summaryrefslogtreecommitdiffstats
path: root/examples/hellogpumipmap/window.cpp
blob: c87de78cef1833cb10839c75f4e2c9d4eeba9421 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing/
**
** This file is part of the examples of the QtD3D12Window module
**
** $QT_BEGIN_LICENSE:BSD$
** You may use this file under the terms of the BSD license as follows:
**
** "Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions are
** met:
**   * Redistributions of source code must retain the above copyright
**     notice, this list of conditions and the following disclaimer.
**   * Redistributions in binary form must reproduce the above copyright
**     notice, this list of conditions and the following disclaimer in
**     the documentation and/or other materials provided with the
**     distribution.
**   * Neither the name of The Qt Company Ltd nor the names of its
**     contributors may be used to endorse or promote products derived
**     from this software without specific prior written permission.
**
**
** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "window.h"
#include "shader_vs.h"
#include "shader_ps.h"
#include "shader_cs.h"

// size must be a power of two due to the way mipmap generation is done
static const int TEXTURE_WIDTH = 512;
static const int TEXTURE_HEIGHT = 512;

static const int TEXTURE_MIP_LEVELS = 10; // ceil(log2(max(width, height))) + 1

Window::Window()
    : f(Q_NULLPTR),
      cbPtr(Q_NULLPTR),
      rotationAngle(0)
{
}

Window::~Window()
{
    if (cbPtr)
        constantBuffer->Unmap(0, Q_NULLPTR);

    delete f;
}

void Window::initializeD3D()
{
    QImage qtLogo = QImage(QStringLiteral(":/qt.png")).convertToFormat(QImage::Format_RGBA8888).scaled(TEXTURE_WIDTH, TEXTURE_HEIGHT);
    if (qtLogo.isNull()) {
        qWarning("Failed to load image data");
        return;
    }

    f = createFence();
    ID3D12Device *dev = device();

    // One static sampler (no sampler heap is needed).
    D3D12_STATIC_SAMPLER_DESC sampler = {};
    sampler.Filter = D3D12_FILTER_MIN_MAG_MIP_LINEAR;
    sampler.AddressU = D3D12_TEXTURE_ADDRESS_MODE_CLAMP;
    sampler.AddressV = D3D12_TEXTURE_ADDRESS_MODE_CLAMP;
    sampler.AddressW = D3D12_TEXTURE_ADDRESS_MODE_CLAMP;
    sampler.MinLOD = 0.0f;
    sampler.MaxLOD = D3D12_FLOAT32_MAX;
    sampler.ShaderRegister = 0;
    sampler.RegisterSpace = 0;
    sampler.ShaderVisibility = D3D12_SHADER_VISIBILITY_PIXEL;

    // In addition to the constant buffer view we will now also have a shader
    // resource view in order to expose the texture to the pixel shader.
    D3D12_DESCRIPTOR_RANGE descRange[2];
    descRange[0].RangeType = D3D12_DESCRIPTOR_RANGE_TYPE_CBV;
    descRange[0].NumDescriptors = 1;
    descRange[0].BaseShaderRegister = 0; // b0
    descRange[0].RegisterSpace = 0;
    descRange[0].OffsetInDescriptorsFromTableStart = D3D12_DESCRIPTOR_RANGE_OFFSET_APPEND;
    descRange[1].RangeType = D3D12_DESCRIPTOR_RANGE_TYPE_SRV;
    descRange[1].NumDescriptors = 1;
    descRange[1].BaseShaderRegister = 0; // t0
    descRange[1].RegisterSpace = 0;
    descRange[1].OffsetInDescriptorsFromTableStart = D3D12_DESCRIPTOR_RANGE_OFFSET_APPEND;

    D3D12_ROOT_PARAMETER rootParameter;
    rootParameter.ParameterType = D3D12_ROOT_PARAMETER_TYPE_DESCRIPTOR_TABLE;
    rootParameter.ShaderVisibility = D3D12_SHADER_VISIBILITY_ALL;
    rootParameter.DescriptorTable.NumDescriptorRanges = 2;
    rootParameter.DescriptorTable.pDescriptorRanges = descRange;

