move paint color to Params

Not really sure why it's still in BlitterUniforms when it doesn't change
from blit to blit... it's really more like the paint SkFilterQuality.

The only real caveat is that we need to take care to push the same
uniforms in cache_key() and build_program(), in particular making sure
we reuse the paint color uniforms if there's a clip shader.

Change-Id: I4c82b43b72b2a64341568f49f2f6dabad17fbc3e
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/319767
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>

Author: Mike Klein

src/core/SkVMBlitter.cpp

@@ -29,7 +29,6 @@ namespace {
     struct BlitterUniforms {
         int       right;  // First device x + blit run length n, used to get device x coordinate.
         int       y;      // Device y coordinate.
-        SkColor4f paint;  // In device color space.
     };
     static_assert(SkIsAlign4(sizeof(BlitterUniforms)), "");
     static constexpr int kBlitterUniformsCount = sizeof(BlitterUniforms) / 4;
@@ -42,6 +41,7 @@ namespace {
         SkColorInfo             dst;
         SkBlendMode             blendMode;
         Coverage                coverage;
+        SkColor4f               paint;
         SkFilterQuality         quality;
         const SkMatrixProvider& matrices;
 
@@ -62,7 +62,7 @@ namespace {
                  blendMode,
                  coverage;
         uint32_t padding{0};
-        // Params::quality and Params::matrices are only passed to {shader,clip}->program(),
+        // Params::{paint,quality,matrices} are only passed to {shader,clip}->program(),
         // not used here by the blitter itself.  No need to include them in the key;
         // they'll be folded into the shader key if used.
 
@@ -120,24 +120,25 @@ namespace {
         };
     }
 
-    static skvm::Color paint_color(skvm::Builder* p, skvm::Uniforms* uniforms) {
-        return {
-            p->uniformF(uniforms->base, offsetof(BlitterUniforms, paint.fR)),
-            p->uniformF(uniforms->base, offsetof(BlitterUniforms, paint.fG)),
-            p->uniformF(uniforms->base, offsetof(BlitterUniforms, paint.fB)),
-            p->uniformF(uniforms->base, offsetof(BlitterUniforms, paint.fA)),
-        };
-    }
-
     // If build_program() can't build this program, cache_key() sets *ok to false.
     static Key cache_key(const Params& params,
                          skvm::Uniforms* uniforms, SkArenaAlloc* alloc, bool* ok) {
+        // Take care to match build_program()'s reuse of the paint color uniforms.
+        skvm::Uniform r = uniforms->pushF(params.paint.fR),
+                      g = uniforms->pushF(params.paint.fG),
+                      b = uniforms->pushF(params.paint.fB),
+                      a = uniforms->pushF(params.paint.fA);
         auto hash_shader = [&](const sk_sp<SkShader>& shader) {
             const SkShaderBase* sb = as_SB(shader);
             skvm::Builder p;
 
             skvm::Coord device = device_coord(&p, uniforms);
-            skvm::Color paint = paint_color(&p, uniforms);
+            skvm::Color paint = {
+                p.uniformF(r),
+                p.uniformF(g),
+                p.uniformF(b),
+                p.uniformF(a),
+            };
 
             uint64_t hash = 0;
             if (auto c = sb->program(&p,
@@ -200,9 +201,9 @@ namespace {
         //    - UniformA8: 8-bit coverage uniform
 
         skvm::Coord device = device_coord(p, uniforms);
-        skvm::Color paint = paint_color(p, uniforms);
+        skvm::Color paint = p->uniformColor(params.paint, uniforms);
 
-        // See note about arguments above... a SpriteShader will call p->arg() once here.
+        // See note about arguments above: a SpriteShader will call p->arg() once during program().
         skvm::Color src = as_SB(params.shader)->program(p, device,/*local=*/device, paint,
                                                         params.matrices, /*localM=*/nullptr,
                                                         params.quality, params.dst,
@@ -509,12 +510,18 @@ namespace {
             blendMode =  SkBlendMode::kSrc;
         }
 
+        SkColor4f paintColor = paint.getColor4f();
+        SkColorSpaceXformSteps{sk_srgb_singleton(), kUnpremul_SkAlphaType,
+                               device.colorSpace(), kUnpremul_SkAlphaType}
+            .apply(paintColor.vec());
+
         return {
             std::move(shader),
             std::move(clip),
             { device.colorType(), device.alphaType(), device.refColorSpace() },
             blendMode,
             Coverage::Full,  // Placeholder... withCoverage() will change as needed.
+            paintColor,
             paint.getFilterQuality(),
             matrices,
         };
@@ -535,13 +542,7 @@ namespace {
             , fUniforms(kBlitterUniformsCount)
             , fParams(effective_params(device, sprite, paint, matrices, std::move(clip)))
             , fKey(cache_key(fParams, &fUniforms, &fAlloc, ok))
-            , fPaint([&]{
-                SkColor4f color = paint.getColor4f();
-                SkColorSpaceXformSteps{sk_srgb_singleton(), kUnpremul_SkAlphaType,
-                                       device.colorSpace(), kUnpremul_SkAlphaType}
-                    .apply(color.vec());
-                return color;
-            }()) {}
+        {}
 
         ~Blitter() override {
             if (SkLRUCache<Key, skvm::Program>* cache = try_acquire_program_cache()) {
@@ -573,7 +574,6 @@ namespace {
         SkArenaAlloc    fAlloc{2*sizeof(void*)};  // but a few effects need to ref large content.
         const Params    fParams;
         const Key       fKey;
-        const SkColor4f fPaint;
         skvm::Program   fBlitH,
                         fBlitAntiH,
                         fBlitMaskA8,
@@ -629,7 +629,7 @@ namespace {
         }
 
         void updateUniforms(int right, int y) {
-            BlitterUniforms uniforms{right, y, fPaint};
+            BlitterUniforms uniforms{right, y};
             memcpy(fUniforms.buf.data(), &uniforms, sizeof(BlitterUniforms));
         }