From 6dce4e3a8319c7a8713463f674965f25b04c8ed2 Mon Sep 17 00:00:00 2001
From: Carlos Sanchez <randomouscrap98@aol.com>
Date: Wed, 31 Jul 2024 01:17:09 -0400
Subject: [PATCH] Move clipping to triangle drawing

---
 renderer1/hrend/render.go | 11 +++++++++++
 renderer1/main.go         | 31 ++++++++++++-------------------
 2 files changed, 23 insertions(+), 19 deletions(-)

diff --git a/renderer1/hrend/render.go b/renderer1/hrend/render.go
index e4b601c..97ded37 100644
--- a/renderer1/hrend/render.go
+++ b/renderer1/hrend/render.go
@@ -36,7 +36,15 @@ func EdgeIncrementi(v1, v2 Vec2i) (int, int) {
 	return (v2.Y - v1.Y), -(v2.X - v1.X)
 }
 
+func ZClip(v0f Vec3f, v1f Vec3f, v2f Vec3f) bool {
+	maxz := max(v0f.Z, v1f.Z, v2f.Z)
+	return maxz < 0 || maxz > 1
+}
+
 func TriangleFlat(fb *RenderBuffer, color uint, v0f Vec3f, v1f Vec3f, v2f Vec3f) {
+	if ZClip(v0f, v1f, v2f) {
+		return
+	}
 	v0 := v0f.ToVec2i()
 	v1 := v1f.ToVec2i()
 	v2 := v2f.ToVec2i()
@@ -103,6 +111,9 @@ func TriangleFlat(fb *RenderBuffer, color uint, v0f Vec3f, v1f Vec3f, v2f Vec3f)
 }
 
 func TriangleTextured(fb *RenderBuffer, texture Framebuffer, intensity float32, v0v Vertex, v1v Vertex, v2v Vertex) {
+	if ZClip(v0v.Pos, v1v.Pos, v2v.Pos) {
+		return
+	}
 	v0 := v0v.Pos.ToVec2i()
 	v1 := v1v.Pos.ToVec2i()
 	v2 := v2v.Pos.ToVec2i()
diff --git a/renderer1/main.go b/renderer1/main.go
index 46d2018..58e441c 100644
--- a/renderer1/main.go
+++ b/renderer1/main.go
@@ -5,7 +5,6 @@ import (
 	"fmt"
 	"image"
 	"log"
-	"math"
 	"os"
 	"renderer1/hrend"
 	"runtime/pprof" // For performance profiling (unnecessary)
@@ -91,11 +90,11 @@ func main() {
 	rb := hrend.NewRenderbuffer(fb, Width, Height)
 	o, texture := loadDefault()
 
-	light := hrend.Vec3f{
-		X: 0,
-		Y: 0,
-		Z: -1,
-	}
+	// light := hrend.Vec3f{
+	// 	X: 0,
+	// 	Y: 0,
+	// 	Z: -1,
+	// }
 
 	var thing hrend.Vec2i
 	log.Print(thing)
@@ -158,24 +157,18 @@ func main() {
 		for _, f := range o.Faces {
 			// Precompute perspective for vertices to save time. Notice Z
 			// is not considered: is this orthographic projection? Yeah probably...
-			var fpt [3]hrend.Vec3f
-			maxz := float32(-math.MaxFloat32)
+			//var fpt [3]hrend.Vec3f
 			for i := range 3 { // Triangles, bro
 				sc[i] = f[i]
 				sc[i].Pos = screenmat.MultiplyPoint3(f[i].Pos)
-				fpt[i] = worldToCamera.MultiplyPoint3(f[i].Pos)
-				maxz = max(maxz, sc[i].Pos.Z)
+				//fpt[i] = worldToCamera.MultiplyPoint3(f[i].Pos)
 			}
 
-			if maxz < 0 || maxz > 1 {
-				//log.Printf("Clipping %f %f %f", sc[0].Pos.Z, sc[1].Pos.Z, sc[2].Pos.Z)
-				continue
-			}
-
-			l1 := fpt[2].Sub(fpt[0])
-			n := l1.CrossProduct(fpt[1].Sub(fpt[0]))
-			n = n.Normalize()
-			intensity := n.MultSimp(&light)
+			//l1 := fpt[2].Sub(fpt[0])
+			//n := l1.CrossProduct(fpt[1].Sub(fpt[0]))
+			//n = n.Normalize()
+			//intensity := n.MultSimp(&light)
+			intensity := float32(1.0)
 			if intensity > 0 {
 				hrend.TriangleTextured(&rb, texture, intensity, sc[0], sc[1], sc[2])
 				//hrend.TriangleFlat(&rb, hrend.Col2Uint(byte(255*intensity), byte(255*intensity), byte(255*intensity)), sc[0].Pos, sc[1].Pos, sc[2].Pos)