From 0995c507cda4f9dbd00838b9c73e0915c686735a Mon Sep 17 00:00:00 2001
From: Paolo Mazzon <pdmazzon@gmail.com>
Date: Sun, 25 Aug 2024 11:15:58 -0700
Subject: [PATCH] Fixed a segfault that occurs when using a shader with a
 uniform buffer and the swapchain min image count is greater than 3

---
 VK2D/Opaque.h   |  1 +
 VK2D/Renderer.c | 14 ++++++++++----
 VK2D/Shader.c   |  2 ++
 3 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/VK2D/Opaque.h b/VK2D/Opaque.h
index 647a446..6c73407 100644
--- a/VK2D/Opaque.h
+++ b/VK2D/Opaque.h
@@ -143,6 +143,7 @@ struct VK2DShader_t {
 	uint32_t uniformSize;    ///< Uniform buffer size in bytes
 	VK2DLogicalDevice dev;   ///< Device this belongs to
 	VK2DDescCon descCons[VK2D_MAX_FRAMES_IN_FLIGHT]; ///< Descriptor sets for the uniform buffers
+	int currentDescCon;      ///< Points to the current desc con since for this frame since we have 1 per image in flight
 };
 
 /// \brief Simple wrapper that groups image things together
diff --git a/VK2D/Renderer.c b/VK2D/Renderer.c
index 92d83a3..c31ee3e 100644
--- a/VK2D/Renderer.c
+++ b/VK2D/Renderer.c
@@ -399,9 +399,15 @@ void vk2dRendererStartFrame(const vec4 clearColour) {
 			}
 
 			// Reset shader desc cons
-			for (int i = 0; i < gRenderer->shaderListSize; i++)
-                if (gRenderer->customShaders[i] != NULL && gRenderer->customShaders[i]->uniformSize != 0)
-					vk2dDescConReset(gRenderer->customShaders[i]->descCons[gRenderer->scImageIndex]);
+			for (int i = 0; i < gRenderer->shaderListSize; i++) {
+                if (gRenderer->customShaders[i] != NULL && gRenderer->customShaders[i]->uniformSize != 0) {
+                    gRenderer->customShaders[i]->currentDescCon += 1;
+                    if (gRenderer->customShaders[i]->currentDescCon >= VK2D_MAX_FRAMES_IN_FLIGHT) {
+                        gRenderer->customShaders[i]->currentDescCon = 0;
+                    }
+                    vk2dDescConReset(gRenderer->customShaders[i]->descCons[gRenderer->customShaders[i]->currentDescCon]);
+                }
+            }
 
 			// Setup render pass
 			VkRect2D rect = {0};
@@ -720,7 +726,7 @@ void vk2dRendererDrawShader(VK2DShader shader, void *data, VK2DTexture tex, floa
 			// Create the data uniform
 			uint32_t setCount = 3;
 			if (shader->uniformSize != 0) {
-				sets[3] = vk2dDescConGetSet(shader->descCons[gRenderer->scImageIndex]);
+				sets[3] = vk2dDescConGetSet(shader->descCons[shader->currentDescCon]);
 				VkBuffer buffer;
 				VkDeviceSize offset;
 				vk2dDescriptorBufferCopyData(gRenderer->descriptorBuffers[gRenderer->currentFrame], data, shader->uniformSize, &buffer, &offset);
diff --git a/VK2D/Shader.c b/VK2D/Shader.c
index 53af43b..c3be3c1 100644
--- a/VK2D/Shader.c
+++ b/VK2D/Shader.c
@@ -83,6 +83,7 @@ VK2DShader vk2dShaderFrom(uint8_t *vertexShaderBuffer, int vertexShaderBufferSiz
         out->spvFragSize = fragmentShaderBufferSize;
         out->uniformSize = uniformBufferSize;
         out->dev = dev;
+        out->currentDescCon = 0;
 
         if (uniformBufferSize != 0) {
             for (i = 0; i < VK2D_MAX_FRAMES_IN_FLIGHT && uniformBufferSize > 0; i++) {
@@ -143,6 +144,7 @@ VK2DShader vk2dShaderLoad(const char *vertexShader, const char *fragmentShader,
 			out->spvFragSize = fragFileSize;
 			out->uniformSize = uniformBufferSize;
 			out->dev = dev;
+			out->currentDescCon = 0;
 
 			if (uniformBufferSize != 0) {
 				for (i = 0; i < VK2D_MAX_FRAMES_IN_FLIGHT && uniformBufferSize > 0; i++) {