    D3D12_ROOT_SIGNATURE_DESC desc;
    desc.NumParameters = 1;
    desc.pParameters = &rootParameter;
    desc.NumStaticSamplers = 1;
    desc.pStaticSamplers = &sampler;
    desc.Flags = D3D12_ROOT_SIGNATURE_FLAG_ALLOW_INPUT_ASSEMBLER_INPUT_LAYOUT;

    ComPtr<ID3DBlob> signature;
    ComPtr<ID3DBlob> error;
    if (FAILED(D3D12SerializeRootSignature(&desc, D3D_ROOT_SIGNATURE_VERSION_1, &signature, &error))) {
        QByteArray msg(static_cast<const char *>(error->GetBufferPointer()), error->GetBufferSize());
        qWarning("Failed to serialize root signature: %s", qPrintable(msg));
        return;
    }
    if (FAILED(dev->CreateRootSignature(0, signature->GetBufferPointer(), signature->GetBufferSize(), IID_PPV_ARGS(&rootSignature)))) {
        qWarning("Failed to create root signature");
        return;
    }

    D3D12_INPUT_ELEMENT_DESC inputElementDescs[] = {
        { "POSITION", 0, DXGI_FORMAT_R32G32B32_FLOAT, 0, 0, D3D12_INPUT_CLASSIFICATION_PER_VERTEX_DATA, 0 },
        { "TEXCOORD", 0, DXGI_FORMAT_R32G32_FLOAT, 0, 12, D3D12_INPUT_CLASSIFICATION_PER_VERTEX_DATA, 0 }
    };

    D3D12_SHADER_BYTECODE vshader;
    vshader.pShaderBytecode = g_VS_Texture;
    vshader.BytecodeLength = sizeof(g_VS_Texture);
    D3D12_SHADER_BYTECODE pshader;
    pshader.pShaderBytecode = g_PS_Texture;
    pshader.BytecodeLength = sizeof(g_PS_Texture);

    D3D12_RASTERIZER_DESC rastDesc = {};
    rastDesc.FillMode = D3D12_FILL_MODE_SOLID;
    rastDesc.CullMode = D3D12_CULL_MODE_BACK;
    rastDesc.FrontCounterClockwise = TRUE; // Vertices are given CCW
    rastDesc.DepthBias = D3D12_DEFAULT_DEPTH_BIAS;
    rastDesc.DepthBiasClamp = D3D12_DEFAULT_DEPTH_BIAS_CLAMP;
    rastDesc.SlopeScaledDepthBias = D3D12_DEFAULT_SLOPE_SCALED_DEPTH_BIAS;
    rastDesc.DepthClipEnable = TRUE;

    // Our material is transparent (the image has alpha < 255). Enable blending.
    const D3D12_RENDER_TARGET_BLEND_DESC defaultRenderTargetBlendDesc = {
        TRUE, FALSE,
        D3D12_BLEND_SRC_ALPHA, D3D12_BLEND_INV_SRC_ALPHA, D3D12_BLEND_OP_ADD,
        D3D12_BLEND_ZERO, D3D12_BLEND_ZERO, D3D12_BLEND_OP_ADD,
        D3D12_LOGIC_OP_NOOP,
        D3D12_COLOR_WRITE_ENABLE_ALL
    };
    D3D12_BLEND_DESC blendDesc = {};
    blendDesc.RenderTarget[0] = defaultRenderTargetBlendDesc;

