textured_quad.c

#include "example_base.h"

#include <string.h>

#include "../webgpu/imgui_overlay.h"
#include "../webgpu/texture.h"

/* -------------------------------------------------------------------------- *
 * WebGPU Example - Textured Quad
 *
 * This example shows how to load and sample textures (including mip maps).
 *
 * Ref:
 * https://github.com/SaschaWillems/Vulkan/blob/master/examples/texture/texture.cpp
 * -------------------------------------------------------------------------- */

/* Vertex layout for this example */
typedef struct {
  vec3 pos;
  vec2 uv;
  vec3 normal;
} vertex_t;

/* Vertex buffer */
static wgpu_buffer_t vertices = {0};

/* Index buffer */
static wgpu_buffer_t indices = {0};

/* Uniform buffer block object */
static wgpu_buffer_t uniform_buffer_vs = {0};

static struct {
  mat4 projection;
  mat4 model_view;
  vec4 view_pos;
  float lodBias;
} ubo_vs = {0};

/* The pipeline layout */
static WGPUPipelineLayout pipeline_layout = NULL; /* solid */

/* Pipeline */
static WGPURenderPipeline pipeline = NULL; /* solid */

/* Render pass descriptor for frame buffer writes */
static struct {
  WGPURenderPassColorAttachment color_attachments[1];
  WGPURenderPassDescriptor descriptor;
} render_pass = {0};

/* Bind groups stores the resources bound to the binding points in a shader */
static WGPUBindGroup bind_group              = NULL;
static WGPUBindGroupLayout bind_group_layout = NULL;

/* Contains all WebGPU objects that are required to store and use a texture */
static texture_t texture = {0};

/* Other variables */
static const char* example_title = "Textured Quad";
static bool prepared             = false;

/* Setup a default look-at camera */
static void setup_camera(wgpu_example_context_t* context)
{
  context->camera       = camera_create();
  context->camera->type = CameraType_LookAt;
  camera_set_position(context->camera, (vec3){0.0f, 0.0f, -2.5f});
  camera_set_rotation(context->camera, (vec3){0.0f, 15.0f, 0.0f});
  camera_set_perspective(context->camera, 60.0f,
                         context->window_size.aspect_ratio, 0.1f, 256.0f);
}

/* Upload texture image data to the GPU */
static void load_texture(wgpu_context_t* wgpu_context)
{
  // We use the Khronos texture format
  // (https:/*www.khronos.org/opengles/sdk/tools/KTX/file_format_spec/)
  texture = wgpu_create_texture_from_file(
    wgpu_context, "textures/metalplate01_rgba.ktx", NULL);
}

static void generate_quad(wgpu_context_t* wgpu_context)
{
  /* Setup vertices for a single uv-mapped quad made from two triangles */
  static const vertex_t vertices_data[4] = {
    [0] = {
      .pos    = {1.0f, 1.0f, 0.0f},
      .uv     = {1.0f, 1.0f},
      .normal = {0.0f, 0.0f, 1.0f},
    },
    [1] = {
      .pos    = {-1.0f, 1.0f, 0.0f},
      .uv     = {0.0f, 1.0f},
      .normal = {0.0f, 0.0f, 1.0f},
    },
    [2] = {
      .pos    = {-1.0f, -1.0f, 0.0f},
      .uv     = {0.0f, 0.0f},
      .normal = {0.0f, 0.0f, 1.0f},
    },
    [3] = {
      .pos    = {1.0f, -1.0f, 0.0f},
      .uv     = {1.0f, 0.0f},
      .normal = {0.0f, 0.0f, 1.0f},
    },
  };
  vertices = wgpu_create_buffer(
    wgpu_context, &(wgpu_buffer_desc_t){
                    .label = "Quad - Vertex buffer",
                    .usage = WGPUBufferUsage_CopyDst | WGPUBufferUsage_Vertex,
                    .size  = sizeof(vertices_data),
                    .count = (uint32_t)ARRAY_SIZE(vertices_data),
                    .initial.data = vertices_data,
                  });

