Kelsidavis-WoWee/src/rendering/vk_render_target.cpp

#include "rendering/vk_render_target.hpp"
#include "rendering/vk_context.hpp"
#include "core/logger.hpp"

namespace wowee {
namespace rendering {

VkRenderTarget::~VkRenderTarget() {
    // Must call destroy() explicitly with device/allocator before destruction
}

bool VkRenderTarget::create(VkContext& ctx, uint32_t width, uint32_t height, VkFormat format) {
    VkDevice device = ctx.getDevice();
    VmaAllocator allocator = ctx.getAllocator();

    // Create color image (COLOR_ATTACHMENT + SAMPLED for reading in subsequent passes)
    colorImage_ = createImage(device, allocator, width, height, format,
        VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT | VK_IMAGE_USAGE_SAMPLED_BIT);

    if (!colorImage_.image) {
        LOG_ERROR("VkRenderTarget: failed to create color image (", width, "x", height, ")");
        return false;
    }

    // Create sampler (linear filtering, clamp to edge)
    VkSamplerCreateInfo samplerInfo{};
    samplerInfo.sType = VK_STRUCTURE_TYPE_SAMPLER_CREATE_INFO;
    samplerInfo.minFilter = VK_FILTER_LINEAR;
    samplerInfo.magFilter = VK_FILTER_LINEAR;
    samplerInfo.addressModeU = VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE;
    samplerInfo.addressModeV = VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE;
    samplerInfo.addressModeW = VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE;
    samplerInfo.mipmapMode = VK_SAMPLER_MIPMAP_MODE_LINEAR;
    samplerInfo.minLod = 0.0f;
    samplerInfo.maxLod = 0.0f;

    if (vkCreateSampler(device, &samplerInfo, nullptr, &sampler_) != VK_SUCCESS) {
        LOG_ERROR("VkRenderTarget: failed to create sampler");
        destroy(device, allocator);
        return false;
    }

    // Create render pass
    // Color attachment: UNDEFINED -> COLOR_ATTACHMENT_OPTIMAL (during pass)
    //                   -> SHADER_READ_ONLY_OPTIMAL (final layout, ready for sampling)
    VkAttachmentDescription colorAttachment{};
    colorAttachment.format = format;
    colorAttachment.samples = VK_SAMPLE_COUNT_1_BIT;
    colorAttachment.loadOp = VK_ATTACHMENT_LOAD_OP_CLEAR;
    colorAttachment.storeOp = VK_ATTACHMENT_STORE_OP_STORE;
    colorAttachment.stencilLoadOp = VK_ATTACHMENT_LOAD_OP_DONT_CARE;
    colorAttachment.stencilStoreOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
    colorAttachment.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED;
    colorAttachment.finalLayout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL;

    VkAttachmentReference colorRef{};
    colorRef.attachment = 0;
    colorRef.layout = VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL;

    VkSubpassDescription subpass{};
    subpass.pipelineBindPoint = VK_PIPELINE_BIND_POINT_GRAPHICS;
    subpass.colorAttachmentCount = 1;
    subpass.pColorAttachments = &colorRef;

    // Dependency: external -> subpass 0 (wait for previous reads to finish)
    VkSubpassDependency dependency{};
    dependency.srcSubpass = VK_SUBPASS_EXTERNAL;
    dependency.dstSubpass = 0;
    dependency.srcStageMask = VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT;
    dependency.dstStageMask = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT;
    dependency.srcAccessMask = VK_ACCESS_SHADER_READ_BIT;
    dependency.dstAccessMask = VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT;

    VkRenderPassCreateInfo rpInfo{};
    rpInfo.sType = VK_STRUCTURE_TYPE_RENDER_PASS_CREATE_INFO;
    rpInfo.attachmentCount = 1;
    rpInfo.pAttachments = &colorAttachment;
    rpInfo.subpassCount = 1;
    rpInfo.pSubpasses = &subpass;
    rpInfo.dependencyCount = 1;
    rpInfo.pDependencies = &dependency;

    if (vkCreateRenderPass(device, &rpInfo, nullptr, &renderPass_) != VK_SUCCESS) {
        LOG_ERROR("VkRenderTarget: failed to create render pass");
        destroy(device, allocator);
        return false;
    }

    // Create framebuffer
    VkFramebufferCreateInfo fbInfo{};
    fbInfo.sType = VK_STRUCTURE_TYPE_FRAMEBUFFER_CREATE_INFO;
    fbInfo.renderPass = renderPass_;
    fbInfo.attachmentCount = 1;
    fbInfo.pAttachments = &colorImage_.imageView;
    fbInfo.width = width;
    fbInfo.height = height;
    fbInfo.layers = 1;

    if (vkCreateFramebuffer(device, &fbInfo, nullptr, &framebuffer_) != VK_SUCCESS) {
        LOG_ERROR("VkRenderTarget: failed to create framebuffer");
        destroy(device, allocator);
        return false;
    }

    LOG_INFO("VkRenderTarget created (", width, "x", height, ")");
    return true;
}

void VkRenderTarget::destroy(VkDevice device, VmaAllocator allocator) {
    if (framebuffer_) {
        vkDestroyFramebuffer(device, framebuffer_, nullptr);
        framebuffer_ = VK_NULL_HANDLE;
    }
    if (renderPass_) {
        vkDestroyRenderPass(device, renderPass_, nullptr);
        renderPass_ = VK_NULL_HANDLE;
    }
    if (sampler_) {
        vkDestroySampler(device, sampler_, nullptr);
        sampler_ = VK_NULL_HANDLE;
    }
    destroyImage(device, allocator, colorImage_);
}

void VkRenderTarget::beginPass(VkCommandBuffer cmd, const VkClearColorValue& clear) {
    VkRenderPassBeginInfo rpBegin{};
    rpBegin.sType = VK_STRUCTURE_TYPE_RENDER_PASS_BEGIN_INFO;
    rpBegin.renderPass = renderPass_;
    rpBegin.framebuffer = framebuffer_;
    rpBegin.renderArea.offset = {0, 0};
    rpBegin.renderArea.extent = getExtent();

    VkClearValue clearValue{};
    clearValue.color = clear;
    rpBegin.clearValueCount = 1;
    rpBegin.pClearValues = &clearValue;

    vkCmdBeginRenderPass(cmd, &rpBegin, VK_SUBPASS_CONTENTS_INLINE);

    // Set viewport and scissor to match render target
    VkViewport viewport{};
    viewport.x = 0.0f;
    viewport.y = 0.0f;
    viewport.width = static_cast<float>(colorImage_.extent.width);
    viewport.height = static_cast<float>(colorImage_.extent.height);
    viewport.minDepth = 0.0f;
    viewport.maxDepth = 1.0f;
    vkCmdSetViewport(cmd, 0, 1, &viewport);

    VkRect2D scissor{};
    scissor.offset = {0, 0};
    scissor.extent = getExtent();
    vkCmdSetScissor(cmd, 0, 1, &scissor);
}

void VkRenderTarget::endPass(VkCommandBuffer cmd) {
    vkCmdEndRenderPass(cmd);
    // Image is now in SHADER_READ_ONLY_OPTIMAL (from render pass finalLayout)
}

VkDescriptorImageInfo VkRenderTarget::descriptorInfo() const {
    VkDescriptorImageInfo info{};
    info.sampler = sampler_;
    info.imageView = colorImage_.imageView;
    info.imageLayout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL;
    return info;
}

} // namespace rendering
} // namespace wowee