Added test for offscreen rendering.

It doesn't validate anything yet, it should (for now) be used
with renderdoc.

@@ -73,0 +94,4 @@
+                          VkShaderModule vertex_module,
+                          VkShaderModule fragment_module,
+                          VkPipelineLayout &pipeline_layout,
+                          const VKBatch &batch,

@@ -344,7 +344,6 @@ static void gpu_backend_create()
 void gpu_backend_delete_resources()
 {
   BLI_assert(g_backend);

@@ -124,0 +155,4 @@
+
+  void wait_idle()
+  {
+    if (device) {

@@ -170,3 +386,1 @@
-  if (m_device) {
-    vkDeviceWaitIdle(m_device);
-  }
+  // TODO: see if we can use a usage counter to free the global device.

@@ -121,3 +126,3 @@
 void VKCommandBuffer::end_render_pass(const VKFrameBuffer &framebuffer)
 {
-  UNUSED_VARS_NDEBUG(framebuffer)
+  UNUSED_VARS_NDEBUG(framebuffer);

@@ -136,1 +160,3 @@
-    image_info.imageLayout = VK_IMAGE_LAYOUT_GENERAL;
+    image_info.sampler = binding.vk_sampler;
+    image_info.imageView = binding.texture->vk_image_view_handle();
+    /* TODO: use the correct one from the texture. */

@@ -1622,6 +1623,7 @@ void DRW_draw_view(const bContext *C)
 {
   View3D *v3d = CTX_wm_view3d(C);
   if (v3d) {
+    GPU_debug_capture_begin();

@@ -304,6 +322,24 @@ bool VKTexture::allocate()
   return result == VK_SUCCESS;
 }
 
+// TODO: move texture/image bindings to shader.

@@ -318,0 +360,4 @@
+void VKTexture::unbind()
+{
+  VKContext &context = *VKContext::get();
+  /* TODO get a list of shaders this texture is bound to. */

@@ -39,3 +39,3 @@
   const VKDescriptorSet::Location descriptor_set_location(
       const shader::ShaderCreateInfo::Resource &resource) const;
-  const VKDescriptorSet::Location descriptor_set_location(
+  const std::optional<VKDescriptorSet::Location> descriptor_set_location(

@@ -513,0 +481,4 @@
+  VkDevice device = vulkan_device->device;
+  if (m_currentFrame != m_lastFrame) {
+    vkResetFences(device, 1, &m_in_flight_fences[m_currentFrame]);
+  }

@@ -848,3 +839,3 @@
 
   /* Driver can stall if only using minimal image count. */
-  uint32_t image_count = capabilities.minImageCount;
+  uint32_t image_count = capabilities.minImageCount + 1;

@@ -10,3 +15,3 @@
 namespace blender::gpu {
 
-void VKBatch::draw(int /*v_first*/, int /*v_count*/, int /*i_first*/, int /*i_count*/) {}
+void VKBatch::draw(int v_first, int v_count, int i_first, int i_count)

@@ -0,0 +16,4 @@
+/**
+ * Helper struct to enable buffers to be bound with an offset.
+ */
+struct VKBufferWithOffset {

@@ -510,3 +478,3 @@
   submit_info.pSignalSemaphores = &m_render_finished_semaphores[m_currentFrame];
 
-  vkResetFences(device, 1, &m_in_flight_fences[m_currentFrame]);
+  assert(vulkan_device.has_value() && vulkan_device->device != VK_NULL_HANDLE);

@@ -65,3 +65,3 @@
 {
   VKContext &context = *VKContext::get();
-  VKShader *shader = static_cast<VKShader *>(context.shader);
+  context.bind_compute_pipeline();