    D3D12_GRAPHICS_PIPELINE_STATE_DESC psoDesc = {};
    psoDesc.InputLayout = { inputElementDescs, _countof(inputElementDescs) };
    psoDesc.pRootSignature = rootSignature.Get();
    psoDesc.VS = vshader;
    psoDesc.PS = pshader;
    psoDesc.RasterizerState = rastDesc;
    psoDesc.BlendState = blendDesc;
    psoDesc.DepthStencilState.DepthEnable = TRUE;
    psoDesc.DepthStencilState.DepthWriteMask = D3D12_DEPTH_WRITE_MASK_ALL;
    psoDesc.DepthStencilState.DepthFunc = D3D12_COMPARISON_FUNC_LESS;
    psoDesc.DepthStencilState.StencilEnable = FALSE;
    psoDesc.SampleMask = UINT_MAX;
    psoDesc.PrimitiveTopologyType = D3D12_PRIMITIVE_TOPOLOGY_TYPE_TRIANGLE;
    psoDesc.NumRenderTargets = 1;
    psoDesc.RTVFormats[0] = DXGI_FORMAT_R8G8B8A8_UNORM;
    psoDesc.DSVFormat = DXGI_FORMAT_D32_FLOAT;
    psoDesc.SampleDesc.Count = 1;
    if (FAILED(dev->CreateGraphicsPipelineState(&psoDesc, IID_PPV_ARGS(&pipelineState)))) {
        qWarning("Failed to create graphics pipeline state");
        return;
    }

    if (FAILED(dev->CreateCommandList(0, D3D12_COMMAND_LIST_TYPE_DIRECT, commandAllocator(), Q_NULLPTR, IID_PPV_ARGS(&commandList)))) {
        qWarning("Failed to create command list");
        return;
    }

    // Vertex buffer
    const float vertices[] = {
        -0.5f, -0.5f, 0, /* coords */ 0, 1, // the image was not flipped so accommodate for it here
        0.5f, -0.5f, 0,               1, 1,
        -0.5f, 0.5f, 0,               0, 0,

        -0.5f, 0.5f, 0,               0, 0,
        0.5f, -0.5f, 0,               1, 1,
        0.5f, 0.5f, 0,                1, 0
    };
    const UINT vertexBufferSize = sizeof(vertices);

    D3D12_HEAP_PROPERTIES defaultHeapProp = {};
    defaultHeapProp.Type = D3D12_HEAP_TYPE_DEFAULT;
    D3D12_HEAP_PROPERTIES uploadHeapProp = defaultHeapProp;
    uploadHeapProp.Type = D3D12_HEAP_TYPE_UPLOAD;

    D3D12_RESOURCE_DESC bufDesc = {};
    bufDesc.Dimension = D3D12_RESOURCE_DIMENSION_BUFFER;
    bufDesc.Width = vertexBufferSize;
    bufDesc.Height = 1;
    bufDesc.DepthOrArraySize = 1;
    bufDesc.MipLevels = 1;
    bufDesc.Format = DXGI_FORMAT_UNKNOWN;
    bufDesc.SampleDesc.Count = 1;
    bufDesc.Layout = D3D12_TEXTURE_LAYOUT_ROW_MAJOR;

    if (FAILED(dev->CreateCommittedResource(&uploadHeapProp, D3D12_HEAP_FLAG_NONE, &bufDesc,
                                            D3D12_RESOURCE_STATE_GENERIC_READ, Q_NULLPTR, IID_PPV_ARGS(&vertexBuffer)))) {
        qWarning("Failed to create committed resource (vertex buffer)");
        return;
    }

    quint8 *p = Q_NULLPTR;
    D3D12_RANGE readRange = { 0, 0 };
    if (FAILED(vertexBuffer->Map(0, &readRange, reinterpret_cast<void **>(&p)))) {
        qWarning("Map failed (vertex buffer)");
        return;
    }
    memcpy(p, vertices, vertexBufferSize);
    vertexBuffer->Unmap(0, Q_NULLPTR);

    vertexBufferView.BufferLocation = vertexBuffer->GetGPUVirtualAddress();
    vertexBufferView.StrideInBytes = (3 + 2) * sizeof(float);
    vertexBufferView.SizeInBytes = vertexBufferSize;

    // Constant buffer
    const UINT CB_SIZE = alignedCBSize(128); // 2 * float4x4
    bufDesc.Width = CB_SIZE;
    if (FAILED(dev->CreateCommittedResource(&uploadHeapProp, D3D12_HEAP_FLAG_NONE, &bufDesc,
                                            D3D12_RESOURCE_STATE_GENERIC_READ, Q_NULLPTR, IID_PPV_ARGS(&constantBuffer)))) {
        qWarning("Failed to create committed resource (constant buffer)");
        return;
    }

    if (FAILED(constantBuffer->Map(0, &readRange, reinterpret_cast<void **>(&p)))) {
        qWarning("Map failed (constant buffer)");
        return;
    }
    cbPtr = p; // won't Unmap() this here

