
-    case FaceFront:
-    case FaceBack:
-        vTexCoords = aTexCoords * vec2(texScale.x, texScale.y) / 2;
-        break;
-    };
 }
diff --git a/core/src/rendering/renderer.cpp b/core/src/rendering/renderer.cpp
index 46de714..7f96356 100644
--- a/core/src/rendering/renderer.cpp
+++ b/core/src/rendering/renderer.cpp
@@ -113,6 +113,11 @@ void renderParts() {
     shader->set("surfaces[1]", SurfaceStuds);
     shader->set("surfaces[4]", SurfaceInlets);
 
+    shader->set("surfaces[0]", SurfaceStuds);
+    shader->set("surfaces[2]", SurfaceStuds);
+    shader->set("surfaces[3]", SurfaceStuds);
+    shader->set("surfaces[5]", SurfaceStuds);
+
     // Pre-calculate the normal matrix for the shader
 
     // Pass in the camera position