  /* Setup indices */
  static const uint16_t index_buffer[6] = {
    0, 1, 2, /* Triangle 1 */
    2, 3, 0  /* Triangle 2 */
  };
  indices = wgpu_create_buffer(
    wgpu_context, &(wgpu_buffer_desc_t){
                    .label = "Quad - Index buffer",
                    .usage = WGPUBufferUsage_CopyDst | WGPUBufferUsage_Index,
                    .size  = sizeof(index_buffer),
                    .count = (uint32_t)ARRAY_SIZE(index_buffer),
                    .initial.data = index_buffer,
                  });
}

static void update_uniform_buffers(wgpu_example_context_t* context)
{
  /* Pass matrices to the shaders */
  glm_mat4_copy(context->camera->matrices.perspective, ubo_vs.projection);
  glm_mat4_copy(context->camera->matrices.view, ubo_vs.model_view);
  glm_vec4_copy(context->camera->view_pos, ubo_vs.view_pos);

  /* Map uniform buffer and update it */
  wgpu_queue_write_buffer(context->wgpu_context, uniform_buffer_vs.buffer, 0,
                          &ubo_vs, sizeof(ubo_vs));
}

/* Prepare and initialize uniform buffer containing shader uniforms */
static void prepare_uniform_buffers(wgpu_example_context_t* context)
{
  /* Vertex shader uniform buffer block */
  uniform_buffer_vs = wgpu_create_buffer(
    context->wgpu_context,
    &(wgpu_buffer_desc_t){
      .label = "Vertex shader - Uniform buffer block",
      .usage = WGPUBufferUsage_CopyDst | WGPUBufferUsage_Uniform,
      .size  = sizeof(ubo_vs),
    });

  /* Update uniform buffer block data */
  update_uniform_buffers(context);
}

static void setup_pipeline_layout(wgpu_context_t* wgpu_context)
{
  /* Bind group layout */
  WGPUBindGroupLayoutEntry bgl_entries[3] = {
    [0] = (WGPUBindGroupLayoutEntry) {
      /* Binding 0: Uniform buffer (Vertex shader) */
      .binding    = 0,
      .visibility = WGPUShaderStage_Vertex,
      .buffer = (WGPUBufferBindingLayout) {
        .type             = WGPUBufferBindingType_Uniform,
        .hasDynamicOffset = false,
        .minBindingSize   = uniform_buffer_vs.size,
      },
      .sampler = {0},
    },
    [1] = (WGPUBindGroupLayoutEntry) {
      /* Binding 1: Texture view (Fragment shader) */
      .binding    = 1,
      .visibility = WGPUShaderStage_Fragment,
      .texture = (WGPUTextureBindingLayout) {
        .sampleType    = WGPUTextureSampleType_Float,
        .viewDimension = WGPUTextureViewDimension_2D,
        .multisampled  = false,
      },
      .storageTexture = {0},
    },
    [2] = (WGPUBindGroupLayoutEntry) {
      /* Binding 2: Sampler (Fragment shader) */
      .binding    = 2,
      .visibility = WGPUShaderStage_Fragment,
      .sampler = (WGPUSamplerBindingLayout) {
        .type  = WGPUSamplerBindingType_Filtering,
      },
      .texture = {0},
    }
  };
  bind_group_layout = wgpuDeviceCreateBindGroupLayout(
    wgpu_context->device, &(WGPUBindGroupLayoutDescriptor){
                            .label      = "Bind group layout",
                            .entryCount = (uint32_t)ARRAY_SIZE(bgl_entries),
                            .entries    = bgl_entries,
                          });
  ASSERT(bind_group_layout != NULL);

