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// Copyright 2023 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "chrome/browser/vr/renderers/grid_renderer.h"
#include "device/vr/vr_gl_util.h"
namespace vr {
namespace {
// clang-format off
static constexpr char const* kVertexShader = SHADER(
precision highp float;
uniform mat4 u_ModelViewProjMatrix;
attribute vec4 a_Position;
varying vec2 v_GridPosition;
void main() {
v_GridPosition = a_Position.xy;
gl_Position = u_ModelViewProjMatrix * a_Position;
}
);
static constexpr char const* kFragmentShader = SHADER(
precision highp float;
varying vec2 v_GridPosition;
uniform vec4 u_GridColor;
uniform mediump float u_Opacity;
uniform float u_LinesCount;
void main() {
vec2 tile_pos = fract(u_LinesCount * abs(v_GridPosition));
vec2 border_dist = min(tile_pos, 1.0 - tile_pos);
float diff = min(border_dist.x, border_dist.y);
if (diff > 0.01)
discard;
lowp float radialOpacity = 1.0 - clamp(length(v_GridPosition), 0.0, 1.0);
lowp float opacity = 1.0 - diff / 0.01;
opacity = u_Opacity * opacity * opacity * radialOpacity * u_GridColor.w;
gl_FragColor = vec4(u_GridColor.xyz * opacity, opacity);
}
);
// clang-format on
} // namespace
GridRenderer::GridRenderer()
: BaseQuadRenderer(kVertexShader, kFragmentShader) {
model_view_proj_matrix_handle_ =
glGetUniformLocation(program_handle_, "u_ModelViewProjMatrix");
grid_color_handle_ = glGetUniformLocation(program_handle_, "u_GridColor");
opacity_handle_ = glGetUniformLocation(program_handle_, "u_Opacity");
lines_count_handle_ = glGetUniformLocation(program_handle_, "u_LinesCount");
}
GridRenderer::~GridRenderer() = default;
void GridRenderer::Draw(const gfx::Transform& model_view_proj_matrix,
SkColor grid_color,
int gridline_count,
float opacity) {
PrepareToDraw(model_view_proj_matrix_handle_, model_view_proj_matrix);
glUniform1f(lines_count_handle_, static_cast<float>(gridline_count));
SetColorUniform(grid_color_handle_, grid_color);
glUniform1f(opacity_handle_, opacity);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, index_buffer_);
glDrawElements(GL_TRIANGLES, BaseQuadRenderer::NumQuadIndices(),
GL_UNSIGNED_SHORT, 0);
glDisableVertexAttribArray(position_handle_);
}
} // namespace vr
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