From 3bb8a63ee12a8c28f9e37b3c55a98e32539ca268 Mon Sep 17 00:00:00 2001
From: Mid <>
Date: Sun, 27 Jul 2025 16:16:45 +0300
Subject: [PATCH] Frustum culling

---
 src/k3.c | 34 +++++++++++++++++++++++++++++++---
 1 file changed, 31 insertions(+), 3 deletions(-)

diff --git a/src/k3.c b/src/k3.c
index ac58d0e..9164acf 100644
--- a/src/k3.c
+++ b/src/k3.c
@@ -12,6 +12,7 @@
 #include<cglm/vec2.h>
 #include<cglm/frustum.h>
 #include<cglm/cam.h>
+#include<cglm/box.h>
 
 #include"ssort.h"
 
@@ -1309,9 +1310,22 @@ static void apply_cpu_skinning(struct k3Mdl *mdl, struct k3AnimationBone *bones)
 	glBufferSubDataARB(GL_ARRAY_BUFFER_ARB, mdl->offV, mdl->verts * sizeof(*boned), boned);
 }
 
-static void forward_subpass(mat4 view, int transparent, int lightsStart, int lightsCount, size_t rbleStart, size_t rbleEnd) {
+static bool outside_frustum(vec3 *aabb, float *modelmat, vec4 *frustum) {
+	vec3 transformedAABB[2];
+	glm_aabb_transform(aabb, modelmat, transformedAABB);
+	
+	return !glm_aabb_frustum(transformedAABB, frustum);
+}
+
+static void forward_subpass(mat4 projection, mat4 view, int transparent, int lightsStart, int lightsCount, size_t rbleStart, size_t rbleEnd) {
 	setup_ff_lights(view, lightsStart, lightsCount);
 	
+	mat4 viewProj;
+	glm_mat4_mul(projection, view, viewProj);
+	
+	vec4 cameraFrustum[6];
+	glm_frustum_planes(viewProj, cameraFrustum);
+	
 	GLhandleARB lastGLSL = -1;
 	GLuint lastVP = 0, lastFP = 0;
 	struct k3Mat *lastMaterial = NULL;
@@ -1327,6 +1341,10 @@ static void forward_subpass(mat4 view, int transparent, int lightsStart, int lig
 		GLuint arbvp = renderQueue[rble].arbvp;
 		GLuint arbfp = renderQueue[rble].arbfp;
 		
+		if(outside_frustum(mdl->aabb, modelmat, cameraFrustum)) {
+			continue;
+		}
+		
 		struct k3Mat *mat = &mesh->mat;
 		
 		if(mat->passes[0].additive && lightsStart != 0) {
@@ -1535,7 +1553,7 @@ void k3PassForward(mat4 projection, mat4 cam) {
 	
 	int l = 0, k = LightCount;
 	while(1) {
-		forward_subpass(view, 0, l, k > 4 ? 4 : k, 0, renderQueueSize);
+		forward_subpass(projection, view, 0, l, k > 4 ? 4 : k, 0, renderQueueSize);
 		
 		l += 4;
 		k -= 4;
@@ -1549,7 +1567,7 @@ void k3PassForward(mat4 projection, mat4 cam) {
 	for(size_t rble = 0; rble < renderQueueSize; rble++) {
 		l = 0, k = LightCount;
 		while(1) {
-			forward_subpass(view, 1, l, k > 4 ? 4 : k, rble, rble + 1);
+			forward_subpass(projection, view, 1, l, k > 4 ? 4 : k, rble, rble + 1);
 			
 			l += 4;
 			k -= 4;
@@ -1573,6 +1591,12 @@ void k3PassDepthOnly(mat4 projection, mat4 cam, int clear, int cull) {
 	
 	setup_arbprog_globals();
 	
+	mat4 viewProj;
+	glm_mat4_mul(projection, view, viewProj);
+	
+	vec4 cameraFrustum[6];
+	glm_frustum_planes(viewProj, cameraFrustum);
+	
 	glEnable(GL_DEPTH_TEST);
 	glColorMask(GL_FALSE, GL_FALSE, GL_FALSE, GL_FALSE);
 	glDepthMask(GL_TRUE);
@@ -1608,6 +1632,10 @@ void k3PassDepthOnly(mat4 projection, mat4 cam, int clear, int cull) {
 			continue;
 		}
 		
+		if(outside_frustum(mdl->aabb, modelmat, cameraFrustum)) {
+			continue;
+		}
+		
 		GLhandleARB glsl = renderQueue[rble].glsl;
 		GLuint arbvp = renderQueue[rble].arbvp;