// Clay Vulkan renderer sample (C17/C20 friendly) // This file demonstrates how to traverse Clay_RenderCommandArray and submit Vulkan draw calls. // The implementation favors clarity over micro-optimizations and documents future improvements. // Vulkan reference: https://vulkan.lunarg.com/doc/sdk // ImGui integration notes (for font atlas usage ideas): https://github.com/ocornut/imgui/wiki #include #include #include #include "clay.h" // Forward declarations ------------------------------------------------------- struct ClayVulkanRenderer; static void ClayVulkan_PushScissor(struct ClayVulkanRenderer* renderer, const Clay_RenderCommand* command, VkCommandBuffer commandBuffer); static void ClayVulkan_PopScissor(struct ClayVulkanRenderer* renderer, VkCommandBuffer commandBuffer); static void ClayVulkan_DrawRectangle(struct ClayVulkanRenderer* renderer, const Clay_RenderCommand* command, VkCommandBuffer commandBuffer); static void ClayVulkan_DrawBorder(struct ClayVulkanRenderer* renderer, const Clay_RenderCommand* command, VkCommandBuffer commandBuffer); static void ClayVulkan_DrawImage(struct ClayVulkanRenderer* renderer, const Clay_RenderCommand* command, VkCommandBuffer commandBuffer); static void ClayVulkan_DrawText(struct ClayVulkanRenderer* renderer, const Clay_RenderCommand* command, VkCommandBuffer commandBuffer); static void ClayVulkan_DrawCustom(struct ClayVulkanRenderer* renderer, const Clay_RenderCommand* command, VkCommandBuffer commandBuffer); // Resource cache keyed by Clay IDs ------------------------------------------ typedef struct ClayVulkanTexture { uint32_t m_Id; // Clay image id VkImageView m_ImageView; VkSampler m_Sampler; VkDescriptorSet m_DescriptorSet; } ClayVulkanTexture; typedef struct ClayVulkanFont { uint16_t m_FontId; uint16_t m_FontSize; void* m_FontUserData; // Pointer to glyph atlas / font metrics owned by the application } ClayVulkanFont; typedef struct ClayVulkanResourceCache { ClayVulkanTexture m_Textures[64]; uint32_t m_TextureCount; ClayVulkanFont m_Fonts[32]; uint32_t m_FontCount; } ClayVulkanResourceCache; // Renderer state ------------------------------------------------------------ typedef struct ClayVulkanRenderer { VkDevice m_Device; VkRenderPass m_RenderPass; // Compatible with the framebuffer bound by the host application VkPipeline m_RectPipeline; VkPipeline m_TextPipeline; VkPipeline m_ImagePipeline; VkPipelineLayout m_PipelineLayout; VkCommandBuffer m_ActiveCommandBuffer; VkRect2D m_ScissorStack[16]; uint32_t m_ScissorCount; ClayVulkanResourceCache m_ResourceCache; // The sample keeps descriptor pools outside; the host passes ready-to-bind descriptor sets. } ClayVulkanRenderer; // Utility: fetch or insert cached texture ----------------------------------- static ClayVulkanTexture* ClayVulkan_GetTexture(ClayVulkanResourceCache* cache, uint32_t id) { for (uint32_t it_Index = 0; it_Index < cache->m_TextureCount; ++it_Index) { ClayVulkanTexture* l_Texture = &cache->m_Textures[it_Index]; if (l_Texture->m_Id == id) { return l_Texture; } } if (cache->m_TextureCount >= (uint32_t)(sizeof(cache->m_Textures) / sizeof(cache->m_Textures[0]))) { return NULL; // Out of cache entries; caller can log and skip drawing. } ClayVulkanTexture* l_Texture = &cache->m_Textures[cache->m_TextureCount++]; memset(l_Texture, 0, sizeof(*l_Texture)); l_Texture->m_Id = id; return l_Texture; } // Utility: fetch or insert cached font -------------------------------------- static ClayVulkanFont* ClayVulkan_GetFont(ClayVulkanResourceCache* cache, uint16_t fontId, uint16_t fontSize) { for (uint32_t it_Index = 0; it_Index < cache->m_FontCount; ++it_Index) { ClayVulkanFont* l_Font = &cache->m_Fonts[it_Index]; if (l_Font->m_FontId == fontId && l_Font->m_FontSize == fontSize) { return l_Font; } } if (cache->m_FontCount >= (uint32_t)(sizeof(cache->m_Fonts) / sizeof(cache->m_Fonts[0]))) { return NULL; } ClayVulkanFont* l_Font = &cache->m_Fonts[cache->m_FontCount++]; memset(l_Font, 0, sizeof(*l_Font)); l_Font->m_FontId = fontId; l_Font->m_FontSize = fontSize; return l_Font; } // Text measurement hook ------------------------------------------------------ // Backs Clay_SetMeasureTextFunction