    // Constant buffer view and shader resource view descriptors are stored in the same heap.
    cbvSrvUavStride = dev->GetDescriptorHandleIncrementSize(D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV);
    D3D12_DESCRIPTOR_HEAP_DESC cbvSrvUavHeapDesc = {};
    // CBV + SRV + (TEXTURE_MIP_LEVELS - 1) * UAV
    cbvSrvUavHeapDesc.NumDescriptors = 1 + 1 + (TEXTURE_MIP_LEVELS - 1);
    cbvSrvUavHeapDesc.Flags = D3D12_DESCRIPTOR_HEAP_FLAG_SHADER_VISIBLE;
    cbvSrvUavHeapDesc.Type = D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV;
    if (FAILED(dev->CreateDescriptorHeap(&cbvSrvUavHeapDesc, IID_PPV_ARGS(&cbvSrvUavHeap)))) {
        qWarning("Failed to create CBV/SRV/UAV descriptor heap");
        return;
    }

    // CBV for the pixel shader
    D3D12_CPU_DESCRIPTOR_HANDLE cbvSrvUavHandle = cbvSrvUavHeap->GetCPUDescriptorHandleForHeapStart();
    D3D12_CONSTANT_BUFFER_VIEW_DESC cbvDesc = {};
    cbvDesc.BufferLocation = constantBuffer->GetGPUVirtualAddress();
    cbvDesc.SizeInBytes = CB_SIZE;
    dev->CreateConstantBufferView(&cbvDesc, cbvSrvUavHandle);
    cbvSrvUavHandle.ptr += cbvSrvUavStride;

    // Texture (with mipmaps and allowing read/write via UAVs)
    D3D12_RESOURCE_DESC textureDesc = {};
    textureDesc.Dimension = D3D12_RESOURCE_DIMENSION_TEXTURE2D;
    textureDesc.Width = TEXTURE_WIDTH;
    textureDesc.Height = TEXTURE_HEIGHT;
    textureDesc.DepthOrArraySize = 1;
    textureDesc.MipLevels = TEXTURE_MIP_LEVELS;
    textureDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
    textureDesc.SampleDesc.Count = 1;
    textureDesc.Layout = D3D12_TEXTURE_LAYOUT_UNKNOWN;
    textureDesc.Flags = D3D12_RESOURCE_FLAG_ALLOW_UNORDERED_ACCESS;

    if (FAILED(dev->CreateCommittedResource(&defaultHeapProp, D3D12_HEAP_FLAG_NONE, &textureDesc,
                                            D3D12_RESOURCE_STATE_COPY_DEST, Q_NULLPTR, IID_PPV_ARGS(&texture)))) {
        qWarning("Failed to create texture resource");
        return;
    }

    // Shader resource view for exposing the texture to the compute and pixel shaders
    D3D12_SHADER_RESOURCE_VIEW_DESC srvDesc = {};
    srvDesc.Shader4ComponentMapping = D3D12_DEFAULT_SHADER_4_COMPONENT_MAPPING;
    srvDesc.Format = textureDesc.Format;
    srvDesc.ViewDimension = D3D12_SRV_DIMENSION_TEXTURE2D;
    srvDesc.Texture2D.MipLevels = TEXTURE_MIP_LEVELS;
    dev->CreateShaderResourceView(texture.Get(), &srvDesc, cbvSrvUavHandle);
    cbvSrvUavHandle.ptr += cbvSrvUavStride;

    // Mipmap generation will need an UAV for each level that needs to be generated.
    for (int level = 1; level < TEXTURE_MIP_LEVELS; ++level) {
        D3D12_UNORDERED_ACCESS_VIEW_DESC uavDesc = {};
        uavDesc.Format = textureDesc.Format;
        uavDesc.ViewDimension = D3D12_UAV_DIMENSION_TEXTURE2D;
        uavDesc.Texture2D.MipSlice = level;
        dev->CreateUnorderedAccessView(texture.Get(), Q_NULLPTR, &uavDesc, cbvSrvUavHandle);
        cbvSrvUavHandle.ptr += cbvSrvUavStride;
    }

