Vulkan : Fix maxVertexOutputComponents

GL_MAX_VERTEX_OUTPUT_COMPONENTS should mirror Vulkan's reported maxVertexOutputComponents; this shouldn't include any gl_Position adjustments. It was previously set as maxVaryingVectors * 4. The workaround for AMD that reserved an extra varying due to driver instability is no longer required (see: https://chromium-review.googlesource.com/c/angle/angle/+/1980272) Bug: angleproject:4233 Change-Id: I8d7b8eafa7edd4c56005dad039fe69e072692fca Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1975851 Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org>

Vulkan : Fix maxVertexOutputComponents
52dae168 · Gary Sweet · Commit Bot · 86d9c93a · 52dae168
Commit 52dae168 authored Dec 19, 2019 by Gary Sweet Committed by Commit Bot Dec 25, 2019
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vk_caps_utils.cpp src/libANGLE/renderer/vulkan/vk_caps_utils.cpp +5 -8

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--- a/src/libANGLE/renderer/vulkan/vk_caps_utils.cpp
+++ b/src/libANGLE/renderer/vulkan/vk_caps_utils.cpp
@@ -427,14 +427,11 @@ void RendererVk::ensureCapsInitialized() const
    // The gles2.0 section 2.10 states that "gl_Position is not a varying variable and does
    // not count against this limit.", but the Vulkan spec has no such mention in its Built-in
    // vars section. It is implicit that we need to actually reserve it for Vulkan in that case.
-    //
-    // Note: AMD has a weird behavior when we edge toward the maximum number of varyings and can
-    // often crash. Reserving an additional varying just for them bringing the total to 2.
-    constexpr GLint kReservedVaryingCount = 2;
-    mNativeCaps.maxVaryingVectors =
-        LimitToInt((limitsVk.maxVertexOutputComponents / 4) - kReservedVaryingCount);
-    mNativeCaps.maxVertexOutputComponents =
-        LimitToInt(static_cast<uint32_t>(mNativeCaps.maxVaryingVectors * 4));
+    GLint reservedVaryingVectorCount = 1;
+
+    mNativeCaps.maxVaryingVectors = LimitToInt(
+        (limitsVk.maxVertexOutputComponents / kComponentsPerVector) - reservedVaryingVectorCount);
+    mNativeCaps.maxVertexOutputComponents = LimitToInt(limitsVk.maxVertexOutputComponents);

    mNativeCaps.maxTransformFeedbackInterleavedComponents =
        gl::IMPLEMENTATION_MAX_TRANSFORM_FEEDBACK_INTERLEAVED_COMPONENTS;