  // Create the pipeline layout that is used to generate the rendering pipelines
  // that are based on this descriptor set layout
  pipeline_layout = wgpuDeviceCreatePipelineLayout(
    wgpu_context->device, &(WGPUPipelineLayoutDescriptor){
                            .label                = "Pipeline layout",
                            .bindGroupLayoutCount = 1,
                            .bindGroupLayouts     = &bind_group_layout,
                          });
  ASSERT(pipeline_layout != NULL);
}

static void setup_bind_group(wgpu_context_t* wgpu_context)
{
  /* Bind Group */
  WGPUBindGroupEntry bg_entries[3] = {
    [0] = (WGPUBindGroupEntry) {
      /* Binding 0 : Vertex shader uniform buffer */
      .binding = 0,
      .buffer  = uniform_buffer_vs.buffer,
      .offset  = 0,
      .size    = uniform_buffer_vs.size,
    },
    [1] = (WGPUBindGroupEntry) {
      /* Binding 1 : Fragment shader texture view */
      .binding     = 1,
      .textureView = texture.view,
    },
    [2] = (WGPUBindGroupEntry) {
      /* Binding 2: Fragment shader image sampler */
      .binding = 2,
      .sampler = texture.sampler,
    },
  };

  bind_group = wgpuDeviceCreateBindGroup(
    wgpu_context->device, &(WGPUBindGroupDescriptor){
                            .label      = "Bind group",
                            .layout     = bind_group_layout,
                            .entryCount = (uint32_t)ARRAY_SIZE(bg_entries),
                            .entries    = bg_entries,
                          });
  ASSERT(bind_group != NULL);
}

static void setup_render_pass(wgpu_context_t* wgpu_context)
{
  /* Color attachment */
  render_pass.color_attachments[0] = (WGPURenderPassColorAttachment) {
      .view       = NULL, /* Assigned later */
      .depthSlice = ~0,
      .loadOp     = WGPULoadOp_Clear,
      .storeOp    = WGPUStoreOp_Store,
      .clearValue = (WGPUColor) {
        .r = 0.0f,
        .g = 0.0f,
        .b = 0.0f,
        .a = 1.0f,
      },
  };

  /* Depth attachment */
  wgpu_setup_deph_stencil(wgpu_context, NULL);

  /* Render pass descriptor */
  render_pass.descriptor = (WGPURenderPassDescriptor){
    .label                  = "Render pass descriptor",
    .colorAttachmentCount   = 1,
    .colorAttachments       = render_pass.color_attachments,
    .depthStencilAttachment = &wgpu_context->depth_stencil.att_desc,
  };
}

/* Create the graphics pipeline */
static void prepare_pipelines(wgpu_context_t* wgpu_context)
{
  /* Primitive state */
  WGPUPrimitiveState primitive_state = {
    .topology  = WGPUPrimitiveTopology_TriangleList,
    .frontFace = WGPUFrontFace_CCW,
    .cullMode  = WGPUCullMode_None,
  };

  /* Color target state */
  WGPUBlendState blend_state              = wgpu_create_blend_state(true);
  WGPUColorTargetState color_target_state = (WGPUColorTargetState){
    .format    = wgpu_context->swap_chain.format,
    .blend     = &blend_state,
    .writeMask = WGPUColorWriteMask_All,
  };

  /* Depth stencil state */
  WGPUDepthStencilState depth_stencil_state
    = wgpu_create_depth_stencil_state(&(create_depth_stencil_state_desc_t){
      .format              = WGPUTextureFormat_Depth24PlusStencil8,
      .depth_write_enabled = true,
    });

  /* Vertex buffer layout */
  WGPU_VERTEX_BUFFER_LAYOUT(
    quad, sizeof(vertex_t),
    /* Attribute descriptions */
    /* Attribute location 0: Position */
    WGPU_VERTATTR_DESC(0, WGPUVertexFormat_Float32x3, offsetof(vertex_t, pos)),
    /* Attribute location 1: Texture coordinates */
    WGPU_VERTATTR_DESC(1, WGPUVertexFormat_Float32x2, offsetof(vertex_t, uv)),
    /* Attribute location 2: Vertex normal */
    WGPU_VERTATTR_DESC(2, WGPUVertexFormat_Float32x3,
                       offsetof(vertex_t, normal)))