    ComPtr<ID3D12Resource> textureUploadBuffer;
    UINT64 textureUploadBufferSize;
    D3D12_PLACED_SUBRESOURCE_FOOTPRINT textureLayout;
    dev->GetCopyableFootprints(&textureDesc, 0, 1, 0, &textureLayout, Q_NULLPTR, Q_NULLPTR, &textureUploadBufferSize);
    bufDesc.Width = textureUploadBufferSize;
    if (FAILED(dev->CreateCommittedResource(&uploadHeapProp, D3D12_HEAP_FLAG_NONE, &bufDesc,
                                            D3D12_RESOURCE_STATE_GENERIC_READ, Q_NULLPTR, IID_PPV_ARGS(&textureUploadBuffer)))) {
        qWarning("Failed to create texture upload buffer resource");
        return;
    }

    // Unlike hellotexture, upload only level 0. Leave the rest to a compute shader.
    if (FAILED(textureUploadBuffer->Map(0, &readRange, reinterpret_cast<void **>(&p)))) {
        qWarning("Map failed (texture upload buffer)");
        return;
    }
    p += textureLayout.Offset;
    for (int y = 0; y < TEXTURE_HEIGHT; ++y) {
        memcpy(p, qtLogo.scanLine(y), TEXTURE_WIDTH * 4);
        p += textureLayout.Footprint.RowPitch;
    }
    textureUploadBuffer->Unmap(0, Q_NULLPTR);

    D3D12_TEXTURE_COPY_LOCATION dstLoc;
    dstLoc.pResource = texture.Get();
    dstLoc.Type = D3D12_TEXTURE_COPY_TYPE_SUBRESOURCE_INDEX;
    dstLoc.SubresourceIndex = 0;
    D3D12_TEXTURE_COPY_LOCATION srcLoc;
    srcLoc.pResource = textureUploadBuffer.Get();
    srcLoc.Type = D3D12_TEXTURE_COPY_TYPE_PLACED_FOOTPRINT;
    srcLoc.PlacedFootprint = textureLayout;
    commandList->CopyTextureRegion(&dstLoc, 0, 0, 0, &srcLoc, Q_NULLPTR);

    // once the copy is done, the texture is ready to be used in the compute shader...
    transitionResource(texture.Get(), commandList.Get(), D3D12_RESOURCE_STATE_COPY_DEST, D3D12_RESOURCE_STATE_UNORDERED_ACCESS);
    uavBarrier(texture.Get(), commandList.Get());

    initMipMaps();
    generateMipMaps();

    // ...and then in the pixel shader
    uavBarrier(texture.Get(), commandList.Get());
    transitionResource(texture.Get(), commandList.Get(), D3D12_RESOURCE_STATE_UNORDERED_ACCESS, D3D12_RESOURCE_STATE_PIXEL_SHADER_RESOURCE);

    // Execute the texture upload and mipmap generation.
    commandList->Close();
    ID3D12CommandList *commandLists[] = { commandList.Get() };
    commandQueue()->ExecuteCommandLists(_countof(commandLists), commandLists);

    // Block until all the above has finished.
    waitForGPU(f);

    setupProjection();
}

void Window::initMipMaps()
{
    ID3D12Device *dev = device();

    D3D12_STATIC_SAMPLER_DESC sampler = {};
    sampler.Filter = D3D12_FILTER_MIN_MAG_MIP_LINEAR;
    sampler.AddressU = D3D12_TEXTURE_ADDRESS_MODE_CLAMP;
    sampler.AddressV = D3D12_TEXTURE_ADDRESS_MODE_CLAMP;
    sampler.AddressW = D3D12_TEXTURE_ADDRESS_MODE_CLAMP;
    sampler.MinLOD = 0.0f;
    sampler.MaxLOD = D3D12_FLOAT32_MAX;

