Add end2end tests for texture subresource

The tests can pass on Metal and OpenGL backend as expected.
But they can't pass on D3D12 and Vulkan backend. I will work
on that soon.

Bug: dawn:157

Change-Id: I4fcf229f7a24369004d5594a3801f0acad804fd0
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/21341
Commit-Queue: Yunchao He <yunchao.he@intel.com>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
diff --git a/src/tests/BUILD.gn b/src/tests/BUILD.gn
index 4e2ebed..6f3799c 100644
--- a/src/tests/BUILD.gn
+++ b/src/tests/BUILD.gn
@@ -289,6 +289,7 @@
     "end2end/ScissorTests.cpp",
     "end2end/StorageTextureTests.cpp",
     "end2end/TextureFormatTests.cpp",
+    "end2end/TextureSubresourceTests.cpp",
     "end2end/TextureViewTests.cpp",
     "end2end/TextureZeroInitTests.cpp",
     "end2end/VertexFormatTests.cpp",
diff --git a/src/tests/end2end/TextureSubresourceTests.cpp b/src/tests/end2end/TextureSubresourceTests.cpp
new file mode 100644
index 0000000..fb3b67d
--- /dev/null
+++ b/src/tests/end2end/TextureSubresourceTests.cpp
@@ -0,0 +1,194 @@
+// Copyright 2020 The Dawn Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "tests/DawnTest.h"
+
+#include "utils/ComboRenderPipelineDescriptor.h"
+#include "utils/WGPUHelpers.h"
+
+class TextureSubresourceTest : public DawnTest {
+  public:
+    static constexpr uint32_t kSize = 4u;
+    static constexpr wgpu::TextureFormat kFormat = wgpu::TextureFormat::RGBA8Unorm;
+
+    wgpu::Texture CreateTexture(uint32_t mipLevelCount,
+                                uint32_t arrayLayerCount,
+                                wgpu::TextureUsage usage) {
+        wgpu::TextureDescriptor texDesc;
+        texDesc.dimension = wgpu::TextureDimension::e2D;
+        texDesc.size = {kSize, kSize, 1};
+        texDesc.arrayLayerCount = arrayLayerCount;
+        texDesc.sampleCount = 1;
+        texDesc.mipLevelCount = mipLevelCount;
+        texDesc.usage = usage;
+        texDesc.format = kFormat;
+        return device.CreateTexture(&texDesc);
+    }
+
+    wgpu::TextureView CreateTextureView(wgpu::Texture texture,
+                                        uint32_t baseMipLevel,
+                                        uint32_t baseArrayLayer) {
+        wgpu::TextureViewDescriptor viewDesc;
+        viewDesc.format = kFormat;
+        viewDesc.baseArrayLayer = baseArrayLayer;
+        viewDesc.arrayLayerCount = 1;
+        viewDesc.baseMipLevel = baseMipLevel;
+        viewDesc.mipLevelCount = 1;
+        viewDesc.dimension = wgpu::TextureViewDimension::e2D;
+        return texture.CreateView(&viewDesc);
+    }
+
+    void DrawTriangle(const wgpu::TextureView& view) {
+        wgpu::ShaderModule vsModule =
+            utils::CreateShaderModule(device, utils::SingleShaderStage::Vertex, R"(
+                #version 450
+                void main() {
+                    const vec2 pos[3] = vec2[3](
+                        vec2(-1.f, 1.f), vec2(-1.f, -1.f), vec2(1.f, -1.f));
+                    gl_Position = vec4(pos[gl_VertexIndex], 0.f, 1.f);
+                 })");
+
+        wgpu::ShaderModule fsModule =
+            utils::CreateShaderModule(device, utils::SingleShaderStage::Fragment, R"(
+                #version 450
+                layout(location = 0) out vec4 fragColor;
+                void main() {
+                    fragColor = vec4(1.0, 0.0, 0.0, 1.0);
+                })");
+
+        utils::ComboRenderPipelineDescriptor descriptor(device);
+        descriptor.vertexStage.module = vsModule;
+        descriptor.cFragmentStage.module = fsModule;
+        descriptor.primitiveTopology = wgpu::PrimitiveTopology::TriangleStrip;
+        descriptor.cColorStates[0].format = kFormat;
+
+        wgpu::RenderPipeline rp = device.CreateRenderPipeline(&descriptor);
+
+        wgpu::CommandEncoder encoder = device.CreateCommandEncoder();
+
+        utils::ComboRenderPassDescriptor renderPassDesc({view});
+        renderPassDesc.cColorAttachments[0].clearColor = {0.0f, 0.0f, 0.0f, 1.0f};
+        wgpu::RenderPassEncoder pass = encoder.BeginRenderPass(&renderPassDesc);
+        pass.SetPipeline(rp);
+        pass.Draw(3);
+        pass.EndPass();
+        wgpu::CommandBuffer commands = encoder.Finish();
+        queue.Submit(1, &commands);
+    }
+
+    void SampleAndDraw(const wgpu::TextureView& samplerView, const wgpu::TextureView& renderView) {
+        wgpu::ShaderModule vsModule =
+            utils::CreateShaderModule(device, utils::SingleShaderStage::Vertex, R"(
+                #version 450
+                void main() {
