From 56b278a47f6161f7284be2086ee2409a9a9bcbf9 Mon Sep 17 00:00:00 2001
From: James Lambert <lambertjamesd@gmail.com>
Date: Mon, 6 Jun 2022 13:04:37 -0600
Subject: [PATCH] Fix portal backface culling

---
 README.md          |  6 ++++--
 src/main.c         | 13 ++++++-------
 src/scene/portal.c |  9 ++++-----
 3 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/README.md b/README.md
index a82af01..996c1bc 100644
--- a/README.md
+++ b/README.md
@@ -57,9 +57,11 @@ where `/home/james/Blender/blender-2.93.1-linux-x64` is the folder where blender
 
 ## Current TODO list
 
-Portal culling
 Doorway collision
     Implement collider bitmask
 Cylinder touching bug
-Blank screen on game start
+Radio
+    Create radio model
+    Create radio texture
+    Implement 3D sound
 cube dispenser
\ No newline at end of file
diff --git a/src/main.c b/src/main.c
index 92bb157..f4b833f 100644
--- a/src/main.c
+++ b/src/main.c
@@ -123,10 +123,13 @@ static void gameProc(void* arg) {
 			OS_VI_DIVOT_OFF |
 			OS_VI_DITHER_FILTER_OFF);
 
+    osViBlack(1);
+
     u32 pendingGFX = 0;
     u32 drawBufferIndex = 0;
     u8 frameControl = 0;
-    u8 inputIgnore = 6;
+    u8 inputIgnore = 5;
+    u8 drawingEnabled = 0;
 
     u16* memoryEnd = graphicsLayoutScreenBuffers((u16*)PHYS_TO_K0(osMemSize));
 
@@ -162,22 +165,18 @@ static void gameProc(void* arg) {
                     break;
                 }
 
-                static int renderSkip = 1;
-
-                if (pendingGFX < 2 && !renderSkip) {
+                if (pendingGFX < 2 && drawingEnabled) {
                     graphicsCreateTask(&gGraphicsTasks[drawBufferIndex], (GraphicsCallback)sceneRender, &gScene);
                     drawBufferIndex = drawBufferIndex ^ 1;
                     ++pendingGFX;
-                } else if (renderSkip) {
-                    --renderSkip;
                 }
 
                 controllersTriggerRead();
                 if (inputIgnore) {
                     --inputIgnore;
                 } else {
-
                     sceneUpdate(&gScene);
+                    drawingEnabled = 1;
                 }
                 timeUpdateDelta();
                 soundPlayerUpdate();
diff --git a/src/scene/portal.c b/src/scene/portal.c
index 27b3efe..4bd745e 100644
--- a/src/scene/portal.c
+++ b/src/scene/portal.c
@@ -121,7 +121,7 @@ void renderPropsNext(struct RenderProps* current, struct RenderProps* next, stru
     next->aspectRatio = current->aspectRatio;
     transformConcat(&portalCombined, &current->camera.transform, &next->camera.transform);
 
-    float zBias = (STARTING_RENDER_DEPTH - current->currentDepth - 1) * (-0.01f / STARTING_RENDER_DEPTH);
+    float zBias = (STARTING_RENDER_DEPTH - current->currentDepth - 1) * -0.005f;
 
     // render any objects halfway through portals
     cameraSetupMatrices(&next->camera, renderState, next->aspectRatio, &next->perspectiveCorrect, current->viewport, NULL, 0.0f);
@@ -177,12 +177,11 @@ void portalRender(struct Portal* portal, struct Portal* otherPortal, struct Rend
     struct Vector3 worldForward;
     quatMultVector(&portal->transform.rotation, &forward, &worldForward);
 
-    struct Quaternion inverseCamera;
-    quatConjugate(&props->camera.transform.rotation, &inverseCamera);
-    quatMultVector(&inverseCamera, &worldForward, &forward);
+    struct Vector3 offsetFromCamera;
+    vector3Sub(&props->camera.transform.position, &portal->transform.position, &offsetFromCamera);
 
     // don't render the portal if it is facing the wrong way
-    if (forward.z < 0.0f) {
+    if (vector3Dot(&worldForward, &offsetFromCamera) < 0.0f) {
         return;
     }