    D3D12_DESCRIPTOR_RANGE descRange[2];
    descRange[0].RangeType = D3D12_DESCRIPTOR_RANGE_TYPE_SRV;
    descRange[0].NumDescriptors = 1;
    descRange[0].BaseShaderRegister = 0; // t0
    descRange[0].RegisterSpace = 0;
    descRange[0].OffsetInDescriptorsFromTableStart = D3D12_DESCRIPTOR_RANGE_OFFSET_APPEND;
    descRange[1].RangeType = D3D12_DESCRIPTOR_RANGE_TYPE_UAV;
    descRange[1].NumDescriptors = 4;
    descRange[1].BaseShaderRegister = 0; // u0..u3
    descRange[1].RegisterSpace = 0;
    descRange[1].OffsetInDescriptorsFromTableStart = D3D12_DESCRIPTOR_RANGE_OFFSET_APPEND;

    // Split into two to allow switching between the first and second set of UAVs later.
    D3D12_ROOT_PARAMETER rootParameters[3];
    rootParameters[0].ParameterType = D3D12_ROOT_PARAMETER_TYPE_DESCRIPTOR_TABLE;
    rootParameters[0].ShaderVisibility = D3D12_SHADER_VISIBILITY_ALL;
    rootParameters[0].DescriptorTable.NumDescriptorRanges = 1;
    rootParameters[0].DescriptorTable.pDescriptorRanges = &descRange[0];

    rootParameters[1].ParameterType = D3D12_ROOT_PARAMETER_TYPE_DESCRIPTOR_TABLE;
    rootParameters[1].ShaderVisibility = D3D12_SHADER_VISIBILITY_ALL;
    rootParameters[1].DescriptorTable.NumDescriptorRanges = 1;
    rootParameters[1].DescriptorTable.pDescriptorRanges = &descRange[1];

    rootParameters[2].ParameterType = D3D12_ROOT_PARAMETER_TYPE_32BIT_CONSTANTS;
    rootParameters[2].ShaderVisibility = D3D12_SHADER_VISIBILITY_ALL;
    rootParameters[2].Constants.Num32BitValues = 4; // uint2 mip1Size, uint sampleLevel, uint totalMips
    rootParameters[2].Constants.ShaderRegister = 0; // b0
    rootParameters[2].Constants.RegisterSpace = 0;

    D3D12_ROOT_SIGNATURE_DESC desc = {};
    desc.NumParameters = 3;
    desc.pParameters = rootParameters;
    desc.NumStaticSamplers = 1;
    desc.pStaticSamplers = &sampler;

    ComPtr<ID3DBlob> signature;
    ComPtr<ID3DBlob> error;
    if (FAILED(D3D12SerializeRootSignature(&desc, D3D_ROOT_SIGNATURE_VERSION_1, &signature, &error))) {
        QByteArray msg(static_cast<const char *>(error->GetBufferPointer()), error->GetBufferSize());
        qWarning("Failed to serialize compute root signature: %s", qPrintable(msg));
        return;
    }
    if (FAILED(dev->CreateRootSignature(0, signature->GetBufferPointer(), signature->GetBufferSize(),
                                        IID_PPV_ARGS(&computeRootSignature)))) {
        qWarning("Failed to create compute root signature");
        return;
    }

    D3D12_COMPUTE_PIPELINE_STATE_DESC psoDesc = {};
    psoDesc.pRootSignature = computeRootSignature.Get();
    psoDesc.CS.pShaderBytecode = g_CS_Generate4MipMaps;
    psoDesc.CS.BytecodeLength = sizeof(g_CS_Generate4MipMaps);

    if (FAILED(dev->CreateComputePipelineState(&psoDesc, IID_PPV_ARGS(&computeState)))) {
        qWarning("Failed to create compute pipeline state");
        return;
    }
}

void Window::generateMipMaps()
{
    commandList->SetPipelineState(computeState.Get());
    commandList->SetComputeRootSignature(computeRootSignature.Get());

    ID3D12DescriptorHeap *heaps[] = { cbvSrvUavHeap.Get() };
    commandList->SetDescriptorHeaps(_countof(heaps), heaps);

