Fix GatherDref on GLSL.

reference/opt/shaders-msl/frag/gather-dref.frag

@@ -0,0 +1,22 @@
+#include <metal_stdlib>
+#include <simd/simd.h>
+
+using namespace metal;
+
+struct main0_in
+{
+    float3 vUV [[user(locn0)]];
+};
+
+struct main0_out
+{
+    float4 FragColor [[color(0)]];
+};
+
+fragment main0_out main0(main0_in in [[stage_in]], depth2d<float> uT [[texture(0)]], sampler uTSmplr [[sampler(0)]])
+{
+    main0_out out = {};
+    out.FragColor = uT.gather_compare(uTSmplr, in.vUV.xy, in.vUV.z);
+    return out;
+}
+

reference/opt/shaders/frag/gather-dref.frag

@@ -0,0 +1,14 @@
+#version 310 es
+precision mediump float;
+precision highp int;
+
+layout(binding = 0) uniform mediump sampler2DShadow uT;
+
+layout(location = 0) out vec4 FragColor;
+layout(location = 0) in vec3 vUV;
+
+void main()
+{
+    FragColor = textureGather(uT, vUV.xy, vUV.z);
+}
+

reference/shaders-msl/frag/gather-dref.frag

@@ -0,0 +1,22 @@
+#include <metal_stdlib>
+#include <simd/simd.h>
+
+using namespace metal;
+
+struct main0_in
+{
+    float3 vUV [[user(locn0)]];
+};
+
+struct main0_out
+{
+    float4 FragColor [[color(0)]];
+};
+
+fragment main0_out main0(main0_in in [[stage_in]], depth2d<float> uT [[texture(0)]], sampler uTSmplr [[sampler(0)]])
+{
+    main0_out out = {};
+    out.FragColor = uT.gather_compare(uTSmplr, in.vUV.xy, in.vUV.z);
+    return out;
+}
+

reference/shaders/frag/gather-dref.frag

@@ -0,0 +1,14 @@
+#version 310 es
+precision mediump float;
+precision highp int;
+
+layout(binding = 0) uniform mediump sampler2DShadow uT;
+
+layout(location = 0) out vec4 FragColor;
+layout(location = 0) in vec3 vUV;
+
+void main()
+{
+    FragColor = textureGather(uT, vUV.xy, vUV.z);
+}
+

shaders-msl/frag/gather-dref.frag

@@ -0,0 +1,11 @@
+#version 310 es
+precision mediump float;
+
+layout(binding = 0) uniform mediump sampler2DShadow uT;
+layout(location = 0) in vec3 vUV;
+layout(location = 0) out vec4 FragColor;
+
+void main()
+{
+	FragColor = textureGather(uT, vUV.xy, vUV.z);
+}

shaders/frag/gather-dref.frag

@@ -0,0 +1,11 @@
+#version 310 es
+precision mediump float;
+
+layout(binding = 0) uniform mediump sampler2DShadow uT;
+layout(location = 0) in vec3 vUV;
+layout(location = 0) out vec4 FragColor;
+
+void main()
+{
+	FragColor = textureGather(uT, vUV.xy, vUV.z);
+}

spirv_glsl.cpp

@@ -3940,7 +3940,7 @@ std::string CompilerGLSL::convert_separate_image_to_combined(uint32_t id)
 }
 
 // Returns the function args for a texture sampling function for the specified image and sampling characteristics.
-string CompilerGLSL::to_function_args(uint32_t img, const SPIRType &imgtype, bool is_fetch, bool, bool is_proj,
+string CompilerGLSL::to_function_args(uint32_t img, const SPIRType &imgtype, bool is_fetch, bool is_gather, bool is_proj,
                                       uint32_t coord, uint32_t coord_components, uint32_t dref, uint32_t grad_x,
                                       uint32_t grad_y, uint32_t lod, uint32_t coffset, uint32_t offset, uint32_t bias,
                                       uint32_t comp, uint32_t sample, bool *p_forward)
@@ -3998,7 +3998,7 @@ string CompilerGLSL::to_function_args(uint32_t img, const SPIRType &imgtype, boo
 		forward = forward && should_forward(dref);
 
 		// SPIR-V splits dref and coordinate.
-		if (coord_components == 4) // GLSL also splits the arguments in two.
+		if (is_gather || coord_components == 4) // GLSL also splits the arguments in two. Same for textureGather.
 		{
 			farg_str += ", ";
 			farg_str += to_expression(coord);