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// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <impeller/blending.glsl>
#include <impeller/color.glsl>
#include <impeller/texture.glsl>
#include <impeller/types.glsl>
uniform BlendInfo {
float16_t dst_input_alpha;
float16_t src_input_alpha;
float16_t color_factor;
f16vec4 color; // This color input is expected to be unpremultiplied.
}
blend_info;
uniform f16sampler2D texture_sampler_dst;
uniform f16sampler2D texture_sampler_src;
in vec2 v_dst_texture_coords;
in vec2 v_src_texture_coords;
out f16vec4 frag_color;
f16vec4 Sample(f16sampler2D texture_sampler, vec2 texture_coords) {
// gles 2.0 is the only backend without native decal support.
#ifdef IMPELLER_TARGET_OPENGLES
return IPSampleDecal(texture_sampler, texture_coords);
#else
return texture(texture_sampler, texture_coords);
#endif
}
void main() {
f16vec4 dst_sample = Sample(texture_sampler_dst, // sampler
v_dst_texture_coords // texture coordinates
) *
blend_info.dst_input_alpha;
f16vec4 dst = IPHalfUnpremultiply(dst_sample);
f16vec4 src = blend_info.color_factor > 0.0hf
? blend_info.color
: IPHalfUnpremultiply(
Sample(texture_sampler_src, // sampler
v_src_texture_coords // texture coordinates
) *
blend_info.src_input_alpha);
f16vec4 blended = f16vec4(Blend(dst.rgb, src.rgb), 1.0hf) * dst.a;
frag_color = mix(dst_sample, blended, src.a);
}