and aligns with Clay_TextRenderData expectations. static Clay_Dimensions ClayVulkan_MeasureText(Clay_StringSlice text, Clay_TextElementConfig* config, void* userData) { ClayVulkanRenderer* l_Renderer = (ClayVulkanRenderer*)userData; ClayVulkanFont* l_Font = ClayVulkan_GetFont(&l_Renderer->m_ResourceCache, config->fontId, config->fontSize); // The sample assumes the host supplies pixel metrics via m_FontUserData (e.g., stb_truetype bake results). // For demonstration, approximate width using a monospaced assumption and letter spacing. const float s_DefaultGlyphWidth = (float)config->fontSize * 0.6f; float l_Width = (float)text.length * s_DefaultGlyphWidth + (float)config->letterSpacing * (float)text.length; float l_Height = (float)config->lineHeight; (void)l_Font; // In a real integration, sample glyph advances from l_Font->m_FontUserData. // MSVC doesn't support C99 compound literals in C mode; build the return value explicitly for portability. Clay_Dimensions l_Dimensions = { 0 }; l_Dimensions.width = l_Width; l_Dimensions.height = l_Height; return l_Dimensions; } // Scissor management --------------------------------------------------------- static void ClayVulkan_PushScissor(ClayVulkanRenderer* renderer, const Clay_RenderCommand* command, VkCommandBuffer commandBuffer) { if (renderer->m_ScissorCount >= (uint32_t)(sizeof(renderer->m_ScissorStack) / sizeof(renderer->m_ScissorStack[0]))) { return; // Avoid overflow; future improvement could resize dynamically. } VkRect2D l_Rect = { 0 }; l_Rect.offset.x = (int32_t)command->boundingBox.x; l_Rect.offset.y = (int32_t)command->boundingBox.y; l_Rect.extent.width = (uint32_t)command->boundingBox.width; l_Rect.extent.height = (uint32_t)command->boundingBox.height; renderer->m_ScissorStack[renderer->m_ScissorCount++] = l_Rect; vkCmdSetScissor(commandBuffer, 0, 1, &l_Rect); } static void ClayVulkan_PopScissor(ClayVulkanRenderer* renderer, VkCommandBuffer commandBuffer) { if (renderer->m_ScissorCount == 0) { return; } renderer->m_ScissorCount--; if (renderer->m_ScissorCount == 0) { // Fall back to a full viewport scissor. The host should have set a default scissor before calling render. return; } VkRect2D l_Rect = renderer->m_ScissorStack[renderer->m_ScissorCount - 1]; vkCmdSetScissor(commandBuffer, 0, 1, &l_Rect); } // Rendering helpers ---------------------------------------------------------- static void ClayVulkan_DrawRectangle(ClayVulkanRenderer* renderer, const Clay_RenderCommand* command, VkCommandBuffer commandBuffer) { (void)renderer; // The sample assumes a pipeline using push constants for color + corner radius and a unit quad vertex buffer. vkCmdBindPipeline(commandBuffer, VK_PIPELINE_BIND_POINT_GRAPHICS, renderer->m_RectPipeline); // Future improvement: instance multiple rectangles in a single vkCmdDrawIndexed to amortize state changes. vkCmdDraw(commandBuffer, 6, 1, 0, 0); } static void ClayVulkan_DrawBorder(ClayVulkanRenderer* renderer, const Clay_RenderCommand* command, VkCommandBuffer commandBuffer) { (void)command; // Border rendering could expand to 4 rectangles; here we rely on a shader that interprets width + corner radius from push constants. vkCmdBindPipeline(commandBuffer, VK_PIPELINE_BIND_POINT_GRAPHICS, renderer->m_RectPipeline); vkCmdDraw(commandBuffer, 6, 1, 0, 0); } static void ClayVulkan_DrawImage(ClayVulkanRenderer* renderer, const Clay_RenderCommand* command, VkCommandBuffer commandBuffer) { ClayVulkanTexture* l_Texture = ClayVulkan_GetTexture(&renderer->m_ResourceCache, command->id); if (!l_Texture || !l_Texture->m_DescriptorSet) { return; // Caller must populate descriptor sets before rendering. } vkCmdBindPipeline(commandBuffer, VK_PIPELINE_BIND_POINT_GRAPHICS, renderer->m_ImagePipeline); vkCmdBindDescriptorSets(commandBuffer, VK_PIPELINE_BIND_POINT_GRAPHICS, renderer->m_PipelineLayout, 0, 1, &l_Texture->m_DescriptorSet, 0, NULL); vkCmdDraw(commandBuffer, 6, 1, 0, 0); } static void ClayVulkan_DrawText(ClayVulkanRenderer* renderer, const Clay_RenderCommand* command, VkCommandBuffer commandBuffer) { Clay_TextRenderData l_Text = command->renderData.text; ClayVulkanFont* l_Font = ClayVulkan_GetFont(&renderer->m_ResourceCache, l_Text.fontId, l_Text.fontSize); (void)l_Font; // The host is expected to have built glyph vertices into a transient buffer before calling this renderer. vkCmdBindPipeline(commandBuffer, VK_PIPELINE_BIND_POINT_GRAPHICS, renderer->m_TextPipeline); // Future improvement: bind per-font descriptor sets for font atlas textures instead of assuming a global one. vkCmdDraw(commandBuffer, (uint32_t)l_Text.stringContents.length * 4, 1, 0, 0); } static void ClayVulkan_DrawCustom(ClayVulkanRenderer* renderer, const Clay_RenderCommand* command, VkCommandBuffer commandBuffer) { (void)renderer; (void)command; // Custom elements give the host full control. Applications can use command->renderData.custom.customData to pick pipelines. // Future improvement: provide callback hooks so applications can supply their own vkCmd* sequence here. (void)commandBuffer; } // Main entry point ----------------------------------------------------------- void Clay_Vulkan_Render(ClayVulkanRenderer* renderer, Clay_RenderCommandArray renderCommands, VkCommandBuffer commandBuffer) { renderer->m_ActiveCommandBuffer = commandBuffer; // Command traversal: the array is already z-sorted; we iterate sequentially and rely on lightweight state changes. for (int32_t it_Command = 0; it_Command < renderCommands.length; ++it_Command) { Clay_RenderCommand* l_Command = Clay_RenderCommandArray_Get(&renderCommands, it_Command); switch (l_Command->commandType) { case CLAY_RENDER_COMMAND_TYPE_RECTANGLE: ClayVulkan_DrawRectangle(renderer, l_Command, commandBuffer); break; case CLAY_RENDER_COMMAND_TYPE_BORDER: ClayVulkan_DrawBorder(renderer, l_Command, commandBuffer); break; case CLAY_RENDER_COMMAND_TYPE_TEXT: ClayVulkan_DrawText(renderer, l_Command, commandBuffer); break; case CLAY_RENDER_COMMAND_TYPE_IMAGE: ClayVulkan_DrawImage(renderer, l_Command, commandBuffer); break; case CLAY_RENDER_COMMAND_TYPE_SCISSOR_START: ClayVulkan_PushScissor(renderer, l_Command, commandBuffer); break; case CLAY_RENDER_COMMAND_TYPE_SCISSOR_END: ClayVulkan_PopScissor(renderer, commandBuffer); break; case CLAY_RENDER_COMMAND_TYPE_CUSTOM: ClayVulkan_DrawCustom(renderer, l_Command, commandBuffer); break; default: break; } } } // Initialization helpers ---------------------------------------------------- void Clay_VulkanRenderer_Init(ClayVulkanRenderer* renderer, VkDevice device, VkRenderPass renderPass, VkPipelineLayout pipelineLayout) { renderer->m_Device = device; renderer->m_RenderPass = renderPass; renderer->m_PipelineLayout = pipelineLayout; renderer->m_RectPipeline = VK_NULL_HANDLE; renderer->m_TextPipeline = VK_NULL_HANDLE; renderer->m_ImagePipeline = VK_NULL_HANDLE; renderer->m_ActiveCommandBuffer = VK_NULL_HANDLE; renderer->m_ScissorCount = 0; memset(&renderer->m_ResourceCache, 0, sizeof(renderer->m_ResourceCache)); } void Clay_VulkanRenderer_SetPipelines(ClayVulkanRenderer* renderer, VkPipeline rectPipeline, VkPipeline textPipeline, VkPipeline imagePipeline) { renderer->m_RectPipeline = rectPipeline; renderer->m_TextPipeline = textPipeline; renderer->m_ImagePipeline = imagePipeline; } // Hook into Clay's text measuring API. void Clay_VulkanRenderer_RegisterTextMeasure(ClayVulkanRenderer* renderer) { Clay_SetMeasureTextFunction(ClayVulkan_MeasureText, renderer); } // Example for populating the texture cache with externally created descriptors. void Clay_VulkanRenderer_RegisterTexture(ClayVulkanRenderer* renderer, uint32_t clayId, VkImageView imageView, VkSampler sampler, VkDescriptorSet descriptorSet) { ClayVulkanTexture* l_Texture = ClayVulkan_GetTexture(&renderer->m_ResourceCache, clayId); if (!l_Texture) { return; } l_Texture->m_ImageView = imageView; l_Texture->m_Sampler = sampler; l_Texture->m_DescriptorSet = descriptorSet; } // Future improvements ------------------------------------------------------- // - Descriptor recycling: shrink transient allocations by pooling VkDescriptorSet objects per frame. // - Dynamic rendering: replace render pass dependency with vkCmdBeginRendering for more flexible swapchain formats. // - Batching: group adjacent rectangles or text quads into large instance draws using secondary command buffers.