  /* Vertex state */
  WGPUVertexState vertex_state = wgpu_create_vertex_state(
                wgpu_context, &(wgpu_vertex_state_t){
                .shader_desc = (wgpu_shader_desc_t){
                  /* Vertex shader SPIR-V */
                  .label = "Texture quad - Vertex shader SPIR-V",
                  .file  = "shaders/textured_quad/texture.vert.spv",
                },
                .buffer_count = 1,
                .buffers      = &quad_vertex_buffer_layout,
              });

  /* Fragment state */
  WGPUFragmentState fragment_state = wgpu_create_fragment_state(
                wgpu_context, &(wgpu_fragment_state_t){
                .shader_desc = (wgpu_shader_desc_t){
                  /* Fragment shader SPIR-V */
                  .label = "Texture quad - Fragment shader SPIR-V",
                  .file  = "shaders/textured_quad/texture.frag.spv",
                },
                .target_count = 1,
                .targets      = &color_target_state,
              });

  /* Multisample state */
  WGPUMultisampleState multisample_state
    = wgpu_create_multisample_state_descriptor(
      &(create_multisample_state_desc_t){
        .sample_count = 1,
      });

  /* Create rendering pipeline using the specified states */
  pipeline = wgpuDeviceCreateRenderPipeline(
    wgpu_context->device, &(WGPURenderPipelineDescriptor){
                            .label        = "Textured quad - Render pipeline",
                            .layout       = pipeline_layout,
                            .primitive    = primitive_state,
                            .vertex       = vertex_state,
                            .fragment     = &fragment_state,
                            .depthStencil = &depth_stencil_state,
                            .multisample  = multisample_state,
                          });
  ASSERT(pipeline != NULL);

  /* Partial cleanup */
  WGPU_RELEASE_RESOURCE(ShaderModule, vertex_state.module);
  WGPU_RELEASE_RESOURCE(ShaderModule, fragment_state.module);
}

static int example_initialize(wgpu_example_context_t* context)
{
  if (context) {
    setup_camera(context);
    load_texture(context->wgpu_context);
    generate_quad(context->wgpu_context);
    prepare_uniform_buffers(context);
    setup_pipeline_layout(context->wgpu_context);
    prepare_pipelines(context->wgpu_context);
    setup_bind_group(context->wgpu_context);
    setup_render_pass(context->wgpu_context);
    prepared = true;
    return EXIT_SUCCESS;
  }

  return EXIT_FAILURE;
}

static void example_on_update_ui_overlay(wgpu_example_context_t* context)
{
  if (imgui_overlay_header("Settings")) {
    if (imgui_overlay_slider_float(context->imgui_overlay, "LOD Bias",
                                   &ubo_vs.lodBias, 0.0f,
                                   (float)texture.mip_level_count, "%.1f")) {
      update_uniform_buffers(context);
    }
  }
}

/* Build separate command buffer for the framebuffer image */
static WGPUCommandBuffer build_command_buffer(wgpu_context_t* wgpu_context)
{
  /* Set target frame  */
  render_pass.color_attachments[0].view = wgpu_context->swap_chain.frame_buffer;

  /* Create command encoder */
  wgpu_context->cmd_enc
    = wgpuDeviceCreateCommandEncoder(wgpu_context->device, NULL);

  /* Create render pass encoder for encoding drawing commands */
  wgpu_context->rpass_enc = wgpuCommandEncoderBeginRenderPass(
    wgpu_context->cmd_enc, &render_pass.descriptor);

  /* Bind the rendering pipeline */
  wgpuRenderPassEncoderSetPipeline(wgpu_context->rpass_enc, pipeline);

  /* Set the bind group */
  wgpuRenderPassEncoderSetBindGroup(wgpu_context->rpass_enc, 0, bind_group, 0,
                                    0);

