Issue a batch when changing render targets in the Vulkan renderer

Otherwise we get rendering artifacts that look like drawing is being applied to the wrong render target

src/render/vulkan/SDL_render_vulkan.c

@@ -3182,9 +3182,24 @@ static bool VULKAN_SetRenderTarget(SDL_Renderer *renderer, SDL_Texture *texture)
 
     VULKAN_EnsureCommandBuffer(rendererData);
 
-    if (!texture) {
-        if (rendererData->textureRenderTarget) {
+    if (texture) {
+        textureData = (VULKAN_TextureData *)texture->internal;
+
+        if (textureData->mainImage.imageView == VK_NULL_HANDLE) {
+            return SDL_SetError("specified texture is not a render target");
+        }
 
+        rendererData->textureRenderTarget = textureData;
+        VULKAN_RecordPipelineImageBarrier(rendererData,
+            VK_ACCESS_TRANSFER_WRITE_BIT | VK_ACCESS_SHADER_READ_BIT | VK_ACCESS_COLOR_ATTACHMENT_READ_BIT | VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT,
+            VK_ACCESS_TRANSFER_WRITE_BIT | VK_ACCESS_SHADER_READ_BIT | VK_ACCESS_COLOR_ATTACHMENT_READ_BIT | VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT,
+            VK_PIPELINE_STAGE_TRANSFER_BIT | VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT | VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT,
+            VK_PIPELINE_STAGE_TRANSFER_BIT | VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT | VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT,
+            VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL,
+            rendererData->textureRenderTarget->mainImage.image,
+            &rendererData->textureRenderTarget->mainImage.imageLayout);
+    } else {
+        if (rendererData->textureRenderTarget) {
             VULKAN_RecordPipelineImageBarrier(rendererData,
                 VK_ACCESS_TRANSFER_WRITE_BIT | VK_ACCESS_SHADER_READ_BIT | VK_ACCESS_COLOR_ATTACHMENT_READ_BIT | VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT,
                 VK_ACCESS_SHADER_READ_BIT,
@@ -3195,24 +3210,9 @@ static bool VULKAN_SetRenderTarget(SDL_Renderer *renderer, SDL_Texture *texture)
                 &rendererData->textureRenderTarget->mainImage.imageLayout);
         }
         rendererData->textureRenderTarget = NULL;
-        return true;
     }
 
-    textureData = (VULKAN_TextureData *)texture->internal;
-
-    if (textureData->mainImage.imageView == VK_NULL_HANDLE) {
-        return SDL_SetError("specified texture is not a render target");
-    }
-
-    rendererData->textureRenderTarget = textureData;
-    VULKAN_RecordPipelineImageBarrier(rendererData,
-                VK_ACCESS_TRANSFER_WRITE_BIT | VK_ACCESS_SHADER_READ_BIT | VK_ACCESS_COLOR_ATTACHMENT_READ_BIT | VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT,
-                VK_ACCESS_TRANSFER_WRITE_BIT | VK_ACCESS_SHADER_READ_BIT | VK_ACCESS_COLOR_ATTACHMENT_READ_BIT | VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT,
-                VK_PIPELINE_STAGE_TRANSFER_BIT | VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT | VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT,
-                VK_PIPELINE_STAGE_TRANSFER_BIT | VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT | VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT,
-                VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL,
-                rendererData->textureRenderTarget->mainImage.image,
-                &rendererData->textureRenderTarget->mainImage.imageLayout);
+    VULKAN_IssueBatch(rendererData);
 
     return true;
 }