SPV: projective texturing: move the project coordinate.

SPV doesn't allow gaps in the components of the texturing coordinate.
It also removes the shadow reference.
So, close up the components so all used components are together.

1 files changed, 24 insertions, 0 deletions

diff --git a/SPIRV/GlslangToSpv.cpp b/SPIRV/GlslangToSpv.cpp
index 39b4ea6e..b41afc59 100755
--- a/SPIRV/GlslangToSpv.cpp
+++ b/SPIRV/GlslangToSpv.cpp
@@ -2677,6 +2677,30 @@ spv::Id TGlslangToSpvTraverser::createImageTextureFunctionCall(glslang::TIntermO
         }
     }
 
+    // projective component (might not to move)
+    // GLSL: "The texture coordinates consumed from P, not including the last component of P,
+    //       are divided by the last component of P."
+    // SPIR-V:  "... (u [, v] [, w], q)... It may be a vector larger than needed, but all
+    //          unused components will appear after all used components."
+    if (cracked.proj) {
+        int projSourceComp = builder.getNumComponents(params.coords) - 1;
+        int projTargetComp;
+        switch (sampler.dim) {
+        case glslang::Esd1D:   projTargetComp = 1;              break;
+        case glslang::Esd2D:   projTargetComp = 2;              break;
+        case glslang::EsdRect: projTargetComp = 2;              break;
+        default:               projTargetComp = projSourceComp; break;
+        }
+        // copy the projective coordinate if we have to
+        if (projTargetComp != projSourceComp) {
+            spv::Id projComp = builder.createCompositeExtract(params.coords, 
+                                                              builder.getScalarTypeId(builder.getTypeId(params.coords)),
+                                                              projSourceComp);
+            params.coords = builder.createCompositeInsert(projComp, params.coords,
+                                                          builder.getTypeId(params.coords), projTargetComp);
+        }
+    }
+
     return builder.createTextureCall(precision, convertGlslangToSpvType(node->getType()), sparse, cracked.fetch, cracked.proj, cracked.gather, noImplicitLod, params);
 }