Merge a371c8f1e0 into 4528441c74

first vertex clipped against last becomes last vertex
theory i had. fixes clipped horizontal line polygons
2024-11-14 13:27:41 -07:00 · 2024-11-10 13:08:54 +09:00 · 2023-11-26 20:27:44 -05:00
1 changed files with 34 additions and 4 deletions
--- a/src/GPU3D.cpp
+++ b/src/GPU3D.cpp
@ -849,6 +849,8 @@ int ClipAgainstPlane(const GPU3D& gpu, Vertex* vertices, int nverts, int clipsta
        temp[1] = vertices[1];
    }

+    Vertex holdit;
+    bool heldit = false;
    for (int i = clipstart; i < nverts; i++)
    {
        prev = i-1; if (prev < 0) prev = nverts-1;
@ -861,10 +863,18 @@ int ClipAgainstPlane(const GPU3D& gpu, Vertex* vertices, int nverts, int clipsta

            Vertex* vprev = &vertices[prev];
            if (vprev->Position[comp] <= vprev->Position[3])
+            {
+                if (i == 0)
+                {
+                    ClipSegment<comp, 1, attribs>(&holdit, &vtx, vprev);
+                    heldit = true;
+                }
+                else
                {
                    ClipSegment<comp, 1, attribs>(&temp[c], &vtx, vprev);
                    c++;
                }
+            }

            Vertex* vnext = &vertices[next];
            if (vnext->Position[comp] <= vnext->Position[3])
@ -877,6 +887,12 @@ int ClipAgainstPlane(const GPU3D& gpu, Vertex* vertices, int nverts, int clipsta
            temp[c++] = vtx;
    }

+    if (heldit)
+    {
+        temp[c++] = holdit;
+    }
+    heldit = false;
+
    nverts = c; c = clipstart;
    for (int i = clipstart; i < nverts; i++)
    {
@ -888,10 +904,19 @@ int ClipAgainstPlane(const GPU3D& gpu, Vertex* vertices, int nverts, int clipsta
        {
            Vertex* vprev = &temp[prev];
            if (vprev->Position[comp] >= -vprev->Position[3])
+            {
+                
+                if (i == 0)
+                {
+                    ClipSegment<comp, -1, attribs>(&holdit, &vtx, vprev);
+                    heldit = true;
+                }
+                else
                {
                    ClipSegment<comp, -1, attribs>(&vertices[c], &vtx, vprev);
                    c++;
                }
+            }

            Vertex* vnext = &temp[next];
            if (vnext->Position[comp] >= -vnext->Position[3])
@ -904,6 +929,11 @@ int ClipAgainstPlane(const GPU3D& gpu, Vertex* vertices, int nverts, int clipsta
            vertices[c++] = vtx;
    }
    
+    if (heldit)
+    {
+        vertices[c++] = holdit;
+    }
+
    // checkme
    for (int i = 0; i < c; i++)
    {
Author	SHA1	Message	Date
Jakly	8c2213e75b	Merge `a371c8f1e0` into `4528441c74`	2024-11-10 13:08:54 +09:00
Jaklyy	a371c8f1e0	first vertex clipped against last becomes last vertex theory i had. fixes clipped horizontal line polygons	2023-11-26 20:27:44 -05:00