make it blend.

impeller/entity/contents/content_context.cc

@@ -443,7 +443,7 @@ ContentContext::ContentContext(
   yuv_to_rgb_filter_pipelines_.CreateDefault(*context_, options_trianglestrip);
   porter_duff_blend_pipelines_.CreateDefault(*context_, options_trianglestrip,
                                              {supports_decal});
-  vertices_uber_shader_.CreateDefault(*context_, options);
+  vertices_uber_shader_.CreateDefault(*context_, options, {supports_decal});
   // GLES only shader that is unsupported on macOS.
 #if defined(IMPELLER_ENABLE_OPENGLES) && !defined(FML_OS_MACOSX)
   if (GetContext()->GetBackendType() == Context::BackendType::kOpenGLES) {

impeller/entity/contents/vertices_contents.cc

@@ -333,7 +333,8 @@ bool VerticesSimpleBlendContents::Render(const ContentContext& renderer,
     frag_info.dst_coeff = blend_coefficients[2];
     frag_info.dst_coeff_src_alpha = blend_coefficients[3];
     frag_info.dst_coeff_src_color = blend_coefficients[4];
-    // Only used on devices that do not natively support advanced blends.
+
+    // These values are ignored if the platform supports native decal mode.
     frag_info.tmx = static_cast<int>(tile_mode_x_);
     frag_info.tmy = static_cast<int>(tile_mode_y_);
 

impeller/entity/shaders/blending/vertices_uber.frag

@@ -6,9 +6,13 @@
 #include <impeller/types.glsl>
 #include "blend_select.glsl"
 
+layout(constant_id = 0) const float supports_decal = 1.0;
+
 uniform FragInfo {
   float16_t alpha;
   float16_t blend_mode;
+  float tmx;
+  float tmy;
 }
 frag_info;
 
@@ -19,13 +23,24 @@ in mediump f16vec4 v_color;
 
 out f16vec4 frag_color;
 
+f16vec4 Sample(f16sampler2D texture_sampler,
+               vec2 texture_coords,
+               float tmx,
+               float tmy) {
+  if (supports_decal > 0.0) {
+    return texture(texture_sampler, texture_coords);
+  }
+  return IPHalfSampleWithTileMode(texture_sampler, texture_coords, tmx, tmy);
+}
+
 // A shader that implements the required src/dst blending for drawVertices and
 // drawAtlas advanced blends without requiring an offscreen render pass. This is
 // done in a single shader to reduce the permutations of PSO needed at runtime
 // for rarely used features.
 void main() {
   f16vec4 dst = IPHalfUnpremultiply(v_color);
-  f16vec4 src = IPHalfUnpremultiply(texture(texture_sampler, v_texture_coords));
+  f16vec4 src = IPHalfUnpremultiply(
+      Sample(texture_sampler, v_texture_coords, frag_info.tmx, frag_info.tmy));
   f16vec3 blend_result =
       AdvancedBlend(dst.rgb, src.rgb, int(frag_info.blend_mode - 14.0));
   frag_color = IPApplyBlendedColor(dst, src, blend_result);