如何在 Vulkan 中绘制基元

Question

假设 Vulkan

已经初始化，您正在录制到命令缓冲区，您有一个帧缓冲区和一个渲染通道，如何使用 Vulkan 绘制原始的 2D 几何形状？

vkCmdBeginRenderPass(command_buffer, &render_pass_info, VK_SUBPASS_CONTENTS_INLINE);
// Draw primitives here
vkCmdEndRenderPass(command_buffer);

Answer 1

绘图设置非常复杂，但绘制所需的实际调用相当简单。从tri.c（绘制 2D 三角形）：

// ...
vkCmdBeginRenderPass(demo->draw_cmd, &rp_begin, VK_SUBPASS_CONTENTS_INLINE);
vkCmdBindPipeline(demo->draw_cmd, VK_PIPELINE_BIND_POINT_GRAPHICS,
                              demo->pipeline);
vkCmdBindDescriptorSets(demo->draw_cmd, VK_PIPELINE_BIND_POINT_GRAPHICS, demo->pipeline_layout,
        0, 1, & demo->desc_set, 0, NULL);
VkViewport viewport = {};
viewport.height = (float) demo->height;
viewport.width = (float) demo->width;
viewport.minDepth = (float) 0.0f;
viewport.maxDepth = (float) 1.0f;
vkCmdSetViewport(demo->draw_cmd, 0, 1, &viewport);
VkRect2D scissor = {};
scissor.extent.width = demo->width;
scissor.extent.height = demo->height;
scissor.offset.x = 0;
scissor.offset.y = 0;
vkCmdSetScissor(demo->draw_cmd, 0, 1, &scissor);
VkDeviceSize offsets[1] = {0};
vkCmdBindVertexBuffers(demo->draw_cmd, VERTEX_BUFFER_BIND_ID, 1, &demo->vertices.buf, offsets);
vkCmdDraw(demo->draw_cmd, 3, 1, 0, 0);
vkCmdEndRenderPass(demo->draw_cmd);
// ...

此代码段假定你已获得处于适当状态的VkPipeline（包括着色器等）、VkBuffer（用于顶点缓冲区）和VkCommandBuffer。执行包含VkCommandBuffer后，实际发出要绘制的命令的是vkCmdDraw。