#!amber

# Copyright 2019 Google LLC.
# Copyright 2019 The Khronos Group Inc.
#
# 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
#
#     https://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.

SHADER vertex vert_shader_mipclear PASSTHROUGH

SHADER vertex vert_shader_lod GLSL
#version 430

layout(location = 0) in vec3 position_in;
layout(location = 0) out vec4 color_out;
layout(set = 0, binding = 0) uniform highp sampler2D tex;

void main() {
  gl_Position = vec4(position_in, 1.0);
  // Vary dPdx and dPdy based on vertex index to force
  // LOD 0 or LOD 1.
  vec2 v = vec2(0);
  if (gl_VertexIndex % 2 != 0)
      v = vec2(1);

  color_out = vec4(textureGrad(tex, vec2(0.5), v, v));
}
END

SHADER fragment frag_shader GLSL
#version 430

layout(location = 0) in vec4 color_in;
layout(location = 0) out vec4 color_out;

void main() {
  color_out = color_in;
}
END

BUFFER texture FORMAT B8G8R8A8_UNORM MIP_LEVELS 2
BUFFER framebuffer FORMAT B8G8R8A8_UNORM
SAMPLER sampler MAX_LOD 2.0

PIPELINE graphics mipclear_pipeline0
  ATTACH vert_shader_mipclear
  ATTACH frag_shader
  BIND BUFFER texture AS color LOCATION 0 BASE_MIP_LEVEL 0
  FRAMEBUFFER_SIZE 512 512
END

PIPELINE graphics mipclear_pipeline1
  ATTACH vert_shader_mipclear
  ATTACH frag_shader
  BIND BUFFER texture AS color LOCATION 0 BASE_MIP_LEVEL 1
  FRAMEBUFFER_SIZE 256 256
END

PIPELINE graphics lod_pipeline
  ATTACH vert_shader_lod
  ATTACH frag_shader
  BIND BUFFER texture AS combined_image_sampler SAMPLER sampler DESCRIPTOR_SET 0 BINDING 0
  BIND BUFFER framebuffer AS color LOCATION 0
  FRAMEBUFFER_SIZE 512 512
END

# Clear all mip levels to different color.
CLEAR_COLOR mipclear_pipeline0 255 0 0 255
CLEAR mipclear_pipeline0
CLEAR_COLOR mipclear_pipeline1 0 255 0 255
CLEAR mipclear_pipeline1

CLEAR_COLOR lod_pipeline 0 0 0 255
CLEAR lod_pipeline
RUN lod_pipeline DRAW_RECT POS 0 0 SIZE 512 512

# Check corners of the frame buffer: even vertices should have LOD 0 and odd ones LOD 1.
EXPECT framebuffer IDX 0   511 SIZE 1 1 EQ_RGBA 255 0   0 255
EXPECT framebuffer IDX 511 0   SIZE 1 1 EQ_RGBA 0   255 0 255
EXPECT framebuffer IDX 511 511 SIZE 1 1 EQ_RGBA 255 0   0 255
EXPECT framebuffer IDX 0   0   SIZE 1 1 EQ_RGBA 0   255 0 255