Metal: Fix Intel's LOD clamp and blit shader's filtering.

src/libANGLE/renderer/metal/TextureMtl.mm

@@ -797,10 +797,12 @@ angle::Result TextureMtl::bindToShader(const gl::Context *context,
 {
     ASSERT(mNativeTexture);
 
-    float maxLodClamp = FLT_MAX;
+    float minLodClamp = std::max(0.f, mState.getSamplerState().getMinLod());
+    float maxLodClamp = mState.getSamplerState().getMaxLod();
 
     cmdEncoder->setTexture(shaderType, mNativeTexture, textureSlotIndex);
-    cmdEncoder->setSamplerState(shaderType, mMetalSamplerState, 0, maxLodClamp, samplerSlotIndex);
+    cmdEncoder->setSamplerState(shaderType, mMetalSamplerState, minLodClamp, maxLodClamp,
+                                samplerSlotIndex);
 
     return angle::Result::Continue;
 }

src/libANGLE/renderer/metal/mtl_render_utils.mm

@@ -756,6 +756,16 @@ void ColorBlitUtils::setupBlitWithDraw(const gl::Context *context,
 
     cmdEncoder->setFragmentTexture(params.src, 0);
 
+    // Set default sampler state with linear filtering.
+    // NOTE(hqle): Support configurable filtering (required by glBitFramebuffer).
+    SamplerDesc samplerDesc;
+    samplerDesc.reset();
+    samplerDesc.minFilter = samplerDesc.magFilter = MTLSamplerMinMagFilterLinear;
+
+    cmdEncoder->setFragmentSamplerState(contextMtl->getDisplay()->getStateCache().getSamplerState(
+                                            contextMtl->getMetalDevice(), samplerDesc),
+                                        0, FLT_MAX, 0);
+
     // Uniform
     SetupBlitWithDrawUniformData(cmdEncoder, params);
 }