From 93e91d7902accb8a78d6f4a7d8e003357720a5ba Mon Sep 17 00:00:00 2001
From: Lorenzo Torres <torres@sideros.org>
Date: Sat, 9 Aug 2025 15:02:53 +0200
Subject: [PATCH] Fixed alignment issue of point lights buffer Instead of using
 an array of descriptors for storing the lights, now only one descriptor maps
 the entire array.

---
 assets/shaders/shader.frag         | 35 +++++++++++++++---------------
 src/rendering/GraphicsPipeline.zig | 18 +++++++--------
 2 files changed, 26 insertions(+), 27 deletions(-)

diff --git a/assets/shaders/shader.frag b/assets/shaders/shader.frag
index d0b894a..28cec73 100644
--- a/assets/shaders/shader.frag
+++ b/assets/shaders/shader.frag
@@ -2,7 +2,13 @@
 
 #define MAX_POINT_LIGHTS 1024
 
-
+struct PointLight {
+	vec3 position;
+	vec3 ambient;
+	vec3 diffuse;
+	vec3 specular;
+	vec3 data;
+};
 
 layout(location = 0) out vec4 outColor;
 
@@ -17,14 +23,9 @@ layout (binding = 2) uniform DirectionalLight {
 	vec3 diffuse;
 	vec3 specular;
 } directional_light;
-layout (binding = 5) uniform PointLight {    
-	vec3 position;
-	vec3 ambient;
-	vec3 diffuse;
-	vec3 specular;
-	vec3 data;
-
-} point_lights[MAX_POINT_LIGHTS];
+layout (binding = 5) uniform PointLights {    
+	PointLight point_lights[MAX_POINT_LIGHTS];
+} point_lights;
 
 layout (binding = 3) uniform ViewUniform {
     vec3 pos;
@@ -49,19 +50,19 @@ vec3 calc_directional_light(vec3 normal, vec3 viewDir) {
 }
 
 vec3 calc_point_light(int index, vec3 normal, vec3 fragPos, vec3 viewDir) {
-	float constant = point_lights[index].data[0];
-	float linear = point_lights[index].data[1];
-	float quadratic = point_lights[index].data[2];
+	float constant = point_lights.point_lights[index].data[0];
+	float linear = point_lights.point_lights[index].data[1];
+	float quadratic = point_lights.point_lights[index].data[2];
 
-	vec3 lightDir = normalize(point_lights[index].position - fragPos);
+	vec3 lightDir = normalize(point_lights.point_lights[index].position - fragPos);
 	float diff = max(dot(normal, lightDir), 0.0);
 	vec3 reflectDir = reflect(-lightDir, normal);
 	float spec = pow(max(dot(viewDir, reflectDir), 0.0), 2);
-	float distance    = length(point_lights[index].position - fragPos);
+	float distance    = length(point_lights.point_lights[index].position - fragPos);
 	float attenuation = 1.0 / (constant + linear * distance + quadratic * (distance * distance));
-	vec3 ambient  = point_lights[index].ambient  * vec3(texture(textureSampler, TexCoords));
-	vec3 diffuse  = point_lights[index].diffuse  * diff * vec3(texture(textureSampler, TexCoords));
-	vec3 specular = point_lights[index].specular * spec * vec3(texture(diffuseSampler, TexCoords));
+	vec3 ambient  = point_lights.point_lights[index].ambient  * vec3(texture(textureSampler, TexCoords));
+	vec3 diffuse  = point_lights.point_lights[index].diffuse  * diff * vec3(texture(textureSampler, TexCoords));
+	vec3 specular = point_lights.point_lights[index].specular * spec * vec3(texture(diffuseSampler, TexCoords));
 	ambient  *= attenuation;
 	diffuse  *= attenuation;
 	specular *= attenuation;
diff --git a/src/rendering/GraphicsPipeline.zig b/src/rendering/GraphicsPipeline.zig
index 26a976c..379c8e7 100644
--- a/src/rendering/GraphicsPipeline.zig
+++ b/src/rendering/GraphicsPipeline.zig
@@ -318,7 +318,7 @@ pub fn init(allocator: Allocator, device: vk.Device, swapchain: vk.Swapchain, re
     const point_lights_binding = c.VkDescriptorSetLayoutBinding{
         .binding = 5,
         .descriptorType = c.VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER,
-        .descriptorCount = max_point_lights,
+        .descriptorCount = 1,
         .stageFlags = c.VK_SHADER_STAGE_FRAGMENT_BIT,
     };
 
@@ -409,7 +409,7 @@ pub fn init(allocator: Allocator, device: vk.Device, swapchain: vk.Swapchain, re
 
     const size = c.VkDescriptorPoolSize{
         .type = c.VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER,
-        .descriptorCount = 5 + max_point_lights,
+        .descriptorCount = 6,
     };
 
     const sampler_size = c.VkDescriptorPoolSize{
@@ -584,21 +584,19 @@ pub fn init(allocator: Allocator, device: vk.Device, swapchain: vk.Swapchain, re
 
     const point_lights: []lights.PointLight = @as([*]lights.PointLight, @alignCast(@ptrCast(point_lights_data)))[0..max_point_lights];
 
-    var point_lights_descriptor_buffer_info: [max_point_lights]c.VkDescriptorBufferInfo = undefined;
-    for (0..max_point_lights) |i| {
-        point_lights_descriptor_buffer_info[i].buffer = point_lights_buffer.handle;
-        point_lights_descriptor_buffer_info[i].offset = @sizeOf(lights.PointLight) * i;
-        point_lights_descriptor_buffer_info[i].range = @sizeOf(lights.PointLight);
-    }
+    var point_lights_descriptor_buffer_info: c.VkDescriptorBufferInfo = undefined;
+    point_lights_descriptor_buffer_info.buffer = point_lights_buffer.handle;
+    point_lights_descriptor_buffer_info.offset = 0;
+    point_lights_descriptor_buffer_info.range = @sizeOf(lights.PointLight) * max_point_lights;
 
     const write_point_lights_descriptor_set = c.VkWriteDescriptorSet{
         .sType = c.VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET,
         .dstSet = descriptor_set,
         .dstBinding = 5,
         .dstArrayElement = 0,
-        .descriptorCount = max_point_lights,
+        .descriptorCount = 1,
         .descriptorType = c.VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER,
-        .pBufferInfo = @ptrCast(point_lights_descriptor_buffer_info[0..].ptr),
+        .pBufferInfo = @ptrCast(&point_lights_descriptor_buffer_info),
     };
 
     c.vkUpdateDescriptorSets(device.handle, 1, &write_point_lights_descriptor_set, 0, null);