    D3D12_GPU_DESCRIPTOR_HANDLE h = cbvSrvUavHeap->GetGPUDescriptorHandleForHeapStart(); // CBV, not needed here
    h.ptr += cbvSrvUavStride; // SRV
    commandList->SetComputeRootDescriptorTable(0, h);

    h.ptr += cbvSrvUavStride; // now points to the first of (TEXTURE_MIP_LEVELS - 1) UAV descriptors

    for (quint32 level = 1; level < TEXTURE_MIP_LEVELS; level += 4, h.ptr += cbvSrvUavStride * 4) {
        commandList->SetComputeRootDescriptorTable(1, h);

        QSize sz(TEXTURE_WIDTH, TEXTURE_HEIGHT);
        sz.setWidth(qMax(1, sz.width() >> level));
        sz.setHeight(qMax(1, sz.height() >> level));

        const quint32 constants[4] = { quint32(sz.width()), quint32(sz.height()),
                                       level - 1,
                                       TEXTURE_MIP_LEVELS - 1 };
        commandList->SetComputeRoot32BitConstants(2, 4, constants, 0);

        commandList->Dispatch(sz.width(), sz.height(), 1);
    }
}

void Window::resizeD3D(const QSize &)
{
    setupProjection();
}

void Window::setupProjection()
{
    projection.setToIdentity();
    projection.perspective(60.0f, width() / float(height()), 0.1f, 100.0f);
}

void Window::paintD3D()
{
    modelview.setToIdentity();
    modelview.translate(0, 0, -2);
    // our highly sophisticated animation
    modelview.rotate(rotationAngle, 0, 0, 1);
    rotationAngle += 1;

    memcpy(cbPtr, modelview.constData(), 16 * sizeof(float));
    memcpy(cbPtr + 16 * sizeof(float), projection.constData(), 16 * sizeof(float));

    commandAllocator()->Reset();
    commandList->Reset(commandAllocator(), pipelineState.Get());

    commandList->SetGraphicsRootSignature(rootSignature.Get());

    ID3D12DescriptorHeap *heaps[] = { cbvSrvUavHeap.Get() };
    commandList->SetDescriptorHeaps(_countof(heaps), heaps);
    commandList->SetGraphicsRootDescriptorTable(0, cbvSrvUavHeap->GetGPUDescriptorHandleForHeapStart());

    D3D12_VIEWPORT viewport = { 0, 0, float(width()), float(height()), 0, 1 };
    commandList->RSSetViewports(1, &viewport);
    D3D12_RECT scissorRect = { 0, 0, width() - 1, height() - 1 };
    commandList->RSSetScissorRects(1, &scissorRect);

    transitionResource(backBufferRenderTarget(), commandList.Get(), D3D12_RESOURCE_STATE_PRESENT, D3D12_RESOURCE_STATE_RENDER_TARGET);

    D3D12_CPU_DESCRIPTOR_HANDLE rtvHandle = backBufferRenderTargetCPUHandle();
    D3D12_CPU_DESCRIPTOR_HANDLE dsvHandle = depthStencilCPUHandle();
    commandList->OMSetRenderTargets(1, &rtvHandle, FALSE, &dsvHandle);

    const float clearColor[] = { 0.0f, 0.2f, 0.4f, 1.0f };
    commandList->ClearRenderTargetView(rtvHandle, clearColor, 0, Q_NULLPTR);
    commandList->ClearDepthStencilView(dsvHandle, D3D12_CLEAR_FLAG_DEPTH, 1.0f, 0, 0, Q_NULLPTR);

    commandList->IASetPrimitiveTopology(D3D_PRIMITIVE_TOPOLOGY_TRIANGLELIST);
    commandList->IASetVertexBuffers(0, 1, &vertexBufferView);
    commandList->DrawInstanced(6, 1, 0, 0);

    transitionResource(backBufferRenderTarget(), commandList.Get(), D3D12_RESOURCE_STATE_RENDER_TARGET, D3D12_RESOURCE_STATE_PRESENT);

    commandList->Close();
    ID3D12CommandList *commandLists[] = { commandList.Get() };
    commandQueue()->ExecuteCommandLists(_countof(commandLists), commandLists);

    update();
}

void Window::afterPresent()
{
    waitForGPU(f);
}