56 lines
1.7 KiB
GLSL
56 lines
1.7 KiB
GLSL
#version 450
|
|
/* Copyright (c) 2024, Google
|
|
*
|
|
* SPDX-License-Identifier: Apache-2.0
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 the "License";
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
layout (location = 0) in vec2 inUV;
|
|
|
|
layout (location = 0) out vec4 outFragColor;
|
|
|
|
////////////////////////////////////////
|
|
|
|
layout(set = 0, binding = 0) uniform SceneConstants
|
|
{
|
|
mat4 model_view_projection;
|
|
float background_grayscale;
|
|
float object_alpha;
|
|
int front_layer_index;
|
|
int back_layer_index;
|
|
} sceneConstants;
|
|
|
|
const int kLayersCount = 8;
|
|
layout(set = 0, binding = 2) uniform sampler2D layerTex[kLayersCount];
|
|
|
|
////////////////////////////////////////
|
|
|
|
void main()
|
|
{
|
|
// Merge all layers using in-shader alpha blending.
|
|
vec4 color = vec4(0.0f, 0.0f, 0.0f, 1.0f);
|
|
const int front_layer_index = clamp(sceneConstants.front_layer_index, 0, kLayersCount - 1);
|
|
const int back_layer_index = clamp(sceneConstants.back_layer_index, front_layer_index, kLayersCount - 1);
|
|
for(int i = back_layer_index; i >= front_layer_index; --i)
|
|
{
|
|
const vec4 fragmentColor = texture(layerTex[i], inUV);
|
|
color.rgb = mix(color.rgb, fragmentColor.rgb, fragmentColor.a);
|
|
color.a *= 1.0f - fragmentColor.a;
|
|
}
|
|
// The final color is blended in the background using fixed-function alpha blending.
|
|
color.a = 1.0f - color.a;
|
|
outFragColor = color;
|
|
}
|
|
|