Fix broken blending for forward pass

Fixes #1237

Author: SaschaWillems

examples/subpasses/subpasses.cpp

@@ -590,6 +590,8 @@ class VulkanExample : public VulkanExampleBase
 		blendAttachmentState.dstAlphaBlendFactor = VK_BLEND_FACTOR_ZERO;
 		blendAttachmentState.alphaBlendOp = VK_BLEND_OP_ADD;
 		blendAttachmentState.colorWriteMask = VK_COLOR_COMPONENT_R_BIT | VK_COLOR_COMPONENT_G_BIT | VK_COLOR_COMPONENT_B_BIT | VK_COLOR_COMPONENT_A_BIT;
+		colorBlendState.attachmentCount = 1;
+		colorBlendState.pAttachments = &blendAttachmentState;
 		pipelineCI.pVertexInputState = vkglTF::Vertex::getPipelineVertexInputState({ vkglTF::VertexComponent::Position, vkglTF::VertexComponent::Color, vkglTF::VertexComponent::Normal, vkglTF::VertexComponent::UV });
 		pipelineCI.layout = pipelineLayouts.transparent;
 		// Used in second subpass