OpenGL: Unconditionally set glFrontFace
Previously glFrontFace was called only if some cull mode was set. This
was incorrect because the front face also influences whether a triangle
uses stencilFront or stencilBack.
Because OpenGL default to GL_CCW (which with the Y-flip is the inverse
of wgpu::FrontFace::CCW that's default in the descriptor), if
stencilFront != stencilBack and cull mode is none, then the incorrect
stencil face descriptor was used.
Also adds a regression test for this issue.
Bug: dawn:508
Change-Id: I00d93bda6d4f030cf9db472a9f2b0deefc72707f
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/26880
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Austin Eng <enga@chromium.org>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
diff --git a/src/dawn_native/opengl/RenderPipelineGL.cpp b/src/dawn_native/opengl/RenderPipelineGL.cpp
index 943dfbb..7c70396 100644
--- a/src/dawn_native/opengl/RenderPipelineGL.cpp
+++ b/src/dawn_native/opengl/RenderPipelineGL.cpp
@@ -43,14 +43,15 @@
void ApplyFrontFaceAndCulling(const OpenGLFunctions& gl,
wgpu::FrontFace face,
wgpu::CullMode mode) {
+ // Note that we invert winding direction in OpenGL. Because Y axis is up in OpenGL,
+ // which is different from WebGPU and other backends (Y axis is down).
+ GLenum direction = (face == wgpu::FrontFace::CCW) ? GL_CW : GL_CCW;
+ gl.FrontFace(direction);
+
if (mode == wgpu::CullMode::None) {
gl.Disable(GL_CULL_FACE);
} else {
gl.Enable(GL_CULL_FACE);
- // Note that we invert winding direction in OpenGL. Because Y axis is up in OpenGL,
- // which is different from WebGPU and other backends (Y axis is down).
- GLenum direction = (face == wgpu::FrontFace::CCW) ? GL_CW : GL_CCW;
- gl.FrontFace(direction);
GLenum cullMode = (mode == wgpu::CullMode::Front) ? GL_FRONT : GL_BACK;
gl.CullFace(cullMode);
diff --git a/src/tests/end2end/DepthStencilStateTests.cpp b/src/tests/end2end/DepthStencilStateTests.cpp
index 4788094..5f5895a 100644
--- a/src/tests/end2end/DepthStencilStateTests.cpp
+++ b/src/tests/end2end/DepthStencilStateTests.cpp
@@ -85,6 +85,7 @@
RGBA8 color;
float depth;
uint32_t stencil;
+ wgpu::FrontFace frontFace = wgpu::FrontFace::CCW;
};
// Check whether a depth comparison function works as expected
@@ -288,6 +289,7 @@
descriptor.cFragmentStage.module = fsModule;
descriptor.cDepthStencilState = test.depthStencilState;
descriptor.cDepthStencilState.format = wgpu::TextureFormat::Depth24PlusStencil8;
+ descriptor.cRasterizationState.frontFace = test.frontFace;
descriptor.depthStencilState = &descriptor.cDepthStencilState;
wgpu::RenderPipeline pipeline = device.CreateRenderPipeline(&descriptor);
@@ -734,6 +736,17 @@
}
}
+// Test that the front and back stencil states are set correctly (and take frontFace into account)
+TEST_P(DepthStencilStateTest, StencilFrontAndBackFace) {
+ wgpu::DepthStencilStateDescriptor state;
+ state.stencilFront.compare = wgpu::CompareFunction::Always;
+ state.stencilBack.compare = wgpu::CompareFunction::Never;
+
+ // The front facing triangle passes the stencil comparison but the back facing one doesn't.
+ DoTest({{state, RGBA8::kRed, 0.f, 0u, wgpu::FrontFace::CCW}}, RGBA8::kRed, RGBA8::kZero);
+ DoTest({{state, RGBA8::kRed, 0.f, 0u, wgpu::FrontFace::CW}}, RGBA8::kZero, RGBA8::kRed);
+}
+
DAWN_INSTANTIATE_TEST(DepthStencilStateTest,
D3D12Backend(),
MetalBackend(),