+                    const vec2 pos[6] = vec2[6](
+                        vec2(-1.f, -1.f), vec2(1.f, 1.f), vec2(-1.f, 1.f),
+                        vec2(-1.f, -1.f), vec2(1.f, -1.f), vec2(1.f, 1.f));
+                    gl_Position = vec4(pos[gl_VertexIndex], 0.f, 1.f);
+                 })");
+
+        wgpu::ShaderModule fsModule =
+            utils::CreateShaderModule(device, utils::SingleShaderStage::Fragment, R"(
+                #version 450
+                layout (set = 0, binding = 0) uniform sampler samp;
+                layout (set = 0, binding = 1) uniform texture2D tex;
+                layout (location = 0) out vec4 fragColor;
+                void main() {
+                    fragColor = texture(sampler2D(tex, samp), gl_FragCoord.xy / 4);
+                })");
+
+        utils::ComboRenderPipelineDescriptor descriptor(device);
+        descriptor.vertexStage.module = vsModule;
+        descriptor.cFragmentStage.module = fsModule;
+        descriptor.primitiveTopology = wgpu::PrimitiveTopology::TriangleStrip;
+        descriptor.cColorStates[0].format = kFormat;
+
+        wgpu::SamplerDescriptor samplerDescriptor = {};
+        wgpu::Sampler sampler = device.CreateSampler(&samplerDescriptor);
+
+        wgpu::RenderPipeline rp = device.CreateRenderPipeline(&descriptor);
+        wgpu::BindGroupLayout bgl = rp.GetBindGroupLayout(0);
+        wgpu::BindGroup bindGroup =
+            utils::MakeBindGroup(device, bgl, {{0, sampler}, {1, samplerView}});
+
+        wgpu::CommandEncoder encoder = device.CreateCommandEncoder();
+
+        utils::ComboRenderPassDescriptor renderPassDesc({renderView});
+        renderPassDesc.cColorAttachments[0].clearColor = {0.0f, 0.0f, 0.0f, 1.0f};
+        wgpu::RenderPassEncoder pass = encoder.BeginRenderPass(&renderPassDesc);
+        pass.SetPipeline(rp);
+        pass.SetBindGroup(0, bindGroup);
+        pass.Draw(6);
+        pass.EndPass();
+        wgpu::CommandBuffer commands = encoder.Finish();
+        queue.Submit(1, &commands);
+    }
+};
+
+// Test different mipmap levels
+TEST_P(TextureSubresourceTest, MipmapLevelsTest) {
+    // Create a texture with 2 mipmap levels and 1 layer
+    wgpu::Texture texture =
+        CreateTexture(2, 1,
+                      wgpu::TextureUsage::Sampled | wgpu::TextureUsage::OutputAttachment |
+                          wgpu::TextureUsage::CopySrc);
+
+    // Create two views on different mipmap levels.
+    wgpu::TextureView samplerView = CreateTextureView(texture, 0, 0);
+    wgpu::TextureView renderView = CreateTextureView(texture, 1, 0);
+
+    // Draw a red triangle at the bottom-left half
+    DrawTriangle(samplerView);
+
+    // Sample from one subresource and draw into another subresource in the same texture
+    SampleAndDraw(samplerView, renderView);
+
+    // Verify that pixel at bottom-left corner is red, while pixel at top-right corner is background
+    // black in render view (mip level 1).
+    RGBA8 topRight = RGBA8::kBlack;
+    RGBA8 bottomLeft = RGBA8::kRed;
+    EXPECT_TEXTURE_RGBA8_EQ(&topRight, texture, kSize / 2 - 1, 0, 1, 1, 1, 0);
+    EXPECT_TEXTURE_RGBA8_EQ(&bottomLeft, texture, 0, kSize / 2 - 1, 1, 1, 1, 0);
+}
+
+// Test different array layers
+TEST_P(TextureSubresourceTest, ArrayLayersTest) {
+    // Create a texture with 1 mipmap level and 2 layers
+    wgpu::Texture texture =
+        CreateTexture(1, 2,
+                      wgpu::TextureUsage::Sampled | wgpu::TextureUsage::OutputAttachment |
+                          wgpu::TextureUsage::CopySrc);
+
+    // Create two views on different layers
+    wgpu::TextureView samplerView = CreateTextureView(texture, 0, 0);
+    wgpu::TextureView renderView = CreateTextureView(texture, 0, 1);
+
+    // Draw a red triangle at the bottom-left half
+    DrawTriangle(samplerView);
+
+    // Sample from one subresource and draw into another subresource in the same texture
+    SampleAndDraw(samplerView, renderView);
+
+    // Verify that pixel at bottom-left corner is red, while pixel at top-right corner is background
+    // black in render view (array layer 1).
+    RGBA8 topRight = RGBA8::kBlack;
+    RGBA8 bottomLeft = RGBA8::kRed;
+    EXPECT_TEXTURE_RGBA8_EQ(&topRight, texture, kSize - 1, 0, 1, 1, 0, 1);
+    EXPECT_TEXTURE_RGBA8_EQ(&bottomLeft, texture, 0, kSize - 1, 1, 1, 0, 1);
+}
+
+// TODO (yunchao.he@intel.com): add tests for storage texture and sampler across miplevel or
+// arraylayer dimensions in the same texture
+
+DAWN_INSTANTIATE_TEST(TextureSubresourceTest, MetalBackend(), OpenGLBackend());