Commit a977acc857696a83f43b22968c99ff8318a547dd
2018-09-19T12:46:05
ES31: Support translating textureGather into HLSL - Part I This patch is the first one in the series of supporting GLSL texture function textureGather/textureGatherOffset on D3D11. According to ESSL 3.1 SPEC (Chapter 8.9.3, Page 130), the definition of textureGather on sampler2D is: gvec4 textureGather (gsampler2D sampler, vec2 P[, int comp]) The parameter "comp" is optional, and if it is specified, the value of "comp" must be a constant integer expression with a value of 0, 1, 2, or 3, identifying the x, y, z, or w postswizzled component of the four-component vector lookup result for each texel, respectively. If comp is not specified, it is treated as 0. According to the definition above, textureGather is equivalent to Texture2D.Gather[Red|Green|Blue|Alpha] in HLSL, where we can use a switch-case expression to choose the right HLSL texture function. The features listed here will be implemented in the following patches: 1. Support textureGatherOffset 2. Support textureGather[Offset] on isamplers and usamplers 3. Support textureGather[Offset] on textures when swizzle is on 4. Support textureGather[Offset] on shadow samplers BUG=angleproject:2826 TEST=dEQP-GLES31.functional.texture.gather.basic.2d.rgba8.* dEQP-GLES31.functional.texture.gather.basic.cube.rgba8.* (without texture_swizzle) dEQP-GLES31.functional.texture.gather.basic.2d_array.rgba8.* (without texture_swizzle) Change-Id: Iff2ed4f8b65dad613cb0bafdfd19f8f0528e832c Reviewed-on: https://chromium-review.googlesource.com/1232980 Commit-Queue: Jiawei Shao <jiawei.shao@intel.com> Reviewed-by: Corentin Wallez <cwallez@chromium.org>