  /* Set viewport */
  wgpuRenderPassEncoderSetViewport(
    wgpu_context->rpass_enc, 0.0f, 0.0f, (float)wgpu_context->surface.width,
    (float)wgpu_context->surface.height, 0.0f, 1.0f);

  /* Set scissor rectangle */
  wgpuRenderPassEncoderSetScissorRect(wgpu_context->rpass_enc, 0u, 0u,
                                      wgpu_context->surface.width,
                                      wgpu_context->surface.height);

  /* Bind triangle vertex buffer (contains position and colors) */
  wgpuRenderPassEncoderSetVertexBuffer(wgpu_context->rpass_enc, 0,
                                       vertices.buffer, 0, WGPU_WHOLE_SIZE);

  /* Bind triangle index buffer */
  wgpuRenderPassEncoderSetIndexBuffer(wgpu_context->rpass_enc, indices.buffer,
                                      WGPUIndexFormat_Uint16, 0,
                                      WGPU_WHOLE_SIZE);

  /* Draw indexed quad */
  wgpuRenderPassEncoderDrawIndexed(wgpu_context->rpass_enc, indices.count, 1, 0,
                                   0, 0);

  /* End render pass */
  wgpuRenderPassEncoderEnd(wgpu_context->rpass_enc);
  WGPU_RELEASE_RESOURCE(RenderPassEncoder, wgpu_context->rpass_enc)

  /* Draw ui overlay */
  draw_ui(wgpu_context->context, example_on_update_ui_overlay);

  /* Get command buffer */
  WGPUCommandBuffer command_buffer
    = wgpu_get_command_buffer(wgpu_context->cmd_enc);
  WGPU_RELEASE_RESOURCE(CommandEncoder, wgpu_context->cmd_enc)

  return command_buffer;
}

static int example_draw(wgpu_example_context_t* context)
{
  /* Prepare frame */
  prepare_frame(context);

  /* Command buffer to be submitted to the queue */
  wgpu_context_t* wgpu_context                   = context->wgpu_context;
  wgpu_context->submit_info.command_buffer_count = 1;
  wgpu_context->submit_info.command_buffers[0]
    = build_command_buffer(context->wgpu_context);

  /* Submit to queue */
  submit_command_buffers(context);

  /* Submit frame */
  submit_frame(context);

  return EXIT_SUCCESS;
}

static int example_render(wgpu_example_context_t* context)
{
  if (!prepared) {
    return EXIT_FAILURE;
  }
  return example_draw(context);
}

static void example_on_view_changed(wgpu_example_context_t* context)
{
  update_uniform_buffers(context);
}

static void example_destroy(wgpu_example_context_t* context)
{
  camera_release(context->camera);
  wgpu_destroy_texture(&texture);
  WGPU_RELEASE_RESOURCE(BindGroupLayout, bind_group_layout)
  WGPU_RELEASE_RESOURCE(PipelineLayout, pipeline_layout)
  WGPU_RELEASE_RESOURCE(BindGroup, bind_group)
  WGPU_RELEASE_RESOURCE(Buffer, uniform_buffer_vs.buffer)
  WGPU_RELEASE_RESOURCE(Buffer, indices.buffer)
  WGPU_RELEASE_RESOURCE(Buffer, vertices.buffer)
  WGPU_RELEASE_RESOURCE(RenderPipeline, pipeline)
}

void example_textured_quad(int argc, char* argv[])
{
  // clang-format off
  example_run(argc, argv, &(refexport_t){
    .example_settings = (wgpu_example_settings_t){
      .title   = example_title,
      .overlay = true,
      .vsync   = true,
    },
    .example_initialize_func      = &example_initialize,
    .example_render_func          = &example_render,
    .example_destroy_func         = &example_destroy,
    .example_on_view_changed_func = &example_on_view_changed,
  });
  // clang-format on
}